Transaction patch series overview

Ronnie Sahlberg· Jul 31, 2014, 21:41 UTC · re: Ronnie Sahlberg · lore

Re: Transaction patch series overview

This is an update.

rs/ref-transaction-0
---------------------------
    Early part of the "ref transaction" topic.

    * rs/ref-transaction-0:
      refs.c: change ref_transaction_update() to do error checking and
return status
      refs.c: remove the onerr argument to ref_transaction_commit
      update-ref: use err argument to get error from ref_transaction_commit
      refs.c: make update_ref_write update a strbuf on failure
      refs.c: make ref_update_reject_duplicates take a strbuf argument
for errors
      refs.c: log_ref_write should try to return meaningful errno
      refs.c: make resolve_ref_unsafe set errno to something meaningful on error
      refs.c: commit_packed_refs to return a meaningful errno on failure
      refs.c: make remove_empty_directories always set errno to something sane
      refs.c: verify_lock should set errno to something meaningful
      refs.c: make sure log_ref_setup returns a meaningful errno
      refs.c: add an err argument to repack_without_refs
      lockfile.c: make lock_file return a meaningful errno on failurei
      lockfile.c: add a new public function unable_to_lock_message
      refs.c: add a strbuf argument to ref_transaction_commit for error logging
      refs.c: allow passing NULL to ref_transaction_free
      refs.c: constify the sha arguments for
ref_transaction_create|delete|update
      refs.c: ref_transaction_commit should not free the transaction
      refs.c: remove ref_transaction_rollback

Has been merged into next.

 - refs.c: make delete_ref use a transaction
 - refs.c: make prune_ref use a transaction to delete the ref
 - refs.c: remove lock_ref_sha1
 - refs.c: remove the update_ref_write function
 - refs.c: remove the update_ref_lock function
 - refs.c: make lock_ref_sha1 static
 - walker.c: use ref transaction for ref updates
 - fast-import.c: use a ref transaction when dumping tags
 - receive-pack.c: use a reference transaction for updating the refs
 - refs.c: change update_ref to use a transaction
 - branch.c: use ref transaction for all ref updates
 - fast-import.c: change update_branch to use ref transactions
 - sequencer.c: use ref transactions for all ref updates
 - commit.c: use ref transactions for updates
 - replace.c: use the ref transaction functions for updates
 - tag.c: use ref transactions when doing updates
 - refs.c: add transaction.status and track OPEN/CLOSED/ERROR
 - refs.c: make ref_transaction_begin take an err argument
 - refs.c: update ref_transaction_delete to check for error and return status
 - refs.c: change ref_transaction_create to do error checking and return status
 (this branch is used by rs/ref-transaction, rs/ref-transaction-multi,
rs/ref-transaction-reflog and rs/ref-transaction-rename.)

 The second batch of the transactional ref update series.

Has been merged into pu

rs/ref-transaction (2014-07-17) 12 commits
-----------------------------------------------------------------
 - refs.c: fix handling of badly named refs
 - refs.c: make write_ref_sha1 static
 - fetch.c: change s_update_ref to use a ref transaction
 - refs.c: propagate any errno==ENOTDIR from _commit back to the callers
 - refs.c: pass a skip list to name_conflict_fn
 - refs.c: call lock_ref_sha1_basic directly from commit
 - refs.c: move the check for valid refname to lock_ref_sha1_basic
 - refs.c: pass NULL as *flags to read_ref_full
 - refs.c: pass the ref log message to _create/delete/update instead of _commit
 - refs.c: add an err argument to delete_ref_loose
 - wrapper.c: add a new function unlink_or_msg
 - wrapper.c: simplify warn_if_unremovable
 (this branch is used by rs/ref-transaction-multi,
rs/ref-transaction-reflog and rs/ref-transaction-rename; uses
rs/ref-transaction-1.)

The third and final part of the basic ref-transaction work.

Has been merged into pu.

rs/ref-transaction-reflog (2014-07-23) 15 commits
-----------------------------------------------------------------------
 - refs.c: allow deleting refs with a broken sha1
 - refs.c: remove lock_any_ref_for_update
 - refs.c: make unlock_ref/close_ref/commit_ref static
 - refs.c: rename log_ref_setup to create_reflog
 - reflog.c: use a reflog transaction when writing during expire
 - refs.c: allow multiple reflog updates during a single transaction
 - refs.c: only write reflog update if msg is non-NULL
 - refs.c: add a flag to allow reflog updates to truncate the log
 - refs.c: add a transaction function to append a reflog entry
 - lockfile.c: make hold_lock_file_for_append preserve meaningful errno
 - refs.c: add a function to append a reflog entry to a fd
 - refs.c: add a new update_type field to ref_update
 - refs.c: rename the transaction functions
 - refs.c: make ref_transaction_delete a wrapper for ref_transaction_update
 - refs.c: make ref_transaction_create a wrapper to ref_transaction_update
 (this branch is used by rs/ref-transaction-multi and
rs/ref-transaction-rename; uses rs/ref-transaction and
rs/ref-transaction-1.)

Has been merged to pu.

As part of this the rename_ref logic is greatly simplified and we
reach several nice goals:
* no need to disallow rename_ref() if the reflog is a symlink
* no need to rename the reflog via a third filename
* make the rename become completely atomic both for the caller but
also for any external observers.

Has been merged into pu.

The new logic is basically:
IF the transaction only touches a single ref, then just do the normal
loose ref operation as before.
   This is to make sure that the very common "git commit" command will
still always be fast.

IF the transaction touches multiple refs, then
 * first copy/move all affected refs to the packed refs file and
commit, then re-lock the packed
   refs file until the transaction has completed.
 * then delete any affected loose refs files (they are already in the
packed refs file)
 * perform the operation by adding/removing/updating packed refs entries
 * finally, commit the packed refs file

Note: we still do have packed refs and they still work the same way as
before. It is just that the packed refs are now an internal
optimization for the refs code and no longer part of the public api.

The following functions are now static to refs.c and no longer part of
the public api:
 add_packed_ref/lock_packed_refs/commit_packed_refs/rollback_packed_refs/repack_without_refs

Has been merged into pu.

Following are the patch series that has not yet made its way into pu.

-enum action_on_err {
-       UPDATE_REFS_MSG_ON_ERR,
-       UPDATE_REFS_DIE_ON_ERR,
-       UPDATE_REFS_QUIET_ON_ERR
-};

wooohooo

Not sent to the list yet.

And that concludes the basic ref-transaction stuff.

regards

Ronnie Sahlberg· Aug 8, 2014, 16:50 UTC · re: Ronnie Sahlberg · lore

Re: Transaction patch series overview

This is an update.

rs/ref-transaction-0
---------------------------
    Early part of the "ref transaction" topic.

    * rs/ref-transaction-0:
      refs.c: change ref_transaction_update() to do error checking and
return status
      refs.c: remove the onerr argument to ref_transaction_commit
      update-ref: use err argument to get error from ref_transaction_commit
      refs.c: make update_ref_write update a strbuf on failure
      refs.c: make ref_update_reject_duplicates take a strbuf argument
for errors
      refs.c: log_ref_write should try to return meaningful errno
      refs.c: make resolve_ref_unsafe set errno to something meaningful on error
      refs.c: commit_packed_refs to return a meaningful errno on failure
      refs.c: make remove_empty_directories always set errno to something sane
      refs.c: verify_lock should set errno to something meaningful
      refs.c: make sure log_ref_setup returns a meaningful errno
      refs.c: add an err argument to repack_without_refs
      lockfile.c: make lock_file return a meaningful errno on failurei
      lockfile.c: add a new public function unable_to_lock_message
      refs.c: add a strbuf argument to ref_transaction_commit for error logging
      refs.c: allow passing NULL to ref_transaction_free
      refs.c: constify the sha arguments for
ref_transaction_create|delete|update
      refs.c: ref_transaction_commit should not free the transaction
      refs.c: remove ref_transaction_rollback

Has been merged into next.

 - refs.c: make delete_ref use a transaction
 - refs.c: make prune_ref use a transaction to delete the ref
 - refs.c: remove lock_ref_sha1
 - refs.c: remove the update_ref_write function
 - refs.c: remove the update_ref_lock function
 - refs.c: make lock_ref_sha1 static
 - walker.c: use ref transaction for ref updates
 - fast-import.c: use a ref transaction when dumping tags
 - receive-pack.c: use a reference transaction for updating the refs
 - refs.c: change update_ref to use a transaction
 - branch.c: use ref transaction for all ref updates
 - fast-import.c: change update_branch to use ref transactions
 - sequencer.c: use ref transactions for all ref updates
 - commit.c: use ref transactions for updates
 - replace.c: use the ref transaction functions for updates
 - tag.c: use ref transactions when doing updates
 - refs.c: add transaction.status and track OPEN/CLOSED/ERROR
 - refs.c: make ref_transaction_begin take an err argument
 - refs.c: update ref_transaction_delete to check for error and return status
 - refs.c: change ref_transaction_create to do error checking and return status
 (this branch is used by rs/ref-transaction, rs/ref-transaction-multi,
rs/ref-transaction-reflog and rs/ref-transaction-rename.)

 The second batch of the transactional ref update series.

Has been merged into pu

rs/ref-transaction (2014-07-17) 12 commits
-----------------------------------------------------------------
 - refs.c: fix handling of badly named refs
 - refs.c: make write_ref_sha1 static
 - fetch.c: change s_update_ref to use a ref transaction
 - refs.c: propagate any errno==ENOTDIR from _commit back to the callers
 - refs.c: pass a skip list to name_conflict_fn
 - refs.c: call lock_ref_sha1_basic directly from commit
 - refs.c: move the check for valid refname to lock_ref_sha1_basic
 - refs.c: pass NULL as *flags to read_ref_full
 - refs.c: pass the ref log message to _create/delete/update instead of _commit
 - refs.c: add an err argument to delete_ref_loose
 - wrapper.c: add a new function unlink_or_msg
 - wrapper.c: simplify warn_if_unremovable
 (this branch is used by rs/ref-transaction-multi,
rs/ref-transaction-reflog and rs/ref-transaction-rename; uses
rs/ref-transaction-1.)

The third and final part of the basic ref-transaction work.

Has been merged into pu.

rs/ref-transaction-reflog (2014-07-23) 15 commits
-----------------------------------------------------------------------
 - refs.c: allow deleting refs with a broken sha1
 - refs.c: remove lock_any_ref_for_update
 - refs.c: make unlock_ref/close_ref/commit_ref static
 - refs.c: rename log_ref_setup to create_reflog
 - reflog.c: use a reflog transaction when writing during expire
 - refs.c: allow multiple reflog updates during a single transaction
 - refs.c: only write reflog update if msg is non-NULL
 - refs.c: add a flag to allow reflog updates to truncate the log
 - refs.c: add a transaction function to append a reflog entry
 - lockfile.c: make hold_lock_file_for_append preserve meaningful errno
 - refs.c: add a function to append a reflog entry to a fd
 - refs.c: add a new update_type field to ref_update
 - refs.c: rename the transaction functions
 - refs.c: make ref_transaction_delete a wrapper for ref_transaction_update
 - refs.c: make ref_transaction_create a wrapper to ref_transaction_update
 (this branch is used by rs/ref-transaction-multi and
rs/ref-transaction-rename; uses rs/ref-transaction and
rs/ref-transaction-1.)

Has been merged to pu.

As part of this the rename_ref logic is greatly simplified and we
reach several nice goals:
* no need to disallow rename_ref() if the reflog is a symlink
* no need to rename the reflog via a third filename
* make the rename become completely atomic both for the caller but
also for any external observers.

Has been merged into pu.

The new logic is basically:
IF the transaction only touches a single ref, then just do the normal
loose ref operation as before.
   This is to make sure that the very common "git commit" command will
still always be fast.

IF the transaction touches multiple refs, then
 * first copy/move all affected refs to the packed refs file and
commit, then re-lock the packed
   refs file until the transaction has completed.
 * then delete any affected loose refs files (they are already in the
packed refs file)
 * perform the operation by adding/removing/updating packed refs entries
 * finally, commit the packed refs file

Note: we still do have packed refs and they still work the same way as
before. It is just that the packed refs are now an internal
optimization for the refs code and no longer part of the public api.

The following functions are now static to refs.c and no longer part of
the public api:
 add_packed_ref/lock_packed_refs/commit_packed_refs/rollback_packed_refs/repack_without_refs

Has been merged into pu.

Following are the patch series that has not yet made its way into pu.

-enum action_on_err {
-       UPDATE_REFS_MSG_ON_ERR,
-       UPDATE_REFS_DIE_ON_ERR,
-       UPDATE_REFS_QUIET_ON_ERR
-};

wooohooo

Sent to the list.

Sent to the list.

Sent to the list

Ronnie Sahlberg· Aug 19, 2014, 19:54 UTC · re: Ronnie Sahlberg · lore

Re: Transaction patch series overview

This is an update.

rs/ref-transaction-0
---------------------------
    Early part of the "ref transaction" topic.

    * rs/ref-transaction-0:
      refs.c: change ref_transaction_update() to do error checking and
return status
      refs.c: remove the onerr argument to ref_transaction_commit
      update-ref: use err argument to get error from ref_transaction_commit
      refs.c: make update_ref_write update a strbuf on failure
      refs.c: make ref_update_reject_duplicates take a strbuf argument
for errors
      refs.c: log_ref_write should try to return meaningful errno
      refs.c: make resolve_ref_unsafe set errno to something meaningful on error
      refs.c: commit_packed_refs to return a meaningful errno on failure
      refs.c: make remove_empty_directories always set errno to something sane
      refs.c: verify_lock should set errno to something meaningful
      refs.c: make sure log_ref_setup returns a meaningful errno
      refs.c: add an err argument to repack_without_refs
      lockfile.c: make lock_file return a meaningful errno on failurei
      lockfile.c: add a new public function unable_to_lock_message
      refs.c: add a strbuf argument to ref_transaction_commit for error logging
      refs.c: allow passing NULL to ref_transaction_free
      refs.c: constify the sha arguments for
ref_transaction_create|delete|update
      refs.c: ref_transaction_commit should not free the transaction
      refs.c: remove ref_transaction_rollback

Has been merged into next.

 - refs.c: make delete_ref use a transaction
 - refs.c: make prune_ref use a transaction to delete the ref
 - refs.c: remove lock_ref_sha1
 - refs.c: remove the update_ref_write function
 - refs.c: remove the update_ref_lock function
 - refs.c: make lock_ref_sha1 static
 - walker.c: use ref transaction for ref updates
 - fast-import.c: use a ref transaction when dumping tags
 - receive-pack.c: use a reference transaction for updating the refs
 - refs.c: change update_ref to use a transaction
 - branch.c: use ref transaction for all ref updates
 - fast-import.c: change update_branch to use ref transactions
 - sequencer.c: use ref transactions for all ref updates
 - commit.c: use ref transactions for updates
 - replace.c: use the ref transaction functions for updates
 - tag.c: use ref transactions when doing updates
 - refs.c: add transaction.status and track OPEN/CLOSED/ERROR
 - refs.c: make ref_transaction_begin take an err argument
 - refs.c: update ref_transaction_delete to check for error and return status
 - refs.c: change ref_transaction_create to do error checking and return status
 (this branch is used by rs/ref-transaction, rs/ref-transaction-multi,
rs/ref-transaction-reflog and rs/ref-transaction-rename.)

 The second batch of the transactional ref update series.

Has been merged into pu

rs/ref-transaction (2014-07-17) 12 commits
-----------------------------------------------------------------
 - refs.c: fix handling of badly named refs
 - refs.c: make write_ref_sha1 static
 - fetch.c: change s_update_ref to use a ref transaction
 - refs.c: propagate any errno==ENOTDIR from _commit back to the callers
 - refs.c: pass a skip list to name_conflict_fn
 - refs.c: call lock_ref_sha1_basic directly from commit
 - refs.c: move the check for valid refname to lock_ref_sha1_basic
 - refs.c: pass NULL as *flags to read_ref_full
 - refs.c: pass the ref log message to _create/delete/update instead of _commit
 - refs.c: add an err argument to delete_ref_loose
 - wrapper.c: add a new function unlink_or_msg
 - wrapper.c: simplify warn_if_unremovable
 (this branch is used by rs/ref-transaction-multi,
rs/ref-transaction-reflog and rs/ref-transaction-rename; uses
rs/ref-transaction-1.)

The third and final part of the basic ref-transaction work.

Has been merged into pu.

rs/ref-transaction-reflog (2014-07-23) 15 commits
-----------------------------------------------------------------------
 - refs.c: allow deleting refs with a broken sha1
 - refs.c: remove lock_any_ref_for_update
 - refs.c: make unlock_ref/close_ref/commit_ref static
 - refs.c: rename log_ref_setup to create_reflog
 - reflog.c: use a reflog transaction when writing during expire
 - refs.c: allow multiple reflog updates during a single transaction
 - refs.c: only write reflog update if msg is non-NULL
 - refs.c: add a flag to allow reflog updates to truncate the log
 - refs.c: add a transaction function to append a reflog entry
 - lockfile.c: make hold_lock_file_for_append preserve meaningful errno
 - refs.c: add a function to append a reflog entry to a fd
 - refs.c: add a new update_type field to ref_update
 - refs.c: rename the transaction functions
 - refs.c: make ref_transaction_delete a wrapper for ref_transaction_update
 - refs.c: make ref_transaction_create a wrapper to ref_transaction_update
 (this branch is used by rs/ref-transaction-multi and
rs/ref-transaction-rename; uses rs/ref-transaction and
rs/ref-transaction-1.)

Has been merged to pu.

As part of this the rename_ref logic is greatly simplified and we
reach several nice goals:
* no need to disallow rename_ref() if the reflog is a symlink
* no need to rename the reflog via a third filename
* make the rename become completely atomic both for the caller but
also for any external observers.

Has been merged into pu.

The new logic is basically:
IF the transaction only touches a single ref, then just do the normal
loose ref operation as before.
   This is to make sure that the very common "git commit" command will
still always be fast.

IF the transaction touches multiple refs, then
 * first copy/move all affected refs to the packed refs file and
commit, then re-lock the packed
   refs file until the transaction has completed.
 * then delete any affected loose refs files (they are already in the
packed refs file)
 * perform the operation by adding/removing/updating packed refs entries
 * finally, commit the packed refs file

Note: we still do have packed refs and they still work the same way as
before. It is just that the packed refs are now an internal
optimization for the refs code and no longer part of the public api.

The following functions are now static to refs.c and no longer part of
the public api:
 add_packed_ref/lock_packed_refs/commit_packed_refs/rollback_packed_refs/repack_without_refs

Has been merged into pu.

Following are the patch series that has not yet made its way into pu.

-enum action_on_err {
-       UPDATE_REFS_MSG_ON_ERR,
-       UPDATE_REFS_DIE_ON_ERR,
-       UPDATE_REFS_QUIET_ON_ERR
-};

wooohooo

Sent to the list.

Sent to the list.

Sent to the list

Junio C Hamano· Aug 19, 2014, 22:28 UTC · re: Ronnie Sahlberg · lore

Re: Transaction patch series overview

Ronnie Sahlberg <sahlberg@google.com> writes:

> List, please see here an overview and ordering of the ref transaction
> patch series.
> These series build on each other and needs to be applied in the order
> listed below.
>
> This is an update.
>
> rs/ref-transaction-0
> ---------------------------
>     Early part of the "ref transaction" topic.
>
>     * rs/ref-transaction-0:
>       refs.c: change ref_transaction_update() to do error checking and
> return status
>       refs.c: remove the onerr argument to ref_transaction_commit
>       update-ref: use err argument to get error from ref_transaction_commit
>       refs.c: make update_ref_write update a strbuf on failure
>       refs.c: make ref_update_reject_duplicates take a strbuf argument
> for errors
>       refs.c: log_ref_write should try to return meaningful errno
>       refs.c: make resolve_ref_unsafe set errno to something meaningful on error
>       refs.c: commit_packed_refs to return a meaningful errno on failure
>       refs.c: make remove_empty_directories always set errno to something sane
>       refs.c: verify_lock should set errno to something meaningful
>       refs.c: make sure log_ref_setup returns a meaningful errno
>       refs.c: add an err argument to repack_without_refs
>       lockfile.c: make lock_file return a meaningful errno on failurei
>       lockfile.c: add a new public function unable_to_lock_message
>       refs.c: add a strbuf argument to ref_transaction_commit for error logging
>       refs.c: allow passing NULL to ref_transaction_free
>       refs.c: constify the sha arguments for
> ref_transaction_create|delete|update
>       refs.c: ref_transaction_commit should not free the transaction
>       refs.c: remove ref_transaction_rollback
>
> Has been merged into next.

> ref-transaction-1 (2014-07-16) 20 commits
> ...
>  The second batch of the transactional ref update series.
>
> Has been merged into pu
>
> rs/ref-transaction (2014-07-17) 12 commits
> ...
> The third and final part of the basic ref-transaction work.
> 
> Has been merged into pu.

> This series is for once the previous transaction changes are in and
> this series will add
> a new backend for refs: refs-be-db.c which offloads all refs access to
> an external database daemon.
> An example reference implementation for an external daemon is also
> provided and can be used as basis for
> creating a daemon to plug into, say, a SQL database or similar.

Thanks.

Jonathan Nieder· Aug 20, 2014, 23:17 UTC · re: Ronnie Sahlberg · lore

Re: Transaction patch series overview

Hi,

Ronnie Sahlberg wrote:

> List, please see here an overview and ordering of the ref transaction
> patch series.

Thanks much for this.

[...]

> rs/ref-transaction-0

[...]

> Has been merged into next.

> ref-transaction-1 (2014-07-16) 20 commits
> -------------------------------------------------------------
> Second batch of ref transactions
>
>  - refs.c: make delete_ref use a transaction
>  - refs.c: make prune_ref use a transaction to delete the ref
>  - refs.c: remove lock_ref_sha1
>  - refs.c: remove the update_ref_write function
>  - refs.c: remove the update_ref_lock function
>  - refs.c: make lock_ref_sha1 static
>  - walker.c: use ref transaction for ref updates
>  - fast-import.c: use a ref transaction when dumping tags
>  - receive-pack.c: use a reference transaction for updating the refs
>  - refs.c: change update_ref to use a transaction
>  - branch.c: use ref transaction for all ref updates
>  - fast-import.c: change update_branch to use ref transactions
>  - sequencer.c: use ref transactions for all ref updates
>  - commit.c: use ref transactions for updates
>  - replace.c: use the ref transaction functions for updates
>  - tag.c: use ref transactions when doing updates
>  - refs.c: add transaction.status and track OPEN/CLOSED/ERROR
>  - refs.c: make ref_transaction_begin take an err argument
>  - refs.c: update ref_transaction_delete to check for error and return status
>  - refs.c: change ref_transaction_create to do error checking and return status
>  (this branch is used by rs/ref-transaction, rs/ref-transaction-multi,
> rs/ref-transaction-reflog and rs/ref-transaction-rename.)
>
>  The second batch of the transactional ref update series.
>
> Has been merged into pu

Are there any pending questions for this part?

 https://code-review.googlesource.com/#/q/topic:ref-transaction-1

	git push https://code.googlesource.com/git \
		HEAD:refs/for/master; # or refs/for/maint

'?' brings up keyboard shortcuts.

	git push https://code.googlesource.com/git \
		HEAD:refs/for/master; # or refs/for/maint

Maybe it can be useful.

Jonathan Nieder· Aug 26, 2014, 00:03 UTC · re: Jonathan Nieder · lore

Re: Transaction patch series overview

Jonathan Nieder wrote:

> Ronnie Sahlberg wrote:

>> ref-transaction-1 (2014-07-16) 20 commits
>> -------------------------------------------------------------
>> Second batch of ref transactions
>>
>>  - refs.c: make delete_ref use a transaction
>>  - refs.c: make prune_ref use a transaction to delete the ref
>>  - refs.c: remove lock_ref_sha1
>>  - refs.c: remove the update_ref_write function
>>  - refs.c: remove the update_ref_lock function
>>  - refs.c: make lock_ref_sha1 static
>>  - walker.c: use ref transaction for ref updates
>>  - fast-import.c: use a ref transaction when dumping tags
>>  - receive-pack.c: use a reference transaction for updating the refs
>>  - refs.c: change update_ref to use a transaction
>>  - branch.c: use ref transaction for all ref updates
>>  - fast-import.c: change update_branch to use ref transactions
>>  - sequencer.c: use ref transactions for all ref updates
>>  - commit.c: use ref transactions for updates
>>  - replace.c: use the ref transaction functions for updates
>>  - tag.c: use ref transactions when doing updates
>>  - refs.c: add transaction.status and track OPEN/CLOSED/ERROR
>>  - refs.c: make ref_transaction_begin take an err argument
>>  - refs.c: update ref_transaction_delete to check for error and return status
>>  - refs.c: change ref_transaction_create to do error checking and return status
>>  (this branch is used by rs/ref-transaction, rs/ref-transaction-multi,
>> rs/ref-transaction-reflog and rs/ref-transaction-rename.)

[...]

> I've having trouble keeping track of how patches change, which patches
> have been reviewed and which haven't, unaddressed comments, and so on,
> so as an experiment I've pushed this part of the series to the Gerrit
> server at
>
>  https://code-review.googlesource.com/#/q/topic:ref-transaction-1

Outcome of the experiment: patches gained some minor changes and then

 1-12
	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

 13
	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

 14
	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

 15-16
	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

 17
	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>

 18
	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

 19
	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

 20
	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>

diff --git a/branch.c b/branch.c
index c1eae00..37ac555 100644
--- a/branch.c
+++ b/branch.c
@@ -305,6 +305,7 @@ void create_branch(const char *head,
 		    ref_transaction_commit(transaction, msg, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
+		strbuf_release(&err);
 	}
 
 	if (real_ref && track)
diff --git a/builtin/commit.c b/builtin/commit.c
index 668fa6a..9bf1003 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1765,8 +1765,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, "HEAD", sha1,
-				   current_head ?
-				   current_head->object.sha1 : NULL,
+				   current_head
+				   ? current_head->object.sha1 : NULL,
 				   0, !!current_head, &err) ||
 	    ref_transaction_commit(transaction, sb.buf, &err)) {
 		rollback_index_files();
@@ -1801,5 +1801,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	if (!quiet)
 		print_summary(prefix, sha1, !current_head);
 
+	strbuf_release(&err);
 	return 0;
 }
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 91099ad..224fadc 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -194,7 +194,7 @@ static void write_head_info(void)
 
 struct command {
 	struct command *next;
-	char *error_string;
+	const char *error_string;
 	unsigned int skip_update:1,
 		     did_not_exist:1;
 	int index;
@@ -468,7 +468,7 @@ static int update_shallow_ref(struct command *cmd, struct shallow_info *si)
 	return 0;
 }
 
-static char *update(struct command *cmd, struct shallow_info *si)
+static const char *update(struct command *cmd, struct shallow_info *si)
 {
 	const char *name = cmd->ref_name;
 	struct strbuf namespaced_name_buf = STRBUF_INIT;
@@ -479,7 +479,7 @@ static char *update(struct command *cmd, struct shallow_info *si)
 	/* only refs/... are allowed */
 	if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
 		rp_error("refusing to create funny ref '%s' remotely", name);
-		return xstrdup("funny refname");
+		return "funny refname";
 	}
 
 	strbuf_addf(&namespaced_name_buf, "%s%s", get_git_namespace(), name);
@@ -497,20 +497,20 @@ static char *update(struct command *cmd, struct shallow_info *si)
 			rp_error("refusing to update checked out branch: %s", name);
 			if (deny_current_branch == DENY_UNCONFIGURED)
 				refuse_unconfigured_deny();
-			return xstrdup("branch is currently checked out");
+			return "branch is currently checked out";
 		}
 	}
 
 	if (!is_null_sha1(new_sha1) && !has_sha1_file(new_sha1)) {
 		error("unpack should have generated %s, "
 		      "but I can't find it!", sha1_to_hex(new_sha1));
-		return xstrdup("bad pack");
+		return "bad pack";
 	}
 
 	if (!is_null_sha1(old_sha1) && is_null_sha1(new_sha1)) {
 		if (deny_deletes && starts_with(name, "refs/heads/")) {
 			rp_error("denying ref deletion for %s", name);
-			return xstrdup("deletion prohibited");
+			return "deletion prohibited";
 		}
 
 		if (!strcmp(namespaced_name, head_name)) {
@@ -525,7 +525,7 @@ static char *update(struct command *cmd, struct shallow_info *si)
 				if (deny_delete_current == DENY_UNCONFIGURED)
 					refuse_unconfigured_deny_delete_current();
 				rp_error("refusing to delete the current branch: %s", name);
-				return xstrdup("deletion of the current branch prohibited");
+				return "deletion of the current branch prohibited";
 			}
 		}
 	}
@@ -543,19 +543,19 @@ static char *update(struct command *cmd, struct shallow_info *si)
 		    old_object->type != OBJ_COMMIT ||
 		    new_object->type != OBJ_COMMIT) {
 			error("bad sha1 objects for %s", name);
-			return xstrdup("bad ref");
+			return "bad ref";
 		}
 		old_commit = (struct commit *)old_object;
 		new_commit = (struct commit *)new_object;
 		if (!in_merge_bases(old_commit, new_commit)) {
 			rp_error("denying non-fast-forward %s"
 				 " (you should pull first)", name);
-			return xstrdup("non-fast-forward");
+			return "non-fast-forward";
 		}
 	}
 	if (run_update_hook(cmd)) {
 		rp_error("hook declined to update %s", name);
-		return xstrdup("hook declined");
+		return "hook declined";
 	}
 
 	if (is_null_sha1(new_sha1)) {
@@ -570,7 +570,7 @@ static char *update(struct command *cmd, struct shallow_info *si)
 		}
 		if (delete_ref(namespaced_name, old_sha1, 0)) {
 			rp_error("failed to delete %s", name);
-			return xstrdup("failed to delete");
+			return "failed to delete";
 		}
 		return NULL; /* good */
 	}
@@ -580,18 +580,18 @@ static char *update(struct command *cmd, struct shallow_info *si)
 
 		if (shallow_update && si->shallow_ref[cmd->index] &&
 		    update_shallow_ref(cmd, si))
-			return xstrdup("shallow error");
+			return "shallow error";
 
 		transaction = ref_transaction_begin(&err);
 		if (!transaction ||
 		    ref_transaction_update(transaction, namespaced_name,
 					   new_sha1, old_sha1, 0, 1, &err) ||
 		    ref_transaction_commit(transaction, "push", &err)) {
-			char *str = strbuf_detach(&err, NULL);
 			ref_transaction_free(transaction);
 
-			rp_error("%s", str);
-			return str;
+			rp_error("%s", err.buf);
+			strbuf_release(&err);
+			return "failed to update ref";
 		}
 
 		ref_transaction_free(transaction);
@@ -654,9 +654,6 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	char cmd_oldh[41], cmd_newh[41], dst_oldh[41], dst_newh[41];
 	int flag;
 
-	if (cmd->error_string)
-		die("BUG: check_aliased_update called with failed cmd");
-
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
 	dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
 	strbuf_release(&buf);
@@ -668,7 +665,7 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	if (!dst_name) {
 		rp_error("refusing update to broken symref '%s'", cmd->ref_name);
 		cmd->skip_update = 1;
-		cmd->error_string = xstrdup("broken symref");
+		cmd->error_string = "broken symref";
 		return;
 	}
 
@@ -694,9 +691,8 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 		 cmd->ref_name, cmd_oldh, cmd_newh,
 		 dst_cmd->ref_name, dst_oldh, dst_newh);
 
-	cmd->error_string = xstrdup("inconsistent aliased update");
-	free(dst_cmd->error_string);
-	dst_cmd->error_string = xstrdup("inconsistent aliased update");
+	cmd->error_string = dst_cmd->error_string =
+		"inconsistent aliased update";
 }
 
 static void check_aliased_updates(struct command *commands)
@@ -744,9 +740,7 @@ static void set_connectivity_errors(struct command *commands,
 		if (!check_everything_connected(command_singleton_iterator,
 						0, &singleton))
 			continue;
-		if (cmd->error_string)  /* can't happen */
-			continue;
-		cmd->error_string = xstrdup("missing necessary objects");
+		cmd->error_string = "missing necessary objects";
 	}
 }
 
@@ -783,9 +777,9 @@ static void reject_updates_to_hidden(struct command *commands)
 		if (cmd->error_string || !ref_is_hidden(cmd->ref_name))
 			continue;
 		if (is_null_sha1(cmd->new_sha1))
-			cmd->error_string = xstrdup("deny deleting a hidden ref");
+			cmd->error_string = "deny deleting a hidden ref";
 		else
-			cmd->error_string = xstrdup("deny updating a hidden ref");
+			cmd->error_string = "deny updating a hidden ref";
 	}
 }
 
@@ -799,11 +793,8 @@ static void execute_commands(struct command *commands,
 	struct iterate_data data;
 
 	if (unpacker_error) {
-		for (cmd = commands; cmd; cmd = cmd->next) {
-			if (cmd->error_string)  /* can't happen */
-				continue;
-			cmd->error_string = xstrdup("unpacker error");
-		}
+		for (cmd = commands; cmd; cmd = cmd->next)
+			cmd->error_string = "unpacker error";
 		return;
 	}
 
@@ -816,9 +807,8 @@ static void execute_commands(struct command *commands,
 
 	if (run_receive_hook(commands, "pre-receive", 0)) {
 		for (cmd = commands; cmd; cmd = cmd->next) {
-			if (cmd->error_string)
-				continue;
-			cmd->error_string = xstrdup("pre-receive hook declined");
+			if (!cmd->error_string)
+				cmd->error_string = "pre-receive hook declined";
 		}
 		return;
 	}
@@ -1096,8 +1086,7 @@ static void update_shallow_info(struct command *commands,
 		if (is_null_sha1(cmd->new_sha1))
 			continue;
 		if (ref_status[cmd->index]) {
-			free(cmd->error_string);
-			cmd->error_string = xstrdup("shallow update not allowed");
+			cmd->error_string = "shallow update not allowed";
 			cmd->skip_update = 1;
 		}
 	}
@@ -1138,17 +1127,6 @@ static int delete_only(struct command *commands)
 	return 1;
 }
 
-static void free_commands(struct command *commands)
-{
-	while (commands) {
-		struct command *next = commands->next;
-
-		free(commands->error_string);
-		free(commands);
-		commands = next;
-	}
-}
-
 int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 {
 	int advertise_refs = 0;
@@ -1244,6 +1222,5 @@ int cmd_receive_pack(int argc, const char **argv, const char *prefix)
 		packet_flush(1);
 	sha1_array_clear(&shallow);
 	sha1_array_clear(&ref);
-	free_commands(commands);
 	return 0;
 }
diff --git a/builtin/replace.c b/builtin/replace.c
index 7528f3d..1fcd06d 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -169,8 +169,7 @@ static int replace_object_sha1(const char *object_ref,
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
-	    ref_transaction_update(transaction, ref, repl, prev,
-				   0, !is_null_sha1(prev), &err) ||
+	    ref_transaction_update(transaction, ref, repl, prev, 0, 1, &err) ||
 	    ref_transaction_commit(transaction, NULL, &err))
 		die("%s", err.buf);
 
diff --git a/builtin/tag.c b/builtin/tag.c
index 1aa88a2..f3f172f 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -712,6 +712,7 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (force && !is_null_sha1(prev) && hashcmp(prev, object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
 
+	strbuf_release(&err);
 	strbuf_release(&buf);
 	strbuf_release(&ref);
 	return 0;
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index c6ad0be..96a53b9 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -366,6 +366,8 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 
 	if (read_stdin) {
 		transaction = ref_transaction_begin(&err);
+		if (!transaction)
+			die("%s", err.buf);
 		if (delete || no_deref || argc > 0)
 			usage_with_options(git_update_ref_usage, options);
 		if (end_null)
@@ -374,6 +376,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		if (ref_transaction_commit(transaction, msg, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
+		strbuf_release(&err);
 		return 0;
 	}
 
diff --git a/fast-import.c b/fast-import.c
index a95e1be..e7f6e37 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1716,6 +1716,7 @@ static int update_branch(struct branch *b)
 		return -1;
 	}
 	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	return 0;
 }
 
diff --git a/refs.c b/refs.c
index 0017d9c..819e25f 100644
--- a/refs.c
+++ b/refs.c
@@ -2074,7 +2074,10 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-/* This function should make sure errno is meaningful on error */
+/*
+ * Locks a "refs/" ref returning the lock on success and NULL on failure.
+ * On failure errno is set to something meaningful.
+ */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
 					    int flags, int *type_p)
@@ -2401,6 +2404,7 @@ static void prune_ref(struct ref_to_prune *r)
 		return;
 	}
 	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	try_remove_empty_parents(r->name);
 }
 
@@ -2575,6 +2579,7 @@ int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 		return 1;
 	}
 	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	return 0;
 }
 
@@ -3352,19 +3357,15 @@ struct ref_update {
  * Transaction states.
  * OPEN:   The transaction is in a valid state and can accept new updates.
  *         An OPEN transaction can be committed.
- * CLOSED: If an open transaction is successfully committed the state will
- *         change to CLOSED. No further changes can be made to a CLOSED
- *         transaction.
- *         CLOSED means that all updates have been successfully committed and
- *         the only thing that remains is to free the completed transaction.
- * ERROR:  The transaction has failed and is no longer committable.
- *         No further changes can be made to a CLOSED transaction and it must
- *         be rolled back using transaction_free.
+ * CLOSED: A closed transaction is no longer active and no other operations
+ *         than free can be used on it in this state.
+ *         A transaction can either become closed by successfully committing
+ *         an active transaction or if there is a failure while building
+ *         the transaction thus rendering it failed/inactive.
  */
 enum ref_transaction_state {
 	REF_TRANSACTION_OPEN   = 0,
-	REF_TRANSACTION_CLOSED = 1,
-	REF_TRANSACTION_ERROR  = 2,
+	REF_TRANSACTION_CLOSED = 1
 };
 
 /*
@@ -3509,6 +3510,7 @@ int update_ref(const char *action, const char *refname,
 		strbuf_release(&err);
 		return 1;
 	}
+	strbuf_release(&err);
 	return 0;
 }
 
@@ -3588,10 +3590,10 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 					     msg);
 			update->lock = NULL; /* freed by write_ref_sha1 */
 			if (ret) {
-				const char *str = "Cannot update the ref '%s'.";
-
 				if (err)
-					strbuf_addf(err, str, update->refname);
+					strbuf_addf(err, "Cannot update the "
+						    "ref '%s'.",
+						    update->refname);
 				goto cleanup;
 			}
 		}
@@ -3614,8 +3616,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	clear_loose_ref_cache(&ref_cache);
 
 cleanup:
-	transaction->state = ret ? REF_TRANSACTION_ERROR
-		: REF_TRANSACTION_CLOSED;
+	transaction->state = REF_TRANSACTION_CLOSED;
 
 	for (i = 0; i < n; i++)
 		if (updates[i]->lock)
diff --git a/refs.h b/refs.h
index aad846c..69ef28c 100644
--- a/refs.h
+++ b/refs.h
@@ -180,8 +180,7 @@ extern int peel_ref(const char *refname, unsigned char *sha1);
  */
 #define REF_NODEREF	0x01
 /*
- * Locks any ref (for 'HEAD' type refs) and sets errno to something
- * meaningful on failure.
+ * This function sets errno to something meaningful on failure.
  */
 extern struct ref_lock *lock_any_ref_for_update(const char *refname,
 						const unsigned char *old_sha1,
diff --git a/sequencer.c b/sequencer.c
index cf17c69..5e93b6a 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -296,6 +296,7 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 	}
 
 	strbuf_release(&sb);
+	strbuf_release(&err);
 	ref_transaction_free(transaction);
 	return 0;
 }
diff --git a/walker.c b/walker.c
index 60d9f9e..b8a5441 100644
--- a/walker.c
+++ b/walker.c
@@ -251,12 +251,12 @@ void walker_targets_free(int targets, char **target, const char **write_ref)
 int walker_fetch(struct walker *walker, int targets, char **target,
 		 const char **write_ref, const char *write_ref_log_details)
 {
-	struct strbuf ref_name = STRBUF_INIT;
+	struct strbuf refname = STRBUF_INIT;
 	struct strbuf err = STRBUF_INIT;
 	struct ref_transaction *transaction = NULL;
 	unsigned char *sha1 = xmalloc(targets * 20);
 	char *msg = NULL;
-	int i;
+	int i, ret = -1;
 
 	save_commit_buffer = 0;
 
@@ -264,7 +264,7 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 		transaction = ref_transaction_begin(&err);
 		if (!transaction) {
 			error("%s", err.buf);
-			goto rollback_and_fail;
+			goto done;
 		}
 	}
 	if (!walker->get_recover)
@@ -273,15 +273,18 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 	for (i = 0; i < targets; i++) {
 		if (interpret_target(walker, target[i], &sha1[20 * i])) {
 			error("Could not interpret response from server '%s' as something to pull", target[i]);
-			goto rollback_and_fail;
+			goto done;
 		}
 		if (process(walker, lookup_unknown_object(&sha1[20 * i])))
-			goto rollback_and_fail;
+			goto done;
 	}
 
 	if (loop(walker))
-		goto rollback_and_fail;
-
+		goto done;
+	if (!write_ref) {
+		ret = 0;
+		goto done;
+	}
 	if (write_ref_log_details) {
 		msg = xmalloc(strlen(write_ref_log_details) + 12);
 		sprintf(msg, "fetch from %s", write_ref_log_details);
@@ -289,37 +292,33 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 		msg = NULL;
 	}
 	for (i = 0; i < targets; i++) {
-		if (!write_ref || !write_ref[i])
+		if (!write_ref[i])
 			continue;
-		strbuf_reset(&ref_name);
-		strbuf_addf(&ref_name, "refs/%s", write_ref[i]);
-		if (ref_transaction_update(transaction, ref_name.buf,
+		strbuf_reset(&refname);
+		strbuf_addf(&refname, "refs/%s", write_ref[i]);
+		if (ref_transaction_update(transaction, refname.buf,
 					   &sha1[20 * i], NULL, 0, 0,
 					   &err)) {
 			error("%s", err.buf);
-			goto rollback_and_fail;
+			goto done;
 		}
 	}
-	if (write_ref) {
-		if (ref_transaction_commit(transaction,
-					   msg ? msg : "fetch (unknown)",
-					   &err)) {
-			error("%s", err.buf);
-			goto rollback_and_fail;
-		}
-		ref_transaction_free(transaction);
+	if (ref_transaction_commit(transaction,
+				   msg ? msg : "fetch (unknown)",
+				   &err)) {
+		error("%s", err.buf);
+		goto done;
 	}
 
-	free(msg);
-	return 0;
+	ret = 0;
 
-rollback_and_fail:
+done:
 	ref_transaction_free(transaction);
 	free(msg);
+	free(sha1);
 	strbuf_release(&err);
-	strbuf_release(&ref_name);
-
-	return -1;
+	strbuf_release(&refname);
+	return ret;
 }
 
 void walker_free(struct walker *walker)

Junio C Hamano· Aug 26, 2014, 21:01 UTC · re: Jonathan Nieder · lore

Re: Transaction patch series overview

Jonathan Nieder <jrnieder@gmail.com> writes:

>>  https://code-review.googlesource.com/#/q/topic:ref-transaction-1
>
> Outcome of the experiment: patches gained some minor changes and then
>
>  1-12
> 	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
>
>  13
> 	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
> 	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
>
>  14
> 	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
>
>  15-16
> 	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
> 	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
>
>  17
> 	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
>
>  18
> 	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
> 	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
>
>  19
> 	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
>
>  20
> 	Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
> 	Reviewed-by: Jonathan Nieder <jrnieder@gmail.com>
>
> I found the web UI helpful in seeing how each patch evolved since I
> last looked at it.  Interdiff relative to the version in pu is below.

> The next series from Ronnie's collection is available at
> https://code-review.googlesource.com/#/q/topic:ref-transaction in case
> someone wants a fresh series to look at.

Thanks.

> diff --git a/builtin/commit.c b/builtin/commit.c
> index 668fa6a..9bf1003 100644
> --- a/builtin/commit.c
> +++ b/builtin/commit.c
> @@ -1765,8 +1765,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
>  	transaction = ref_transaction_begin(&err);
>  	if (!transaction ||
>  	    ref_transaction_update(transaction, "HEAD", sha1,
> -				   current_head ?
> -				   current_head->object.sha1 : NULL,
> +				   current_head
> +				   ? current_head->object.sha1 : NULL,
>  				   0, !!current_head, &err) ||
>  	    ref_transaction_commit(transaction, sb.buf, &err)) {
>  		rollback_index_files();

Perhaps this is nicer, but probably most people would not care.

> diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
> index 91099ad..224fadc 100644
> --- a/builtin/receive-pack.c
> +++ b/builtin/receive-pack.c
> @@ -580,18 +580,18 @@ static char *update(struct command *cmd, struct shallow_info *si)
>  
>  		if (shallow_update && si->shallow_ref[cmd->index] &&
>  		    update_shallow_ref(cmd, si))
> -			return xstrdup("shallow error");
> +			return "shallow error";
>  
>  		transaction = ref_transaction_begin(&err);
>  		if (!transaction ||
>  		    ref_transaction_update(transaction, namespaced_name,
>  					   new_sha1, old_sha1, 0, 1, &err) ||
>  		    ref_transaction_commit(transaction, "push", &err)) {
> -			char *str = strbuf_detach(&err, NULL);
>  			ref_transaction_free(transaction);
>  
> -			rp_error("%s", str);
> -			return str;
> +			rp_error("%s", err.buf);
> +			strbuf_release(&err);
> +			return "failed to update ref";
>  		}

> diff --git a/refs.h b/refs.h
> index aad846c..69ef28c 100644
> --- a/refs.h
> +++ b/refs.h
> @@ -180,8 +180,7 @@ extern int peel_ref(const char *refname, unsigned char *sha1);
>   */
>  #define REF_NODEREF	0x01
>  /*
> - * Locks any ref (for 'HEAD' type refs) and sets errno to something
> - * meaningful on failure.
> + * This function sets errno to something meaningful on failure.
>   */
>  extern struct ref_lock *lock_any_ref_for_update(const char *refname,
>  						const unsigned char *old_sha1,

Thanks again.

Jonathan Nieder· Aug 26, 2014, 22:14 UTC · re: Junio C Hamano · lore

Re: Transaction patch series overview

Hi again,

Junio C Hamano wrote:

> It seems that I can hold the topic in 'pu' a bit longer and expect a
> reroll from this effort before merging it to 'next'?

  git://repo.or.cz/git/jrn.git tags/rs/ref-transaction-1

for you to fetch changes up to 432ad1f39fd773b37757dd8f10b3075dc3d0d0a2:

  refs.c: make delete_ref use a transaction (2014-08-26 14:22:53 -0700)

Ronnie explains:

	This patch series expands on the transaction API. It converts
	ref updates, inside refs.c as well as external, to use the
	transaction API for updates. This makes most ref updates
	atomic when there are failures locking or writing to a ref.

Reviewed at https://code-review.googlesource.com/#/q/topic:ref-transaction-1

----------------------------------------------------------------
Ronnie Sahlberg (20):
      refs.c: change ref_transaction_create to do error checking and return status
      refs.c: update ref_transaction_delete to check for error and return status
      refs.c: make ref_transaction_begin take an err argument
      refs.c: add transaction.status and track OPEN/CLOSED
      tag.c: use ref transactions when doing updates
      replace.c: use the ref transaction functions for updates
      commit.c: use ref transactions for updates
      sequencer.c: use ref transactions for all ref updates
      fast-import.c: change update_branch to use ref transactions
      branch.c: use ref transaction for all ref updates
      refs.c: change update_ref to use a transaction
      receive-pack.c: use a reference transaction for updating the refs
      fast-import.c: use a ref transaction when dumping tags
      walker.c: use ref transaction for ref updates
      refs.c: make lock_ref_sha1 static
      refs.c: remove the update_ref_lock function
      refs.c: remove the update_ref_write function
      refs.c: remove lock_ref_sha1
      refs.c: make prune_ref use a transaction to delete the ref
      refs.c: make delete_ref use a transaction

 branch.c               |  31 ++++---
 builtin/commit.c       |  25 +++--
 builtin/receive-pack.c |  25 +++--
 builtin/replace.c      |  14 +--
 builtin/tag.c          |  16 ++--
 builtin/update-ref.c   |  14 ++-
 fast-import.c          |  54 +++++++----
 refs.c                 | 244 ++++++++++++++++++++++++++++---------------------
 refs.h                 |  77 ++++++++++++----
 sequencer.c            |  26 ++++--
 walker.c               |  70 ++++++++------
 11 files changed, 367 insertions(+), 229 deletions(-)

[...]

> Jonathan Nieder <jrnieder@gmail.com> writes:

>> --- a/builtin/receive-pack.c
>> +++ b/builtin/receive-pack.c
>> @@ -580,18 +580,18 @@ static char *update(struct command *cmd, struct shallow_info *si)

[...]

>>  		if (!transaction ||
>>  		    ref_transaction_update(transaction, namespaced_name,
>>  					   new_sha1, old_sha1, 0, 1, &err) ||
>>  		    ref_transaction_commit(transaction, "push", &err)) {
>> -			char *str = strbuf_detach(&err, NULL);
>>  			ref_transaction_free(transaction);
>>  
>> -			rp_error("%s", str);
>> -			return str;
>> +			rp_error("%s", err.buf);
>> +			strbuf_release(&err);
>> +			return "failed to update ref";
>>  		}
>
> I am guessing that the purpose of this change is to make sure that
> cmd->error_string is taken from a fixed set of strings, not an
> arbitrary collection of errors from the transaction subsystem, but
> what is the significance of doing so?  Do the other side i18n while
> running print_ref_status() or something?

Side effects:

 * a less invasive patch --- no more need to change the calling
   convention to return a dynamically allocated string, with
   assertions throughout the file that check for leaks

 * using the same "all lowercase and brief" convention makes the
   message less jarring next to other statuses for "! rejected" lines,
   like "non-fast-forward"

 * no more O(n) stall from traversing the linked list to free messages
   when receive-pack is about to exit

[...]

>> diff --git a/refs.h b/refs.h
>> index aad846c..69ef28c 100644
>> --- a/refs.h
>> +++ b/refs.h
>> @@ -180,8 +180,7 @@ extern int peel_ref(const char *refname, unsigned char *sha1);
>>   */
>>  #define REF_NODEREF	0x01
>>  /*
>> - * Locks any ref (for 'HEAD' type refs) and sets errno to something
>> - * meaningful on failure.
>> + * This function sets errno to something meaningful on failure.
>>   */
>>  extern struct ref_lock *lock_any_ref_for_update(const char *refname,
>>  						const unsigned char *old_sha1,
>
> To contrast this function with lock_ref_sha1() that only allowed
> refs under refs/ hierarchy, the comment may have made sense, but now
> that other function is gone, losing the comment makes sense.

Ahhh.  Thanks for explaining.

Jonathan

Jonathan Nieder· Aug 27, 2014, 00:28 UTC · re: Jonathan Nieder · lore

[PATCH 0/20] rs/ref-transaction-1 (Re: Transaction patch series overview)

Jonathan Nieder wrote:

> This series teaches the tag, replace, commit, cherry-pick,
> fast-import, checkout -b, branch, receive-pack, and http-fetch
> commands and all update_ref and delete_ref callers to use the ref
> transaction API instead of lock_ref_sha1.
>
> The main user-visible change should be some cosmetic changes to error
> messages.  The series also combines multiple ref updates into a single
> transaction in 'git http-fetch -w' and when writing tags in
> fast-import but otherwise doesn't change the granularity of
> transactions.
>
> Reviewed at https://code-review.googlesource.com/#/q/topic:ref-transaction-1
>
> ----------------------------------------------------------------
> Ronnie Sahlberg (20):
>       refs.c: change ref_transaction_create to do error checking and return status
>       refs.c: update ref_transaction_delete to check for error and return status
>       refs.c: make ref_transaction_begin take an err argument
>       refs.c: add transaction.status and track OPEN/CLOSED
>       tag.c: use ref transactions when doing updates
>       replace.c: use the ref transaction functions for updates
>       commit.c: use ref transactions for updates
>       sequencer.c: use ref transactions for all ref updates
>       fast-import.c: change update_branch to use ref transactions
>       branch.c: use ref transaction for all ref updates
>       refs.c: change update_ref to use a transaction
>       receive-pack.c: use a reference transaction for updating the refs
>       fast-import.c: use a ref transaction when dumping tags
>       walker.c: use ref transaction for ref updates
>       refs.c: make lock_ref_sha1 static
>       refs.c: remove the update_ref_lock function
>       refs.c: remove the update_ref_write function
>       refs.c: remove lock_ref_sha1
>       refs.c: make prune_ref use a transaction to delete the ref
>       refs.c: make delete_ref use a transaction

And here are the patches.

Jonathan Nieder· Aug 27, 2014, 00:29 UTC · re: Jonathan Nieder · lore

[PATCH 01/20] refs.c: change ref_transaction_create to do error checking and return status

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:26:44 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/update-ref.c |  4 +++-
 refs.c               | 18 ++++++++++++------
 refs.h               | 48 +++++++++++++++++++++++++++++++++++++++++-------
 3 files changed, 56 insertions(+), 14 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 3067b11..41121fa 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -226,7 +226,9 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)
 	if (*next != line_termination)
 		die("create %s: extra input: %s", refname, next);
 
-	ref_transaction_create(transaction, refname, new_sha1, update_flags);
+	if (ref_transaction_create(transaction, refname, new_sha1,
+				   update_flags, &err))
+		die("%s", err.buf);
 
 	update_flags = 0;
 	free(refname);
diff --git a/refs.c b/refs.c
index 3f05e88..c49f1c6 100644
--- a/refs.c
+++ b/refs.c
@@ -3449,18 +3449,24 @@ int ref_transaction_update(struct ref_transaction *transaction,
 	return 0;
 }
 
-void ref_transaction_create(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *new_sha1,
-			    int flags)
+int ref_transaction_create(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *new_sha1,
+			   int flags,
+			   struct strbuf *err)
 {
-	struct ref_update *update = add_update(transaction, refname);
+	struct ref_update *update;
+
+	if (!new_sha1 || is_null_sha1(new_sha1))
+		die("BUG: create ref with null new_sha1");
+
+	update = add_update(transaction, refname);
 
-	assert(!is_null_sha1(new_sha1));
 	hashcpy(update->new_sha1, new_sha1);
 	hashclr(update->old_sha1);
 	update->flags = flags;
 	update->have_old = 1;
+	return 0;
 }
 
 void ref_transaction_delete(struct ref_transaction *transaction,
diff --git a/refs.h b/refs.h
index c5376ce..b648819 100644
--- a/refs.h
+++ b/refs.h
@@ -10,6 +10,38 @@ struct ref_lock {
 	int force_write;
 };
 
+/*
+ * A ref_transaction represents a collection of ref updates
+ * that should succeed or fail together.
+ *
+ * Calling sequence
+ * ----------------
+ * - Allocate and initialize a `struct ref_transaction` by calling
+ *   `ref_transaction_begin()`.
+ *
+ * - List intended ref updates by calling functions like
+ *   `ref_transaction_update()` and `ref_transaction_create()`.
+ *
+ * - Call `ref_transaction_commit()` to execute the transaction.
+ *   If this succeeds, the ref updates will have taken place and
+ *   the transaction cannot be rolled back.
+ *
+ * - At any time call `ref_transaction_free()` to discard the
+ *   transaction and free associated resources.  In particular,
+ *   this rolls back the transaction if it has not been
+ *   successfully committed.
+ *
+ * Error handling
+ * --------------
+ *
+ * On error, transaction functions append a message about what
+ * went wrong to the 'err' argument.  The message mentions what
+ * ref was being updated (if any) when the error occurred so it
+ * can be passed to 'die' or 'error' as-is.
+ *
+ * The message is appended to err without first clearing err.
+ * err will not be '\n' terminated.
+ */
 struct ref_transaction;
 
 /*
@@ -248,7 +280,7 @@ struct ref_transaction *ref_transaction_begin(void);
  * it must not have existed beforehand.
  * Function returns 0 on success and non-zero on failure. A failure to update
  * means that the transaction as a whole has failed and will need to be
- * rolled back. On failure the err buffer will be updated.
+ * rolled back.
  */
 int ref_transaction_update(struct ref_transaction *transaction,
 			   const char *refname,
@@ -262,11 +294,15 @@ int ref_transaction_update(struct ref_transaction *transaction,
  * that the reference should have after the update; it must not be the
  * null SHA-1.  It is verified that the reference does not exist
  * already.
+ * Function returns 0 on success and non-zero on failure. A failure to create
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
  */
-void ref_transaction_create(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *new_sha1,
-			    int flags);
+int ref_transaction_create(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *new_sha1,
+			   int flags,
+			   struct strbuf *err);
 
 /*
  * Add a reference deletion to transaction.  If have_old is true, then
@@ -282,8 +318,6 @@ void ref_transaction_delete(struct ref_transaction *transaction,
  * Commit all of the changes that have been queued in transaction, as
  * atomically as possible.  Return a nonzero value if there is a
  * problem.
- * If err is non-NULL we will add an error string to it to explain why
- * the transaction failed. The string does not end in newline.
  */
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   const char *msg, struct strbuf *err);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:29 UTC · re: Jonathan Nieder · lore

[PATCH 02/20] refs.c: update ref_transaction_delete to check for error and return status

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:27:45 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/update-ref.c |  5 +++--
 refs.c               | 16 +++++++++++-----
 refs.h               | 12 ++++++++----
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 41121fa..7c9c248 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -258,8 +258,9 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
 	if (*next != line_termination)
 		die("delete %s: extra input: %s", refname, next);
 
-	ref_transaction_delete(transaction, refname, old_sha1,
-			       update_flags, have_old);
+	if (ref_transaction_delete(transaction, refname, old_sha1,
+				   update_flags, have_old, &err))
+		die("%s", err.buf);
 
 	update_flags = 0;
 	free(refname);
diff --git a/refs.c b/refs.c
index c49f1c6..40f04f4 100644
--- a/refs.c
+++ b/refs.c
@@ -3469,19 +3469,25 @@ int ref_transaction_create(struct ref_transaction *transaction,
 	return 0;
 }
 
-void ref_transaction_delete(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old)
+int ref_transaction_delete(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old,
+			   struct strbuf *err)
 {
-	struct ref_update *update = add_update(transaction, refname);
+	struct ref_update *update;
 
+	if (have_old && !old_sha1)
+		die("BUG: have_old is true but old_sha1 is NULL");
+
+	update = add_update(transaction, refname);
 	update->flags = flags;
 	update->have_old = have_old;
 	if (have_old) {
 		assert(!is_null_sha1(old_sha1));
 		hashcpy(update->old_sha1, old_sha1);
 	}
+	return 0;
 }
 
 int update_ref(const char *action, const char *refname,
diff --git a/refs.h b/refs.h
index b648819..71389a1 100644
--- a/refs.h
+++ b/refs.h
@@ -308,11 +308,15 @@ int ref_transaction_create(struct ref_transaction *transaction,
  * Add a reference deletion to transaction.  If have_old is true, then
  * old_sha1 holds the value that the reference should have had before
  * the update (which must not be the null SHA-1).
+ * Function returns 0 on success and non-zero on failure. A failure to delete
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
  */
-void ref_transaction_delete(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old);
+int ref_transaction_delete(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old,
+			   struct strbuf *err);
 
 /*
  * Commit all of the changes that have been queued in transaction, as

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:30 UTC · re: Jonathan Nieder · lore

[PATCH 03/20] refs.c: make ref_transaction_begin take an err argument

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 19 May 2014 10:42:34 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/update-ref.c | 5 ++++-
 refs.c               | 2 +-
 refs.h               | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 7c9c248..96a53b9 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -365,7 +365,9 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		die("Refusing to perform update with empty message.");
 
 	if (read_stdin) {
-		transaction = ref_transaction_begin();
+		transaction = ref_transaction_begin(&err);
+		if (!transaction)
+			die("%s", err.buf);
 		if (delete || no_deref || argc > 0)
 			usage_with_options(git_update_ref_usage, options);
 		if (end_null)
@@ -374,6 +376,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		if (ref_transaction_commit(transaction, msg, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
+		strbuf_release(&err);
 		return 0;
 	}
 
diff --git a/refs.c b/refs.c
index 40f04f4..9cb7908 100644
--- a/refs.c
+++ b/refs.c
@@ -3397,7 +3397,7 @@ struct ref_transaction {
 	size_t nr;
 };
 
-struct ref_transaction *ref_transaction_begin(void)
+struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
 	return xcalloc(1, sizeof(struct ref_transaction));
 }
diff --git a/refs.h b/refs.h
index 71389a1..3f37c65 100644
--- a/refs.h
+++ b/refs.h
@@ -262,7 +262,7 @@ enum action_on_err {
  * Begin a reference transaction.  The reference transaction must
  * be freed by calling ref_transaction_free().
  */
-struct ref_transaction *ref_transaction_begin(void);
+struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 
 /*
  * The following functions add a reference check or update to a

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:30 UTC · re: Jonathan Nieder · lore

[PATCH 04/20] refs.c: add transaction.status and track OPEN/CLOSED

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 12:06:19 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index 9cb7908..cc63056 100644
--- a/refs.c
+++ b/refs.c
@@ -3387,6 +3387,21 @@ struct ref_update {
 };
 
 /*
+ * Transaction states.
+ * OPEN:   The transaction is in a valid state and can accept new updates.
+ *         An OPEN transaction can be committed.
+ * CLOSED: A closed transaction is no longer active and no other operations
+ *         than free can be used on it in this state.
+ *         A transaction can either become closed by successfully committing
+ *         an active transaction or if there is a failure while building
+ *         the transaction thus rendering it failed/inactive.
+ */
+enum ref_transaction_state {
+	REF_TRANSACTION_OPEN   = 0,
+	REF_TRANSACTION_CLOSED = 1
+};
+
+/*
  * Data structure for holding a reference transaction, which can
  * consist of checks and updates to multiple references, carried out
  * as atomically as possible.  This structure is opaque to callers.
@@ -3395,6 +3410,7 @@ struct ref_transaction {
 	struct ref_update **updates;
 	size_t alloc;
 	size_t nr;
+	enum ref_transaction_state state;
 };
 
 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
@@ -3437,6 +3453,9 @@ int ref_transaction_update(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: update called for transaction that is not open");
+
 	if (have_old && !old_sha1)
 		die("BUG: have_old is true but old_sha1 is NULL");
 
@@ -3457,6 +3476,9 @@ int ref_transaction_create(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: create called for transaction that is not open");
+
 	if (!new_sha1 || is_null_sha1(new_sha1))
 		die("BUG: create ref with null new_sha1");
 
@@ -3477,6 +3499,9 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: delete called for transaction that is not open");
+
 	if (have_old && !old_sha1)
 		die("BUG: have_old is true but old_sha1 is NULL");
 
@@ -3532,8 +3557,13 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	int n = transaction->nr;
 	struct ref_update **updates = transaction->updates;
 
-	if (!n)
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: commit called for transaction that is not open");
+
+	if (!n) {
+		transaction->state = REF_TRANSACTION_CLOSED;
 		return 0;
+	}
 
 	/* Allocate work space */
 	delnames = xmalloc(sizeof(*delnames) * n);
@@ -3595,6 +3625,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	clear_loose_ref_cache(&ref_cache);
 
 cleanup:
+	transaction->state = REF_TRANSACTION_CLOSED;
+
 	for (i = 0; i < n; i++)
 		if (updates[i]->lock)
 			unlock_ref(updates[i]->lock);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:30 UTC · re: Jonathan Nieder · lore

[PATCH 05/20] tag.c: use ref transactions when doing updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:30:41 -0700

Change tag.c to use ref transactions for all ref updates.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/tag.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/builtin/tag.c b/builtin/tag.c
index c6e8a71..f3f172f 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -548,7 +548,6 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	struct strbuf ref = STRBUF_INIT;
 	unsigned char object[20], prev[20];
 	const char *object_ref, *tag;
-	struct ref_lock *lock;
 	struct create_tag_options opt;
 	char *cleanup_arg = NULL;
 	int annotate = 0, force = 0, lines = -1;
@@ -556,6 +555,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	const char *msgfile = NULL, *keyid = NULL;
 	struct msg_arg msg = { 0, STRBUF_INIT };
 	struct commit_list *with_commit = NULL;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 	struct option options[] = {
 		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
 		{ OPTION_INTEGER, 'n', NULL, &lines, N_("n"),
@@ -701,14 +702,17 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (annotate)
 		create_tag(object, tag, &buf, &opt, prev, object);
 
-	lock = lock_any_ref_for_update(ref.buf, prev, 0, NULL);
-	if (!lock)
-		die(_("%s: cannot lock the ref"), ref.buf);
-	if (write_ref_sha1(lock, object, NULL) < 0)
-		die(_("%s: cannot update the ref"), ref.buf);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref.buf, object, prev,
+				   0, 1, &err) ||
+	    ref_transaction_commit(transaction, NULL, &err))
+		die("%s", err.buf);
+	ref_transaction_free(transaction);
 	if (force && !is_null_sha1(prev) && hashcmp(prev, object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
 
+	strbuf_release(&err);
 	strbuf_release(&buf);
 	strbuf_release(&ref);
 	return 0;

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:31 UTC · re: Jonathan Nieder · lore

[PATCH 06/20] replace.c: use the ref transaction functions for updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:32:29 -0700

Update replace.c to use ref transactions for updates.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/replace.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/builtin/replace.c b/builtin/replace.c
index 1bb491d..1fcd06d 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -153,7 +153,8 @@ static int replace_object_sha1(const char *object_ref,
 	unsigned char prev[20];
 	enum object_type obj_type, repl_type;
 	char ref[PATH_MAX];
-	struct ref_lock *lock;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	obj_type = sha1_object_info(object, NULL);
 	repl_type = sha1_object_info(repl, NULL);
@@ -166,12 +167,13 @@ static int replace_object_sha1(const char *object_ref,
 
 	check_ref_valid(object, prev, ref, sizeof(ref), force);
 
-	lock = lock_any_ref_for_update(ref, prev, 0, NULL);
-	if (!lock)
-		die("%s: cannot lock the ref", ref);
-	if (write_ref_sha1(lock, repl, NULL) < 0)
-		die("%s: cannot update the ref", ref);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref, repl, prev, 0, 1, &err) ||
+	    ref_transaction_commit(transaction, NULL, &err))
+		die("%s", err.buf);
 
+	ref_transaction_free(transaction);
 	return 0;
 }
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:31 UTC · re: Jonathan Nieder · lore

[PATCH 07/20] commit.c: use ref transactions for updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:34:19 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/commit.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/builtin/commit.c b/builtin/commit.c
index 5e2221c..9bf1003 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1627,11 +1627,12 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	const char *index_file, *reflog_msg;
 	char *nl;
 	unsigned char sha1[20];
-	struct ref_lock *ref_lock;
 	struct commit_list *parents = NULL, **pptr = &parents;
 	struct stat statbuf;
 	struct commit *current_head = NULL;
 	struct commit_extra_header *extra = NULL;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_commit_usage, builtin_commit_options);
@@ -1753,16 +1754,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_release(&author_ident);
 	free_commit_extra_headers(extra);
 
-	ref_lock = lock_any_ref_for_update("HEAD",
-					   !current_head
-					   ? NULL
-					   : current_head->object.sha1,
-					   0, NULL);
-	if (!ref_lock) {
-		rollback_index_files();
-		die(_("cannot lock HEAD ref"));
-	}
-
 	nl = strchr(sb.buf, '\n');
 	if (nl)
 		strbuf_setlen(&sb, nl + 1 - sb.buf);
@@ -1771,10 +1762,17 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
 	strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
 
-	if (write_ref_sha1(ref_lock, sha1, sb.buf) < 0) {
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD", sha1,
+				   current_head
+				   ? current_head->object.sha1 : NULL,
+				   0, !!current_head, &err) ||
+	    ref_transaction_commit(transaction, sb.buf, &err)) {
 		rollback_index_files();
-		die(_("cannot update HEAD ref"));
+		die("%s", err.buf);
 	}
+	ref_transaction_free(transaction);
 
 	unlink(git_path("CHERRY_PICK_HEAD"));
 	unlink(git_path("REVERT_HEAD"));
@@ -1803,5 +1801,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	if (!quiet)
 		print_summary(prefix, sha1, !current_head);
 
+	strbuf_release(&err);
 	return 0;
 }

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:32 UTC · re: Jonathan Nieder · lore

[PATCH 08/20] sequencer.c: use ref transactions for all ref updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:37:45 -0700

Change to use ref transactions for all updates to refs.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 sequencer.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index 0a80c58..5e93b6a 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -272,23 +272,33 @@ static int error_dirty_index(struct replay_opts *opts)
 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 			int unborn, struct replay_opts *opts)
 {
-	struct ref_lock *ref_lock;
+	struct ref_transaction *transaction;
 	struct strbuf sb = STRBUF_INIT;
-	int ret;
+	struct strbuf err = STRBUF_INIT;
 
 	read_cache();
 	if (checkout_fast_forward(from, to, 1))
 		exit(1); /* the callee should have complained already */
-	ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
-					   0, NULL);
-	if (!ref_lock)
-		return error(_("Failed to lock HEAD during fast_forward_to"));
 
 	strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
-	ret = write_ref_sha1(ref_lock, to, sb.buf);
+
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD",
+				   to, unborn ? null_sha1 : from,
+				   0, 1, &err) ||
+	    ref_transaction_commit(transaction, sb.buf, &err)) {
+		ref_transaction_free(transaction);
+		error("%s", err.buf);
+		strbuf_release(&sb);
+		strbuf_release(&err);
+		return -1;
+	}
 
 	strbuf_release(&sb);
-	return ret;
+	strbuf_release(&err);
+	ref_transaction_free(transaction);
+	return 0;
 }
 
 static int do_recursive_merge(struct commit *base, struct commit *next,

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:32 UTC · re: Jonathan Nieder · lore

[PATCH 09/20] fast-import.c: change update_branch to use ref transactions

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 16:21:13 -0700

Change update_branch() to use ref transactions for updates.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 fast-import.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/fast-import.c b/fast-import.c
index 6707a66..79160d5 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1679,8 +1679,9 @@ found_entry:
 static int update_branch(struct branch *b)
 {
 	static const char *msg = "fast-import";
-	struct ref_lock *lock;
+	struct ref_transaction *transaction;
 	unsigned char old_sha1[20];
+	struct strbuf err = STRBUF_INIT;
 
 	if (read_ref(b->name, old_sha1))
 		hashclr(old_sha1);
@@ -1689,29 +1690,33 @@ static int update_branch(struct branch *b)
 			delete_ref(b->name, old_sha1, 0);
 		return 0;
 	}
-	lock = lock_any_ref_for_update(b->name, old_sha1, 0, NULL);
-	if (!lock)
-		return error("Unable to lock %s", b->name);
 	if (!force_update && !is_null_sha1(old_sha1)) {
 		struct commit *old_cmit, *new_cmit;
 
 		old_cmit = lookup_commit_reference_gently(old_sha1, 0);
 		new_cmit = lookup_commit_reference_gently(b->sha1, 0);
-		if (!old_cmit || !new_cmit) {
-			unlock_ref(lock);
+		if (!old_cmit || !new_cmit)
 			return error("Branch %s is missing commits.", b->name);
-		}
 
 		if (!in_merge_bases(old_cmit, new_cmit)) {
-			unlock_ref(lock);
 			warning("Not updating %s"
 				" (new tip %s does not contain %s)",
 				b->name, sha1_to_hex(b->sha1), sha1_to_hex(old_sha1));
 			return -1;
 		}
 	}
-	if (write_ref_sha1(lock, b->sha1, msg) < 0)
-		return error("Unable to update %s", b->name);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
+				   0, 1, &err) ||
+	    ref_transaction_commit(transaction, msg, &err)) {
+		ref_transaction_free(transaction);
+		error("%s", err.buf);
+		strbuf_release(&err);
+		return -1;
+	}
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	return 0;
 }
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:32 UTC · re: Jonathan Nieder · lore

[PATCH 10/20] branch.c: use ref transaction for all ref updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 16:21:53 -0700

Change create_branch to use a ref transaction when creating the new branch.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 branch.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/branch.c b/branch.c
index 660097b..37ac555 100644
--- a/branch.c
+++ b/branch.c
@@ -226,7 +226,6 @@ void create_branch(const char *head,
 		   int force, int reflog, int clobber_head,
 		   int quiet, enum branch_track track)
 {
-	struct ref_lock *lock = NULL;
 	struct commit *commit;
 	unsigned char sha1[20];
 	char *real_ref, msg[PATH_MAX + 20];
@@ -285,15 +284,6 @@ void create_branch(const char *head,
 		die(_("Not a valid branch point: '%s'."), start_name);
 	hashcpy(sha1, commit->object.sha1);
 
-	if (!dont_change_ref) {
-		lock = lock_any_ref_for_update(ref.buf, NULL, 0, NULL);
-		if (!lock)
-			die_errno(_("Failed to lock ref for update"));
-	}
-
-	if (reflog)
-		log_all_ref_updates = 1;
-
 	if (forcing)
 		snprintf(msg, sizeof msg, "branch: Reset to %s",
 			 start_name);
@@ -301,13 +291,26 @@ void create_branch(const char *head,
 		snprintf(msg, sizeof msg, "branch: Created from %s",
 			 start_name);
 
+	if (reflog)
+		log_all_ref_updates = 1;
+
+	if (!dont_change_ref) {
+		struct ref_transaction *transaction;
+		struct strbuf err = STRBUF_INIT;
+
+		transaction = ref_transaction_begin(&err);
+		if (!transaction ||
+		    ref_transaction_update(transaction, ref.buf, sha1,
+					   null_sha1, 0, !forcing, &err) ||
+		    ref_transaction_commit(transaction, msg, &err))
+			die("%s", err.buf);
+		ref_transaction_free(transaction);
+		strbuf_release(&err);
+	}
+
 	if (real_ref && track)
 		setup_tracking(ref.buf + 11, real_ref, track, quiet);
 
-	if (!dont_change_ref)
-		if (write_ref_sha1(lock, sha1, msg) < 0)
-			die_errno(_("Failed to write ref"));
-
 	strbuf_release(&ref);
 	free(real_ref);
 }

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:33 UTC · re: Jonathan Nieder · lore

[PATCH 11/20] refs.c: change update_ref to use a transaction

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 24 Apr 2014 16:36:55 -0700

Change the update_ref helper function to use a ref transaction internally.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 29 +++++++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/refs.c b/refs.c
index cc63056..dcc877b 100644
--- a/refs.c
+++ b/refs.c
@@ -3519,11 +3519,32 @@ int update_ref(const char *action, const char *refname,
 	       const unsigned char *sha1, const unsigned char *oldval,
 	       int flags, enum action_on_err onerr)
 {
-	struct ref_lock *lock;
-	lock = update_ref_lock(refname, oldval, flags, NULL, onerr);
-	if (!lock)
+	struct ref_transaction *t;
+	struct strbuf err = STRBUF_INIT;
+
+	t = ref_transaction_begin(&err);
+	if (!t ||
+	    ref_transaction_update(t, refname, sha1, oldval, flags,
+				   !!oldval, &err) ||
+	    ref_transaction_commit(t, action, &err)) {
+		const char *str = "update_ref failed for ref '%s': %s";
+
+		ref_transaction_free(t);
+		switch (onerr) {
+		case UPDATE_REFS_MSG_ON_ERR:
+			error(str, refname, err.buf);
+			break;
+		case UPDATE_REFS_DIE_ON_ERR:
+			die(str, refname, err.buf);
+			break;
+		case UPDATE_REFS_QUIET_ON_ERR:
+			break;
+		}
+		strbuf_release(&err);
 		return 1;
-	return update_ref_write(action, refname, sha1, lock, NULL, onerr);
+	}
+	strbuf_release(&err);
+	return 0;
 }
 
 static int ref_update_compare(const void *r1, const void *r2)

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:33 UTC · re: Jonathan Nieder · lore

[PATCH 12/20] receive-pack.c: use a reference transaction for updating the refs

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 14:36:15 -0700

Wrap all the ref updates inside a transaction.

Example, before:

 error: there are still refs under 'refs/heads/topic'
 remote: error: failed to lock refs/heads/topic
 To foo
  ! [remote rejected] HEAD -> topic (failed to lock)

After:

 error: there are still refs under 'refs/heads/topic'
 remote: error: Cannot lock the ref 'refs/heads/topic'.
 To foo
  ! [remote rejected] HEAD -> topic (failed to update ref)

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/receive-pack.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index c323081..224fadc 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -475,7 +475,6 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 	const char *namespaced_name;
 	unsigned char *old_sha1 = cmd->old_sha1;
 	unsigned char *new_sha1 = cmd->new_sha1;
-	struct ref_lock *lock;
 
 	/* only refs/... are allowed */
 	if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
@@ -576,19 +575,27 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		return NULL; /* good */
 	}
 	else {
+		struct strbuf err = STRBUF_INIT;
+		struct ref_transaction *transaction;
+
 		if (shallow_update && si->shallow_ref[cmd->index] &&
 		    update_shallow_ref(cmd, si))
 			return "shallow error";
 
-		lock = lock_any_ref_for_update(namespaced_name, old_sha1,
-					       0, NULL);
-		if (!lock) {
-			rp_error("failed to lock %s", name);
-			return "failed to lock";
-		}
-		if (write_ref_sha1(lock, new_sha1, "push")) {
-			return "failed to write"; /* error() already called */
+		transaction = ref_transaction_begin(&err);
+		if (!transaction ||
+		    ref_transaction_update(transaction, namespaced_name,
+					   new_sha1, old_sha1, 0, 1, &err) ||
+		    ref_transaction_commit(transaction, "push", &err)) {
+			ref_transaction_free(transaction);
+
+			rp_error("%s", err.buf);
+			strbuf_release(&err);
+			return "failed to update ref";
 		}
+
+		ref_transaction_free(transaction);
+		strbuf_release(&err);
 		return NULL; /* good */
 	}
 }

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:33 UTC · re: Jonathan Nieder · lore

[PATCH 13/20] fast-import.c: use a ref transaction when dumping tags

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 15:23:58 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 fast-import.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/fast-import.c b/fast-import.c
index 79160d5..e7f6e37 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1735,15 +1735,32 @@ static void dump_tags(void)
 {
 	static const char *msg = "fast-import";
 	struct tag *t;
-	struct ref_lock *lock;
-	char ref_name[PATH_MAX];
+	struct strbuf ref_name = STRBUF_INIT;
+	struct strbuf err = STRBUF_INIT;
+	struct ref_transaction *transaction;
 
+	transaction = ref_transaction_begin(&err);
+	if (!transaction) {
+		failure |= error("%s", err.buf);
+		goto cleanup;
+	}
 	for (t = first_tag; t; t = t->next_tag) {
-		sprintf(ref_name, "tags/%s", t->name);
-		lock = lock_ref_sha1(ref_name, NULL);
-		if (!lock || write_ref_sha1(lock, t->sha1, msg) < 0)
-			failure |= error("Unable to update %s", ref_name);
+		strbuf_reset(&ref_name);
+		strbuf_addf(&ref_name, "refs/tags/%s", t->name);
+
+		if (ref_transaction_update(transaction, ref_name.buf, t->sha1,
+					   NULL, 0, 0, &err)) {
+			failure |= error("%s", err.buf);
+			goto cleanup;
+		}
 	}
+	if (ref_transaction_commit(transaction, msg, &err))
+		failure |= error("%s", err.buf);
+
+ cleanup:
+	ref_transaction_free(transaction);
+	strbuf_release(&ref_name);
+	strbuf_release(&err);
 }
 
 static void dump_marks_helper(FILE *f,

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:34 UTC · re: Jonathan Nieder · lore

[PATCH 14/20] walker.c: use ref transaction for ref updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 17 Apr 2014 11:31:06 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 walker.c | 72 ++++++++++++++++++++++++++++++++++++----------------------------
 1 file changed, 41 insertions(+), 31 deletions(-)

diff --git a/walker.c b/walker.c
index 1dd86b8..b8a5441 100644
--- a/walker.c
+++ b/walker.c
@@ -251,40 +251,40 @@ void walker_targets_free(int targets, char **target, const char **write_ref)
 int walker_fetch(struct walker *walker, int targets, char **target,
 		 const char **write_ref, const char *write_ref_log_details)
 {
-	struct ref_lock **lock = xcalloc(targets, sizeof(struct ref_lock *));
+	struct strbuf refname = STRBUF_INIT;
+	struct strbuf err = STRBUF_INIT;
+	struct ref_transaction *transaction = NULL;
 	unsigned char *sha1 = xmalloc(targets * 20);
-	char *msg;
-	int ret;
-	int i;
+	char *msg = NULL;
+	int i, ret = -1;
 
 	save_commit_buffer = 0;
 
-	for (i = 0; i < targets; i++) {
-		if (!write_ref || !write_ref[i])
-			continue;
-
-		lock[i] = lock_ref_sha1(write_ref[i], NULL);
-		if (!lock[i]) {
-			error("Can't lock ref %s", write_ref[i]);
-			goto unlock_and_fail;
+	if (write_ref) {
+		transaction = ref_transaction_begin(&err);
+		if (!transaction) {
+			error("%s", err.buf);
+			goto done;
 		}
 	}
-
 	if (!walker->get_recover)
 		for_each_ref(mark_complete, NULL);
 
 	for (i = 0; i < targets; i++) {
 		if (interpret_target(walker, target[i], &sha1[20 * i])) {
 			error("Could not interpret response from server '%s' as something to pull", target[i]);
-			goto unlock_and_fail;
+			goto done;
 		}
 		if (process(walker, lookup_unknown_object(&sha1[20 * i])))
-			goto unlock_and_fail;
+			goto done;
 	}
 
 	if (loop(walker))
-		goto unlock_and_fail;
-
+		goto done;
+	if (!write_ref) {
+		ret = 0;
+		goto done;
+	}
 	if (write_ref_log_details) {
 		msg = xmalloc(strlen(write_ref_log_details) + 12);
 		sprintf(msg, "fetch from %s", write_ref_log_details);
@@ -292,23 +292,33 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 		msg = NULL;
 	}
 	for (i = 0; i < targets; i++) {
-		if (!write_ref || !write_ref[i])
+		if (!write_ref[i])
 			continue;
-		ret = write_ref_sha1(lock[i], &sha1[20 * i], msg ? msg : "fetch (unknown)");
-		lock[i] = NULL;
-		if (ret)
-			goto unlock_and_fail;
+		strbuf_reset(&refname);
+		strbuf_addf(&refname, "refs/%s", write_ref[i]);
+		if (ref_transaction_update(transaction, refname.buf,
+					   &sha1[20 * i], NULL, 0, 0,
+					   &err)) {
+			error("%s", err.buf);
+			goto done;
+		}
 	}
+	if (ref_transaction_commit(transaction,
+				   msg ? msg : "fetch (unknown)",
+				   &err)) {
+		error("%s", err.buf);
+		goto done;
+	}
+
+	ret = 0;
+
+done:
+	ref_transaction_free(transaction);
 	free(msg);
-
-	return 0;
-
-unlock_and_fail:
-	for (i = 0; i < targets; i++)
-		if (lock[i])
-			unlock_ref(lock[i]);
-
-	return -1;
+	free(sha1);
+	strbuf_release(&err);
+	strbuf_release(&refname);
+	return ret;
 }
 
 void walker_free(struct walker *walker)

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:34 UTC · re: Jonathan Nieder · lore

[PATCH 15/20] refs.c: make lock_ref_sha1 static

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 15:38:47 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 7 +++++--
 refs.h | 6 ------
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/refs.c b/refs.c
index dcc877b..0dc093c 100644
--- a/refs.c
+++ b/refs.c
@@ -2069,7 +2069,10 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-/* This function should make sure errno is meaningful on error */
+/*
+ * Locks a "refs/" ref returning the lock on success and NULL on failure.
+ * On failure errno is set to something meaningful.
+ */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
 					    int flags, int *type_p)
@@ -2170,7 +2173,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	return NULL;
 }
 
-struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
+static struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
 {
 	char refpath[PATH_MAX];
 	if (check_refname_format(refname, 0))
diff --git a/refs.h b/refs.h
index 3f37c65..65dd593 100644
--- a/refs.h
+++ b/refs.h
@@ -170,12 +170,6 @@ extern int ref_exists(const char *);
  */
 extern int peel_ref(const char *refname, unsigned char *sha1);
 
-/*
- * Locks a "refs/" ref returning the lock on success and NULL on failure.
- * On failure errno is set to something meaningful.
- */
-extern struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1);
-
 /** Locks any ref (for 'HEAD' type refs). */
 #define REF_NODEREF	0x01
 /* errno is set to something meaningful on failure */

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:35 UTC · re: Jonathan Nieder · lore

[PATCH 16/20] refs.c: remove the update_ref_lock function

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 12:14:47 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 30 ++++++------------------------
 1 file changed, 6 insertions(+), 24 deletions(-)

diff --git a/refs.c b/refs.c
index 0dc093c..de07791 100644
--- a/refs.c
+++ b/refs.c
@@ -3336,24 +3336,6 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 	return retval;
 }
 
-static struct ref_lock *update_ref_lock(const char *refname,
-					const unsigned char *oldval,
-					int flags, int *type_p,
-					enum action_on_err onerr)
-{
-	struct ref_lock *lock;
-	lock = lock_any_ref_for_update(refname, oldval, flags, type_p);
-	if (!lock) {
-		const char *str = "Cannot lock the ref '%s'.";
-		switch (onerr) {
-		case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
-		case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
-		case UPDATE_REFS_QUIET_ON_ERR: break;
-		}
-	}
-	return lock;
-}
-
 static int update_ref_write(const char *action, const char *refname,
 			    const unsigned char *sha1, struct ref_lock *lock,
 			    struct strbuf *err, enum action_on_err onerr)
@@ -3602,12 +3584,12 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	for (i = 0; i < n; i++) {
 		struct ref_update *update = updates[i];
 
-		update->lock = update_ref_lock(update->refname,
-					       (update->have_old ?
-						update->old_sha1 : NULL),
-					       update->flags,
-					       &update->type,
-					       UPDATE_REFS_QUIET_ON_ERR);
+		update->lock = lock_any_ref_for_update(update->refname,
+						       (update->have_old ?
+							update->old_sha1 :
+							NULL),
+						       update->flags,
+						       &update->type);
 		if (!update->lock) {
 			if (err)
 				strbuf_addf(err, "Cannot lock the ref '%s'.",

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:35 UTC · re: Jonathan Nieder · lore

[PATCH 17/20] refs.c: remove the update_ref_write function

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 13:42:07 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 34 ++++++++--------------------------
 1 file changed, 8 insertions(+), 26 deletions(-)

diff --git a/refs.c b/refs.c
index de07791..ef7660a 100644
--- a/refs.c
+++ b/refs.c
@@ -3336,25 +3336,6 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 	return retval;
 }
 
-static int update_ref_write(const char *action, const char *refname,
-			    const unsigned char *sha1, struct ref_lock *lock,
-			    struct strbuf *err, enum action_on_err onerr)
-{
-	if (write_ref_sha1(lock, sha1, action) < 0) {
-		const char *str = "Cannot update the ref '%s'.";
-		if (err)
-			strbuf_addf(err, str, refname);
-
-		switch (onerr) {
-		case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
-		case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
-		case UPDATE_REFS_QUIET_ON_ERR: break;
-		}
-		return 1;
-	}
-	return 0;
-}
-
 /**
  * Information needed for a single ref update.  Set new_sha1 to the
  * new value or to zero to delete the ref.  To check the old value
@@ -3604,14 +3585,15 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 		struct ref_update *update = updates[i];
 
 		if (!is_null_sha1(update->new_sha1)) {
-			ret = update_ref_write(msg,
-					       update->refname,
-					       update->new_sha1,
-					       update->lock, err,
-					       UPDATE_REFS_QUIET_ON_ERR);
-			update->lock = NULL; /* freed by update_ref_write */
-			if (ret)
+			ret = write_ref_sha1(update->lock, update->new_sha1,
+					     msg);
+			update->lock = NULL; /* freed by write_ref_sha1 */
+			if (ret) {
+				if (err)
+					strbuf_addf(err, "Cannot update the ref '%s'.",
+						    update->refname);
 				goto cleanup;
+			}
 		}
 	}
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:35 UTC · re: Jonathan Nieder · lore

[PATCH 18/20] refs.c: remove lock_ref_sha1

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 15:45:52 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/refs.c b/refs.c
index ef7660a..f0883d0 100644
--- a/refs.c
+++ b/refs.c
@@ -2173,15 +2173,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	return NULL;
 }
 
-static struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
-{
-	char refpath[PATH_MAX];
-	if (check_refname_format(refname, 0))
-		return NULL;
-	strcpy(refpath, mkpath("refs/%s", refname));
-	return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
-}
-
 struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
@@ -2391,8 +2382,12 @@ static void try_remove_empty_parents(char *name)
 /* make sure nobody touched the ref, and unlink */
 static void prune_ref(struct ref_to_prune *r)
 {
-	struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
+	struct ref_lock *lock;
 
+	if (check_refname_format(r->name + 5, 0))
+		return;
+
+	lock = lock_ref_sha1_basic(r->name, r->sha1, 0, NULL);
 	if (lock) {
 		unlink_or_warn(git_path("%s", r->name));
 		unlock_ref(lock);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:36 UTC · re: Jonathan Nieder · lore

[PATCH 19/20] refs.c: make prune_ref use a transaction to delete the ref

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 30 Apr 2014 09:03:36 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 28 +++++++++++++++++++++-------
 refs.h | 13 +++++++++++--
 2 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index f0883d0..5b2d335 100644
--- a/refs.c
+++ b/refs.c
@@ -25,6 +25,11 @@ static unsigned char refname_disposition[256] = {
 };
 
 /*
+ * Used as a flag to ref_transaction_delete when a loose ref is being
+ * pruned.
+ */
+#define REF_ISPRUNING	0x0100
+/*
  * Try to read one refname component from the front of refname.
  * Return the length of the component found, or -1 if the component is
  * not legal.  It is legal if it is something reasonable to have under
@@ -2382,17 +2387,25 @@ static void try_remove_empty_parents(char *name)
 /* make sure nobody touched the ref, and unlink */
 static void prune_ref(struct ref_to_prune *r)
 {
-	struct ref_lock *lock;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	if (check_refname_format(r->name + 5, 0))
 		return;
 
-	lock = lock_ref_sha1_basic(r->name, r->sha1, 0, NULL);
-	if (lock) {
-		unlink_or_warn(git_path("%s", r->name));
-		unlock_ref(lock);
-		try_remove_empty_parents(r->name);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_delete(transaction, r->name, r->sha1,
+				   REF_ISPRUNING, 1, &err) ||
+	    ref_transaction_commit(transaction, NULL, &err)) {
+		ref_transaction_free(transaction);
+		error("%s", err.buf);
+		strbuf_release(&err);
+		return;
 	}
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
+	try_remove_empty_parents(r->name);
 }
 
 static void prune_refs(struct ref_to_prune *r)
@@ -3597,8 +3610,9 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 		struct ref_update *update = updates[i];
 
 		if (update->lock) {
-			delnames[delnum++] = update->lock->ref_name;
 			ret |= delete_ref_loose(update->lock, update->type);
+			if (!(update->flags & REF_ISPRUNING))
+				delnames[delnum++] = update->lock->ref_name;
 		}
 	}
 
diff --git a/refs.h b/refs.h
index 65dd593..69ef28c 100644
--- a/refs.h
+++ b/refs.h
@@ -170,9 +170,18 @@ extern int ref_exists(const char *);
  */
 extern int peel_ref(const char *refname, unsigned char *sha1);
 
-/** Locks any ref (for 'HEAD' type refs). */
+/*
+ * Flags controlling lock_any_ref_for_update(), ref_transaction_update(),
+ * ref_transaction_create(), etc.
+ * REF_NODEREF: act on the ref directly, instead of dereferencing
+ *              symbolic references.
+ *
+ * Flags >= 0x100 are reserved for internal use.
+ */
 #define REF_NODEREF	0x01
-/* errno is set to something meaningful on failure */
+/*
+ * This function sets errno to something meaningful on failure.
+ */
 extern struct ref_lock *lock_any_ref_for_update(const char *refname,
 						const unsigned char *old_sha1,
 						int flags, int *type_p);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Aug 27, 2014, 00:36 UTC · re: Jonathan Nieder · lore

[PATCH 20/20] refs.c: make delete_ref use a transaction

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 30 Apr 2014 09:22:45 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
Thanks for reading.

 refs.c | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/refs.c b/refs.c
index 5b2d335..7996be9 100644
--- a/refs.c
+++ b/refs.c
@@ -2548,11 +2548,6 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 	return ret;
 }
 
-static int repack_without_ref(const char *refname)
-{
-	return repack_without_refs(&refname, 1, NULL);
-}
-
 static int delete_ref_loose(struct ref_lock *lock, int flag)
 {
 	if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
@@ -2570,24 +2565,22 @@ static int delete_ref_loose(struct ref_lock *lock, int flag)
 
 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 {
-	struct ref_lock *lock;
-	int ret = 0, flag = 0;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
-	lock = lock_ref_sha1_basic(refname, sha1, delopt, &flag);
-	if (!lock)
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_delete(transaction, refname, sha1, delopt,
+				   sha1 && !is_null_sha1(sha1), &err) ||
+	    ref_transaction_commit(transaction, NULL, &err)) {
+		error("%s", err.buf);
+		ref_transaction_free(transaction);
+		strbuf_release(&err);
 		return 1;
-	ret |= delete_ref_loose(lock, flag);
-
-	/* removing the loose one could have resurrected an earlier
-	 * packed one.  Also, if it was not loose we need to repack
-	 * without it.
-	 */
-	ret |= repack_without_ref(lock->ref_name);
-
-	unlink_or_warn(git_path("logs/%s", lock->ref_name));
-	clear_loose_ref_cache(&ref_cache);
-	unlock_ref(lock);
-	return ret;
+	}
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
+	return 0;
 }
 
 /*

-- 
2.1.0.rc2.206.gedb03e5

Junio C Hamano· Aug 27, 2014, 21:29 UTC · re: Jonathan Nieder · lore

Re: [PATCH 0/20] rs/ref-transaction-1 (Re: Transaction patch series overview)

Jonathan Nieder <jrnieder@gmail.com> writes:

> Jonathan Nieder wrote:
>
>> This series teaches the tag, replace, commit, cherry-pick,
>> fast-import, checkout -b, branch, receive-pack, and http-fetch
>> commands and all update_ref and delete_ref callers to use the ref
>> transaction API instead of lock_ref_sha1.
>>
>> The main user-visible change should be some cosmetic changes to error
>> messages.  The series also combines multiple ref updates into a single
>> transaction in 'git http-fetch -w' and when writing tags in
>> fast-import but otherwise doesn't change the granularity of
>> transactions.
>>
>> Reviewed at https://code-review.googlesource.com/#/q/topic:ref-transaction-1

Thanks.

Junio C Hamano· Aug 27, 2014, 22:37 UTC · re: Junio C Hamano · lore

Re: [PATCH 0/20] rs/ref-transaction-1 (Re: Transaction patch series overview)

Junio C Hamano <gitster@pobox.com> writes:

> Jonathan Nieder <jrnieder@gmail.com> writes:
>
>> Jonathan Nieder wrote:
>>
>>> This series teaches the tag, replace, commit, cherry-pick,
>>> fast-import, checkout -b, branch, receive-pack, and http-fetch
>>> commands and all update_ref and delete_ref callers to use the ref
>>> transaction API instead of lock_ref_sha1.
>>>
>>> The main user-visible change should be some cosmetic changes to error
>>> messages.  The series also combines multiple ref updates into a single
>>> transaction in 'git http-fetch -w' and when writing tags in
>>> fast-import but otherwise doesn't change the granularity of
>>> transactions.
>>>
>>> Reviewed at https://code-review.googlesource.com/#/q/topic:ref-transaction-1
>
> Thanks.
>
> Will queue, but the some other topics may have to disappear from my
> tree while I try to rebase them on top (or while I wait for you guys
> to send a reroll, making it unnecesary to do the rebase myself).

Jonathan Nieder· Sep 2, 2014, 20:58 UTC · re: Jonathan Nieder · lore

[PATCH v22 0/22] rs/ref-transaction-1 (Re: Transaction patch series overview)

Hi Junio,

These patches are also available from the git repository at

  git://repo.or.cz/git/jrn.git tags/rs/ref-transaction-1

"Use ref transactions", early part

Ronnie explains:

	This patch series expands on the transaction API. It converts
	ref updates, inside refs.c as well as external, to use the
	transaction API for updates. This makes most ref updates
	atomic when there are failures locking or writing to a ref.

Jonathan Nieder (2):
      update-ref --stdin: narrow scope of err strbuf
      update-ref --stdin: pass transaction around explicitly

Ronnie Sahlberg (20):
      refs.c: change ref_transaction_create to do error checking and return status
      refs.c: update ref_transaction_delete to check for error and return status
      refs.c: make ref_transaction_begin take an err argument
      refs.c: add transaction.status and track OPEN/CLOSED
      tag.c: use ref transactions when doing updates
      replace.c: use the ref transaction functions for updates
      commit.c: use ref transactions for updates
      sequencer.c: use ref transactions for all ref updates
      fast-import.c: change update_branch to use ref transactions
      branch.c: use ref transaction for all ref updates
      refs.c: change update_ref to use a transaction
      receive-pack.c: use a reference transaction for updating the refs
      fast-import.c: use a ref transaction when dumping tags
      walker.c: use ref transaction for ref updates
      refs.c: make lock_ref_sha1 static
      refs.c: remove the update_ref_lock function
      refs.c: remove the update_ref_write function
      refs.c: remove lock_ref_sha1
      refs.c: make prune_ref use a transaction to delete the ref
      refs.c: make delete_ref use a transaction

 branch.c               |  31 ++++---
 builtin/commit.c       |  25 +++--
 builtin/receive-pack.c |  25 +++--
 builtin/replace.c      |  14 +--
 builtin/tag.c          |  16 ++--
 builtin/update-ref.c   |  52 +++++++----
 fast-import.c          |  54 +++++++----
 refs.c                 | 245 ++++++++++++++++++++++++++++---------------------
 refs.h                 |  77 ++++++++++++----
 sequencer.c            |  26 ++++--
 walker.c               |  70 ++++++++------
 11 files changed, 393 insertions(+), 242 deletions(-)
---
Changes since v21:

 builtin/update-ref.c | 38 +++++++++++++++++++++++++-------------
 refs.c               |  1 +
 2 files changed, 26 insertions(+), 13 deletions(-)

diff --git c/builtin/update-ref.c w/builtin/update-ref.c
index 96a53b9..54a48c0 100644
--- c/builtin/update-ref.c
+++ w/builtin/update-ref.c
@@ -12,11 +12,8 @@ static const char * const git_update_ref_usage[] = {
 	NULL
 };
 
-static struct ref_transaction *transaction;
-
 static char line_termination = '\n';
 static int update_flags;
-static struct strbuf err = STRBUF_INIT;
 
 /*
  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
@@ -177,8 +174,10 @@ static int parse_next_sha1(struct strbuf *input, const char **next,
  * depending on how line_termination is set.
  */
 
-static const char *parse_cmd_update(struct strbuf *input, const char *next)
+static const char *parse_cmd_update(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];
 	unsigned char old_sha1[20];
@@ -204,12 +203,15 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
 
-static const char *parse_cmd_create(struct strbuf *input, const char *next)
+static const char *parse_cmd_create(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];
 
@@ -232,12 +234,15 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
 
-static const char *parse_cmd_delete(struct strbuf *input, const char *next)
+static const char *parse_cmd_delete(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char old_sha1[20];
 	int have_old;
@@ -264,12 +269,15 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
 
-static const char *parse_cmd_verify(struct strbuf *input, const char *next)
+static const char *parse_cmd_verify(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];
 	unsigned char old_sha1[20];
@@ -297,6 +305,7 @@ static const char *parse_cmd_verify(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
@@ -310,7 +319,7 @@ static const char *parse_cmd_option(struct strbuf *input, const char *next)
 	return next + 8;
 }
 
-static void update_refs_stdin(void)
+static void update_refs_stdin(struct ref_transaction *transaction)
 {
 	struct strbuf input = STRBUF_INIT;
 	const char *next;
@@ -325,13 +334,13 @@ static void update_refs_stdin(void)
 		else if (isspace(*next))
 			die("whitespace before command: %s", next);
 		else if (starts_with(next, "update "))
-			next = parse_cmd_update(&input, next + 7);
+			next = parse_cmd_update(transaction, &input, next + 7);
 		else if (starts_with(next, "create "))
-			next = parse_cmd_create(&input, next + 7);
+			next = parse_cmd_create(transaction, &input, next + 7);
 		else if (starts_with(next, "delete "))
-			next = parse_cmd_delete(&input, next + 7);
+			next = parse_cmd_delete(transaction, &input, next + 7);
 		else if (starts_with(next, "verify "))
-			next = parse_cmd_verify(&input, next + 7);
+			next = parse_cmd_verify(transaction, &input, next + 7);
 		else if (starts_with(next, "option "))
 			next = parse_cmd_option(&input, next + 7);
 		else
@@ -365,6 +374,9 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		die("Refusing to perform update with empty message.");
 
 	if (read_stdin) {
+		struct strbuf err = STRBUF_INIT;
+		struct ref_transaction *transaction;
+
 		transaction = ref_transaction_begin(&err);
 		if (!transaction)
 			die("%s", err.buf);
@@ -372,7 +384,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 			usage_with_options(git_update_ref_usage, options);
 		if (end_null)
 			line_termination = '\0';
-		update_refs_stdin();
+		update_refs_stdin(transaction);
 		if (ref_transaction_commit(transaction, msg, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
diff --git c/refs.c w/refs.c
index 7996be9..7235574 100644
--- c/refs.c
+++ w/refs.c
@@ -3511,6 +3511,7 @@ int update_ref(const char *action, const char *refname,
 		return 1;
 	}
 	strbuf_release(&err);
+	ref_transaction_free(t);
 	return 0;
 }
 

Jonathan Nieder· Sep 2, 2014, 20:59 UTC · re: Jonathan Nieder · lore

[PATCH 01/22] refs.c: change ref_transaction_create to do error checking and return status

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:26:44 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/update-ref.c |  4 +++-
 refs.c               | 18 ++++++++++++------
 refs.h               | 48 +++++++++++++++++++++++++++++++++++++++++-------
 3 files changed, 56 insertions(+), 14 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 3067b11..41121fa 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -226,7 +226,9 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)
 	if (*next != line_termination)
 		die("create %s: extra input: %s", refname, next);
 
-	ref_transaction_create(transaction, refname, new_sha1, update_flags);
+	if (ref_transaction_create(transaction, refname, new_sha1,
+				   update_flags, &err))
+		die("%s", err.buf);
 
 	update_flags = 0;
 	free(refname);
diff --git a/refs.c b/refs.c
index 3f05e88..c49f1c6 100644
--- a/refs.c
+++ b/refs.c
@@ -3449,18 +3449,24 @@ int ref_transaction_update(struct ref_transaction *transaction,
 	return 0;
 }
 
-void ref_transaction_create(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *new_sha1,
-			    int flags)
+int ref_transaction_create(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *new_sha1,
+			   int flags,
+			   struct strbuf *err)
 {
-	struct ref_update *update = add_update(transaction, refname);
+	struct ref_update *update;
+
+	if (!new_sha1 || is_null_sha1(new_sha1))
+		die("BUG: create ref with null new_sha1");
+
+	update = add_update(transaction, refname);
 
-	assert(!is_null_sha1(new_sha1));
 	hashcpy(update->new_sha1, new_sha1);
 	hashclr(update->old_sha1);
 	update->flags = flags;
 	update->have_old = 1;
+	return 0;
 }
 
 void ref_transaction_delete(struct ref_transaction *transaction,
diff --git a/refs.h b/refs.h
index c5376ce..b648819 100644
--- a/refs.h
+++ b/refs.h
@@ -10,6 +10,38 @@ struct ref_lock {
 	int force_write;
 };
 
+/*
+ * A ref_transaction represents a collection of ref updates
+ * that should succeed or fail together.
+ *
+ * Calling sequence
+ * ----------------
+ * - Allocate and initialize a `struct ref_transaction` by calling
+ *   `ref_transaction_begin()`.
+ *
+ * - List intended ref updates by calling functions like
+ *   `ref_transaction_update()` and `ref_transaction_create()`.
+ *
+ * - Call `ref_transaction_commit()` to execute the transaction.
+ *   If this succeeds, the ref updates will have taken place and
+ *   the transaction cannot be rolled back.
+ *
+ * - At any time call `ref_transaction_free()` to discard the
+ *   transaction and free associated resources.  In particular,
+ *   this rolls back the transaction if it has not been
+ *   successfully committed.
+ *
+ * Error handling
+ * --------------
+ *
+ * On error, transaction functions append a message about what
+ * went wrong to the 'err' argument.  The message mentions what
+ * ref was being updated (if any) when the error occurred so it
+ * can be passed to 'die' or 'error' as-is.
+ *
+ * The message is appended to err without first clearing err.
+ * err will not be '\n' terminated.
+ */
 struct ref_transaction;
 
 /*
@@ -248,7 +280,7 @@ struct ref_transaction *ref_transaction_begin(void);
  * it must not have existed beforehand.
  * Function returns 0 on success and non-zero on failure. A failure to update
  * means that the transaction as a whole has failed and will need to be
- * rolled back. On failure the err buffer will be updated.
+ * rolled back.
  */
 int ref_transaction_update(struct ref_transaction *transaction,
 			   const char *refname,
@@ -262,11 +294,15 @@ int ref_transaction_update(struct ref_transaction *transaction,
  * that the reference should have after the update; it must not be the
  * null SHA-1.  It is verified that the reference does not exist
  * already.
+ * Function returns 0 on success and non-zero on failure. A failure to create
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
  */
-void ref_transaction_create(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *new_sha1,
-			    int flags);
+int ref_transaction_create(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *new_sha1,
+			   int flags,
+			   struct strbuf *err);
 
 /*
  * Add a reference deletion to transaction.  If have_old is true, then
@@ -282,8 +318,6 @@ void ref_transaction_delete(struct ref_transaction *transaction,
  * Commit all of the changes that have been queued in transaction, as
  * atomically as possible.  Return a nonzero value if there is a
  * problem.
- * If err is non-NULL we will add an error string to it to explain why
- * the transaction failed. The string does not end in newline.
  */
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   const char *msg, struct strbuf *err);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:00 UTC · re: Jonathan Nieder · lore

[PATCH 02/22] refs.c: update ref_transaction_delete to check for error and return status

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:27:45 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/update-ref.c |  5 +++--
 refs.c               | 16 +++++++++++-----
 refs.h               | 12 ++++++++----
 3 files changed, 22 insertions(+), 11 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 41121fa..7c9c248 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -258,8 +258,9 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
 	if (*next != line_termination)
 		die("delete %s: extra input: %s", refname, next);
 
-	ref_transaction_delete(transaction, refname, old_sha1,
-			       update_flags, have_old);
+	if (ref_transaction_delete(transaction, refname, old_sha1,
+				   update_flags, have_old, &err))
+		die("%s", err.buf);
 
 	update_flags = 0;
 	free(refname);
diff --git a/refs.c b/refs.c
index c49f1c6..40f04f4 100644
--- a/refs.c
+++ b/refs.c
@@ -3469,19 +3469,25 @@ int ref_transaction_create(struct ref_transaction *transaction,
 	return 0;
 }
 
-void ref_transaction_delete(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old)
+int ref_transaction_delete(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old,
+			   struct strbuf *err)
 {
-	struct ref_update *update = add_update(transaction, refname);
+	struct ref_update *update;
 
+	if (have_old && !old_sha1)
+		die("BUG: have_old is true but old_sha1 is NULL");
+
+	update = add_update(transaction, refname);
 	update->flags = flags;
 	update->have_old = have_old;
 	if (have_old) {
 		assert(!is_null_sha1(old_sha1));
 		hashcpy(update->old_sha1, old_sha1);
 	}
+	return 0;
 }
 
 int update_ref(const char *action, const char *refname,
diff --git a/refs.h b/refs.h
index b648819..71389a1 100644
--- a/refs.h
+++ b/refs.h
@@ -308,11 +308,15 @@ int ref_transaction_create(struct ref_transaction *transaction,
  * Add a reference deletion to transaction.  If have_old is true, then
  * old_sha1 holds the value that the reference should have had before
  * the update (which must not be the null SHA-1).
+ * Function returns 0 on success and non-zero on failure. A failure to delete
+ * means that the transaction as a whole has failed and will need to be
+ * rolled back.
  */
-void ref_transaction_delete(struct ref_transaction *transaction,
-			    const char *refname,
-			    const unsigned char *old_sha1,
-			    int flags, int have_old);
+int ref_transaction_delete(struct ref_transaction *transaction,
+			   const char *refname,
+			   const unsigned char *old_sha1,
+			   int flags, int have_old,
+			   struct strbuf *err);
 
 /*
  * Commit all of the changes that have been queued in transaction, as

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:00 UTC · re: Jonathan Nieder · lore

[PATCH 03/22] refs.c: make ref_transaction_begin take an err argument

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 19 May 2014 10:42:34 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/update-ref.c | 5 ++++-
 refs.c               | 2 +-
 refs.h               | 2 +-
 3 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 7c9c248..96a53b9 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -365,7 +365,9 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		die("Refusing to perform update with empty message.");
 
 	if (read_stdin) {
-		transaction = ref_transaction_begin();
+		transaction = ref_transaction_begin(&err);
+		if (!transaction)
+			die("%s", err.buf);
 		if (delete || no_deref || argc > 0)
 			usage_with_options(git_update_ref_usage, options);
 		if (end_null)
@@ -374,6 +376,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		if (ref_transaction_commit(transaction, msg, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
+		strbuf_release(&err);
 		return 0;
 	}
 
diff --git a/refs.c b/refs.c
index 40f04f4..9cb7908 100644
--- a/refs.c
+++ b/refs.c
@@ -3397,7 +3397,7 @@ struct ref_transaction {
 	size_t nr;
 };
 
-struct ref_transaction *ref_transaction_begin(void)
+struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
 	return xcalloc(1, sizeof(struct ref_transaction));
 }
diff --git a/refs.h b/refs.h
index 71389a1..3f37c65 100644
--- a/refs.h
+++ b/refs.h
@@ -262,7 +262,7 @@ enum action_on_err {
  * Begin a reference transaction.  The reference transaction must
  * be freed by calling ref_transaction_free().
  */
-struct ref_transaction *ref_transaction_begin(void);
+struct ref_transaction *ref_transaction_begin(struct strbuf *err);
 
 /*
  * The following functions add a reference check or update to a

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:00 UTC · re: Jonathan Nieder · lore

[PATCH 04/22] refs.c: add transaction.status and track OPEN/CLOSED

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 12:06:19 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 34 +++++++++++++++++++++++++++++++++-
 1 file changed, 33 insertions(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index 9cb7908..cc63056 100644
--- a/refs.c
+++ b/refs.c
@@ -3387,6 +3387,21 @@ struct ref_update {
 };
 
 /*
+ * Transaction states.
+ * OPEN:   The transaction is in a valid state and can accept new updates.
+ *         An OPEN transaction can be committed.
+ * CLOSED: A closed transaction is no longer active and no other operations
+ *         than free can be used on it in this state.
+ *         A transaction can either become closed by successfully committing
+ *         an active transaction or if there is a failure while building
+ *         the transaction thus rendering it failed/inactive.
+ */
+enum ref_transaction_state {
+	REF_TRANSACTION_OPEN   = 0,
+	REF_TRANSACTION_CLOSED = 1
+};
+
+/*
  * Data structure for holding a reference transaction, which can
  * consist of checks and updates to multiple references, carried out
  * as atomically as possible.  This structure is opaque to callers.
@@ -3395,6 +3410,7 @@ struct ref_transaction {
 	struct ref_update **updates;
 	size_t alloc;
 	size_t nr;
+	enum ref_transaction_state state;
 };
 
 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
@@ -3437,6 +3453,9 @@ int ref_transaction_update(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: update called for transaction that is not open");
+
 	if (have_old && !old_sha1)
 		die("BUG: have_old is true but old_sha1 is NULL");
 
@@ -3457,6 +3476,9 @@ int ref_transaction_create(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: create called for transaction that is not open");
+
 	if (!new_sha1 || is_null_sha1(new_sha1))
 		die("BUG: create ref with null new_sha1");
 
@@ -3477,6 +3499,9 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: delete called for transaction that is not open");
+
 	if (have_old && !old_sha1)
 		die("BUG: have_old is true but old_sha1 is NULL");
 
@@ -3532,8 +3557,13 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	int n = transaction->nr;
 	struct ref_update **updates = transaction->updates;
 
-	if (!n)
+	if (transaction->state != REF_TRANSACTION_OPEN)
+		die("BUG: commit called for transaction that is not open");
+
+	if (!n) {
+		transaction->state = REF_TRANSACTION_CLOSED;
 		return 0;
+	}
 
 	/* Allocate work space */
 	delnames = xmalloc(sizeof(*delnames) * n);
@@ -3595,6 +3625,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	clear_loose_ref_cache(&ref_cache);
 
 cleanup:
+	transaction->state = REF_TRANSACTION_CLOSED;
+
 	for (i = 0; i < n; i++)
 		if (updates[i]->lock)
 			unlock_ref(updates[i]->lock);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:01 UTC · re: Jonathan Nieder · lore

[PATCH 05/22] tag.c: use ref transactions when doing updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:30:41 -0700

Change tag.c to use ref transactions for all ref updates.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/tag.c | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/builtin/tag.c b/builtin/tag.c
index c6e8a71..f3f172f 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -548,7 +548,6 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	struct strbuf ref = STRBUF_INIT;
 	unsigned char object[20], prev[20];
 	const char *object_ref, *tag;
-	struct ref_lock *lock;
 	struct create_tag_options opt;
 	char *cleanup_arg = NULL;
 	int annotate = 0, force = 0, lines = -1;
@@ -556,6 +555,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	const char *msgfile = NULL, *keyid = NULL;
 	struct msg_arg msg = { 0, STRBUF_INIT };
 	struct commit_list *with_commit = NULL;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 	struct option options[] = {
 		OPT_CMDMODE('l', "list", &cmdmode, N_("list tag names"), 'l'),
 		{ OPTION_INTEGER, 'n', NULL, &lines, N_("n"),
@@ -701,14 +702,17 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	if (annotate)
 		create_tag(object, tag, &buf, &opt, prev, object);
 
-	lock = lock_any_ref_for_update(ref.buf, prev, 0, NULL);
-	if (!lock)
-		die(_("%s: cannot lock the ref"), ref.buf);
-	if (write_ref_sha1(lock, object, NULL) < 0)
-		die(_("%s: cannot update the ref"), ref.buf);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref.buf, object, prev,
+				   0, 1, &err) ||
+	    ref_transaction_commit(transaction, NULL, &err))
+		die("%s", err.buf);
+	ref_transaction_free(transaction);
 	if (force && !is_null_sha1(prev) && hashcmp(prev, object))
 		printf(_("Updated tag '%s' (was %s)\n"), tag, find_unique_abbrev(prev, DEFAULT_ABBREV));
 
+	strbuf_release(&err);
 	strbuf_release(&buf);
 	strbuf_release(&ref);
 	return 0;

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:01 UTC · re: Jonathan Nieder · lore

[PATCH 06/22] replace.c: use the ref transaction functions for updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:32:29 -0700

Update replace.c to use ref transactions for updates.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/replace.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/builtin/replace.c b/builtin/replace.c
index 1bb491d..1fcd06d 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -153,7 +153,8 @@ static int replace_object_sha1(const char *object_ref,
 	unsigned char prev[20];
 	enum object_type obj_type, repl_type;
 	char ref[PATH_MAX];
-	struct ref_lock *lock;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	obj_type = sha1_object_info(object, NULL);
 	repl_type = sha1_object_info(repl, NULL);
@@ -166,12 +167,13 @@ static int replace_object_sha1(const char *object_ref,
 
 	check_ref_valid(object, prev, ref, sizeof(ref), force);
 
-	lock = lock_any_ref_for_update(ref, prev, 0, NULL);
-	if (!lock)
-		die("%s: cannot lock the ref", ref);
-	if (write_ref_sha1(lock, repl, NULL) < 0)
-		die("%s: cannot update the ref", ref);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref, repl, prev, 0, 1, &err) ||
+	    ref_transaction_commit(transaction, NULL, &err))
+		die("%s", err.buf);
 
+	ref_transaction_free(transaction);
 	return 0;
 }
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:02 UTC · re: Jonathan Nieder · lore

[PATCH 07/22] commit.c: use ref transactions for updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:34:19 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/commit.c | 25 ++++++++++++-------------
 1 file changed, 12 insertions(+), 13 deletions(-)

diff --git a/builtin/commit.c b/builtin/commit.c
index 5e2221c..9bf1003 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1627,11 +1627,12 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	const char *index_file, *reflog_msg;
 	char *nl;
 	unsigned char sha1[20];
-	struct ref_lock *ref_lock;
 	struct commit_list *parents = NULL, **pptr = &parents;
 	struct stat statbuf;
 	struct commit *current_head = NULL;
 	struct commit_extra_header *extra = NULL;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	if (argc == 2 && !strcmp(argv[1], "-h"))
 		usage_with_options(builtin_commit_usage, builtin_commit_options);
@@ -1753,16 +1754,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_release(&author_ident);
 	free_commit_extra_headers(extra);
 
-	ref_lock = lock_any_ref_for_update("HEAD",
-					   !current_head
-					   ? NULL
-					   : current_head->object.sha1,
-					   0, NULL);
-	if (!ref_lock) {
-		rollback_index_files();
-		die(_("cannot lock HEAD ref"));
-	}
-
 	nl = strchr(sb.buf, '\n');
 	if (nl)
 		strbuf_setlen(&sb, nl + 1 - sb.buf);
@@ -1771,10 +1762,17 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	strbuf_insert(&sb, 0, reflog_msg, strlen(reflog_msg));
 	strbuf_insert(&sb, strlen(reflog_msg), ": ", 2);
 
-	if (write_ref_sha1(ref_lock, sha1, sb.buf) < 0) {
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD", sha1,
+				   current_head
+				   ? current_head->object.sha1 : NULL,
+				   0, !!current_head, &err) ||
+	    ref_transaction_commit(transaction, sb.buf, &err)) {
 		rollback_index_files();
-		die(_("cannot update HEAD ref"));
+		die("%s", err.buf);
 	}
+	ref_transaction_free(transaction);
 
 	unlink(git_path("CHERRY_PICK_HEAD"));
 	unlink(git_path("REVERT_HEAD"));
@@ -1803,5 +1801,6 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	if (!quiet)
 		print_summary(prefix, sha1, !current_head);
 
+	strbuf_release(&err);
 	return 0;
 }

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:02 UTC · re: Jonathan Nieder · lore

[PATCH 08/22] sequencer.c: use ref transactions for all ref updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 15:37:45 -0700

Change to use ref transactions for all updates to refs.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 sequencer.c | 26 ++++++++++++++++++--------
 1 file changed, 18 insertions(+), 8 deletions(-)

diff --git a/sequencer.c b/sequencer.c
index 0a80c58..5e93b6a 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -272,23 +272,33 @@ static int error_dirty_index(struct replay_opts *opts)
 static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 			int unborn, struct replay_opts *opts)
 {
-	struct ref_lock *ref_lock;
+	struct ref_transaction *transaction;
 	struct strbuf sb = STRBUF_INIT;
-	int ret;
+	struct strbuf err = STRBUF_INIT;
 
 	read_cache();
 	if (checkout_fast_forward(from, to, 1))
 		exit(1); /* the callee should have complained already */
-	ref_lock = lock_any_ref_for_update("HEAD", unborn ? null_sha1 : from,
-					   0, NULL);
-	if (!ref_lock)
-		return error(_("Failed to lock HEAD during fast_forward_to"));
 
 	strbuf_addf(&sb, "%s: fast-forward", action_name(opts));
-	ret = write_ref_sha1(ref_lock, to, sb.buf);
+
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, "HEAD",
+				   to, unborn ? null_sha1 : from,
+				   0, 1, &err) ||
+	    ref_transaction_commit(transaction, sb.buf, &err)) {
+		ref_transaction_free(transaction);
+		error("%s", err.buf);
+		strbuf_release(&sb);
+		strbuf_release(&err);
+		return -1;
+	}
 
 	strbuf_release(&sb);
-	return ret;
+	strbuf_release(&err);
+	ref_transaction_free(transaction);
+	return 0;
 }
 
 static int do_recursive_merge(struct commit *base, struct commit *next,

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:03 UTC · re: Jonathan Nieder · lore

[PATCH 09/22] fast-import.c: change update_branch to use ref transactions

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 16:21:13 -0700

Change update_branch() to use ref transactions for updates.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 fast-import.c | 25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

diff --git a/fast-import.c b/fast-import.c
index 6707a66..79160d5 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1679,8 +1679,9 @@ found_entry:
 static int update_branch(struct branch *b)
 {
 	static const char *msg = "fast-import";
-	struct ref_lock *lock;
+	struct ref_transaction *transaction;
 	unsigned char old_sha1[20];
+	struct strbuf err = STRBUF_INIT;
 
 	if (read_ref(b->name, old_sha1))
 		hashclr(old_sha1);
@@ -1689,29 +1690,33 @@ static int update_branch(struct branch *b)
 			delete_ref(b->name, old_sha1, 0);
 		return 0;
 	}
-	lock = lock_any_ref_for_update(b->name, old_sha1, 0, NULL);
-	if (!lock)
-		return error("Unable to lock %s", b->name);
 	if (!force_update && !is_null_sha1(old_sha1)) {
 		struct commit *old_cmit, *new_cmit;
 
 		old_cmit = lookup_commit_reference_gently(old_sha1, 0);
 		new_cmit = lookup_commit_reference_gently(b->sha1, 0);
-		if (!old_cmit || !new_cmit) {
-			unlock_ref(lock);
+		if (!old_cmit || !new_cmit)
 			return error("Branch %s is missing commits.", b->name);
-		}
 
 		if (!in_merge_bases(old_cmit, new_cmit)) {
-			unlock_ref(lock);
 			warning("Not updating %s"
 				" (new tip %s does not contain %s)",
 				b->name, sha1_to_hex(b->sha1), sha1_to_hex(old_sha1));
 			return -1;
 		}
 	}
-	if (write_ref_sha1(lock, b->sha1, msg) < 0)
-		return error("Unable to update %s", b->name);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
+				   0, 1, &err) ||
+	    ref_transaction_commit(transaction, msg, &err)) {
+		ref_transaction_free(transaction);
+		error("%s", err.buf);
+		strbuf_release(&err);
+		return -1;
+	}
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	return 0;
 }
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:04 UTC · re: Jonathan Nieder · lore

[PATCH 10/22] branch.c: use ref transaction for all ref updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Apr 2014 16:21:53 -0700

Change create_branch to use a ref transaction when creating the new branch.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 branch.c | 31 +++++++++++++++++--------------
 1 file changed, 17 insertions(+), 14 deletions(-)

diff --git a/branch.c b/branch.c
index 660097b..37ac555 100644
--- a/branch.c
+++ b/branch.c
@@ -226,7 +226,6 @@ void create_branch(const char *head,
 		   int force, int reflog, int clobber_head,
 		   int quiet, enum branch_track track)
 {
-	struct ref_lock *lock = NULL;
 	struct commit *commit;
 	unsigned char sha1[20];
 	char *real_ref, msg[PATH_MAX + 20];
@@ -285,15 +284,6 @@ void create_branch(const char *head,
 		die(_("Not a valid branch point: '%s'."), start_name);
 	hashcpy(sha1, commit->object.sha1);
 
-	if (!dont_change_ref) {
-		lock = lock_any_ref_for_update(ref.buf, NULL, 0, NULL);
-		if (!lock)
-			die_errno(_("Failed to lock ref for update"));
-	}
-
-	if (reflog)
-		log_all_ref_updates = 1;
-
 	if (forcing)
 		snprintf(msg, sizeof msg, "branch: Reset to %s",
 			 start_name);
@@ -301,13 +291,26 @@ void create_branch(const char *head,
 		snprintf(msg, sizeof msg, "branch: Created from %s",
 			 start_name);
 
+	if (reflog)
+		log_all_ref_updates = 1;
+
+	if (!dont_change_ref) {
+		struct ref_transaction *transaction;
+		struct strbuf err = STRBUF_INIT;
+
+		transaction = ref_transaction_begin(&err);
+		if (!transaction ||
+		    ref_transaction_update(transaction, ref.buf, sha1,
+					   null_sha1, 0, !forcing, &err) ||
+		    ref_transaction_commit(transaction, msg, &err))
+			die("%s", err.buf);
+		ref_transaction_free(transaction);
+		strbuf_release(&err);
+	}
+
 	if (real_ref && track)
 		setup_tracking(ref.buf + 11, real_ref, track, quiet);
 
-	if (!dont_change_ref)
-		if (write_ref_sha1(lock, sha1, msg) < 0)
-			die_errno(_("Failed to write ref"));
-
 	strbuf_release(&ref);
 	free(real_ref);
 }

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:04 UTC · re: Jonathan Nieder · lore

[PATCH 11/22] refs.c: change update_ref to use a transaction

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 24 Apr 2014 16:36:55 -0700

Change the update_ref helper function to use a ref transaction internally.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 30 ++++++++++++++++++++++++++----
 1 file changed, 26 insertions(+), 4 deletions(-)

diff --git a/refs.c b/refs.c
index cc63056..a3532ab 100644
--- a/refs.c
+++ b/refs.c
@@ -3519,11 +3519,33 @@ int update_ref(const char *action, const char *refname,
 	       const unsigned char *sha1, const unsigned char *oldval,
 	       int flags, enum action_on_err onerr)
 {
-	struct ref_lock *lock;
-	lock = update_ref_lock(refname, oldval, flags, NULL, onerr);
-	if (!lock)
+	struct ref_transaction *t;
+	struct strbuf err = STRBUF_INIT;
+
+	t = ref_transaction_begin(&err);
+	if (!t ||
+	    ref_transaction_update(t, refname, sha1, oldval, flags,
+				   !!oldval, &err) ||
+	    ref_transaction_commit(t, action, &err)) {
+		const char *str = "update_ref failed for ref '%s': %s";
+
+		ref_transaction_free(t);
+		switch (onerr) {
+		case UPDATE_REFS_MSG_ON_ERR:
+			error(str, refname, err.buf);
+			break;
+		case UPDATE_REFS_DIE_ON_ERR:
+			die(str, refname, err.buf);
+			break;
+		case UPDATE_REFS_QUIET_ON_ERR:
+			break;
+		}
+		strbuf_release(&err);
 		return 1;
-	return update_ref_write(action, refname, sha1, lock, NULL, onerr);
+	}
+	strbuf_release(&err);
+	ref_transaction_free(t);
+	return 0;
 }
 
 static int ref_update_compare(const void *r1, const void *r2)

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:05 UTC · re: Jonathan Nieder · lore

[PATCH 12/22] receive-pack.c: use a reference transaction for updating the refs

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 14:36:15 -0700

Wrap all the ref updates inside a transaction.

Example, before:

 error: there are still refs under 'refs/heads/topic'
 remote: error: failed to lock refs/heads/topic
 To foo
  ! [remote rejected] HEAD -> topic (failed to lock)

After:

 error: there are still refs under 'refs/heads/topic'
 remote: error: Cannot lock the ref 'refs/heads/topic'.
 To foo
  ! [remote rejected] HEAD -> topic (failed to update ref)

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/receive-pack.c | 25 ++++++++++++++++---------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index c323081..224fadc 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -475,7 +475,6 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 	const char *namespaced_name;
 	unsigned char *old_sha1 = cmd->old_sha1;
 	unsigned char *new_sha1 = cmd->new_sha1;
-	struct ref_lock *lock;
 
 	/* only refs/... are allowed */
 	if (!starts_with(name, "refs/") || check_refname_format(name + 5, 0)) {
@@ -576,19 +575,27 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		return NULL; /* good */
 	}
 	else {
+		struct strbuf err = STRBUF_INIT;
+		struct ref_transaction *transaction;
+
 		if (shallow_update && si->shallow_ref[cmd->index] &&
 		    update_shallow_ref(cmd, si))
 			return "shallow error";
 
-		lock = lock_any_ref_for_update(namespaced_name, old_sha1,
-					       0, NULL);
-		if (!lock) {
-			rp_error("failed to lock %s", name);
-			return "failed to lock";
-		}
-		if (write_ref_sha1(lock, new_sha1, "push")) {
-			return "failed to write"; /* error() already called */
+		transaction = ref_transaction_begin(&err);
+		if (!transaction ||
+		    ref_transaction_update(transaction, namespaced_name,
+					   new_sha1, old_sha1, 0, 1, &err) ||
+		    ref_transaction_commit(transaction, "push", &err)) {
+			ref_transaction_free(transaction);
+
+			rp_error("%s", err.buf);
+			strbuf_release(&err);
+			return "failed to update ref";
 		}
+
+		ref_transaction_free(transaction);
+		strbuf_release(&err);
 		return NULL; /* good */
 	}
 }

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:06 UTC · re: Jonathan Nieder · lore

[PATCH 13/22] fast-import.c: use a ref transaction when dumping tags

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 15:23:58 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 fast-import.c | 29 +++++++++++++++++++++++------
 1 file changed, 23 insertions(+), 6 deletions(-)

diff --git a/fast-import.c b/fast-import.c
index 79160d5..e7f6e37 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1735,15 +1735,32 @@ static void dump_tags(void)
 {
 	static const char *msg = "fast-import";
 	struct tag *t;
-	struct ref_lock *lock;
-	char ref_name[PATH_MAX];
+	struct strbuf ref_name = STRBUF_INIT;
+	struct strbuf err = STRBUF_INIT;
+	struct ref_transaction *transaction;
 
+	transaction = ref_transaction_begin(&err);
+	if (!transaction) {
+		failure |= error("%s", err.buf);
+		goto cleanup;
+	}
 	for (t = first_tag; t; t = t->next_tag) {
-		sprintf(ref_name, "tags/%s", t->name);
-		lock = lock_ref_sha1(ref_name, NULL);
-		if (!lock || write_ref_sha1(lock, t->sha1, msg) < 0)
-			failure |= error("Unable to update %s", ref_name);
+		strbuf_reset(&ref_name);
+		strbuf_addf(&ref_name, "refs/tags/%s", t->name);
+
+		if (ref_transaction_update(transaction, ref_name.buf, t->sha1,
+					   NULL, 0, 0, &err)) {
+			failure |= error("%s", err.buf);
+			goto cleanup;
+		}
 	}
+	if (ref_transaction_commit(transaction, msg, &err))
+		failure |= error("%s", err.buf);
+
+ cleanup:
+	ref_transaction_free(transaction);
+	strbuf_release(&ref_name);
+	strbuf_release(&err);
 }
 
 static void dump_marks_helper(FILE *f,

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:07 UTC · re: Jonathan Nieder · lore

[PATCH 14/22] walker.c: use ref transaction for ref updates

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 17 Apr 2014 11:31:06 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 walker.c | 72 ++++++++++++++++++++++++++++++++++++----------------------------
 1 file changed, 41 insertions(+), 31 deletions(-)

diff --git a/walker.c b/walker.c
index 1dd86b8..b8a5441 100644
--- a/walker.c
+++ b/walker.c
@@ -251,40 +251,40 @@ void walker_targets_free(int targets, char **target, const char **write_ref)
 int walker_fetch(struct walker *walker, int targets, char **target,
 		 const char **write_ref, const char *write_ref_log_details)
 {
-	struct ref_lock **lock = xcalloc(targets, sizeof(struct ref_lock *));
+	struct strbuf refname = STRBUF_INIT;
+	struct strbuf err = STRBUF_INIT;
+	struct ref_transaction *transaction = NULL;
 	unsigned char *sha1 = xmalloc(targets * 20);
-	char *msg;
-	int ret;
-	int i;
+	char *msg = NULL;
+	int i, ret = -1;
 
 	save_commit_buffer = 0;
 
-	for (i = 0; i < targets; i++) {
-		if (!write_ref || !write_ref[i])
-			continue;
-
-		lock[i] = lock_ref_sha1(write_ref[i], NULL);
-		if (!lock[i]) {
-			error("Can't lock ref %s", write_ref[i]);
-			goto unlock_and_fail;
+	if (write_ref) {
+		transaction = ref_transaction_begin(&err);
+		if (!transaction) {
+			error("%s", err.buf);
+			goto done;
 		}
 	}
-
 	if (!walker->get_recover)
 		for_each_ref(mark_complete, NULL);
 
 	for (i = 0; i < targets; i++) {
 		if (interpret_target(walker, target[i], &sha1[20 * i])) {
 			error("Could not interpret response from server '%s' as something to pull", target[i]);
-			goto unlock_and_fail;
+			goto done;
 		}
 		if (process(walker, lookup_unknown_object(&sha1[20 * i])))
-			goto unlock_and_fail;
+			goto done;
 	}
 
 	if (loop(walker))
-		goto unlock_and_fail;
-
+		goto done;
+	if (!write_ref) {
+		ret = 0;
+		goto done;
+	}
 	if (write_ref_log_details) {
 		msg = xmalloc(strlen(write_ref_log_details) + 12);
 		sprintf(msg, "fetch from %s", write_ref_log_details);
@@ -292,23 +292,33 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 		msg = NULL;
 	}
 	for (i = 0; i < targets; i++) {
-		if (!write_ref || !write_ref[i])
+		if (!write_ref[i])
 			continue;
-		ret = write_ref_sha1(lock[i], &sha1[20 * i], msg ? msg : "fetch (unknown)");
-		lock[i] = NULL;
-		if (ret)
-			goto unlock_and_fail;
+		strbuf_reset(&refname);
+		strbuf_addf(&refname, "refs/%s", write_ref[i]);
+		if (ref_transaction_update(transaction, refname.buf,
+					   &sha1[20 * i], NULL, 0, 0,
+					   &err)) {
+			error("%s", err.buf);
+			goto done;
+		}
 	}
+	if (ref_transaction_commit(transaction,
+				   msg ? msg : "fetch (unknown)",
+				   &err)) {
+		error("%s", err.buf);
+		goto done;
+	}
+
+	ret = 0;
+
+done:
+	ref_transaction_free(transaction);
 	free(msg);
-
-	return 0;
-
-unlock_and_fail:
-	for (i = 0; i < targets; i++)
-		if (lock[i])
-			unlock_ref(lock[i]);
-
-	return -1;
+	free(sha1);
+	strbuf_release(&err);
+	strbuf_release(&refname);
+	return ret;
 }
 
 void walker_free(struct walker *walker)

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:08 UTC · re: Jonathan Nieder · lore

[PATCH 15/22] refs.c: make lock_ref_sha1 static

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 15:38:47 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 7 +++++--
 refs.h | 6 ------
 2 files changed, 5 insertions(+), 8 deletions(-)

diff --git a/refs.c b/refs.c
index a3532ab..d4cd44b 100644
--- a/refs.c
+++ b/refs.c
@@ -2069,7 +2069,10 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 	return logs_found;
 }
 
-/* This function should make sure errno is meaningful on error */
+/*
+ * Locks a "refs/" ref returning the lock on success and NULL on failure.
+ * On failure errno is set to something meaningful.
+ */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
 					    int flags, int *type_p)
@@ -2170,7 +2173,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	return NULL;
 }
 
-struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
+static struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
 {
 	char refpath[PATH_MAX];
 	if (check_refname_format(refname, 0))
diff --git a/refs.h b/refs.h
index 3f37c65..65dd593 100644
--- a/refs.h
+++ b/refs.h
@@ -170,12 +170,6 @@ extern int ref_exists(const char *);
  */
 extern int peel_ref(const char *refname, unsigned char *sha1);
 
-/*
- * Locks a "refs/" ref returning the lock on success and NULL on failure.
- * On failure errno is set to something meaningful.
- */
-extern struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1);
-
 /** Locks any ref (for 'HEAD' type refs). */
 #define REF_NODEREF	0x01
 /* errno is set to something meaningful on failure */

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:08 UTC · re: Jonathan Nieder · lore

[PATCH 16/22] refs.c: remove the update_ref_lock function

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 12:14:47 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 30 ++++++------------------------
 1 file changed, 6 insertions(+), 24 deletions(-)

diff --git a/refs.c b/refs.c
index d4cd44b..a4445a1 100644
--- a/refs.c
+++ b/refs.c
@@ -3336,24 +3336,6 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 	return retval;
 }
 
-static struct ref_lock *update_ref_lock(const char *refname,
-					const unsigned char *oldval,
-					int flags, int *type_p,
-					enum action_on_err onerr)
-{
-	struct ref_lock *lock;
-	lock = lock_any_ref_for_update(refname, oldval, flags, type_p);
-	if (!lock) {
-		const char *str = "Cannot lock the ref '%s'.";
-		switch (onerr) {
-		case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
-		case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
-		case UPDATE_REFS_QUIET_ON_ERR: break;
-		}
-	}
-	return lock;
-}
-
 static int update_ref_write(const char *action, const char *refname,
 			    const unsigned char *sha1, struct ref_lock *lock,
 			    struct strbuf *err, enum action_on_err onerr)
@@ -3603,12 +3585,12 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	for (i = 0; i < n; i++) {
 		struct ref_update *update = updates[i];
 
-		update->lock = update_ref_lock(update->refname,
-					       (update->have_old ?
-						update->old_sha1 : NULL),
-					       update->flags,
-					       &update->type,
-					       UPDATE_REFS_QUIET_ON_ERR);
+		update->lock = lock_any_ref_for_update(update->refname,
+						       (update->have_old ?
+							update->old_sha1 :
+							NULL),
+						       update->flags,
+						       &update->type);
 		if (!update->lock) {
 			if (err)
 				strbuf_addf(err, "Cannot lock the ref '%s'.",

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:08 UTC · re: Jonathan Nieder · lore

[PATCH 17/22] refs.c: remove the update_ref_write function

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 13:42:07 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 34 ++++++++--------------------------
 1 file changed, 8 insertions(+), 26 deletions(-)

diff --git a/refs.c b/refs.c
index a4445a1..a6b39ec 100644
--- a/refs.c
+++ b/refs.c
@@ -3336,25 +3336,6 @@ int for_each_reflog(each_ref_fn fn, void *cb_data)
 	return retval;
 }
 
-static int update_ref_write(const char *action, const char *refname,
-			    const unsigned char *sha1, struct ref_lock *lock,
-			    struct strbuf *err, enum action_on_err onerr)
-{
-	if (write_ref_sha1(lock, sha1, action) < 0) {
-		const char *str = "Cannot update the ref '%s'.";
-		if (err)
-			strbuf_addf(err, str, refname);
-
-		switch (onerr) {
-		case UPDATE_REFS_MSG_ON_ERR: error(str, refname); break;
-		case UPDATE_REFS_DIE_ON_ERR: die(str, refname); break;
-		case UPDATE_REFS_QUIET_ON_ERR: break;
-		}
-		return 1;
-	}
-	return 0;
-}
-
 /**
  * Information needed for a single ref update.  Set new_sha1 to the
  * new value or to zero to delete the ref.  To check the old value
@@ -3605,14 +3586,15 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 		struct ref_update *update = updates[i];
 
 		if (!is_null_sha1(update->new_sha1)) {
-			ret = update_ref_write(msg,
-					       update->refname,
-					       update->new_sha1,
-					       update->lock, err,
-					       UPDATE_REFS_QUIET_ON_ERR);
-			update->lock = NULL; /* freed by update_ref_write */
-			if (ret)
+			ret = write_ref_sha1(update->lock, update->new_sha1,
+					     msg);
+			update->lock = NULL; /* freed by write_ref_sha1 */
+			if (ret) {
+				if (err)
+					strbuf_addf(err, "Cannot update the ref '%s'.",
+						    update->refname);
 				goto cleanup;
+			}
 		}
 	}
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:09 UTC · re: Jonathan Nieder · lore

[PATCH 18/22] refs.c: remove lock_ref_sha1

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 29 Apr 2014 15:45:52 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 15 +++++----------
 1 file changed, 5 insertions(+), 10 deletions(-)

diff --git a/refs.c b/refs.c
index a6b39ec..fd67684 100644
--- a/refs.c
+++ b/refs.c
@@ -2173,15 +2173,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	return NULL;
 }
 
-static struct ref_lock *lock_ref_sha1(const char *refname, const unsigned char *old_sha1)
-{
-	char refpath[PATH_MAX];
-	if (check_refname_format(refname, 0))
-		return NULL;
-	strcpy(refpath, mkpath("refs/%s", refname));
-	return lock_ref_sha1_basic(refpath, old_sha1, 0, NULL);
-}
-
 struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
@@ -2391,8 +2382,12 @@ static void try_remove_empty_parents(char *name)
 /* make sure nobody touched the ref, and unlink */
 static void prune_ref(struct ref_to_prune *r)
 {
-	struct ref_lock *lock = lock_ref_sha1(r->name + 5, r->sha1);
+	struct ref_lock *lock;
 
+	if (check_refname_format(r->name + 5, 0))
+		return;
+
+	lock = lock_ref_sha1_basic(r->name, r->sha1, 0, NULL);
 	if (lock) {
 		unlink_or_warn(git_path("%s", r->name));
 		unlock_ref(lock);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:09 UTC · re: Jonathan Nieder · lore

[PATCH 19/22] refs.c: make prune_ref use a transaction to delete the ref

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 30 Apr 2014 09:03:36 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 28 +++++++++++++++++++++-------
 refs.h | 13 +++++++++++--
 2 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/refs.c b/refs.c
index fd67684..22eb3dd 100644
--- a/refs.c
+++ b/refs.c
@@ -25,6 +25,11 @@ static unsigned char refname_disposition[256] = {
 };
 
 /*
+ * Used as a flag to ref_transaction_delete when a loose ref is being
+ * pruned.
+ */
+#define REF_ISPRUNING	0x0100
+/*
  * Try to read one refname component from the front of refname.
  * Return the length of the component found, or -1 if the component is
  * not legal.  It is legal if it is something reasonable to have under
@@ -2382,17 +2387,25 @@ static void try_remove_empty_parents(char *name)
 /* make sure nobody touched the ref, and unlink */
 static void prune_ref(struct ref_to_prune *r)
 {
-	struct ref_lock *lock;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
 	if (check_refname_format(r->name + 5, 0))
 		return;
 
-	lock = lock_ref_sha1_basic(r->name, r->sha1, 0, NULL);
-	if (lock) {
-		unlink_or_warn(git_path("%s", r->name));
-		unlock_ref(lock);
-		try_remove_empty_parents(r->name);
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_delete(transaction, r->name, r->sha1,
+				   REF_ISPRUNING, 1, &err) ||
+	    ref_transaction_commit(transaction, NULL, &err)) {
+		ref_transaction_free(transaction);
+		error("%s", err.buf);
+		strbuf_release(&err);
+		return;
 	}
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
+	try_remove_empty_parents(r->name);
 }
 
 static void prune_refs(struct ref_to_prune *r)
@@ -3598,8 +3611,9 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 		struct ref_update *update = updates[i];
 
 		if (update->lock) {
-			delnames[delnum++] = update->lock->ref_name;
 			ret |= delete_ref_loose(update->lock, update->type);
+			if (!(update->flags & REF_ISPRUNING))
+				delnames[delnum++] = update->lock->ref_name;
 		}
 	}
 
diff --git a/refs.h b/refs.h
index 65dd593..69ef28c 100644
--- a/refs.h
+++ b/refs.h
@@ -170,9 +170,18 @@ extern int ref_exists(const char *);
  */
 extern int peel_ref(const char *refname, unsigned char *sha1);
 
-/** Locks any ref (for 'HEAD' type refs). */
+/*
+ * Flags controlling lock_any_ref_for_update(), ref_transaction_update(),
+ * ref_transaction_create(), etc.
+ * REF_NODEREF: act on the ref directly, instead of dereferencing
+ *              symbolic references.
+ *
+ * Flags >= 0x100 are reserved for internal use.
+ */
 #define REF_NODEREF	0x01
-/* errno is set to something meaningful on failure */
+/*
+ * This function sets errno to something meaningful on failure.
+ */
 extern struct ref_lock *lock_any_ref_for_update(const char *refname,
 						const unsigned char *old_sha1,
 						int flags, int *type_p);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:10 UTC · re: Jonathan Nieder · lore

[PATCH 20/22] refs.c: make delete_ref use a transaction

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 30 Apr 2014 09:22:45 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 35 ++++++++++++++---------------------
 1 file changed, 14 insertions(+), 21 deletions(-)

diff --git a/refs.c b/refs.c
index 22eb3dd..7235574 100644
--- a/refs.c
+++ b/refs.c
@@ -2548,11 +2548,6 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 	return ret;
 }
 
-static int repack_without_ref(const char *refname)
-{
-	return repack_without_refs(&refname, 1, NULL);
-}
-
 static int delete_ref_loose(struct ref_lock *lock, int flag)
 {
 	if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
@@ -2570,24 +2565,22 @@ static int delete_ref_loose(struct ref_lock *lock, int flag)
 
 int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 {
-	struct ref_lock *lock;
-	int ret = 0, flag = 0;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
 
-	lock = lock_ref_sha1_basic(refname, sha1, delopt, &flag);
-	if (!lock)
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_delete(transaction, refname, sha1, delopt,
+				   sha1 && !is_null_sha1(sha1), &err) ||
+	    ref_transaction_commit(transaction, NULL, &err)) {
+		error("%s", err.buf);
+		ref_transaction_free(transaction);
+		strbuf_release(&err);
 		return 1;
-	ret |= delete_ref_loose(lock, flag);
-
-	/* removing the loose one could have resurrected an earlier
-	 * packed one.  Also, if it was not loose we need to repack
-	 * without it.
-	 */
-	ret |= repack_without_ref(lock->ref_name);
-
-	unlink_or_warn(git_path("logs/%s", lock->ref_name));
-	clear_loose_ref_cache(&ref_cache);
-	unlock_ref(lock);
-	return ret;
+	}
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
+	return 0;
 }
 
 /*

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:10 UTC · re: Jonathan Nieder · lore

[PATCH 21/22] update-ref --stdin: narrow scope of err strbuf

 * errors piling up and being concatenated with no newline between
   them
 * errors unhandled in one function, to be later handled in another
 * concurrency issues, if this code starts using threads some day

No functional change intended.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
---
 builtin/update-ref.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 96a53b9..866bbee 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -16,7 +16,6 @@ static struct ref_transaction *transaction;
 
 static char line_termination = '\n';
 static int update_flags;
-static struct strbuf err = STRBUF_INIT;
 
 /*
  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
@@ -179,6 +178,7 @@ static int parse_next_sha1(struct strbuf *input, const char **next,
 
 static const char *parse_cmd_update(struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];
 	unsigned char old_sha1[20];
@@ -204,12 +204,14 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
 
 static const char *parse_cmd_create(struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];
 
@@ -232,12 +234,14 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
 
 static const char *parse_cmd_delete(struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char old_sha1[20];
 	int have_old;
@@ -264,12 +268,14 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
 
 static const char *parse_cmd_verify(struct strbuf *input, const char *next)
 {
+	struct strbuf err = STRBUF_INIT;
 	char *refname;
 	unsigned char new_sha1[20];
 	unsigned char old_sha1[20];
@@ -297,6 +303,7 @@ static const char *parse_cmd_verify(struct strbuf *input, const char *next)
 
 	update_flags = 0;
 	free(refname);
+	strbuf_release(&err);
 
 	return next;
 }
@@ -365,6 +372,8 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		die("Refusing to perform update with empty message.");
 
 	if (read_stdin) {
+		struct strbuf err = STRBUF_INIT;
+
 		transaction = ref_transaction_begin(&err);
 		if (!transaction)
 			die("%s", err.buf);

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 2, 2014, 21:11 UTC · re: Jonathan Nieder · lore

[PATCH 22/22] update-ref --stdin: pass transaction around explicitly

No functional change intended.

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Michael Haggerty <mhagger@alum.mit.edu>
---
Thanks for reading.

 builtin/update-ref.c | 27 +++++++++++++++------------
 1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 866bbee..54a48c0 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -12,8 +12,6 @@ static const char * const git_update_ref_usage[] = {
 	NULL
 };
 
-static struct ref_transaction *transaction;
-
 static char line_termination = '\n';
 static int update_flags;
 
@@ -176,7 +174,8 @@ static int parse_next_sha1(struct strbuf *input, const char **next,
  * depending on how line_termination is set.
  */
 
-static const char *parse_cmd_update(struct strbuf *input, const char *next)
+static const char *parse_cmd_update(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
@@ -209,7 +208,8 @@ static const char *parse_cmd_update(struct strbuf *input, const char *next)
 	return next;
 }
 
-static const char *parse_cmd_create(struct strbuf *input, const char *next)
+static const char *parse_cmd_create(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
@@ -239,7 +239,8 @@ static const char *parse_cmd_create(struct strbuf *input, const char *next)
 	return next;
 }
 
-static const char *parse_cmd_delete(struct strbuf *input, const char *next)
+static const char *parse_cmd_delete(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
@@ -273,7 +274,8 @@ static const char *parse_cmd_delete(struct strbuf *input, const char *next)
 	return next;
 }
 
-static const char *parse_cmd_verify(struct strbuf *input, const char *next)
+static const char *parse_cmd_verify(struct ref_transaction *transaction,
+				    struct strbuf *input, const char *next)
 {
 	struct strbuf err = STRBUF_INIT;
 	char *refname;
@@ -317,7 +319,7 @@ static const char *parse_cmd_option(struct strbuf *input, const char *next)
 	return next + 8;
 }
 
-static void update_refs_stdin(void)
+static void update_refs_stdin(struct ref_transaction *transaction)
 {
 	struct strbuf input = STRBUF_INIT;
 	const char *next;
@@ -332,13 +334,13 @@ static void update_refs_stdin(void)
 		else if (isspace(*next))
 			die("whitespace before command: %s", next);
 		else if (starts_with(next, "update "))
-			next = parse_cmd_update(&input, next + 7);
+			next = parse_cmd_update(transaction, &input, next + 7);
 		else if (starts_with(next, "create "))
-			next = parse_cmd_create(&input, next + 7);
+			next = parse_cmd_create(transaction, &input, next + 7);
 		else if (starts_with(next, "delete "))
-			next = parse_cmd_delete(&input, next + 7);
+			next = parse_cmd_delete(transaction, &input, next + 7);
 		else if (starts_with(next, "verify "))
-			next = parse_cmd_verify(&input, next + 7);
+			next = parse_cmd_verify(transaction, &input, next + 7);
 		else if (starts_with(next, "option "))
 			next = parse_cmd_option(&input, next + 7);
 		else
@@ -373,6 +375,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 
 	if (read_stdin) {
 		struct strbuf err = STRBUF_INIT;
+		struct ref_transaction *transaction;
 
 		transaction = ref_transaction_begin(&err);
 		if (!transaction)
@@ -381,7 +384,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 			usage_with_options(git_update_ref_usage, options);
 		if (end_null)
 			line_termination = '\0';
-		update_refs_stdin();
+		update_refs_stdin(transaction);
 		if (ref_transaction_commit(transaction, msg, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);

-- 
2.1.0.rc2.206.gedb03e5

Michael Haggerty· Aug 27, 2014, 21:53 UTC · re: Jonathan Nieder · lore

Using Gerrit to review Git patches (was: Re: Transaction patch series overview)

On 08/26/2014 02:03 AM, Jonathan Nieder wrote:

> Jonathan Nieder wrote:
> [...]
>> I've having trouble keeping track of how patches change, which patches
>> have been reviewed and which haven't, unaddressed comments, and so on,
>> so as an experiment I've pushed this part of the series to the Gerrit
>> server at
>>
>>  https://code-review.googlesource.com/#/q/topic:ref-transaction-1
> 
> Outcome of the experiment: patches gained some minor changes and then
> [...]
> 
> I found the web UI helpful in seeing how each patch evolved since I
> last looked at it.  Interdiff relative to the version in pu is below.
> I'm still hoping for a tweak in response to a minor comment and then I
> can put up a copy of the updated series to pull.

* Overall, I found it easier to review commits in Gerrit than on the
mailing list, especially a long patch series like this one that has seen
so much flux. It was easier to see the comments from all reviewers that
apply to a patch, which is difficult on the mailing list when comments
are scattered over the many iterations of the patch series. It was
easier to incrementally increase the context around a patch. It was easy
to use the copy-paste commands provided in the "download" menu to fetch
the commit that I was reviewing into my local Git repository, and from
there to build it or investigate it using other tools.

* The Gerrit interface is very busy. It was somewhat overwhelming to me
as a beginner. On the other hand, the help menus ("?" key) are good and
the keyboard shortcuts are convenient. I didn't have to read much
documentation to get started doing review in Gerrit, at least at a basic
level.

* During two of my big Gerrit sessions the website was very responsive
and pleasant to use. During the third, it was terribly slow, like 5 - 15
seconds per page update. If I had only experienced the slow behavior, I
would have rejected Gerrit immediately. I hope that the slow behavior
was a rare anomaly.

* Gerrit sends out an endless flood of emails that mostly seem pretty
useless to me. I wish it weren't so chatty and that its emails were
better organized.

* At one point a back-and-forth in a line comment grew into a more
general issue that was more appropriate for the mailing list. The
transition from Gerrit to mailing list was a bit awkward.

Michael

-- 
Michael Haggerty
mhagger@alum.mit.edu

Shawn Pearce· Aug 28, 2014, 05:07 UTC · re: Michael Haggerty · lore

Re: Using Gerrit to review Git patches (was: Re: Transaction patch series overview)

On Wed, Aug 27, 2014 at 2:53 PM, Michael Haggerty <mhagger@alum.mit.edu> wrote:

> On 08/26/2014 02:03 AM, Jonathan Nieder wrote:
>> Jonathan Nieder wrote:
>> [...]
>>> I've having trouble keeping track of how patches change, which patches
>>> have been reviewed and which haven't, unaddressed comments, and so on,
>>> so as an experiment I've pushed this part of the series to the Gerrit
>>> server at
>>>
>>>  https://code-review.googlesource.com/#/q/topic:ref-transaction-1
>>
>> Outcome of the experiment: patches gained some minor changes and then
>> [...]
>>
>> I found the web UI helpful in seeing how each patch evolved since I
>> last looked at it.  Interdiff relative to the version in pu is below.
>> I'm still hoping for a tweak in response to a minor comment and then I
>> can put up a copy of the updated series to pull.
>
> Thanks for organizing this "experiment". I was one of the guinea pigs
> :-) I have wanted to review more of Ronnie's patches (actually, all of
> them!) but have been overwhelmed by the number of iterations and the
> number of patch series flying around in parallel. I was also interested
> to try out Gerrit, which I haven't used before. So I took up Jonathan's
> invitation and reviewed the first patch series in Gerrit. Here are some
> of my first impressions.

> * Overall, I found it easier to review commits in Gerrit than on the
> mailing list, especially a long patch series like this one that has seen
> so much flux. It was easier to see the comments from all reviewers that
> apply to a patch, which is difficult on the mailing list when comments
> are scattered over the many iterations of the patch series. It was
> easier to incrementally increase the context around a patch. It was easy
> to use the copy-paste commands provided in the "download" menu to fetch
> the commit that I was reviewing into my local Git repository, and from
> there to build it or investigate it using other tools.
>
> * The Gerrit interface is very busy. It was somewhat overwhelming to me
> as a beginner.

> On the other hand, the help menus ("?" key) are good and
> the keyboard shortcuts are convenient. I didn't have to read much
> documentation to get started doing review in Gerrit, at least at a basic
> level.

Yay!

> * During two of my big Gerrit sessions the website was very responsive
> and pleasant to use. During the third, it was terribly slow, like 5 - 15
> seconds per page update. If I had only experienced the slow behavior, I
> would have rejected Gerrit immediately. I hope that the slow behavior
> was a rare anomaly.

> * Gerrit sends out an endless flood of emails that mostly seem pretty
> useless to me. I wish it weren't so chatty and that its emails were
> better organized.

Absolutely agree.

> * At one point a back-and-forth in a line comment grew into a more
> general issue that was more appropriate for the mailing list. The
> transition from Gerrit to mailing list was a bit awkward.

> So, overall I found it pleasant and efficient to review patches in
> Gerrit. I would welcome more such "experiments". It would have been even
> better if Gerrit would generate more useful notification emails.

Jonathan Nieder· Sep 11, 2014, 03:03 UTC · re: Jonathan Nieder · lore

[PATCH v21 0/19] rs/ref-transaction (Re: Transaction patch series overview)

Jonathan Nieder wrote:

> The next series from Ronnie's collection is available at
> https://code-review.googlesource.com/#/q/topic:ref-transaction in case
> someone wants a fresh series to look at.

These patches are also available from the git repository at

  git://repo.or.cz/git/jrn.git tags/rs/ref-transaction

"Use ref transactions", part 3

Ronnie explains:

	This is the third and final part of the original 48 patch
	series for basic transaction support.  This version implements
	some changes suggested by mhagger for the warn_if_unremovable
	changes.  It also adds a new patch "fix handling of badly
	named refs" that repairs the handling of badly named refs.

Jonathan Nieder (5):
  mv test: recreate mod/ directory instead of relying on stale copy
  branch -d: avoid repeated symref resolution
  refs.c: do not permit err == NULL
  lockfile: remove unable_to_lock_error
  ref_transaction_commit: bail out on failure to remove a ref

Ronnie Sahlberg (14):
  wrapper.c: remove/unlink_or_warn: simplify, treat ENOENT as success
  wrapper.c: add a new function unlink_or_msg
  refs.c: add an err argument to delete_ref_loose
  refs.c: pass the ref log message to _create/delete/update instead of
    _commit
  rename_ref: don't ask read_ref_full where the ref came from
  refs.c: move the check for valid refname to lock_ref_sha1_basic
  refs.c: call lock_ref_sha1_basic directly from commit
  refs.c: pass a skip list to name_conflict_fn
  refs.c: ref_transaction_commit: distinguish name conflicts from other
    errors
  fetch.c: change s_update_ref to use a ref transaction
  refs.c: make write_ref_sha1 static
  refs.c: change resolve_ref_unsafe reading argument to be a flags field
  refs.c: fix handling of badly named refs
  for-each-ref.c: improve message before aborting on broken ref

 branch.c                    |   6 +-
 builtin/blame.c             |   2 +-
 builtin/branch.c            |  19 ++-
 builtin/checkout.c          |   6 +-
 builtin/clone.c             |   2 +-
 builtin/commit.c            |   6 +-
 builtin/fetch.c             |  34 +++--
 builtin/fmt-merge-msg.c     |   2 +-
 builtin/for-each-ref.c      |  12 +-
 builtin/fsck.c              |   2 +-
 builtin/log.c               |   3 +-
 builtin/merge.c             |   2 +-
 builtin/notes.c             |   2 +-
 builtin/receive-pack.c      |   9 +-
 builtin/remote.c            |   5 +-
 builtin/replace.c           |   5 +-
 builtin/show-branch.c       |   6 +-
 builtin/symbolic-ref.c      |   2 +-
 builtin/tag.c               |   4 +-
 builtin/update-ref.c        |  16 ++-
 bundle.c                    |   2 +-
 cache.h                     |  31 +++--
 fast-import.c               |   8 +-
 git-compat-util.h           |  16 ++-
 http-backend.c              |   3 +-
 lockfile.c                  |  10 --
 notes-merge.c               |   2 +-
 reflog-walk.c               |   5 +-
 refs.c                      | 321 ++++++++++++++++++++++++++++++--------------
 refs.h                      |  18 ++-
 remote.c                    |  10 +-
 sequencer.c                 |   8 +-
 t/t1400-update-ref.sh       |  16 +++
 t/t1402-check-ref-format.sh |  48 +++++++
 t/t3200-branch.sh           |   9 ++
 t/t7001-mv.sh               |  15 ++-
 transport-helper.c          |   4 +-
 transport.c                 |   5 +-
 upload-pack.c               |   2 +-
 walker.c                    |   5 +-
 wrapper.c                   |  28 ++--
 wt-status.c                 |   2 +-
 42 files changed, 487 insertions(+), 226 deletions(-)
---
Changes since last appearance:

diff --git c/branch.c w/branch.c
index 76a8ec9..ba3e1c1 100644
--- c/branch.c
+++ w/branch.c
@@ -186,7 +186,7 @@ int validate_new_branchname(const char *name, struct strbuf *ref,
 		const char *head;
 		unsigned char sha1[20];
 
-		head = resolve_ref_unsafe("HEAD", sha1, 0, NULL);
+		head = resolve_ref_unsafe("HEAD", sha1, NULL, 0);
 		if (!is_bare_repository() && head && !strcmp(head, ref->buf))
 			die(_("Cannot force update the current branch."));
 	}
diff --git c/builtin/blame.c w/builtin/blame.c
index 1568bd8..b8bec0a 100644
--- c/builtin/blame.c
+++ w/builtin/blame.c
@@ -2292,7 +2292,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	commit->object.type = OBJ_COMMIT;
 	parent_tail = &commit->parents;
 
-	if (!resolve_ref_unsafe("HEAD", head_sha1, RESOLVE_REF_READING, NULL))
+	if (!resolve_ref_unsafe("HEAD", head_sha1, NULL, RESOLVE_REF_READING))
 		die("no such ref: HEAD");
 
 	parent_tail = append_parent(parent_tail, head_sha1);
diff --git c/builtin/branch.c w/builtin/branch.c
index 5c95656..5d5bc56 100644
--- c/builtin/branch.c
+++ w/builtin/branch.c
@@ -130,7 +130,7 @@ static int branch_merged(int kind, const char *name,
 		    branch->merge[0]->dst &&
 		    (reference_name = reference_name_to_free =
 		     resolve_refdup(branch->merge[0]->dst, sha1,
-				    RESOLVE_REF_READING, NULL)) != NULL)
+				    NULL, RESOLVE_REF_READING)) != NULL)
 			reference_rev = lookup_commit_reference(sha1);
 	}
 	if (!reference_rev)
@@ -234,10 +234,13 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		free(name);
 
 		name = mkpathdup(fmt, bname.buf);
-		target = resolve_ref_unsafe(name, sha1,
-					    RESOLVE_REF_ALLOW_BAD_NAME, &flags);
+		target = resolve_ref_unsafe(name, sha1, &flags,
+					    RESOLVE_REF_READING
+					    | RESOLVE_REF_NODEREF
+					    | RESOLVE_REF_ALLOW_BAD_NAME);
 		if (!target ||
-		    (!(flags & REF_ISSYMREF) && is_null_sha1(sha1))) {
+		    (!(flags & (REF_ISSYMREF|REF_ISBROKEN)) &&
+		     is_null_sha1(sha1))) {
 			error(remote_branch
 			      ? _("remote branch '%s' not found.")
 			      : _("branch '%s' not found."), bname.buf);
@@ -245,14 +248,14 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 			continue;
 		}
 
-		if (!(flags & REF_ISSYMREF) &&
+		if (!(flags & (REF_ISSYMREF|REF_ISBROKEN)) &&
 		    check_branch_commit(bname.buf, name, sha1, head_rev, kinds,
 					force)) {
 			ret = 1;
 			continue;
 		}
 
-		if (delete_ref(name, sha1, REF_NODEREF)) {
+		if (delete_ref(name, sha1, REF_NODEREF|REF_BADNAMEOK)) {
 			error(remote_branch
 			      ? _("Error deleting remote branch '%s'")
 			      : _("Error deleting branch '%s'"),
@@ -298,7 +301,7 @@ static char *resolve_symref(const char *src, const char *prefix)
 	int flag;
 	const char *dst, *cp;
 
-	dst = resolve_ref_unsafe(src, sha1, 0, &flag);
+	dst = resolve_ref_unsafe(src, sha1, &flag, 0);
 	if (!(dst && (flag & REF_ISSYMREF)))
 		return NULL;
 	if (prefix && (cp = skip_prefix(dst, prefix)))
@@ -864,7 +867,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 	track = git_branch_track;
 
-	head = resolve_refdup("HEAD", head_sha1, 0, NULL);
+	head = resolve_refdup("HEAD", head_sha1, NULL, 0);
 	if (!head)
 		die(_("Failed to resolve HEAD as a valid ref."));
 	if (!strcmp(head, "HEAD")) {
diff --git c/builtin/checkout.c w/builtin/checkout.c
index f1dc56e..64af1f7 100644
--- c/builtin/checkout.c
+++ w/builtin/checkout.c
@@ -356,7 +356,7 @@ static int checkout_paths(const struct checkout_opts *opts,
 	    commit_locked_index(lock_file))
 		die(_("unable to write new index file"));
 
-	read_ref_full("HEAD", rev, 0, &flag);
+	read_ref_full("HEAD", rev, &flag, 0);
 	head = lookup_commit_reference_gently(rev, 1);
 
 	errs |= post_checkout_hook(head, head, 0);
@@ -771,7 +771,7 @@ static int switch_branches(const struct checkout_opts *opts,
 	unsigned char rev[20];
 	int flag, writeout_error = 0;
 	memset(&old, 0, sizeof(old));
-	old.path = path_to_free = resolve_refdup("HEAD", rev, 0, &flag);
+	old.path = path_to_free = resolve_refdup("HEAD", rev, &flag, 0);
 	old.commit = lookup_commit_reference_gently(rev, 1);
 	if (!(flag & REF_ISSYMREF))
 		old.path = NULL;
@@ -1068,7 +1068,7 @@ static int checkout_branch(struct checkout_opts *opts,
 		unsigned char rev[20];
 		int flag;
 
-		if (!read_ref_full("HEAD", rev, 0, &flag) &&
+		if (!read_ref_full("HEAD", rev, &flag, 0) &&
 		    (flag & REF_ISSYMREF) && is_null_sha1(rev))
 			return switch_unborn_to_new_branch(opts);
 	}
diff --git c/builtin/clone.c w/builtin/clone.c
index f7307e6..12a78e1 100644
--- c/builtin/clone.c
+++ w/builtin/clone.c
@@ -622,7 +622,7 @@ static int checkout(void)
 	if (option_no_checkout)
 		return 0;
 
-	head = resolve_refdup("HEAD", sha1, RESOLVE_REF_READING, NULL);
+	head = resolve_refdup("HEAD", sha1, NULL, RESOLVE_REF_READING);
 	if (!head) {
 		warning(_("remote HEAD refers to nonexistent ref, "
 			  "unable to checkout.\n"));
diff --git c/builtin/commit.c w/builtin/commit.c
index d23e876..3536330 100644
--- c/builtin/commit.c
+++ w/builtin/commit.c
@@ -1468,7 +1468,7 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref_unsafe("HEAD", junk_sha1, 0, NULL);
+	head = resolve_ref_unsafe("HEAD", junk_sha1, NULL, 0);
 	printf("[%s%s ",
 		starts_with(head, "refs/heads/") ?
 			head + 11 :
diff --git c/builtin/fetch.c w/builtin/fetch.c
index 52f1ebc..2e3bc73 100644
--- c/builtin/fetch.c
+++ w/builtin/fetch.c
@@ -398,6 +398,7 @@ static int s_update_ref(const char *action,
 		goto fail;
 
 	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	return 0;
 fail:
 	ref_transaction_free(transaction);
@@ -686,9 +687,10 @@ static int store_updated_refs(const char *raw_url, const char *remote_name,
 			}
 		}
 	}
+
 	if (rc & STORE_REF_ERROR_DF_CONFLICT)
 		error(_("some local refs could not be updated; try running\n"
-		      "'git remote prune %s' to remove any old, conflicting "
+		      " 'git remote prune %s' to remove any old, conflicting "
 		      "branches"), remote_name);
 
  abort:
diff --git c/builtin/fmt-merge-msg.c w/builtin/fmt-merge-msg.c
index d8ab177..b2355ad 100644
--- c/builtin/fmt-merge-msg.c
+++ w/builtin/fmt-merge-msg.c
@@ -602,7 +602,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 
 	/* get current branch */
 	current_branch = current_branch_to_free =
-		resolve_refdup("HEAD", head_sha1, RESOLVE_REF_READING, NULL);
+		resolve_refdup("HEAD", head_sha1, NULL, RESOLVE_REF_READING);
 	if (!current_branch)
 		die("No current branch");
 	if (starts_with(current_branch, "refs/heads/"))
diff --git c/builtin/for-each-ref.c w/builtin/for-each-ref.c
index 7c5b479..090390c 100644
--- c/builtin/for-each-ref.c
+++ w/builtin/for-each-ref.c
@@ -650,7 +650,7 @@ static void populate_value(struct refinfo *ref)
 	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
 		unsigned char unused1[20];
 		ref->symref = resolve_refdup(ref->refname, unused1,
-					     RESOLVE_REF_READING, NULL);
+					     NULL, RESOLVE_REF_READING);
 		if (!ref->symref)
 			ref->symref = "";
 	}
@@ -709,7 +709,7 @@ static void populate_value(struct refinfo *ref)
 			unsigned char sha1[20];
 
 			head = resolve_ref_unsafe("HEAD", sha1,
-						  RESOLVE_REF_READING, NULL);
+						  NULL, RESOLVE_REF_READING);
 			if (!strcmp(ref->refname, head))
 				v->s = "*";
 			else
@@ -853,6 +853,12 @@ static int grab_single_ref(const char *refname, const unsigned char *sha1, int f
 	struct refinfo *ref;
 	int cnt;
 
+	if ((flag & REF_ISBROKEN) &&
+	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+		  warning("ignoring ref with broken name %s", refname);
+		  return 0;
+	}
+
 	if (*cb->grab_pattern) {
 		const char **pattern;
 		int namelen = strlen(refname);
diff --git c/builtin/fsck.c w/builtin/fsck.c
index fc150c8..506e32b 100644
--- c/builtin/fsck.c
+++ w/builtin/fsck.c
@@ -560,7 +560,7 @@ static int fsck_head_link(void)
 	if (verbose)
 		fprintf(stderr, "Checking HEAD link\n");
 
-	head_points_at = resolve_ref_unsafe("HEAD", head_sha1, 0, &flag);
+	head_points_at = resolve_ref_unsafe("HEAD", head_sha1, &flag, 0);
 	if (!head_points_at)
 		return error("Invalid HEAD");
 	if (!strcmp(head_points_at, "HEAD"))
diff --git c/builtin/log.c w/builtin/log.c
index 92db809..230a9ef 100644
--- c/builtin/log.c
+++ w/builtin/log.c
@@ -1395,8 +1395,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		if (check_head) {
 			unsigned char sha1[20];
 			const char *ref;
-			ref = resolve_ref_unsafe("HEAD", sha1,
-						 RESOLVE_REF_READING, NULL);
+			ref = resolve_ref_unsafe("HEAD", sha1, NULL,
+						 RESOLVE_REF_READING);
 			if (ref && starts_with(ref, "refs/heads/"))
 				branch_name = xstrdup(ref + strlen("refs/heads/"));
 			else
diff --git c/builtin/merge.c w/builtin/merge.c
index 428ca24..d262279 100644
--- c/builtin/merge.c
+++ w/builtin/merge.c
@@ -1108,7 +1108,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * Check if we are _not_ on a detached HEAD, i.e. if there is a
 	 * current branch.
 	 */
-	branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
+	branch = branch_to_free = resolve_refdup("HEAD", head_sha1, &flag, 0);
 	if (branch && starts_with(branch, "refs/heads/"))
 		branch += 11;
 	if (!branch || is_null_sha1(head_sha1))
diff --git c/builtin/notes.c w/builtin/notes.c
index 820c341..16df78c 100644
--- c/builtin/notes.c
+++ w/builtin/notes.c
@@ -703,7 +703,7 @@ static int merge_commit(struct notes_merge_options *o)
 	init_notes(t, "NOTES_MERGE_PARTIAL", combine_notes_overwrite, 0);
 
 	o->local_ref = local_ref_to_free =
-		resolve_refdup("NOTES_MERGE_REF", sha1, 0, NULL);
+		resolve_refdup("NOTES_MERGE_REF", sha1, NULL, 0);
 	if (!o->local_ref)
 		die("Failed to resolve NOTES_MERGE_REF");
 
diff --git c/builtin/receive-pack.c w/builtin/receive-pack.c
index d1f4cf7..555a4a6 100644
--- c/builtin/receive-pack.c
+++ w/builtin/receive-pack.c
@@ -656,7 +656,7 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	int flag;
 
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
-	dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
+	dst_name = resolve_ref_unsafe(buf.buf, sha1, &flag, 0);
 	strbuf_release(&buf);
 
 	if (!(flag & REF_ISSYMREF))
@@ -817,7 +817,7 @@ static void execute_commands(struct command *commands,
 	check_aliased_updates(commands);
 
 	free(head_name_to_free);
-	head_name = head_name_to_free = resolve_refdup("HEAD", sha1, 0, NULL);
+	head_name = head_name_to_free = resolve_refdup("HEAD", sha1, NULL, 0);
 
 	checked_connectivity = 1;
 	for (cmd = commands; cmd; cmd = cmd->next) {
diff --git c/builtin/remote.c w/builtin/remote.c
index be8ebac..6eaeee7 100644
--- c/builtin/remote.c
+++ w/builtin/remote.c
@@ -568,8 +568,8 @@ static int read_remote_branches(const char *refname,
 	strbuf_addf(&buf, "refs/remotes/%s/", rename->old);
 	if (starts_with(refname, buf.buf)) {
 		item = string_list_append(rename->remote_branches, xstrdup(refname));
-		symref = resolve_ref_unsafe(refname, orig_sha1,
-					    RESOLVE_REF_READING, &flag);
+		symref = resolve_ref_unsafe(refname, orig_sha1, &flag,
+					    RESOLVE_REF_READING);
 		if (flag & REF_ISSYMREF)
 			item->util = xstrdup(symref);
 		else
@@ -705,7 +705,7 @@ static int mv(int argc, const char **argv)
 		int flag = 0;
 		unsigned char sha1[20];
 
-		read_ref_full(item->string, sha1, RESOLVE_REF_READING, &flag);
+		read_ref_full(item->string, sha1, &flag, RESOLVE_REF_READING);
 		if (!(flag & REF_ISSYMREF))
 			continue;
 		if (delete_ref(item->string, NULL, REF_NODEREF))
diff --git c/builtin/replace.c w/builtin/replace.c
index df060f8..9d03b84 100644
--- c/builtin/replace.c
+++ w/builtin/replace.c
@@ -170,7 +170,7 @@ static int replace_object_sha1(const char *object_ref,
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, ref, repl, prev,
-				   0, !is_null_sha1(prev), NULL, &err) ||
+				   0, 1, NULL, &err) ||
 	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 
diff --git c/builtin/show-branch.c w/builtin/show-branch.c
index a9a5eb3..ef6ea52 100644
--- c/builtin/show-branch.c
+++ w/builtin/show-branch.c
@@ -727,8 +727,8 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		if (ac == 0) {
 			static const char *fake_av[2];
 
-			fake_av[0] = resolve_refdup("HEAD", sha1,
-						    RESOLVE_REF_READING, NULL);
+			fake_av[0] = resolve_refdup("HEAD", sha1, NULL,
+						    RESOLVE_REF_READING);
 			fake_av[1] = NULL;
 			av = fake_av;
 			ac = 1;
@@ -790,8 +790,8 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		}
 	}
 
-	head_p = resolve_ref_unsafe("HEAD", head_sha1,
-				    RESOLVE_REF_READING, NULL);
+	head_p = resolve_ref_unsafe("HEAD", head_sha1, NULL,
+				    RESOLVE_REF_READING);
 	if (head_p) {
 		head_len = strlen(head_p);
 		memcpy(head, head_p, head_len + 1);
diff --git c/builtin/symbolic-ref.c w/builtin/symbolic-ref.c
index b6a711d..1dd04af 100644
--- c/builtin/symbolic-ref.c
+++ w/builtin/symbolic-ref.c
@@ -13,7 +13,7 @@ static int check_symref(const char *HEAD, int quiet, int shorten, int print)
 {
 	unsigned char sha1[20];
 	int flag;
-	const char *refname = resolve_ref_unsafe(HEAD, sha1, 0, &flag);
+	const char *refname = resolve_ref_unsafe(HEAD, sha1, &flag, 0);
 
 	if (!refname)
 		die("No such ref: %s", HEAD);
diff --git c/builtin/update-ref.c w/builtin/update-ref.c
index 6c9be05..e379fdd 100644
--- c/builtin/update-ref.c
+++ w/builtin/update-ref.c
@@ -419,7 +419,8 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 	if (no_deref)
 		flags = REF_NODEREF;
 	if (delete)
-		return delete_ref(refname, oldval ? oldsha1 : NULL, flags);
+		return delete_ref(refname, oldval ? oldsha1 : NULL,
+				  flags|REF_BADNAMEOK);
 	else
 		return update_ref(msg, refname, sha1, oldval ? oldsha1 : NULL,
 				  flags, UPDATE_REFS_DIE_ON_ERR);
diff --git c/bundle.c w/bundle.c
index 8aaf5f8..32dd2f7 100644
--- c/bundle.c
+++ w/bundle.c
@@ -311,7 +311,7 @@ int create_bundle(struct bundle_header *header, const char *path,
 			continue;
 		if (dwim_ref(e->name, strlen(e->name), sha1, &ref) != 1)
 			continue;
-		if (read_ref_full(e->name, sha1, RESOLVE_REF_READING, &flag))
+		if (read_ref_full(e->name, sha1, &flag, RESOLVE_REF_READING))
 			flag = 0;
 		display_ref = (flag & REF_ISSYMREF) ? e->name : ref;
 
diff --git c/cache.h w/cache.h
index 3a4b087..995729f 100644
--- c/cache.h
+++ w/cache.h
@@ -558,7 +558,6 @@ struct lock_file {
 };
 #define LOCK_DIE_ON_ERROR 1
 #define LOCK_NODEREF 2
-extern int unable_to_lock_error(const char *path, int err);
 extern void unable_to_lock_message(const char *path, int err,
 				   struct strbuf *buf);
 extern NORETURN void unable_to_lock_index_die(const char *path, int err);
@@ -948,7 +947,7 @@ extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 
 extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
 extern int read_ref_full(const char *refname, unsigned char *sha1,
-			 int flags, int *ref_flag);
+			 int *flags, int resolve_flags);
 extern int read_ref(const char *refname, unsigned char *sha1);
 
 /*
@@ -970,21 +969,27 @@ extern int read_ref(const char *refname, unsigned char *sha1);
  *   "writing" to the ref, the return value is the name of the ref
  *   that will actually be created or changed.
  *
- * If ref_flag is non-NULL, set the value that it points to the
+ * If flags is non-NULL, set the value that it points to the
  * combination of REF_ISPACKED (if the reference was found among the
- * packed references) and REF_ISSYMREF (if the initial reference was a
- * symbolic reference).
+ * packed references), REF_ISSYMREF (if the initial reference was a
+ * symbolic reference) and REF_ISBROKEN (if the ref is malformed).
  *
  * If ref is not a properly-formatted, normalized reference, return
  * NULL.  If more than MAXDEPTH recursive symbolic lookups are needed,
  * give up and return NULL.
  *
- * errno is set to something meaningful on error.
+ * RESOLVE_REF_ALLOW_BAD_NAME disables most of the ref name checking except
+ * for names that are absolute paths or contain ".." components. For both
+ * these cases the function will return NULL and set errno to EINVAL.
+ * If the name is bad then the function will set the REF_ISBROKEN flag and
+ * return the name, if the ref exists, or NULL, if it does not.
+ * When this flag is set, any badly named refs will resolve to nullsha1.
  */
-#define RESOLVE_REF_READING        0x01
-#define RESOLVE_REF_ALLOW_BAD_NAME 0x02
-extern const char *resolve_ref_unsafe(const char *ref, unsigned char *sha1, int flags, int *ref_flag);
-extern char *resolve_refdup(const char *ref, unsigned char *sha1, int flags, int *ref_flag);
+#define RESOLVE_REF_READING 0x01
+#define RESOLVE_REF_NODEREF 0x02
+#define RESOLVE_REF_ALLOW_BAD_NAME 0x04
+extern const char *resolve_ref_unsafe(const char *ref, unsigned char *sha1, int *flags, int resolve_flags);
+extern char *resolve_refdup(const char *ref, unsigned char *sha1, int *flags, int resolve_flags);
 
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
diff --git c/git-compat-util.h w/git-compat-util.h
index 426bc98..5ee140c 100644
--- c/git-compat-util.h
+++ w/git-compat-util.h
@@ -307,6 +307,8 @@ extern char *gitbasename(char *);
 
 #include "wildmatch.h"
 
+struct strbuf;
+
 /* General helper functions */
 extern void vreportf(const char *prefix, const char *err, va_list params);
 extern void vwritef(int fd, const char *prefix, const char *err, va_list params);
@@ -704,19 +706,23 @@ void git_qsort(void *base, size_t nmemb, size_t size,
 #endif
 #endif
 
-#include "strbuf.h"
-
 /*
  * Preserves errno, prints a message, but gives no warning for ENOENT.
- * Always returns the return value of unlink(2).
+ * Returns 0 on success which includes trying to unlink an object that does
+ * not exist.
  */
 int unlink_or_warn(const char *path);
-/*
- * Like unlink_or_warn but populates a strbuf
- */
+ /*
+  * Tries to unlink file.  Returns 0 if unlink succeeded
+  * or the file already didn't exist.  Returns -1 and
+  * appends a message to err suitable for
+  * 'error("%s", err->buf)' on error.
+  */
 int unlink_or_msg(const char *file, struct strbuf *err);
 /*
- * Likewise for rmdir(2).
+ * Preserves errno, prints a message, but gives no warning for ENOENT.
+ * Returns 0 on success which includes trying to remove a directory that does
+ * not exist.
  */
 int rmdir_or_warn(const char *path);
 /*
diff --git c/http-backend.c w/http-backend.c
index 059f790..8f94f9b 100644
--- c/http-backend.c
+++ w/http-backend.c
@@ -418,7 +418,7 @@ static int show_head_ref(const char *refname, const unsigned char *sha1,
 	if (flag & REF_ISSYMREF) {
 		unsigned char unused[20];
 		const char *target = resolve_ref_unsafe(refname, unused,
-						RESOLVE_REF_READING, NULL);
+						NULL, RESOLVE_REF_READING);
 		const char *target_nons = strip_namespace(target);
 
 		strbuf_addf(buf, "ref: %s\n", target_nons);
diff --git c/lockfile.c w/lockfile.c
index a921d77..dbd4101 100644
--- c/lockfile.c
+++ w/lockfile.c
@@ -176,16 +176,6 @@ void unable_to_lock_message(const char *path, int err, struct strbuf *buf)
 			    absolute_path(path), strerror(err));
 }
 
-int unable_to_lock_error(const char *path, int err)
-{
-	struct strbuf buf = STRBUF_INIT;
-
-	unable_to_lock_message(path, err, &buf);
-	error("%s", buf.buf);
-	strbuf_release(&buf);
-	return -1;
-}
-
 NORETURN void unable_to_lock_index_die(const char *path, int err)
 {
 	struct strbuf buf = STRBUF_INIT;
diff --git c/notes-merge.c w/notes-merge.c
index 94a1a8a..ffca602 100644
--- c/notes-merge.c
+++ w/notes-merge.c
@@ -549,7 +549,7 @@ int notes_merge(struct notes_merge_options *o,
 	       o->local_ref, o->remote_ref);
 
 	/* Dereference o->local_ref into local_sha1 */
-	if (read_ref_full(o->local_ref, local_sha1, 0, NULL))
+	if (read_ref_full(o->local_ref, local_sha1, NULL, 0))
 		die("Failed to resolve local notes ref '%s'", o->local_ref);
 	else if (!check_refname_format(o->local_ref, 0) &&
 		is_null_sha1(local_sha1))
diff --git c/reflog-walk.c w/reflog-walk.c
index d80a42a..feeaf0a 100644
--- c/reflog-walk.c
+++ w/reflog-walk.c
@@ -48,8 +48,8 @@ static struct complete_reflogs *read_complete_reflog(const char *ref)
 		unsigned char sha1[20];
 		const char *name;
 		void *name_to_free;
-		name = name_to_free = resolve_refdup(ref, sha1,
-						     RESOLVE_REF_READING, NULL);
+		name = name_to_free = resolve_refdup(ref, sha1, NULL,
+						     RESOLVE_REF_READING);
 		if (name) {
 			for_each_reflog_ent(name, read_one_reflog, reflogs);
 			free(name_to_free);
@@ -175,7 +175,7 @@ int add_reflog_for_walk(struct reflog_walk_info *info,
 		if (*branch == '\0') {
 			unsigned char sha1[20];
 			free(branch);
-			branch = resolve_refdup("HEAD", sha1, 0, NULL);
+			branch = resolve_refdup("HEAD", sha1, NULL, 0);
 			if (!branch)
 				die ("No current branch");
 
diff --git c/refs.c w/refs.c
index b14bbf0..3b27758 100644
--- c/refs.c
+++ w/refs.c
@@ -281,11 +281,15 @@ static struct ref_dir *get_ref_dir(struct ref_entry *entry)
 }
 
 static struct ref_entry *create_ref_entry(const char *refname,
-					  const unsigned char *sha1, int flag)
+					  const unsigned char *sha1, int flag,
+					  int check_name)
 {
 	int len;
 	struct ref_entry *ref;
 
+	if (check_name &&
+	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
+		die("Reference has invalid format: '%s'", refname);
 	len = strlen(refname) + 1;
 	ref = xmalloc(sizeof(struct ref_entry) + len);
 	hashcpy(ref->u.value.sha1, sha1);
@@ -798,17 +802,16 @@ static int names_conflict(const char *refname1, const char *refname2)
 struct name_conflict_cb {
 	const char *refname;
 	const char *conflicting_refname;
-	const char **skip;
-	int skipnum;
+	struct string_list *skiplist;
 };
 
 static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
 {
 	struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
-	int i;
-	for (i = 0; i < data->skipnum; i++)
-		if (!strcmp(entry->name, data->skip[i]))
-			return 0;
+
+	if (data->skiplist &&
+	    string_list_has_string(data->skiplist, entry->name))
+		return 0;
 	if (names_conflict(data->refname, entry->name)) {
 		data->conflicting_refname = entry->name;
 		return 1;
@@ -821,18 +824,17 @@ static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
  * conflicting with the name of an existing reference in dir.  If
  * oldrefname is non-NULL, ignore potential conflicts with oldrefname
  * (e.g., because oldrefname is scheduled for deletion in the same
- * operation). skip contains a list of refs we want to skip checking for
- * conflicts with.
+ * operation). skiplist contains a list of refs we want to skip checking for
+ * conflicts with. skiplist must be sorted.
  */
 static int is_refname_available(const char *refname,
 				struct ref_dir *dir,
-				const char **skip, int skipnum)
+				struct string_list *skiplist)
 {
 	struct name_conflict_cb data;
 	data.refname = refname;
 	data.conflicting_refname = NULL;
-	data.skip = skip;
-	data.skipnum = skipnum;
+	data.skiplist = skiplist;
 
 	sort_ref_dir(dir);
 	if (do_for_each_entry_in_dir(dir, 0, name_conflict_fn, &data)) {
@@ -1062,8 +1064,9 @@ static void read_packed_refs(FILE *f, struct ref_dir *dir)
 
 			if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT)) {
 				flag |= REF_ISBROKEN;
+				hashclr(sha1);
 			}
-			last = create_ref_entry(refname, sha1, flag);
+			last = create_ref_entry(refname, sha1, flag, 0);
 			if (peeled == PEELED_FULLY ||
 			    (peeled == PEELED_TAGS && starts_with(refname, "refs/tags/")))
 				last->flag |= REF_KNOWS_PEELED;
@@ -1136,10 +1139,8 @@ void add_packed_ref(const char *refname, const unsigned char *sha1)
 
 	if (!packed_ref_cache->lock)
 		die("internal error: packed refs not locked");
-	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT))
-		die("Reference has invalid format: '%s'", refname);
 	add_ref(get_packed_ref_dir(packed_ref_cache),
-		create_ref_entry(refname, sha1, REF_ISPACKED));
+		create_ref_entry(refname, sha1, REF_ISPACKED, 1));
 }
 
 /*
@@ -1197,17 +1198,19 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 					hashclr(sha1);
 					flag |= REF_ISBROKEN;
 				}
-			} else if (read_ref_full(refname.buf, sha1,
-						 RESOLVE_REF_READING, &flag)) {
+			} else if (read_ref_full(refname.buf, sha1, &flag,
+						 RESOLVE_REF_READING)) {
 				hashclr(sha1);
 				flag |= REF_ISBROKEN;
 			}
-			if (check_refname_format(refname.buf, REFNAME_ALLOW_ONELEVEL|REFNAME_DOT_COMPONENT)) {
+			if (check_refname_format(refname.buf,
+						 REFNAME_ALLOW_ONELEVEL|
+						 REFNAME_DOT_COMPONENT)) {
 				hashclr(sha1);
 				flag |= REF_ISBROKEN;
 			}
 			add_entry_to_dir(dir,
-					 create_ref_entry(refname.buf, sha1, flag));
+					 create_ref_entry(refname.buf, sha1, flag, 0));
 		}
 		strbuf_setlen(&refname, dirnamelen);
 	}
@@ -1353,21 +1356,40 @@ static const char *handle_missing_loose_ref(const char *refname,
 	}
 }
 
+static int escapes_cwd(const char *path) {
+	char *buf;
+	int result;
+
+	if (is_absolute_path(path))
+		return 1;
+	buf = xmalloc(strlen(path) + 1);
+	result = normalize_path_copy(buf, path);
+	free(buf);
+	return result;
+}
+
 /* This function needs to return a meaningful errno on failure */
-const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int flags, int *ref_flag)
+const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int *flags, int resolve_flags)
 {
 	int depth = MAXDEPTH;
 	ssize_t len;
 	char buffer[256];
 	static char refname_buffer[256];
+	int bad_name = 0;
 
-	if (ref_flag)
-		*ref_flag = 0;
+	if (flags)
+		*flags = 0;
 
-	if (!(flags & RESOLVE_REF_ALLOW_BAD_NAME) &&
-	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
-		errno = EINVAL;
-		return NULL;
+	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+		if (!(resolve_flags & RESOLVE_REF_ALLOW_BAD_NAME) ||
+		    escapes_cwd(refname)) {
+			errno = EINVAL;
+			return NULL;
+		}
+		hashclr(sha1);
+		if (flags)
+			*flags |= REF_ISBROKEN;
+		bad_name = 1;
 	}
 	for (;;) {
 		char path[PATH_MAX];
@@ -1395,8 +1417,8 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int fla
 		if (lstat(path, &st) < 0) {
 			if (errno == ENOENT)
 				return handle_missing_loose_ref(refname, sha1,
-						flags & RESOLVE_REF_READING,
-						ref_flag);
+					resolve_flags & RESOLVE_REF_READING,
+					flags);
 			else
 				return NULL;
 		}
@@ -1416,8 +1438,12 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int fla
 					!check_refname_format(buffer, 0)) {
 				strcpy(refname_buffer, buffer);
 				refname = refname_buffer;
-				if (ref_flag)
-					*ref_flag |= REF_ISSYMREF;
+				if (flags)
+					*flags |= REF_ISSYMREF;
+				if (resolve_flags & RESOLVE_REF_NODEREF) {
+					hashclr(sha1);
+					return refname;
+				}
 				continue;
 			}
 		}
@@ -1462,31 +1488,37 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int fla
 			 */
 			if (get_sha1_hex(buffer, sha1) ||
 			    (buffer[40] != '\0' && !isspace(buffer[40]))) {
-				if (ref_flag)
-					*ref_flag |= REF_ISBROKEN;
+				if (flags)
+					*flags |= REF_ISBROKEN;
 				errno = EINVAL;
 				return NULL;
 			}
+			if (bad_name)
+				hashclr(sha1);
 			return refname;
 		}
-		if (ref_flag)
-			*ref_flag |= REF_ISSYMREF;
+		if (flags)
+			*flags |= REF_ISSYMREF;
 		buf = buffer + 4;
 		while (isspace(*buf))
 			buf++;
 		if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
-			if (ref_flag)
-				*ref_flag |= REF_ISBROKEN;
+			if (flags)
+				*flags |= REF_ISBROKEN;
 			errno = EINVAL;
 			return NULL;
 		}
 		refname = strcpy(refname_buffer, buf);
+		if (resolve_flags & RESOLVE_REF_NODEREF) {
+			hashclr(sha1);
+			return refname;
+		}
 	}
 }
 
-char *resolve_refdup(const char *ref, unsigned char *sha1, int flags, int *ref_flag)
+char *resolve_refdup(const char *ref, unsigned char *sha1, int *flags, int resolve_flags)
 {
-	const char *ret = resolve_ref_unsafe(ref, sha1, flags, ref_flag);
+	const char *ret = resolve_ref_unsafe(ref, sha1, flags, resolve_flags);
 	return ret ? xstrdup(ret) : NULL;
 }
 
@@ -1497,22 +1529,22 @@ struct ref_filter {
 	void *cb_data;
 };
 
-int read_ref_full(const char *refname, unsigned char *sha1, int flags, int *ref_flag)
+int read_ref_full(const char *refname, unsigned char *sha1, int *flags, int resolve_flags)
 {
-	if (resolve_ref_unsafe(refname, sha1, flags, ref_flag))
+	if (resolve_ref_unsafe(refname, sha1, flags, resolve_flags))
 		return 0;
 	return -1;
 }
 
 int read_ref(const char *refname, unsigned char *sha1)
 {
-	return read_ref_full(refname, sha1, RESOLVE_REF_READING, NULL);
+	return read_ref_full(refname, sha1, NULL, RESOLVE_REF_READING);
 }
 
 int ref_exists(const char *refname)
 {
 	unsigned char sha1[20];
-	return !!resolve_ref_unsafe(refname, sha1, RESOLVE_REF_READING, NULL);
+	return !!resolve_ref_unsafe(refname, sha1, NULL, RESOLVE_REF_READING);
 }
 
 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
@@ -1626,7 +1658,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 		return 0;
 	}
 
-	if (read_ref_full(refname, base, RESOLVE_REF_READING, &flag))
+	if (read_ref_full(refname, base, &flag, RESOLVE_REF_READING))
 		return -1;
 
 	/*
@@ -1667,7 +1699,7 @@ static int warn_if_dangling_symref(const char *refname, const unsigned char *sha
 	if (!(flags & REF_ISSYMREF))
 		return 0;
 
-	resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
+	resolves_to = resolve_ref_unsafe(refname, junk, NULL, 0);
 	if (!resolves_to
 	    || (d->refname
 		? strcmp(resolves_to, d->refname)
@@ -1792,7 +1824,7 @@ static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
 		return 0;
 	}
 
-	if (!read_ref_full("HEAD", sha1, RESOLVE_REF_READING, &flag))
+	if (!read_ref_full("HEAD", sha1, &flag, RESOLVE_REF_READING))
 		return fn("HEAD", sha1, flag, cb_data);
 
 	return 0;
@@ -1872,7 +1904,7 @@ int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 	int flag;
 
 	strbuf_addf(&buf, "%sHEAD", get_git_namespace());
-	if (!read_ref_full(buf.buf, sha1, RESOLVE_REF_READING, &flag))
+	if (!read_ref_full(buf.buf, sha1, &flag, RESOLVE_REF_READING))
 		ret = fn(buf.buf, sha1, flag, cb_data);
 	strbuf_release(&buf);
 
@@ -1967,8 +1999,8 @@ int refname_match(const char *abbrev_name, const char *full_name)
 static struct ref_lock *verify_lock(struct ref_lock *lock,
 	const unsigned char *old_sha1, int mustexist)
 {
-	if (read_ref_full(lock->ref_name, lock->old_sha1,
-			  mustexist ? RESOLVE_REF_READING : 0, NULL)) {
+	if (read_ref_full(lock->ref_name, lock->old_sha1, NULL,
+			  mustexist ? RESOLVE_REF_READING : 0)) {
 		int save_errno = errno;
 		error("Can't verify ref %s", lock->ref_name);
 		unlock_ref(lock);
@@ -2041,8 +2073,8 @@ int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 
 		this_result = refs_found ? sha1_from_ref : sha1;
 		mksnpath(fullref, sizeof(fullref), *p, len, str);
-		r = resolve_ref_unsafe(fullref, this_result,
-				       RESOLVE_REF_READING, &flag);
+		r = resolve_ref_unsafe(fullref, this_result, &flag,
+				       RESOLVE_REF_READING);
 		if (r) {
 			if (!refs_found++)
 				*ref = xstrdup(r);
@@ -2071,7 +2103,7 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 		const char *ref, *it;
 
 		mksnpath(path, sizeof(path), *p, len, str);
-		ref = resolve_ref_unsafe(path, hash, RESOLVE_REF_READING, NULL);
+		ref = resolve_ref_unsafe(path, hash, NULL, RESOLVE_REF_READING);
 		if (!ref)
 			continue;
 		if (reflog_exists(path))
@@ -2097,8 +2129,8 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
  */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
-					    int flags, int *type_p,
-					    const char **skip, int skipnum)
+					    struct string_list *skiplist,
+					    int flags, int *type_p)
 {
 	char *ref_file;
 	const char *orig_refname = refname;
@@ -2106,22 +2138,23 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	int last_errno = 0;
 	int type, lflags;
 	int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
-	int resolve_flags;
+	int resolve_flags = 0;
 	int missing = 0;
 	int attempts_remaining = 3;
-	int bad_refname;
 
 	lock = xcalloc(1, sizeof(struct ref_lock));
 	lock->lock_fd = -1;
 
-	bad_refname = check_refname_format(refname, REFNAME_ALLOW_ONELEVEL);
+	if (flags & REF_BADNAMEOK)
+		resolve_flags |= RESOLVE_REF_ALLOW_BAD_NAME;
 
-	resolve_flags = RESOLVE_REF_ALLOW_BAD_NAME;
 	if (mustexist)
 		resolve_flags |= RESOLVE_REF_READING;
+	if (flags & REF_NODEREF)
+		resolve_flags |= RESOLVE_REF_NODEREF;
 
-	refname = resolve_ref_unsafe(refname, lock->old_sha1, resolve_flags,
-				     &type);
+	refname = resolve_ref_unsafe(refname, lock->old_sha1, &type,
+				     resolve_flags);
 	if (!refname && errno == EISDIR) {
 		/* we are trying to lock foo but we used to
 		 * have foo/bar which now does not exist;
@@ -2135,7 +2168,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 			goto error_return;
 		}
 		refname = resolve_ref_unsafe(orig_refname, lock->old_sha1,
-					     resolve_flags, &type);
+					     &type, resolve_flags);
 	}
 	if (type_p)
 	    *type_p = type;
@@ -2153,7 +2186,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	 */
 	if (missing &&
 	     !is_refname_available(refname, get_packed_refs(&ref_cache),
-				   skip, skipnum)) {
+				   skiplist)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
@@ -2199,8 +2232,6 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 		else
 			unable_to_lock_index_die(ref_file, errno);
 	}
-	if (bad_refname)
-		return lock;
 	return old_sha1 ? verify_lock(lock, old_sha1, mustexist) : lock;
 
  error_return:
@@ -2213,7 +2244,7 @@ struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
 {
-	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p, NULL, 0);
+	return lock_ref_sha1_basic(refname, old_sha1, NULL, flags, type_p);
 }
 
 /*
@@ -2364,9 +2395,8 @@ static int pack_if_possible_fn(struct ref_entry *entry, void *cb_data)
 		packed_entry->flag = REF_ISPACKED | REF_KNOWS_PEELED;
 		hashcpy(packed_entry->u.value.sha1, entry->u.value.sha1);
 	} else {
-		packed_entry = create_ref_entry(entry->name,
-					entry->u.value.sha1,
-					REF_ISPACKED | REF_KNOWS_PEELED);
+		packed_entry = create_ref_entry(entry->name, entry->u.value.sha1,
+						REF_ISPACKED | REF_KNOWS_PEELED, 0);
 		add_ref(cb->packed_refs, packed_entry);
 	}
 	hashcpy(packed_entry->u.value.peeled, entry->u.value.peeled);
@@ -2491,7 +2521,7 @@ static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
 		unsigned char sha1[20];
 		int flags;
 
-		if (read_ref_full(entry->name, sha1, 0, &flags))
+		if (read_ref_full(entry->name, sha1, &flags, 0))
 			/* We should at least have found the packed ref. */
 			die("Internal error");
 		if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
@@ -2530,6 +2560,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 	struct string_list_item *ref_to_delete;
 	int i, ret, removed = 0;
 
+	assert(err);
+
 	/* Look for a packed ref */
 	for (i = 0; i < n; i++)
 		if (get_packed_ref(refnames[i]))
@@ -2540,13 +2572,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 		return 0; /* no refname exists in packed refs */
 
 	if (lock_packed_refs(0)) {
-		if (err) {
-			unable_to_lock_message(git_path("packed-refs"), errno,
-					       err);
-			return -1;
-		}
-		unable_to_lock_error(git_path("packed-refs"), errno);
-		return error("cannot delete '%s' from packed refs", refnames[i]);
+		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		return -1;
 	}
 	packed = get_packed_refs(&ref_cache);
 
@@ -2572,7 +2599,7 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
 	/* Write what remains */
 	ret = commit_packed_refs();
-	if (ret && err)
+	if (ret)
 		strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
 			    strerror(errno));
 	return ret;
@@ -2580,6 +2607,8 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 
 static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
 {
+	assert(err);
+
 	if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
 		/* loose */
 		int res, i = strlen(lock->lk->filename) - 5; /* .lock */
@@ -2678,25 +2707,31 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	struct stat loginfo;
 	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
 	const char *symref = NULL;
+	struct string_list skiplist = STRING_LIST_INIT_NODUP;
 
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
-	symref = resolve_ref_unsafe(oldrefname, orig_sha1,
-				    RESOLVE_REF_READING, &flag);
+	symref = resolve_ref_unsafe(oldrefname, orig_sha1, &flag,
+				    RESOLVE_REF_READING);
 	if (flag & REF_ISSYMREF)
 		return error("refname %s is a symbolic ref, renaming it is not supported",
 			oldrefname);
 	if (!symref)
 		return error("refname %s not found", oldrefname);
 
+	string_list_insert(&skiplist, oldrefname);
 	if (!is_refname_available(newrefname, get_packed_refs(&ref_cache),
-				  &oldrefname, 1))
+				  &skiplist)) {
+		string_list_clear(&skiplist, 0);
 		return 1;
-
+	}
 	if (!is_refname_available(newrefname, get_loose_refs(&ref_cache),
-				  &oldrefname, 1))
+				  &skiplist)) {
+		string_list_clear(&skiplist, 0);
 		return 1;
+	}
+	string_list_clear(&skiplist, 0);
 
 	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
@@ -2707,7 +2742,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 		goto rollback;
 	}
 
-	if (!read_ref_full(newrefname, sha1, RESOLVE_REF_READING, NULL) &&
+	if (!read_ref_full(newrefname, sha1, NULL, RESOLVE_REF_READING) &&
 	    delete_ref(newrefname, sha1, REF_NODEREF)) {
 		if (errno==EISDIR) {
 			if (remove_empty_directories(git_path("%s", newrefname))) {
@@ -2725,7 +2760,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 
 	logmoved = log;
 
-	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL, NULL, 0);
+	lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
 	if (!lock) {
 		error("unable to lock %s for update", newrefname);
 		goto rollback;
@@ -2740,7 +2775,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	return 0;
 
  rollback:
-	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL, NULL, 0);
+	lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
 	if (!lock) {
 		error("unable to lock %s for rollback", oldrefname);
 		goto rollbacklog;
@@ -2985,8 +3020,8 @@ static int write_ref_sha1(struct ref_lock *lock,
 		unsigned char head_sha1[20];
 		int head_flag;
 		const char *head_ref;
-		head_ref = resolve_ref_unsafe("HEAD", head_sha1,
-					      RESOLVE_REF_READING, &head_flag);
+		head_ref = resolve_ref_unsafe("HEAD", head_sha1, &head_flag,
+					      RESOLVE_REF_READING);
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name))
 			log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
@@ -3353,7 +3388,7 @@ static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data
 				retval = do_for_each_reflog(name, fn, cb_data);
 			} else {
 				unsigned char sha1[20];
-				if (read_ref_full(name->buf, sha1, 0, NULL))
+				if (read_ref_full(name->buf, sha1, NULL, 0))
 					retval = error("bad ref for %s", name->buf);
 				else
 					retval = fn(name->buf, sha1, 0, cb_data);
@@ -3423,6 +3458,8 @@ struct ref_transaction {
 
 struct ref_transaction *ref_transaction_begin(struct strbuf *err)
 {
+	assert(err);
+
 	return xcalloc(1, sizeof(struct ref_transaction));
 }
 
@@ -3462,6 +3499,8 @@ int ref_transaction_update(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: update called for transaction that is not open");
 
@@ -3470,7 +3509,8 @@ int ref_transaction_update(struct ref_transaction *transaction,
 
 	if (!is_null_sha1(new_sha1) &&
 	    check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
-		strbuf_addf(err, "Bad refname: %s", refname);
+		strbuf_addf(err, "refusing to update ref with bad name %s",
+			    refname);
 		return -1;
 	}
 
@@ -3493,6 +3533,8 @@ int ref_transaction_create(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: create called for transaction that is not open");
 
@@ -3500,7 +3542,8 @@ int ref_transaction_create(struct ref_transaction *transaction,
 		die("BUG: create ref with null new_sha1");
 
 	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
-		strbuf_addf(err, "Bad refname: %s", refname);
+		strbuf_addf(err, "refusing to create ref with bad name %s",
+			    refname);
 		return -1;
 	}
 
@@ -3523,6 +3566,8 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 {
 	struct ref_update *update;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: delete called for transaction that is not open");
 
@@ -3585,13 +3630,14 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
 					struct strbuf *err)
 {
 	int i;
+
+	assert(err);
+
 	for (i = 1; i < n; i++)
 		if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
-			const char *str =
-				"Multiple updates for ref '%s' not allowed.";
-			if (err)
-				strbuf_addf(err, str, updates[i]->refname);
-
+			strbuf_addf(err,
+				    "Multiple updates for ref '%s' not allowed.",
+				    updates[i]->refname);
 			return 1;
 		}
 	return 0;
@@ -3600,11 +3646,13 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err)
 {
-	int ret = 0, delnum = 0, i, df_conflict = 0;
+	int ret = 0, delnum = 0, i;
 	const char **delnames;
 	int n = transaction->nr;
 	struct ref_update **updates = transaction->updates;
 
+	assert(err);
+
 	if (transaction->state != REF_TRANSACTION_OPEN)
 		die("BUG: commit called for transaction that is not open");
 
@@ -3631,16 +3679,15 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 						   (update->have_old ?
 						    update->old_sha1 :
 						    NULL),
+						   NULL,
 						   update->flags,
-						   &update->type,
-						   delnames, delnum);
+						   &update->type);
 		if (!update->lock) {
-			if (errno == ENOTDIR)
-				df_conflict = 1;
-			if (err)
-				strbuf_addf(err, "Cannot lock the ref '%s'.",
-					    update->refname);
-			ret = -1;
+			int df_conflict = (errno == ENOTDIR);
+
+			strbuf_addf(err, "Cannot lock the ref '%s'.",
+				    update->refname);
+			ret = df_conflict ? UPDATE_REFS_NAME_CONFLICT : -1;
 			goto cleanup;
 		}
 	}
@@ -3654,9 +3701,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 					     update->msg);
 			update->lock = NULL; /* freed by write_ref_sha1 */
 			if (ret) {
-				if (err)
-					strbuf_addf(err, "Cannot update the ref '%s'.",
-						    update->refname);
+				strbuf_addf(err, "Cannot update the ref '%s'.",
+					    update->refname);
 				ret = -1;
 				goto cleanup;
 			}
@@ -3668,16 +3714,20 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 		struct ref_update *update = updates[i];
 
 		if (update->lock) {
-			if (delete_ref_loose(update->lock, update->type, err))
+			if (delete_ref_loose(update->lock, update->type, err)) {
 				ret = -1;
+				goto cleanup;
+			}
 
 			if (!(update->flags & REF_ISPRUNING))
 				delnames[delnum++] = update->lock->ref_name;
 		}
 	}
 
-	if (repack_without_refs(delnames, delnum, err))
+	if (repack_without_refs(delnames, delnum, err)) {
 		ret = -1;
+		goto cleanup;
+	}
 	for (i = 0; i < delnum; i++)
 		unlink_or_warn(git_path("logs/%s", delnames[i]));
 	clear_loose_ref_cache(&ref_cache);
@@ -3689,8 +3739,6 @@ cleanup:
 		if (updates[i]->lock)
 			unlock_ref(updates[i]->lock);
 	free(delnames);
-	if (df_conflict)
-		ret = -2;
 	return ret;
 }
 
diff --git c/refs.h w/refs.h
index a7b8009..a96e174 100644
--- c/refs.h
+++ w/refs.h
@@ -175,10 +175,12 @@ extern int peel_ref(const char *refname, unsigned char *sha1);
  * ref_transaction_create(), etc.
  * REF_NODEREF: act on the ref directly, instead of dereferencing
  *              symbolic references.
+ * REF_BADNAMEOK: allow locking a ref that has a bad name.
  *
  * Flags >= 0x100 are reserved for internal use.
  */
 #define REF_NODEREF	0x01
+#define REF_BADNAMEOK	0x02
 /*
  * This function sets errno to something meaningful on failure.
  */
@@ -322,11 +324,10 @@ int ref_transaction_delete(struct ref_transaction *transaction,
  * Commit all of the changes that have been queued in transaction, as
  * atomically as possible.  Return a nonzero value if there is a
  * problem.
- * If the transaction is already in failed state this function will return
- * an error.
+ *
  * Function returns 0 on success, -1 for generic failures and
- * UPDATE_REFS_NAME_CONFLICT (-2) if the failure was due to a name
- * collision (ENOTDIR).
+ * UPDATE_REFS_NAME_CONFLICT (-2) if the failure was due to a naming conflict.
+ * For example, the ref names A and A/B conflict.
  */
 #define UPDATE_REFS_NAME_CONFLICT -2
 int ref_transaction_commit(struct ref_transaction *transaction,
diff --git c/remote.c w/remote.c
index 2adb31c..67c375d 100644
--- c/remote.c
+++ w/remote.c
@@ -486,7 +486,7 @@ static void read_config(void)
 		return;
 	default_remote_name = "origin";
 	current_branch = NULL;
-	head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
+	head_ref = resolve_ref_unsafe("HEAD", sha1, &flag, 0);
 	if (head_ref && (flag & REF_ISSYMREF) &&
 	    starts_with(head_ref, "refs/heads/")) {
 		current_branch =
@@ -1121,8 +1121,8 @@ static char *guess_ref(const char *name, struct ref *peer)
 	struct strbuf buf = STRBUF_INIT;
 	unsigned char sha1[20];
 
-	const char *r = resolve_ref_unsafe(peer->name, sha1,
-					   RESOLVE_REF_READING, NULL);
+	const char *r = resolve_ref_unsafe(peer->name, sha1, NULL,
+					   RESOLVE_REF_READING);
 	if (!r)
 		return NULL;
 
@@ -1183,8 +1183,8 @@ static int match_explicit(struct ref *src, struct ref *dst,
 		unsigned char sha1[20];
 		int flag;
 
-		dst_value = resolve_ref_unsafe(matched_src->name, sha1,
-					       RESOLVE_REF_READING, &flag);
+		dst_value = resolve_ref_unsafe(matched_src->name, sha1, &flag,
+					       RESOLVE_REF_READING);
 		if (!dst_value ||
 		    ((flag & REF_ISSYMREF) &&
 		     !starts_with(dst_value, "refs/heads/")))
@@ -1658,7 +1658,7 @@ static int ignore_symref_update(const char *refname)
 	unsigned char sha1[20];
 	int flag;
 
-	if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
+	if (!resolve_ref_unsafe(refname, sha1, &flag, 0))
 		return 0; /* non-existing refs are OK */
 	return (flag & REF_ISSYMREF);
 }
diff --git c/sequencer.c w/sequencer.c
index ebe8713..6a05ad4 100644
--- c/sequencer.c
+++ w/sequencer.c
@@ -366,7 +366,7 @@ static int is_index_unchanged(void)
 	unsigned char head_sha1[20];
 	struct commit *head_commit;
 
-	if (!resolve_ref_unsafe("HEAD", head_sha1, RESOLVE_REF_READING, NULL))
+	if (!resolve_ref_unsafe("HEAD", head_sha1, NULL, RESOLVE_REF_READING))
 		return error(_("Could not resolve HEAD commit\n"));
 
 	head_commit = lookup_commit(head_sha1);
@@ -912,7 +912,7 @@ static int rollback_single_pick(void)
 	if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 	    !file_exists(git_path("REVERT_HEAD")))
 		return error(_("no cherry-pick or revert in progress"));
-	if (read_ref_full("HEAD", head_sha1, 0, NULL))
+	if (read_ref_full("HEAD", head_sha1, NULL, 0))
 		return error(_("cannot resolve HEAD"));
 	if (is_null_sha1(head_sha1))
 		return error(_("cannot abort from a branch yet to be born"));
diff --git c/t/t1400-update-ref.sh w/t/t1400-update-ref.sh
index 0218e96..ff4607b 100755
--- c/t/t1400-update-ref.sh
+++ w/t/t1400-update-ref.sh
@@ -110,6 +110,22 @@ test_expect_success "delete symref without dereference when the referred ref is
 cp -f .git/HEAD.orig .git/HEAD
 git update-ref -d $m
 
+test_expect_success 'update-ref -d is not confused by self-reference' '
+	git symbolic-ref refs/heads/self refs/heads/self &&
+	test_when_finished "rm -f .git/refs/heads/self" &&
+	test_path_is_file .git/refs/heads/self &&
+	test_must_fail git update-ref -d refs/heads/self &&
+	test_path_is_file .git/refs/heads/self
+'
+
+test_expect_success 'update-ref --no-deref -d can delete self-reference' '
+	git symbolic-ref refs/heads/self refs/heads/self &&
+	test_when_finished "rm -f .git/refs/heads/self" &&
+	test_path_is_file .git/refs/heads/self &&
+	git update-ref --no-deref -d refs/heads/self &&
+	test_path_is_missing .git/refs/heads/self
+'
+
 test_expect_success '(not) create HEAD with old sha1' "
 	test_must_fail git update-ref HEAD $A $B
 "
diff --git c/t/t1402-check-ref-format.sh w/t/t1402-check-ref-format.sh
index 1a5a5f3..058fa37 100755
--- c/t/t1402-check-ref-format.sh
+++ w/t/t1402-check-ref-format.sh
@@ -196,4 +196,52 @@ invalid_ref_normalized 'heads///foo.lock'
 invalid_ref_normalized 'foo.lock/bar'
 invalid_ref_normalized 'foo.lock///bar'
 
+test_expect_success 'git branch shows badly named ref' '
+	cp .git/refs/heads/master .git/refs/heads/broken...ref &&
+	test_when_finished "rm -f .git/refs/heads/broken...ref" &&
+	git branch >output &&
+	grep -e "broken...ref" output
+'
+
+test_expect_success 'git branch -d can delete badly named ref' '
+	cp .git/refs/heads/master .git/refs/heads/broken...ref &&
+	test_when_finished "rm -f .git/refs/heads/broken...ref" &&
+	git branch -d broken...ref &&
+	git branch >output &&
+	! grep -e "broken...ref" output
+'
+
+test_expect_success 'git branch -D can delete badly named ref' '
+	cp .git/refs/heads/master .git/refs/heads/broken...ref &&
+	test_when_finished "rm -f .git/refs/heads/broken...ref" &&
+	git branch -D broken...ref &&
+	git branch >output &&
+	! grep -e "broken...ref" output
+'
+
+test_expect_success 'git update-ref -d can delete badly named ref' '
+	cp .git/refs/heads/master .git/refs/heads/broken...ref &&
+	test_when_finished "rm -f .git/refs/heads/broken...ref" &&
+	git update-ref -d refs/heads/broken...ref &&
+	git branch >output &&
+	! grep -e "broken...ref" output
+'
+
+test_expect_success 'git branch can not create a badly named ref' '
+	test_must_fail git branch broken...ref
+'
+
+test_expect_success 'git branch can not rename to a bad ref name' '
+	git branch goodref &&
+	test_must_fail git branch -m goodref broken...ref
+'
+
+test_expect_failure 'git branch can rename from a bad ref name' '
+	cp .git/refs/heads/master .git/refs/heads/broken...ref &&
+	test_when_finished "rm -f .git/refs/heads/broken...ref" &&
+	git branch -m broken...ref renamed &&
+	test_must_fail git rev-parse broken...ref &&
+	test_cmp_rev master renamed
+'
+
 test_done
diff --git c/t/t3200-branch.sh w/t/t3200-branch.sh
index ac31b71..432921b 100755
--- c/t/t3200-branch.sh
+++ w/t/t3200-branch.sh
@@ -285,6 +285,15 @@ test_expect_success 'deleting a dangling symref' '
 	test_i18ncmp expect actual
 '
 
+test_expect_success 'deleting a self-referential symref' '
+	git symbolic-ref refs/heads/self-reference refs/heads/self-reference &&
+	test_path_is_file .git/refs/heads/self-reference &&
+	echo "Deleted branch self-reference (was refs/heads/self-reference)." >expect &&
+	git branch -d self-reference >actual &&
+	test_path_is_missing .git/refs/heads/self-reference &&
+	test_i18ncmp expect actual
+'
+
 test_expect_success 'renaming a symref is not allowed' '
 	git symbolic-ref refs/heads/master2 refs/heads/master &&
 	test_must_fail git branch -m master2 master3 &&
diff --git c/t/t7001-mv.sh w/t/t7001-mv.sh
index 54d7807..69f11bd 100755
--- c/t/t7001-mv.sh
+++ w/t/t7001-mv.sh
@@ -350,10 +350,11 @@ test_expect_success 'git mv moves a submodule with a .git directory and .gitmodu
 '
 
 test_expect_success 'git mv moves a submodule with gitfile' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
+	mkdir mod &&
 	(
 		cd mod &&
 		git mv ../sub/ .
@@ -372,11 +373,12 @@ test_expect_success 'git mv moves a submodule with gitfile' '
 '
 
 test_expect_success 'mv does not complain when no .gitmodules file is found' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	git rm .gitmodules &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
+	mkdir mod &&
 	git mv sub mod/sub 2>actual.err &&
 	! test -s actual.err &&
 	! test -e sub &&
@@ -390,11 +392,12 @@ test_expect_success 'mv does not complain when no .gitmodules file is found' '
 '
 
 test_expect_success 'mv will error out on a modified .gitmodules file unless staged' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	git config -f .gitmodules foo.bar true &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
+	mkdir mod &&
 	test_must_fail git mv sub mod/sub 2>actual.err &&
 	test -s actual.err &&
 	test -e sub &&
@@ -413,13 +416,14 @@ test_expect_success 'mv will error out on a modified .gitmodules file unless sta
 '
 
 test_expect_success 'mv issues a warning when section is not found in .gitmodules' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	git config -f .gitmodules --remove-section submodule.sub &&
 	git add .gitmodules &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
 	echo "warning: Could not find section in .gitmodules where path=sub" >expect.err &&
+	mkdir mod &&
 	git mv sub mod/sub 2>actual.err &&
 	test_i18ncmp expect.err actual.err &&
 	! test -e sub &&
@@ -433,9 +437,10 @@ test_expect_success 'mv issues a warning when section is not found in .gitmodule
 '
 
 test_expect_success 'mv --dry-run does not touch the submodule or .gitmodules' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
+	mkdir mod &&
 	git mv -n sub mod/sub 2>actual.err &&
 	test -f sub/.git &&
 	git diff-index --exit-code HEAD &&
diff --git c/transport-helper.c w/transport-helper.c
index 270ae28..8365441 100644
--- c/transport-helper.c
+++ w/transport-helper.c
@@ -889,7 +889,9 @@ static int push_refs_with_export(struct transport *transport,
 					int flag;
 
 					/* Follow symbolic refs (mainly for HEAD). */
-					name = resolve_ref_unsafe(ref->peer_ref->name, sha1, RESOLVE_REF_READING, &flag);
+					name = resolve_ref_unsafe(
+						 ref->peer_ref->name, sha1,
+						 &flag, RESOLVE_REF_READING);
 					if (!name || !(flag & REF_ISSYMREF))
 						name = ref->peer_ref->name;
 
diff --git c/transport.c w/transport.c
index f40e950..3ba7bbf 100644
--- c/transport.c
+++ w/transport.c
@@ -168,8 +168,8 @@ static void set_upstreams(struct transport *transport, struct ref *refs,
 		/* Follow symbolic refs (mainly for HEAD). */
 		localname = ref->peer_ref->name;
 		remotename = ref->name;
-		tmp = resolve_ref_unsafe(localname, sha,
-					 RESOLVE_REF_READING, &flag);
+		tmp = resolve_ref_unsafe(localname, sha, &flag,
+					 RESOLVE_REF_READING);
 		if (tmp && flag & REF_ISSYMREF &&
 			starts_with(tmp, "refs/heads/"))
 			localname = tmp;
@@ -754,7 +754,7 @@ void transport_print_push_status(const char *dest, struct ref *refs,
 	unsigned char head_sha1[20];
 	char *head;
 
-	head = resolve_refdup("HEAD", head_sha1, RESOLVE_REF_READING, NULL);
+	head = resolve_refdup("HEAD", head_sha1, NULL, RESOLVE_REF_READING);
 
 	if (verbose) {
 		for (ref = refs; ref; ref = ref->next)
diff --git c/upload-pack.c w/upload-pack.c
index 01de944..3b51ccb 100644
--- c/upload-pack.c
+++ w/upload-pack.c
@@ -743,7 +743,7 @@ static int find_symref(const char *refname, const unsigned char *sha1, int flag,
 
 	if ((flag & REF_ISSYMREF) == 0)
 		return 0;
-	symref_target = resolve_ref_unsafe(refname, unused, 0, &flag);
+	symref_target = resolve_ref_unsafe(refname, unused, &flag, 0);
 	if (!symref_target || (flag & REF_ISSYMREF) == 0)
 		die("'%s' is a symref but it is not?", refname);
 	item = string_list_append(cb_data, refname);
diff --git c/wrapper.c w/wrapper.c
index 74a0cc0..ec7a08b 100644
--- c/wrapper.c
+++ w/wrapper.c
@@ -430,8 +430,8 @@ int xmkstemp_mode(char *template, int mode)
 static int warn_if_unremovable(const char *op, const char *file, int rc)
 {
 	int err;
-	if (rc >= 0 || errno == ENOENT)
-		return rc;
+	if (!rc || errno == ENOENT)
+		return 0;
 	err = errno;
 	warning("unable to %s %s: %s", op, file, strerror(errno));
 	errno = err;
@@ -440,20 +440,16 @@ static int warn_if_unremovable(const char *op, const char *file, int rc)
 
 int unlink_or_msg(const char *file, struct strbuf *err)
 {
-	if (err) {
-		int rc = unlink(file);
-		int save_errno = errno;
+	int rc = unlink(file);
 
-		if (rc < 0 && errno != ENOENT) {
-			strbuf_addf(err, "unable to unlink %s: %s",
-				    file, strerror(errno));
-			errno = save_errno;
-			return -1;
-		}
+	assert(err);
+
+	if (!rc || errno == ENOENT)
 		return 0;
-	}
 
-	return unlink_or_warn(file);
+	strbuf_addf(err, "unable to unlink %s: %s",
+		    file, strerror(errno));
+	return -1;
 }
 
 int unlink_or_warn(const char *file)
diff --git c/wt-status.c w/wt-status.c
index 318a191..6819e2b 100644
--- c/wt-status.c
+++ w/wt-status.c
@@ -128,7 +128,7 @@ void wt_status_prepare(struct wt_status *s)
 	s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
 	s->use_color = -1;
 	s->relative_paths = 1;
-	s->branch = resolve_refdup("HEAD", sha1, 0, NULL);
+	s->branch = resolve_refdup("HEAD", sha1, NULL, 0);
 	s->reference = "HEAD";
 	s->fp = stdout;
 	s->index_file = get_index_file();

Jonathan Nieder· Sep 11, 2014, 03:04 UTC · re: Jonathan Nieder · lore

[PATCH 01/19] mv test: recreate mod/ directory instead of relying on stale copy

	git mv sub mod/sub

	rmdir("mod/sub")
	rmdir("mod")

Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Reviewed-by: Ronnie Sahlberg <sahlberg@google.com>
---
 t/t7001-mv.sh | 15 ++++++++++-----
 1 file changed, 10 insertions(+), 5 deletions(-)

diff --git a/t/t7001-mv.sh b/t/t7001-mv.sh
index 54d7807..69f11bd 100755
--- a/t/t7001-mv.sh
+++ b/t/t7001-mv.sh
@@ -350,10 +350,11 @@ test_expect_success 'git mv moves a submodule with a .git directory and .gitmodu
 '
 
 test_expect_success 'git mv moves a submodule with gitfile' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
+	mkdir mod &&
 	(
 		cd mod &&
 		git mv ../sub/ .
@@ -372,11 +373,12 @@ test_expect_success 'git mv moves a submodule with gitfile' '
 '
 
 test_expect_success 'mv does not complain when no .gitmodules file is found' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	git rm .gitmodules &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
+	mkdir mod &&
 	git mv sub mod/sub 2>actual.err &&
 	! test -s actual.err &&
 	! test -e sub &&
@@ -390,11 +392,12 @@ test_expect_success 'mv does not complain when no .gitmodules file is found' '
 '
 
 test_expect_success 'mv will error out on a modified .gitmodules file unless staged' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	git config -f .gitmodules foo.bar true &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
+	mkdir mod &&
 	test_must_fail git mv sub mod/sub 2>actual.err &&
 	test -s actual.err &&
 	test -e sub &&
@@ -413,13 +416,14 @@ test_expect_success 'mv will error out on a modified .gitmodules file unless sta
 '
 
 test_expect_success 'mv issues a warning when section is not found in .gitmodules' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
 	git config -f .gitmodules --remove-section submodule.sub &&
 	git add .gitmodules &&
 	entry="$(git ls-files --stage sub | cut -f 1)" &&
 	echo "warning: Could not find section in .gitmodules where path=sub" >expect.err &&
+	mkdir mod &&
 	git mv sub mod/sub 2>actual.err &&
 	test_i18ncmp expect.err actual.err &&
 	! test -e sub &&
@@ -433,9 +437,10 @@ test_expect_success 'mv issues a warning when section is not found in .gitmodule
 '
 
 test_expect_success 'mv --dry-run does not touch the submodule or .gitmodules' '
-	rm -rf mod/sub &&
+	rm -rf mod &&
 	git reset --hard &&
 	git submodule update &&
+	mkdir mod &&
 	git mv -n sub mod/sub 2>actual.err &&
 	test -f sub/.git &&
 	git diff-index --exit-code HEAD &&

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:04 UTC · re: Jonathan Nieder · lore

[PATCH 02/19] wrapper.c: remove/unlink_or_warn: simplify, treat ENOENT as success

From: Ronnie Sahlberg <sahlberg@google.com>

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 git-compat-util.h |  7 +++++--
 wrapper.c         | 14 ++++++--------
 2 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/git-compat-util.h b/git-compat-util.h
index b6f03b3..611e77b 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -706,11 +706,14 @@ void git_qsort(void *base, size_t nmemb, size_t size,
 
 /*
  * Preserves errno, prints a message, but gives no warning for ENOENT.
- * Always returns the return value of unlink(2).
+ * Returns 0 on success which includes trying to unlink an object that does
+ * not exist.
  */
 int unlink_or_warn(const char *path);
 /*
- * Likewise for rmdir(2).
+ * Preserves errno, prints a message, but gives no warning for ENOENT.
+ * Returns 0 on success which includes trying to remove a directory that does
+ * not exist.
  */
 int rmdir_or_warn(const char *path);
 /*
diff --git a/wrapper.c b/wrapper.c
index bc1bfb8..c9605cd 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -429,14 +429,12 @@ int xmkstemp_mode(char *template, int mode)
 
 static int warn_if_unremovable(const char *op, const char *file, int rc)
 {
-	if (rc < 0) {
-		int err = errno;
-		if (ENOENT != err) {
-			warning("unable to %s %s: %s",
-				op, file, strerror(errno));
-			errno = err;
-		}
-	}
+	int err;
+	if (!rc || errno == ENOENT)
+		return 0;
+	err = errno;
+	warning("unable to %s %s: %s", op, file, strerror(errno));
+	errno = err;
 	return rc;
 }
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:05 UTC · re: Jonathan Nieder · lore

[PATCH 03/19] wrapper.c: add a new function unlink_or_msg

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 16 Jul 2014 11:20:36 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 git-compat-util.h |  9 +++++++++
 wrapper.c         | 14 ++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/git-compat-util.h b/git-compat-util.h
index 611e77b..5ee140c 100644
--- a/git-compat-util.h
+++ b/git-compat-util.h
@@ -307,6 +307,8 @@ extern char *gitbasename(char *);
 
 #include "wildmatch.h"
 
+struct strbuf;
+
 /* General helper functions */
 extern void vreportf(const char *prefix, const char *err, va_list params);
 extern void vwritef(int fd, const char *prefix, const char *err, va_list params);
@@ -710,6 +712,13 @@ void git_qsort(void *base, size_t nmemb, size_t size,
  * not exist.
  */
 int unlink_or_warn(const char *path);
+ /*
+  * Tries to unlink file.  Returns 0 if unlink succeeded
+  * or the file already didn't exist.  Returns -1 and
+  * appends a message to err suitable for
+  * 'error("%s", err->buf)' on error.
+  */
+int unlink_or_msg(const char *file, struct strbuf *err);
 /*
  * Preserves errno, prints a message, but gives no warning for ENOENT.
  * Returns 0 on success which includes trying to remove a directory that does
diff --git a/wrapper.c b/wrapper.c
index c9605cd..ec7a08b 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -438,6 +438,20 @@ static int warn_if_unremovable(const char *op, const char *file, int rc)
 	return rc;
 }
 
+int unlink_or_msg(const char *file, struct strbuf *err)
+{
+	int rc = unlink(file);
+
+	assert(err);
+
+	if (!rc || errno == ENOENT)
+		return 0;
+
+	strbuf_addf(err, "unable to unlink %s: %s",
+		    file, strerror(errno));
+	return -1;
+}
+
 int unlink_or_warn(const char *file)
 {
 	return warn_if_unremovable("unlink", file, unlink(file));

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:06 UTC · re: Jonathan Nieder · lore

[PATCH 04/19] refs.c: add an err argument to delete_ref_loose

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 15 May 2014 08:25:23 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/refs.c b/refs.c
index 7235574..5609622 100644
--- a/refs.c
+++ b/refs.c
@@ -2548,16 +2548,16 @@ int repack_without_refs(const char **refnames, int n, struct strbuf *err)
 	return ret;
 }
 
-static int delete_ref_loose(struct ref_lock *lock, int flag)
+static int delete_ref_loose(struct ref_lock *lock, int flag, struct strbuf *err)
 {
 	if (!(flag & REF_ISPACKED) || flag & REF_ISSYMREF) {
 		/* loose */
-		int err, i = strlen(lock->lk->filename) - 5; /* .lock */
+		int res, i = strlen(lock->lk->filename) - 5; /* .lock */
 
 		lock->lk->filename[i] = 0;
-		err = unlink_or_warn(lock->lk->filename);
+		res = unlink_or_msg(lock->lk->filename, err);
 		lock->lk->filename[i] = '.';
-		if (err && errno != ENOENT)
+		if (res)
 			return 1;
 	}
 	return 0;
@@ -3604,7 +3604,8 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 		struct ref_update *update = updates[i];
 
 		if (update->lock) {
-			ret |= delete_ref_loose(update->lock, update->type);
+			ret |= delete_ref_loose(update->lock, update->type,
+						err);
 			if (!(update->flags & REF_ISPRUNING))
 				delnames[delnum++] = update->lock->ref_name;
 		}

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:06 UTC · re: Jonathan Nieder · lore

[PATCH 05/19] refs.c: pass the ref log message to _create/delete/update instead of _commit

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 30 Apr 2014 12:22:42 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 branch.c               |  4 ++--
 builtin/commit.c       |  4 ++--
 builtin/receive-pack.c |  5 +++--
 builtin/replace.c      |  5 +++--
 builtin/tag.c          |  4 ++--
 builtin/update-ref.c   | 13 +++++++------
 fast-import.c          |  8 ++++----
 refs.c                 | 34 +++++++++++++++++++++-------------
 refs.h                 |  8 ++++----
 sequencer.c            |  4 ++--
 walker.c               |  5 ++---
 11 files changed, 52 insertions(+), 42 deletions(-)

diff --git a/branch.c b/branch.c
index 37ac555..76a8ec9 100644
--- a/branch.c
+++ b/branch.c
@@ -301,8 +301,8 @@ void create_branch(const char *head,
 		transaction = ref_transaction_begin(&err);
 		if (!transaction ||
 		    ref_transaction_update(transaction, ref.buf, sha1,
-					   null_sha1, 0, !forcing, &err) ||
-		    ref_transaction_commit(transaction, msg, &err))
+					   null_sha1, 0, !forcing, msg, &err) ||
+		    ref_transaction_commit(transaction, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
 		strbuf_release(&err);
diff --git a/builtin/commit.c b/builtin/commit.c
index 9bf1003..d23e876 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1767,8 +1767,8 @@ int cmd_commit(int argc, const char **argv, const char *prefix)
 	    ref_transaction_update(transaction, "HEAD", sha1,
 				   current_head
 				   ? current_head->object.sha1 : NULL,
-				   0, !!current_head, &err) ||
-	    ref_transaction_commit(transaction, sb.buf, &err)) {
+				   0, !!current_head, sb.buf, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
 		rollback_index_files();
 		die("%s", err.buf);
 	}
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index 224fadc..d1f4cf7 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -585,8 +585,9 @@ static const char *update(struct command *cmd, struct shallow_info *si)
 		transaction = ref_transaction_begin(&err);
 		if (!transaction ||
 		    ref_transaction_update(transaction, namespaced_name,
-					   new_sha1, old_sha1, 0, 1, &err) ||
-		    ref_transaction_commit(transaction, "push", &err)) {
+					   new_sha1, old_sha1, 0, 1, "push",
+					   &err) ||
+		    ref_transaction_commit(transaction, &err)) {
 			ref_transaction_free(transaction);
 
 			rp_error("%s", err.buf);
diff --git a/builtin/replace.c b/builtin/replace.c
index 1fcd06d..9d03b84 100644
--- a/builtin/replace.c
+++ b/builtin/replace.c
@@ -169,8 +169,9 @@ static int replace_object_sha1(const char *object_ref,
 
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
-	    ref_transaction_update(transaction, ref, repl, prev, 0, 1, &err) ||
-	    ref_transaction_commit(transaction, NULL, &err))
+	    ref_transaction_update(transaction, ref, repl, prev,
+				   0, 1, NULL, &err) ||
+	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 
 	ref_transaction_free(transaction);
diff --git a/builtin/tag.c b/builtin/tag.c
index f3f172f..70d28c5 100644
--- a/builtin/tag.c
+++ b/builtin/tag.c
@@ -705,8 +705,8 @@ int cmd_tag(int argc, const char **argv, const char *prefix)
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, ref.buf, object, prev,
-				   0, 1, &err) ||
-	    ref_transaction_commit(transaction, NULL, &err))
+				   0, 1, NULL, &err) ||
+	    ref_transaction_commit(transaction, &err))
 		die("%s", err.buf);
 	ref_transaction_free(transaction);
 	if (force && !is_null_sha1(prev) && hashcmp(prev, object))
diff --git a/builtin/update-ref.c b/builtin/update-ref.c
index 54a48c0..6c9be05 100644
--- a/builtin/update-ref.c
+++ b/builtin/update-ref.c
@@ -14,6 +14,7 @@ static const char * const git_update_ref_usage[] = {
 
 static char line_termination = '\n';
 static int update_flags;
+static const char *msg;
 
 /*
  * Parse one whitespace- or NUL-terminated, possibly C-quoted argument
@@ -198,7 +199,7 @@ static const char *parse_cmd_update(struct ref_transaction *transaction,
 		die("update %s: extra input: %s", refname, next);
 
 	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-				   update_flags, have_old, &err))
+				   update_flags, have_old, msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -229,7 +230,7 @@ static const char *parse_cmd_create(struct ref_transaction *transaction,
 		die("create %s: extra input: %s", refname, next);
 
 	if (ref_transaction_create(transaction, refname, new_sha1,
-				   update_flags, &err))
+				   update_flags, msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -264,7 +265,7 @@ static const char *parse_cmd_delete(struct ref_transaction *transaction,
 		die("delete %s: extra input: %s", refname, next);
 
 	if (ref_transaction_delete(transaction, refname, old_sha1,
-				   update_flags, have_old, &err))
+				   update_flags, have_old, msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -300,7 +301,7 @@ static const char *parse_cmd_verify(struct ref_transaction *transaction,
 		die("verify %s: extra input: %s", refname, next);
 
 	if (ref_transaction_update(transaction, refname, new_sha1, old_sha1,
-				   update_flags, have_old, &err))
+				   update_flags, have_old, msg, &err))
 		die("%s", err.buf);
 
 	update_flags = 0;
@@ -354,7 +355,7 @@ static void update_refs_stdin(struct ref_transaction *transaction)
 
 int cmd_update_ref(int argc, const char **argv, const char *prefix)
 {
-	const char *refname, *oldval, *msg = NULL;
+	const char *refname, *oldval;
 	unsigned char sha1[20], oldsha1[20];
 	int delete = 0, no_deref = 0, read_stdin = 0, end_null = 0, flags = 0;
 	struct option options[] = {
@@ -385,7 +386,7 @@ int cmd_update_ref(int argc, const char **argv, const char *prefix)
 		if (end_null)
 			line_termination = '\0';
 		update_refs_stdin(transaction);
-		if (ref_transaction_commit(transaction, msg, &err))
+		if (ref_transaction_commit(transaction, &err))
 			die("%s", err.buf);
 		ref_transaction_free(transaction);
 		strbuf_release(&err);
diff --git a/fast-import.c b/fast-import.c
index e7f6e37..51dfaad 100644
--- a/fast-import.c
+++ b/fast-import.c
@@ -1708,8 +1708,8 @@ static int update_branch(struct branch *b)
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_update(transaction, b->name, b->sha1, old_sha1,
-				   0, 1, &err) ||
-	    ref_transaction_commit(transaction, msg, &err)) {
+				   0, 1, msg, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
 		error("%s", err.buf);
 		strbuf_release(&err);
@@ -1749,12 +1749,12 @@ static void dump_tags(void)
 		strbuf_addf(&ref_name, "refs/tags/%s", t->name);
 
 		if (ref_transaction_update(transaction, ref_name.buf, t->sha1,
-					   NULL, 0, 0, &err)) {
+					   NULL, 0, 0, msg, &err)) {
 			failure |= error("%s", err.buf);
 			goto cleanup;
 		}
 	}
-	if (ref_transaction_commit(transaction, msg, &err))
+	if (ref_transaction_commit(transaction, &err))
 		failure |= error("%s", err.buf);
 
  cleanup:
diff --git a/refs.c b/refs.c
index 5609622..99a9b86 100644
--- a/refs.c
+++ b/refs.c
@@ -2396,8 +2396,8 @@ static void prune_ref(struct ref_to_prune *r)
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, r->name, r->sha1,
-				   REF_ISPRUNING, 1, &err) ||
-	    ref_transaction_commit(transaction, NULL, &err)) {
+				   REF_ISPRUNING, 1, NULL, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
 		error("%s", err.buf);
 		strbuf_release(&err);
@@ -2571,8 +2571,8 @@ int delete_ref(const char *refname, const unsigned char *sha1, int delopt)
 	transaction = ref_transaction_begin(&err);
 	if (!transaction ||
 	    ref_transaction_delete(transaction, refname, sha1, delopt,
-				   sha1 && !is_null_sha1(sha1), &err) ||
-	    ref_transaction_commit(transaction, NULL, &err)) {
+				   sha1 && !is_null_sha1(sha1), NULL, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
 		error("%s", err.buf);
 		ref_transaction_free(transaction);
 		strbuf_release(&err);
@@ -3350,6 +3350,7 @@ struct ref_update {
 	int have_old; /* 1 if old_sha1 is valid, 0 otherwise */
 	struct ref_lock *lock;
 	int type;
+	char *msg;
 	const char refname[FLEX_ARRAY];
 };
 
@@ -3392,9 +3393,10 @@ void ref_transaction_free(struct ref_transaction *transaction)
 	if (!transaction)
 		return;
 
-	for (i = 0; i < transaction->nr; i++)
+	for (i = 0; i < transaction->nr; i++) {
+		free(transaction->updates[i]->msg);
 		free(transaction->updates[i]);
-
+	}
 	free(transaction->updates);
 	free(transaction);
 }
@@ -3415,7 +3417,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *new_sha1,
 			   const unsigned char *old_sha1,
-			   int flags, int have_old,
+			   int flags, int have_old, const char *msg,
 			   struct strbuf *err)
 {
 	struct ref_update *update;
@@ -3432,13 +3434,15 @@ int ref_transaction_update(struct ref_transaction *transaction,
 	update->have_old = have_old;
 	if (have_old)
 		hashcpy(update->old_sha1, old_sha1);
+	if (msg)
+		update->msg = xstrdup(msg);
 	return 0;
 }
 
 int ref_transaction_create(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *new_sha1,
-			   int flags,
+			   int flags, const char *msg,
 			   struct strbuf *err)
 {
 	struct ref_update *update;
@@ -3455,13 +3459,15 @@ int ref_transaction_create(struct ref_transaction *transaction,
 	hashclr(update->old_sha1);
 	update->flags = flags;
 	update->have_old = 1;
+	if (msg)
+		update->msg = xstrdup(msg);
 	return 0;
 }
 
 int ref_transaction_delete(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *old_sha1,
-			   int flags, int have_old,
+			   int flags, int have_old, const char *msg,
 			   struct strbuf *err)
 {
 	struct ref_update *update;
@@ -3479,6 +3485,8 @@ int ref_transaction_delete(struct ref_transaction *transaction,
 		assert(!is_null_sha1(old_sha1));
 		hashcpy(update->old_sha1, old_sha1);
 	}
+	if (msg)
+		update->msg = xstrdup(msg);
 	return 0;
 }
 
@@ -3492,8 +3500,8 @@ int update_ref(const char *action, const char *refname,
 	t = ref_transaction_begin(&err);
 	if (!t ||
 	    ref_transaction_update(t, refname, sha1, oldval, flags,
-				   !!oldval, &err) ||
-	    ref_transaction_commit(t, action, &err)) {
+				   !!oldval, action, &err) ||
+	    ref_transaction_commit(t, &err)) {
 		const char *str = "update_ref failed for ref '%s': %s";
 
 		ref_transaction_free(t);
@@ -3539,7 +3547,7 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
 }
 
 int ref_transaction_commit(struct ref_transaction *transaction,
-			   const char *msg, struct strbuf *err)
+			   struct strbuf *err)
 {
 	int ret = 0, delnum = 0, i;
 	const char **delnames;
@@ -3588,7 +3596,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 
 		if (!is_null_sha1(update->new_sha1)) {
 			ret = write_ref_sha1(update->lock, update->new_sha1,
-					     msg);
+					     update->msg);
 			update->lock = NULL; /* freed by write_ref_sha1 */
 			if (ret) {
 				if (err)
diff --git a/refs.h b/refs.h
index 69ef28c..7c1bf95 100644
--- a/refs.h
+++ b/refs.h
@@ -289,7 +289,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *new_sha1,
 			   const unsigned char *old_sha1,
-			   int flags, int have_old,
+			   int flags, int have_old, const char *msg,
 			   struct strbuf *err);
 
 /*
@@ -304,7 +304,7 @@ int ref_transaction_update(struct ref_transaction *transaction,
 int ref_transaction_create(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *new_sha1,
-			   int flags,
+			   int flags, const char *msg,
 			   struct strbuf *err);
 
 /*
@@ -318,7 +318,7 @@ int ref_transaction_create(struct ref_transaction *transaction,
 int ref_transaction_delete(struct ref_transaction *transaction,
 			   const char *refname,
 			   const unsigned char *old_sha1,
-			   int flags, int have_old,
+			   int flags, int have_old, const char *msg,
 			   struct strbuf *err);
 
 /*
@@ -327,7 +327,7 @@ int ref_transaction_delete(struct ref_transaction *transaction,
  * problem.
  */
 int ref_transaction_commit(struct ref_transaction *transaction,
-			   const char *msg, struct strbuf *err);
+			   struct strbuf *err);
 
 /*
  * Free an existing transaction and all associated data.
diff --git a/sequencer.c b/sequencer.c
index 5e93b6a..c5b7b8a 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -286,8 +286,8 @@ static int fast_forward_to(const unsigned char *to, const unsigned char *from,
 	if (!transaction ||
 	    ref_transaction_update(transaction, "HEAD",
 				   to, unborn ? null_sha1 : from,
-				   0, 1, &err) ||
-	    ref_transaction_commit(transaction, sb.buf, &err)) {
+				   0, 1, sb.buf, &err) ||
+	    ref_transaction_commit(transaction, &err)) {
 		ref_transaction_free(transaction);
 		error("%s", err.buf);
 		strbuf_release(&sb);
diff --git a/walker.c b/walker.c
index b8a5441..3c6fb8a 100644
--- a/walker.c
+++ b/walker.c
@@ -298,14 +298,13 @@ int walker_fetch(struct walker *walker, int targets, char **target,
 		strbuf_addf(&refname, "refs/%s", write_ref[i]);
 		if (ref_transaction_update(transaction, refname.buf,
 					   &sha1[20 * i], NULL, 0, 0,
+					   msg ? msg : "fetch (unknown)",
 					   &err)) {
 			error("%s", err.buf);
 			goto done;
 		}
 	}
-	if (ref_transaction_commit(transaction,
-				   msg ? msg : "fetch (unknown)",
-				   &err)) {
+	if (ref_transaction_commit(transaction, &err)) {
 		error("%s", err.buf);
 		goto done;
 	}

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:06 UTC · re: Jonathan Nieder · lore

[PATCH 06/19] rename_ref: don't ask read_ref_full where the ref came from

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Wed, 30 Apr 2014 12:41:04 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/refs.c b/refs.c
index 99a9b86..39571f5 100644
--- a/refs.c
+++ b/refs.c
@@ -2671,7 +2671,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 		goto rollback;
 	}
 
-	if (!read_ref_full(newrefname, sha1, 1, &flag) &&
+	if (!read_ref_full(newrefname, sha1, 1, NULL) &&
 	    delete_ref(newrefname, sha1, REF_NODEREF)) {
 		if (errno==EISDIR) {
 			if (remove_empty_directories(git_path("%s", newrefname))) {

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:07 UTC · re: Jonathan Nieder · lore

[PATCH 07/19] refs.c: move the check for valid refname to lock_ref_sha1_basic

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 1 May 2014 10:40:10 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/refs.c b/refs.c
index 39571f5..3c2ce57 100644
--- a/refs.c
+++ b/refs.c
@@ -2091,6 +2091,11 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	int missing = 0;
 	int attempts_remaining = 3;
 
+	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
+		errno = EINVAL;
+		return NULL;
+	}
+
 	lock = xcalloc(1, sizeof(struct ref_lock));
 	lock->lock_fd = -1;
 
@@ -2182,8 +2187,6 @@ struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
 {
-	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL))
-		return NULL;
 	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p);
 }
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:07 UTC · re: Jonathan Nieder · lore

[PATCH 08/19] refs.c: call lock_ref_sha1_basic directly from commit

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 1 May 2014 10:43:39 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/refs.c b/refs.c
index 3c2ce57..f124c2b 100644
--- a/refs.c
+++ b/refs.c
@@ -3578,12 +3578,12 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 	for (i = 0; i < n; i++) {
 		struct ref_update *update = updates[i];
 
-		update->lock = lock_any_ref_for_update(update->refname,
-						       (update->have_old ?
-							update->old_sha1 :
-							NULL),
-						       update->flags,
-						       &update->type);
+		update->lock = lock_ref_sha1_basic(update->refname,
+						   (update->have_old ?
+						    update->old_sha1 :
+						    NULL),
+						   update->flags,
+						   &update->type);
 		if (!update->lock) {
 			if (err)
 				strbuf_addf(err, "Cannot lock the ref '%s'.",

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:08 UTC · re: Jonathan Nieder · lore

[PATCH 09/19] refs.c: pass a skip list to name_conflict_fn

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Thu, 1 May 2014 11:16:07 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 41 ++++++++++++++++++++++++++++-------------
 1 file changed, 28 insertions(+), 13 deletions(-)

diff --git a/refs.c b/refs.c
index f124c2b..b63ab2f 100644
--- a/refs.c
+++ b/refs.c
@@ -801,14 +801,16 @@ static int names_conflict(const char *refname1, const char *refname2)
 
 struct name_conflict_cb {
 	const char *refname;
-	const char *oldrefname;
 	const char *conflicting_refname;
+	struct string_list *skiplist;
 };
 
 static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
 {
 	struct name_conflict_cb *data = (struct name_conflict_cb *)cb_data;
-	if (data->oldrefname && !strcmp(data->oldrefname, entry->name))
+
+	if (data->skiplist &&
+	    string_list_has_string(data->skiplist, entry->name))
 		return 0;
 	if (names_conflict(data->refname, entry->name)) {
 		data->conflicting_refname = entry->name;
@@ -822,15 +824,17 @@ static int name_conflict_fn(struct ref_entry *entry, void *cb_data)
  * conflicting with the name of an existing reference in dir.  If
  * oldrefname is non-NULL, ignore potential conflicts with oldrefname
  * (e.g., because oldrefname is scheduled for deletion in the same
- * operation).
+ * operation). skiplist contains a list of refs we want to skip checking for
+ * conflicts with. skiplist must be sorted.
  */
-static int is_refname_available(const char *refname, const char *oldrefname,
-				struct ref_dir *dir)
+static int is_refname_available(const char *refname,
+				struct ref_dir *dir,
+				struct string_list *skiplist)
 {
 	struct name_conflict_cb data;
 	data.refname = refname;
-	data.oldrefname = oldrefname;
 	data.conflicting_refname = NULL;
+	data.skiplist = skiplist;
 
 	sort_ref_dir(dir);
 	if (do_for_each_entry_in_dir(dir, 0, name_conflict_fn, &data)) {
@@ -2080,6 +2084,7 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
  */
 static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 					    const unsigned char *old_sha1,
+					    struct string_list *skiplist,
 					    int flags, int *type_p)
 {
 	char *ref_file;
@@ -2129,7 +2134,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	 * name is a proper prefix of our refname.
 	 */
 	if (missing &&
-	     !is_refname_available(refname, NULL, get_packed_refs(&ref_cache))) {
+	     !is_refname_available(refname, get_packed_refs(&ref_cache),
+				   skiplist)) {
 		last_errno = ENOTDIR;
 		goto error_return;
 	}
@@ -2187,7 +2193,7 @@ struct ref_lock *lock_any_ref_for_update(const char *refname,
 					 const unsigned char *old_sha1,
 					 int flags, int *type_p)
 {
-	return lock_ref_sha1_basic(refname, old_sha1, flags, type_p);
+	return lock_ref_sha1_basic(refname, old_sha1, NULL, flags, type_p);
 }
 
 /*
@@ -2648,6 +2654,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	struct stat loginfo;
 	int log = !lstat(git_path("logs/%s", oldrefname), &loginfo);
 	const char *symref = NULL;
+	struct string_list skiplist = STRING_LIST_INIT_NODUP;
 
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
@@ -2659,11 +2666,18 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	if (!symref)
 		return error("refname %s not found", oldrefname);
 
-	if (!is_refname_available(newrefname, oldrefname, get_packed_refs(&ref_cache)))
+	string_list_insert(&skiplist, oldrefname);
+	if (!is_refname_available(newrefname, get_packed_refs(&ref_cache),
+				  &skiplist)) {
+		string_list_clear(&skiplist, 0);
 		return 1;
-
-	if (!is_refname_available(newrefname, oldrefname, get_loose_refs(&ref_cache)))
+	}
+	if (!is_refname_available(newrefname, get_loose_refs(&ref_cache),
+				  &skiplist)) {
+		string_list_clear(&skiplist, 0);
 		return 1;
+	}
+	string_list_clear(&skiplist, 0);
 
 	if (log && rename(git_path("logs/%s", oldrefname), git_path(TMP_RENAMED_LOG)))
 		return error("unable to move logfile logs/%s to "TMP_RENAMED_LOG": %s",
@@ -2692,7 +2706,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 
 	logmoved = log;
 
-	lock = lock_ref_sha1_basic(newrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(newrefname, NULL, NULL, 0, NULL);
 	if (!lock) {
 		error("unable to lock %s for update", newrefname);
 		goto rollback;
@@ -2707,7 +2721,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	return 0;
 
  rollback:
-	lock = lock_ref_sha1_basic(oldrefname, NULL, 0, NULL);
+	lock = lock_ref_sha1_basic(oldrefname, NULL, NULL, 0, NULL);
 	if (!lock) {
 		error("unable to lock %s for rollback", oldrefname);
 		goto rollbacklog;
@@ -3582,6 +3596,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 						   (update->have_old ?
 						    update->old_sha1 :
 						    NULL),
+						   NULL,
 						   update->flags,
 						   &update->type);
 		if (!update->lock) {

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:08 UTC · re: Jonathan Nieder · lore

[PATCH 10/19] refs.c: ref_transaction_commit: distinguish name conflicts from other errors

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Fri, 16 May 2014 14:14:38 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 18 ++++++++++++------
 refs.h |  5 +++++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/refs.c b/refs.c
index b63ab2f..86c708a 100644
--- a/refs.c
+++ b/refs.c
@@ -3584,9 +3584,10 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 
 	/* Copy, sort, and reject duplicate refs */
 	qsort(updates, n, sizeof(*updates), ref_update_compare);
-	ret = ref_update_reject_duplicates(updates, n, err);
-	if (ret)
+	if (ref_update_reject_duplicates(updates, n, err)) {
+		ret = -1;
 		goto cleanup;
+	}
 
 	/* Acquire all locks while verifying old values */
 	for (i = 0; i < n; i++) {
@@ -3600,10 +3601,12 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 						   update->flags,
 						   &update->type);
 		if (!update->lock) {
+			int df_conflict = (errno == ENOTDIR);
+
 			if (err)
 				strbuf_addf(err, "Cannot lock the ref '%s'.",
 					    update->refname);
-			ret = 1;
+			ret = df_conflict ? UPDATE_REFS_NAME_CONFLICT : -1;
 			goto cleanup;
 		}
 	}
@@ -3620,6 +3623,7 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 				if (err)
 					strbuf_addf(err, "Cannot update the ref '%s'.",
 						    update->refname);
+				ret = -1;
 				goto cleanup;
 			}
 		}
@@ -3630,14 +3634,16 @@ int ref_transaction_commit(struct ref_transaction *transaction,
 		struct ref_update *update = updates[i];
 
 		if (update->lock) {
-			ret |= delete_ref_loose(update->lock, update->type,
-						err);
+			if (delete_ref_loose(update->lock, update->type, err))
+				ret = -1;
+
 			if (!(update->flags & REF_ISPRUNING))
 				delnames[delnum++] = update->lock->ref_name;
 		}
 	}
 
-	ret |= repack_without_refs(delnames, delnum, err);
+	if (repack_without_refs(delnames, delnum, err))
+		ret = -1;
 	for (i = 0; i < delnum; i++)
 		unlink_or_warn(git_path("logs/%s", delnames[i]));
 	clear_loose_ref_cache(&ref_cache);
diff --git a/refs.h b/refs.h
index 7c1bf95..e14aa31 100644
--- a/refs.h
+++ b/refs.h
@@ -325,7 +325,12 @@ int ref_transaction_delete(struct ref_transaction *transaction,
  * Commit all of the changes that have been queued in transaction, as
  * atomically as possible.  Return a nonzero value if there is a
  * problem.
+ *
+ * Function returns 0 on success, -1 for generic failures and
+ * UPDATE_REFS_NAME_CONFLICT (-2) if the failure was due to a naming conflict.
+ * For example, the ref names A and A/B conflict.
  */
+#define UPDATE_REFS_NAME_CONFLICT -2
 int ref_transaction_commit(struct ref_transaction *transaction,
 			   struct strbuf *err);
 

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:08 UTC · re: Jonathan Nieder · lore

[PATCH 11/19] fetch.c: change s_update_ref to use a ref transaction

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 13:49:07 -0700

Change s_update_ref to use a ref transaction for the ref update.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 builtin/fetch.c | 34 ++++++++++++++++++++++++----------
 1 file changed, 24 insertions(+), 10 deletions(-)

diff --git a/builtin/fetch.c b/builtin/fetch.c
index 55f457c..2e3bc73 100644
--- a/builtin/fetch.c
+++ b/builtin/fetch.c
@@ -375,23 +375,37 @@ static int s_update_ref(const char *action,
 {
 	char msg[1024];
 	char *rla = getenv("GIT_REFLOG_ACTION");
-	static struct ref_lock *lock;
+	struct ref_transaction *transaction;
+	struct strbuf err = STRBUF_INIT;
+	int ret, df_conflict = 0;
 
 	if (dry_run)
 		return 0;
 	if (!rla)
 		rla = default_rla.buf;
 	snprintf(msg, sizeof(msg), "%s: %s", rla, action);
-	lock = lock_any_ref_for_update(ref->name,
-				       check_old ? ref->old_sha1 : NULL,
-				       0, NULL);
-	if (!lock)
-		return errno == ENOTDIR ? STORE_REF_ERROR_DF_CONFLICT :
-					  STORE_REF_ERROR_OTHER;
-	if (write_ref_sha1(lock, ref->new_sha1, msg) < 0)
-		return errno == ENOTDIR ? STORE_REF_ERROR_DF_CONFLICT :
-					  STORE_REF_ERROR_OTHER;
+
+	transaction = ref_transaction_begin(&err);
+	if (!transaction ||
+	    ref_transaction_update(transaction, ref->name, ref->new_sha1,
+				   ref->old_sha1, 0, check_old, msg, &err))
+		goto fail;
+
+	ret = ref_transaction_commit(transaction, &err);
+	if (ret == UPDATE_REFS_NAME_CONFLICT)
+		df_conflict = 1;
+	if (ret)
+		goto fail;
+
+	ref_transaction_free(transaction);
+	strbuf_release(&err);
 	return 0;
+fail:
+	ref_transaction_free(transaction);
+	error("%s", err.buf);
+	strbuf_release(&err);
+	return df_conflict ? STORE_REF_ERROR_DF_CONFLICT
+			   : STORE_REF_ERROR_OTHER;
 }
 
 #define REFCOL_WIDTH  10

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:08 UTC · re: Jonathan Nieder · lore

[PATCH 12/19] refs.c: make write_ref_sha1 static

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Mon, 28 Apr 2014 15:36:58 -0700

No external users call write_ref_sha1 any more so lets declare it static.

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 refs.c | 10 ++++++++--
 refs.h |  3 ---
 2 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/refs.c b/refs.c
index 86c708a..c2dab4a 100644
--- a/refs.c
+++ b/refs.c
@@ -2646,6 +2646,9 @@ static int rename_tmp_log(const char *newrefname)
 	return 0;
 }
 
+static int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1,
+			  const char *logmsg);
+
 int rename_ref(const char *oldrefname, const char *newrefname, const char *logmsg)
 {
 	unsigned char sha1[20], orig_sha1[20];
@@ -2901,8 +2904,11 @@ static int is_branch(const char *refname)
 	return !strcmp(refname, "HEAD") || starts_with(refname, "refs/heads/");
 }
 
-/* This function must return a meaningful errno */
-int write_ref_sha1(struct ref_lock *lock,
+/*
+ * Writes sha1 into the ref specified by the lock. Makes sure that errno
+ * is sane on error.
+ */
+static int write_ref_sha1(struct ref_lock *lock,
 	const unsigned char *sha1, const char *logmsg)
 {
 	static char term = '\n';
diff --git a/refs.h b/refs.h
index e14aa31..fafa493 100644
--- a/refs.h
+++ b/refs.h
@@ -195,9 +195,6 @@ extern int commit_ref(struct ref_lock *lock);
 /** Release any lock taken but not written. **/
 extern void unlock_ref(struct ref_lock *lock);
 
-/** Writes sha1 into the ref specified by the lock. **/
-extern int write_ref_sha1(struct ref_lock *lock, const unsigned char *sha1, const char *msg);
-
 /*
  * Setup reflog before using. Set errno to something meaningful on failure.
  */

-- 
2.1.0.rc2.206.gedb03e5

Jonathan Nieder· Sep 11, 2014, 03:09 UTC · re: Jonathan Nieder · lore

[PATCH 13/19] refs.c: change resolve_ref_unsafe reading argument to be a flags field

From: Ronnie Sahlberg <sahlberg@google.com>
Date: Tue, 15 Jul 2014 12:59:36 -0700

Signed-off-by: Ronnie Sahlberg <sahlberg@google.com>
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
---
 branch.c                |  2 +-
 builtin/blame.c         |  2 +-
 builtin/branch.c        |  9 +++---
 builtin/checkout.c      |  6 ++--
 builtin/clone.c         |  2 +-
 builtin/commit.c        |  2 +-
 builtin/fmt-merge-msg.c |  2 +-
 builtin/for-each-ref.c  |  6 ++--
 builtin/fsck.c          |  2 +-
 builtin/log.c           |  3 +-
 builtin/merge.c         |  2 +-
 builtin/notes.c         |  2 +-
 builtin/receive-pack.c  |  4 +--
 builtin/remote.c        |  5 ++--
 builtin/show-branch.c   |  6 ++--
 builtin/symbolic-ref.c  |  2 +-
 bundle.c                |  2 +-
 cache.h                 | 21 ++++++-------
 http-backend.c          |  3 +-
 notes-merge.c           |  2 +-
 reflog-walk.c           |  5 ++--
 refs.c                  | 79 ++++++++++++++++++++++++++++---------------------
 remote.c                | 10 ++++---
 sequencer.c             |  4 +--
 transport-helper.c      |  4 ++-
 transport.c             |  5 ++--
 upload-pack.c           |  2 +-
 wt-status.c             |  2 +-
 28 files changed, 111 insertions(+), 85 deletions(-)

diff --git a/branch.c b/branch.c
index 76a8ec9..ba3e1c1 100644
--- a/branch.c
+++ b/branch.c
@@ -186,7 +186,7 @@ int validate_new_branchname(const char *name, struct strbuf *ref,
 		const char *head;
 		unsigned char sha1[20];
 
-		head = resolve_ref_unsafe("HEAD", sha1, 0, NULL);
+		head = resolve_ref_unsafe("HEAD", sha1, NULL, 0);
 		if (!is_bare_repository() && head && !strcmp(head, ref->buf))
 			die(_("Cannot force update the current branch."));
 	}
diff --git a/builtin/blame.c b/builtin/blame.c
index a52a279..b8bec0a 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -2292,7 +2292,7 @@ static struct commit *fake_working_tree_commit(struct diff_options *opt,
 	commit->object.type = OBJ_COMMIT;
 	parent_tail = &commit->parents;
 
-	if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
+	if (!resolve_ref_unsafe("HEAD", head_sha1, NULL, RESOLVE_REF_READING))
 		die("no such ref: HEAD");
 
 	parent_tail = append_parent(parent_tail, head_sha1);
diff --git a/builtin/branch.c b/builtin/branch.c
index 652b1d2..f144808 100644
--- a/builtin/branch.c
+++ b/builtin/branch.c
@@ -129,7 +129,8 @@ static int branch_merged(int kind, const char *name,
 		    branch->merge[0] &&
 		    branch->merge[0]->dst &&
 		    (reference_name = reference_name_to_free =
-		     resolve_refdup(branch->merge[0]->dst, sha1, 1, NULL)) != NULL)
+		     resolve_refdup(branch->merge[0]->dst, sha1,
+				    NULL, RESOLVE_REF_READING)) != NULL)
 			reference_rev = lookup_commit_reference(sha1);
 	}
 	if (!reference_rev)
@@ -233,7 +234,7 @@ static int delete_branches(int argc, const char **argv, int force, int kinds,
 		free(name);
 
 		name = mkpathdup(fmt, bname.buf);
-		target = resolve_ref_unsafe(name, sha1, 0, &flags);
+		target = resolve_ref_unsafe(name, sha1, &flags, 0);
 		if (!target ||
 		    (!(flags & REF_ISSYMREF) && is_null_sha1(sha1))) {
 			error(remote_branch
@@ -296,7 +297,7 @@ static char *resolve_symref(const char *src, const char *prefix)
 	int flag;
 	const char *dst, *cp;
 
-	dst = resolve_ref_unsafe(src, sha1, 0, &flag);
+	dst = resolve_ref_unsafe(src, sha1, &flag, 0);
 	if (!(dst && (flag & REF_ISSYMREF)))
 		return NULL;
 	if (prefix && (cp = skip_prefix(dst, prefix)))
@@ -862,7 +863,7 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 
 	track = git_branch_track;
 
-	head = resolve_refdup("HEAD", head_sha1, 0, NULL);
+	head = resolve_refdup("HEAD", head_sha1, NULL, 0);
 	if (!head)
 		die(_("Failed to resolve HEAD as a valid ref."));
 	if (!strcmp(head, "HEAD")) {
diff --git a/builtin/checkout.c b/builtin/checkout.c
index f1dc56e..64af1f7 100644
--- a/builtin/checkout.c
+++ b/builtin/checkout.c
@@ -356,7 +356,7 @@ static int checkout_paths(const struct checkout_opts *opts,
 	    commit_locked_index(lock_file))
 		die(_("unable to write new index file"));
 
-	read_ref_full("HEAD", rev, 0, &flag);
+	read_ref_full("HEAD", rev, &flag, 0);
 	head = lookup_commit_reference_gently(rev, 1);
 
 	errs |= post_checkout_hook(head, head, 0);
@@ -771,7 +771,7 @@ static int switch_branches(const struct checkout_opts *opts,
 	unsigned char rev[20];
 	int flag, writeout_error = 0;
 	memset(&old, 0, sizeof(old));
-	old.path = path_to_free = resolve_refdup("HEAD", rev, 0, &flag);
+	old.path = path_to_free = resolve_refdup("HEAD", rev, &flag, 0);
 	old.commit = lookup_commit_reference_gently(rev, 1);
 	if (!(flag & REF_ISSYMREF))
 		old.path = NULL;
@@ -1068,7 +1068,7 @@ static int checkout_branch(struct checkout_opts *opts,
 		unsigned char rev[20];
 		int flag;
 
-		if (!read_ref_full("HEAD", rev, 0, &flag) &&
+		if (!read_ref_full("HEAD", rev, &flag, 0) &&
 		    (flag & REF_ISSYMREF) && is_null_sha1(rev))
 			return switch_unborn_to_new_branch(opts);
 	}
diff --git a/builtin/clone.c b/builtin/clone.c
index b12989d..12a78e1 100644
--- a/builtin/clone.c
+++ b/builtin/clone.c
@@ -622,7 +622,7 @@ static int checkout(void)
 	if (option_no_checkout)
 		return 0;
 
-	head = resolve_refdup("HEAD", sha1, 1, NULL);
+	head = resolve_refdup("HEAD", sha1, NULL, RESOLVE_REF_READING);
 	if (!head) {
 		warning(_("remote HEAD refers to nonexistent ref, "
 			  "unable to checkout.\n"));
diff --git a/builtin/commit.c b/builtin/commit.c
index d23e876..3536330 100644
--- a/builtin/commit.c
+++ b/builtin/commit.c
@@ -1468,7 +1468,7 @@ static void print_summary(const char *prefix, const unsigned char *sha1,
 	rev.diffopt.break_opt = 0;
 	diff_setup_done(&rev.diffopt);
 
-	head = resolve_ref_unsafe("HEAD", junk_sha1, 0, NULL);
+	head = resolve_ref_unsafe("HEAD", junk_sha1, NULL, 0);
 	printf("[%s%s ",
 		starts_with(head, "refs/heads/") ?
 			head + 11 :
diff --git a/builtin/fmt-merge-msg.c b/builtin/fmt-merge-msg.c
index 3906eda..b2355ad 100644
--- a/builtin/fmt-merge-msg.c
+++ b/builtin/fmt-merge-msg.c
@@ -602,7 +602,7 @@ int fmt_merge_msg(struct strbuf *in, struct strbuf *out,
 
 	/* get current branch */
 	current_branch = current_branch_to_free =
-		resolve_refdup("HEAD", head_sha1, 1, NULL);
+		resolve_refdup("HEAD", head_sha1, NULL, RESOLVE_REF_READING);
 	if (!current_branch)
 		die("No current branch");
 	if (starts_with(current_branch, "refs/heads/"))
diff --git a/builtin/for-each-ref.c b/builtin/for-each-ref.c
index 3e1d5c3..e193073 100644
--- a/builtin/for-each-ref.c
+++ b/builtin/for-each-ref.c
@@ -649,7 +649,8 @@ static void populate_value(struct refinfo *ref)
 
 	if (need_symref && (ref->flag & REF_ISSYMREF) && !ref->symref) {
 		unsigned char unused1[20];
-		ref->symref = resolve_refdup(ref->refname, unused1, 1, NULL);
+		ref->symref = resolve_refdup(ref->refname, unused1,
+					     NULL, RESOLVE_REF_READING);
 		if (!ref->symref)
 			ref->symref = "";
 	}
@@ -707,7 +708,8 @@ static void populate_value(struct refinfo *ref)
 			const char *head;
 			unsigned char sha1[20];
 
-			head = resolve_ref_unsafe("HEAD", sha1, 1, NULL);
+			head = resolve_ref_unsafe("HEAD", sha1,
+						  NULL, RESOLVE_REF_READING);
 			if (!strcmp(ref->refname, head))
 				v->s = "*";
 			else
diff --git a/builtin/fsck.c b/builtin/fsck.c
index fc150c8..506e32b 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -560,7 +560,7 @@ static int fsck_head_link(void)
 	if (verbose)
 		fprintf(stderr, "Checking HEAD link\n");
 
-	head_points_at = resolve_ref_unsafe("HEAD", head_sha1, 0, &flag);
+	head_points_at = resolve_ref_unsafe("HEAD", head_sha1, &flag, 0);
 	if (!head_points_at)
 		return error("Invalid HEAD");
 	if (!strcmp(head_points_at, "HEAD"))
diff --git a/builtin/log.c b/builtin/log.c
index a7ba211..230a9ef 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1395,7 +1395,8 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 		if (check_head) {
 			unsigned char sha1[20];
 			const char *ref;
-			ref = resolve_ref_unsafe("HEAD", sha1, 1, NULL);
+			ref = resolve_ref_unsafe("HEAD", sha1, NULL,
+						 RESOLVE_REF_READING);
 			if (ref && starts_with(ref, "refs/heads/"))
 				branch_name = xstrdup(ref + strlen("refs/heads/"));
 			else
diff --git a/builtin/merge.c b/builtin/merge.c
index 428ca24..d262279 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1108,7 +1108,7 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 	 * Check if we are _not_ on a detached HEAD, i.e. if there is a
 	 * current branch.
 	 */
-	branch = branch_to_free = resolve_refdup("HEAD", head_sha1, 0, &flag);
+	branch = branch_to_free = resolve_refdup("HEAD", head_sha1, &flag, 0);
 	if (branch && starts_with(branch, "refs/heads/"))
 		branch += 11;
 	if (!branch || is_null_sha1(head_sha1))
diff --git a/builtin/notes.c b/builtin/notes.c
index 820c341..16df78c 100644
--- a/builtin/notes.c
+++ b/builtin/notes.c
@@ -703,7 +703,7 @@ static int merge_commit(struct notes_merge_options *o)
 	init_notes(t, "NOTES_MERGE_PARTIAL", combine_notes_overwrite, 0);
 
 	o->local_ref = local_ref_to_free =
-		resolve_refdup("NOTES_MERGE_REF", sha1, 0, NULL);
+		resolve_refdup("NOTES_MERGE_REF", sha1, NULL, 0);
 	if (!o->local_ref)
 		die("Failed to resolve NOTES_MERGE_REF");
 
diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c
index d1f4cf7..555a4a6 100644
--- a/builtin/receive-pack.c
+++ b/builtin/receive-pack.c
@@ -656,7 +656,7 @@ static void check_aliased_update(struct command *cmd, struct string_list *list)
 	int flag;
 
 	strbuf_addf(&buf, "%s%s", get_git_namespace(), cmd->ref_name);
-	dst_name = resolve_ref_unsafe(buf.buf, sha1, 0, &flag);
+	dst_name = resolve_ref_unsafe(buf.buf, sha1, &flag, 0);
 	strbuf_release(&buf);
 
 	if (!(flag & REF_ISSYMREF))
@@ -817,7 +817,7 @@ static void execute_commands(struct command *commands,
 	check_aliased_updates(commands);
 
 	free(head_name_to_free);
-	head_name = head_name_to_free = resolve_refdup("HEAD", sha1, 0, NULL);
+	head_name = head_name_to_free = resolve_refdup("HEAD", sha1, NULL, 0);
 
 	checked_connectivity = 1;
 	for (cmd = commands; cmd; cmd = cmd->next) {
diff --git a/builtin/remote.c b/builtin/remote.c
index 401feb3..6eaeee7 100644
--- a/builtin/remote.c
+++ b/builtin/remote.c
@@ -568,7 +568,8 @@ static int read_remote_branches(const char *refname,
 	strbuf_addf(&buf, "refs/remotes/%s/", rename->old);
 	if (starts_with(refname, buf.buf)) {
 		item = string_list_append(rename->remote_branches, xstrdup(refname));
-		symref = resolve_ref_unsafe(refname, orig_sha1, 1, &flag);
+		symref = resolve_ref_unsafe(refname, orig_sha1, &flag,
+					    RESOLVE_REF_READING);
 		if (flag & REF_ISSYMREF)
 			item->util = xstrdup(symref);
 		else
@@ -704,7 +705,7 @@ static int mv(int argc, const char **argv)
 		int flag = 0;
 		unsigned char sha1[20];
 
-		read_ref_full(item->string, sha1, 1, &flag);
+		read_ref_full(item->string, sha1, &flag, RESOLVE_REF_READING);
 		if (!(flag & REF_ISSYMREF))
 			continue;
 		if (delete_ref(item->string, NULL, REF_NODEREF))
diff --git a/builtin/show-branch.c b/builtin/show-branch.c
index d873172..ef6ea52 100644
--- a/builtin/show-branch.c
+++ b/builtin/show-branch.c
@@ -727,7 +727,8 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		if (ac == 0) {
 			static const char *fake_av[2];
 
-			fake_av[0] = resolve_refdup("HEAD", sha1, 1, NULL);
+			fake_av[0] = resolve_refdup("HEAD", sha1, NULL,
+						    RESOLVE_REF_READING);
 			fake_av[1] = NULL;
 			av = fake_av;
 			ac = 1;
@@ -789,7 +790,8 @@ int cmd_show_branch(int ac, const char **av, const char *prefix)
 		}
 	}
 
-	head_p = resolve_ref_unsafe("HEAD", head_sha1, 1, NULL);
+	head_p = resolve_ref_unsafe("HEAD", head_sha1, NULL,
+				    RESOLVE_REF_READING);
 	if (head_p) {
 		head_len = strlen(head_p);
 		memcpy(head, head_p, head_len + 1);
diff --git a/builtin/symbolic-ref.c b/builtin/symbolic-ref.c
index b6a711d..1dd04af 100644
--- a/builtin/symbolic-ref.c
+++ b/builtin/symbolic-ref.c
@@ -13,7 +13,7 @@ static int check_symref(const char *HEAD, int quiet, int shorten, int print)
 {
 	unsigned char sha1[20];
 	int flag;
-	const char *refname = resolve_ref_unsafe(HEAD, sha1, 0, &flag);
+	const char *refname = resolve_ref_unsafe(HEAD, sha1, &flag, 0);
 
 	if (!refname)
 		die("No such ref: %s", HEAD);
diff --git a/bundle.c b/bundle.c
index 1222952..32dd2f7 100644
--- a/bundle.c
+++ b/bundle.c
@@ -311,7 +311,7 @@ int create_bundle(struct bundle_header *header, const char *path,
 			continue;
 		if (dwim_ref(e->name, strlen(e->name), sha1, &ref) != 1)
 			continue;
-		if (read_ref_full(e->name, sha1, 1, &flag))
+		if (read_ref_full(e->name, sha1, &flag, RESOLVE_REF_READING))
 			flag = 0;
 		display_ref = (flag & REF_ISSYMREF) ? e->name : ref;
 
diff --git a/cache.h b/cache.h
index e7ec626..2d3c5ed 100644
--- a/cache.h
+++ b/cache.h
@@ -948,7 +948,7 @@ extern int get_sha1_hex(const char *hex, unsigned char *sha1);
 
 extern char *sha1_to_hex(const unsigned char *sha1);	/* static buffer result! */
 extern int read_ref_full(const char *refname, unsigned char *sha1,
-			 int reading, int *flags);
+			 int *flags, int resolve_flags);
 extern int read_ref(const char *refname, unsigned char *sha1);
 
 /*
@@ -960,20 +960,20 @@ extern int read_ref(const char *refname, unsigned char *sha1);
  * or the input ref.
  *
  * If the reference cannot be resolved to an object, the behavior
- * depends on the "reading" argument:
+ * depends on the RESOLVE_REF_READING flag:
  *
- * - If reading is set, return NULL.
+ * - If RESOLVE_REF_READING is set, return NULL.
  *
- * - If reading is not set, clear sha1 and return the name of the last
- *   reference name in the chain, which will either be a non-symbolic
+ * - If RESOLVE_REF_READING is not set, clear sha1 and return the name of
+ *   the last reference name in the chain, which will either be a non-symbolic
  *   reference or an undefined reference.  If this is a prelude to
  *   "writing" to the ref, the return value is the name of the ref
  *   that will actually be created or changed.
  *
- * If flag is non-NULL, set the value that it points to the
+ * If flags is non-NULL, set the value that it points to the
  * combination of REF_ISPACKED (if the reference was found among the
- * packed references) and REF_ISSYMREF (if the initial reference was a
- * symbolic reference).
+ * packed references), REF_ISSYMREF (if the initial reference was a
+ * symbolic reference) and REF_ISBROKEN (if the ref is malformed).
  *
  * If ref is not a properly-formatted, normalized reference, return
  * NULL.  If more than MAXDEPTH recursive symbolic lookups are needed,
@@ -981,8 +981,9 @@ extern int read_ref(const char *refname, unsigned char *sha1);
  *
  * errno is set to something meaningful on error.
  */
-extern const char *resolve_ref_unsafe(const char *ref, unsigned char *sha1, int reading, int *flag);
-extern char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag);
+#define RESOLVE_REF_READING 0x01
+extern const char *resolve_ref_unsafe(const char *ref, unsigned char *sha1, int *flags, int resolve_flags);
+extern char *resolve_refdup(const char *ref, unsigned char *sha1, int *flags, int resolve_flags);
 
 extern int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref);
 extern int dwim_log(const char *str, int len, unsigned char *sha1, char **ref);
diff --git a/http-backend.c b/http-backend.c
index d2c0a62..8f94f9b 100644
--- a/http-backend.c
+++ b/http-backend.c
@@ -417,7 +417,8 @@ static int show_head_ref(const char *refname, const unsigned char *sha1,
 
 	if (flag & REF_ISSYMREF) {
 		unsigned char unused[20];
-		const char *target = resolve_ref_unsafe(refname, unused, 1, NULL);
+		const char *target = resolve_ref_unsafe(refname, unused,
+						NULL, RESOLVE_REF_READING);
 		const char *target_nons = strip_namespace(target);
 
 		strbuf_addf(buf, "ref: %s\n", target_nons);
diff --git a/notes-merge.c b/notes-merge.c
index 94a1a8a..ffca602 100644
--- a/notes-merge.c
+++ b/notes-merge.c
@@ -549,7 +549,7 @@ int notes_merge(struct notes_merge_options *o,
 	       o->local_ref, o->remote_ref);
 
 	/* Dereference o->local_ref into local_sha1 */
-	if (read_ref_full(o->local_ref, local_sha1, 0, NULL))
+	if (read_ref_full(o->local_ref, local_sha1, NULL, 0))
 		die("Failed to resolve local notes ref '%s'", o->local_ref);
 	else if (!check_refname_format(o->local_ref, 0) &&
 		is_null_sha1(local_sha1))
diff --git a/reflog-walk.c b/reflog-walk.c
index 9ce8b53..feeaf0a 100644
--- a/reflog-walk.c
+++ b/reflog-walk.c
@@ -48,7 +48,8 @@ static struct complete_reflogs *read_complete_reflog(const char *ref)
 		unsigned char sha1[20];
 		const char *name;
 		void *name_to_free;
-		name = name_to_free = resolve_refdup(ref, sha1, 1, NULL);
+		name = name_to_free = resolve_refdup(ref, sha1, NULL,
+						     RESOLVE_REF_READING);
 		if (name) {
 			for_each_reflog_ent(name, read_one_reflog, reflogs);
 			free(name_to_free);
@@ -174,7 +175,7 @@ int add_reflog_for_walk(struct reflog_walk_info *info,
 		if (*branch == '\0') {
 			unsigned char sha1[20];
 			free(branch);
-			branch = resolve_refdup("HEAD", sha1, 0, NULL);
+			branch = resolve_refdup("HEAD", sha1, NULL, 0);
 			if (!branch)
 				die ("No current branch");
 
diff --git a/refs.c b/refs.c
index c2dab4a..a5f9734 100644
--- a/refs.c
+++ b/refs.c
@@ -1192,7 +1192,8 @@ static void read_loose_refs(const char *dirname, struct ref_dir *dir)
 					hashclr(sha1);
 					flag |= REF_ISBROKEN;
 				}
-			} else if (read_ref_full(refname.buf, sha1, 1, &flag)) {
+			} else if (read_ref_full(refname.buf, sha1, &flag,
+						 RESOLVE_REF_READING)) {
 				hashclr(sha1);
 				flag |= REF_ISBROKEN;
 			}
@@ -1344,21 +1345,20 @@ static const char *handle_missing_loose_ref(const char *refname,
 }
 
 /* This function needs to return a meaningful errno on failure */
-const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int reading, int *flag)
+const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int *flags, int resolve_flags)
 {
 	int depth = MAXDEPTH;
 	ssize_t len;
 	char buffer[256];
 	static char refname_buffer[256];
 
-	if (flag)
-		*flag = 0;
+	if (flags)
+		*flags = 0;
 
 	if (check_refname_format(refname, REFNAME_ALLOW_ONELEVEL)) {
 		errno = EINVAL;
 		return NULL;
 	}
-
 	for (;;) {
 		char path[PATH_MAX];
 		struct stat st;
@@ -1385,7 +1385,8 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int rea
 		if (lstat(path, &st) < 0) {
 			if (errno == ENOENT)
 				return handle_missing_loose_ref(refname, sha1,
-								reading, flag);
+					resolve_flags & RESOLVE_REF_READING,
+					flags);
 			else
 				return NULL;
 		}
@@ -1405,8 +1406,8 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int rea
 					!check_refname_format(buffer, 0)) {
 				strcpy(refname_buffer, buffer);
 				refname = refname_buffer;
-				if (flag)
-					*flag |= REF_ISSYMREF;
+				if (flags)
+					*flags |= REF_ISSYMREF;
 				continue;
 			}
 		}
@@ -1451,21 +1452,21 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int rea
 			 */
 			if (get_sha1_hex(buffer, sha1) ||
 			    (buffer[40] != '\0' && !isspace(buffer[40]))) {
-				if (flag)
-					*flag |= REF_ISBROKEN;
+				if (flags)
+					*flags |= REF_ISBROKEN;
 				errno = EINVAL;
 				return NULL;
 			}
 			return refname;
 		}
-		if (flag)
-			*flag |= REF_ISSYMREF;
+		if (flags)
+			*flags |= REF_ISSYMREF;
 		buf = buffer + 4;
 		while (isspace(*buf))
 			buf++;
 		if (check_refname_format(buf, REFNAME_ALLOW_ONELEVEL)) {
-			if (flag)
-				*flag |= REF_ISBROKEN;
+			if (flags)
+				*flags |= REF_ISBROKEN;
 			errno = EINVAL;
 			return NULL;
 		}
@@ -1473,9 +1474,9 @@ const char *resolve_ref_unsafe(const char *refname, unsigned char *sha1, int rea
 	}
 }
 
-char *resolve_refdup(const char *ref, unsigned char *sha1, int reading, int *flag)
+char *resolve_refdup(const char *ref, unsigned char *sha1, int *flags, int resolve_flags)
 {
-	const char *ret = resolve_ref_unsafe(ref, sha1, reading, flag);
+	const char *ret = resolve_ref_unsafe(ref, sha1, flags, resolve_flags);
 	return ret ? xstrdup(ret) : NULL;
 }
 
@@ -1486,22 +1487,22 @@ struct ref_filter {
 	void *cb_data;
 };
 
-int read_ref_full(const char *refname, unsigned char *sha1, int reading, int *flags)
+int read_ref_full(const char *refname, unsigned char *sha1, int *flags, int resolve_flags)
 {
-	if (resolve_ref_unsafe(refname, sha1, reading, flags))
+	if (resolve_ref_unsafe(refname, sha1, flags, resolve_flags))
 		return 0;
 	return -1;
 }
 
 int read_ref(const char *refname, unsigned char *sha1)
 {
-	return read_ref_full(refname, sha1, 1, NULL);
+	return read_ref_full(refname, sha1, NULL, RESOLVE_REF_READING);
 }
 
 int ref_exists(const char *refname)
 {
 	unsigned char sha1[20];
-	return !!resolve_ref_unsafe(refname, sha1, 1, NULL);
+	return !!resolve_ref_unsafe(refname, sha1, NULL, RESOLVE_REF_READING);
 }
 
 static int filter_refs(const char *refname, const unsigned char *sha1, int flags,
@@ -1615,7 +1616,7 @@ int peel_ref(const char *refname, unsigned char *sha1)
 		return 0;
 	}
 
-	if (read_ref_full(refname, base, 1, &flag))
+	if (read_ref_full(refname, base, &flag, RESOLVE_REF_READING))
 		return -1;
 
 	/*
@@ -1656,7 +1657,7 @@ static int warn_if_dangling_symref(const char *refname, const unsigned char *sha
 	if (!(flags & REF_ISSYMREF))
 		return 0;
 
-	resolves_to = resolve_ref_unsafe(refname, junk, 0, NULL);
+	resolves_to = resolve_ref_unsafe(refname, junk, NULL, 0);
 	if (!resolves_to
 	    || (d->refname
 		? strcmp(resolves_to, d->refname)
@@ -1781,7 +1782,7 @@ static int do_head_ref(const char *submodule, each_ref_fn fn, void *cb_data)
 		return 0;
 	}
 
-	if (!read_ref_full("HEAD", sha1, 1, &flag))
+	if (!read_ref_full("HEAD", sha1, &flag, RESOLVE_REF_READING))
 		return fn("HEAD", sha1, flag, cb_data);
 
 	return 0;
@@ -1861,7 +1862,7 @@ int head_ref_namespaced(each_ref_fn fn, void *cb_data)
 	int flag;
 
 	strbuf_addf(&buf, "%sHEAD", get_git_namespace());
-	if (!read_ref_full(buf.buf, sha1, 1, &flag))
+	if (!read_ref_full(buf.buf, sha1, &flag, RESOLVE_REF_READING))
 		ret = fn(buf.buf, sha1, flag, cb_data);
 	strbuf_release(&buf);
 
@@ -1956,7 +1957,8 @@ int refname_match(const char *abbrev_name, const char *full_name)
 static struct ref_lock *verify_lock(struct ref_lock *lock,
 	const unsigned char *old_sha1, int mustexist)
 {
-	if (read_ref_full(lock->ref_name, lock->old_sha1, mustexist, NULL)) {
+	if (read_ref_full(lock->ref_name, lock->old_sha1, NULL,
+			  mustexist ? RESOLVE_REF_READING : 0)) {
 		int save_errno = errno;
 		error("Can't verify ref %s", lock->ref_name);
 		unlock_ref(lock);
@@ -2029,7 +2031,8 @@ int dwim_ref(const char *str, int len, unsigned char *sha1, char **ref)
 
 		this_result = refs_found ? sha1_from_ref : sha1;
 		mksnpath(fullref, sizeof(fullref), *p, len, str);
-		r = resolve_ref_unsafe(fullref, this_result, 1, &flag);
+		r = resolve_ref_unsafe(fullref, this_result, &flag,
+				       RESOLVE_REF_READING);
 		if (r) {
 			if (!refs_found++)
 				*ref = xstrdup(r);
@@ -2058,7 +2061,7 @@ int dwim_log(const char *str, int len, unsigned char *sha1, char **log)
 		const char *ref, *it;
 
 		mksnpath(path, sizeof(path), *p, len, str);
-		ref = resolve_ref_unsafe(path, hash, 1, NULL);
+		ref = resolve_ref_unsafe(path, hash, NULL, RESOLVE_REF_READING);
 		if (!ref)
 			continue;
 		if (reflog_exists(path))
@@ -2093,6 +2096,7 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	int last_errno = 0;
 	int type, lflags;
 	int mustexist = (old_sha1 && !is_null_sha1(old_sha1));
+	int resolve_flags = 0;
 	int missing = 0;
 	int attempts_remaining = 3;
 
@@ -2104,7 +2108,11 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 	lock = xcalloc(1, sizeof(struct ref_lock));
 	lock->lock_fd = -1;
 
-	refname = resolve_ref_unsafe(refname, lock->old_sha1, mustexist, &type);
+	if (mustexist)
+		resolve_flags |= RESOLVE_REF_READING;
+
+	refname = resolve_ref_unsafe(refname, lock->old_sha1, &type,
+				     resolve_flags);
 	if (!refname && errno == EISDIR) {
 		/* we are trying to lock foo but we used to
 		 * have foo/bar which now does not exist;
@@ -2117,7 +2125,8 @@ static struct ref_lock *lock_ref_sha1_basic(const char *refname,
 			error("there are still refs under '%s'", orig_refname);
 			goto error_return;
 		}
-		refname = resolve_ref_unsafe(orig_refname, lock->old_sha1, mustexist, &type);
+		refname = resolve_ref_unsafe(orig_refname, lock->old_sha1,
+					     &type, resolve_flags);
 	}
 	if (type_p)
 	    *type_p = type;
@@ -2470,7 +2479,7 @@ static int curate_packed_ref_fn(struct ref_entry *entry, void *cb_data)
 		unsigned char sha1[20];
 		int flags;
 
-		if (read_ref_full(entry->name, sha1, 0, &flags))
+		if (read_ref_full(entry->name, sha1, &flags, 0))
 			/* We should at least have found the packed ref. */
 			die("Internal error");
 		if ((flags & REF_ISSYMREF) || !(flags & REF_ISPACKED)) {
@@ -2662,7 +2671,8 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 	if (log && S_ISLNK(loginfo.st_mode))
 		return error("reflog for %s is a symlink", oldrefname);
 
-	symref = resolve_ref_unsafe(oldrefname, orig_sha1, 1, &flag);
+	symref = resolve_ref_unsafe(oldrefname, orig_sha1, &flag,
+				    RESOLVE_REF_READING);
 	if (flag & REF_ISSYMREF)
 		return error("refname %s is a symbolic ref, renaming it is not supported",
 			oldrefname);
@@ -2691,7 +2701,7 @@ int rename_ref(const char *oldrefname, const char *newrefname, const char *logms
 		goto rollback;
 	}
 
-	if (!read_ref_full(newrefname, sha1, 1, NULL) &&
+	if (!read_ref_full(newrefname, sha1, NULL, RESOLVE_REF_READING) &&
 	    delete_ref(newrefname, sha1, REF_NODEREF)) {
 		if (errno==EISDIR) {
 			if (remove_empty_directories(git_path("%s", newrefname))) {
@@ -2969,7 +2979,8 @@ static int write_ref_sha1(struct ref_lock *lock,
 		unsigned char head_sha1[20];
 		int head_flag;
 		const char *head_ref;
-		head_ref = resolve_ref_unsafe("HEAD", head_sha1, 1, &head_flag);
+		head_ref = resolve_ref_unsafe("HEAD", head_sha1, &head_flag,
+					      RESOLVE_REF_READING);
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name))
 			log_ref_write("HEAD", lock->old_sha1, sha1, logmsg);
@@ -3336,7 +3347,7 @@ static int do_for_each_reflog(struct strbuf *name, each_ref_fn fn, void *cb_data
 				retval = do_for_each_reflog(name, fn, cb_data);
 			} else {
 				unsigned char sha1[20];
-				if (read_ref_full(name->buf, sha1, 0, NULL))
+				if (read_ref_full(name->buf, sha1, NULL, 0))
 					retval = error("bad ref for %s", name->buf);
 				else
 					retval = fn(name->buf, sha1, 0, cb_data);
diff --git a/remote.c b/remote.c
index 0e9459c..67c375d 100644
--- a/remote.c
+++ b/remote.c
@@ -486,7 +486,7 @@ static void read_config(void)
 		return;
 	default_remote_name = "origin";
 	current_branch = NULL;
-	head_ref = resolve_ref_unsafe("HEAD", sha1, 0, &flag);
+	head_ref = resolve_ref_unsafe("HEAD", sha1, &flag, 0);
 	if (head_ref && (flag & REF_ISSYMREF) &&
 	    starts_with(head_ref, "refs/heads/")) {
 		current_branch =
@@ -1121,7 +1121,8 @@ static char *guess_ref(const char *name, struct ref *peer)
 	struct strbuf buf = STRBUF_INIT;
 	unsigned char sha1[20];
 
-	const char *r = resolve_ref_unsafe(peer->name, sha1, 1, NULL);
+	const char *r = resolve_ref_unsafe(peer->name, sha1, NULL,
+					   RESOLVE_REF_READING);
 	if (!r)
 		return NULL;
 
@@ -1182,7 +1183,8 @@ static int match_explicit(struct ref *src, struct ref *dst,
 		unsigned char sha1[20];
 		int flag;
 
-		dst_value = resolve_ref_unsafe(matched_src->name, sha1, 1, &flag);
+		dst_value = resolve_ref_unsafe(matched_src->name, sha1, &flag,
+					       RESOLVE_REF_READING);
 		if (!dst_value ||
 		    ((flag & REF_ISSYMREF) &&
 		     !starts_with(dst_value, "refs/heads/")))
@@ -1656,7 +1658,7 @@ static int ignore_symref_update(const char *refname)
 	unsigned char sha1[20];
 	int flag;
 
-	if (!resolve_ref_unsafe(refname, sha1, 0, &flag))
+	if (!resolve_ref_unsafe(refname, sha1, &flag, 0))
 		return 0; /* non-existing refs are OK */
 	return (flag & REF_ISSYMREF);
 }
diff --git a/sequencer.c b/sequencer.c
index c5b7b8a..6a05ad4 100644
--- a/sequencer.c
+++ b/sequencer.c
@@ -366,7 +366,7 @@ static int is_index_unchanged(void)
 	unsigned char head_sha1[20];
 	struct commit *head_commit;
 
-	if (!resolve_ref_unsafe("HEAD", head_sha1, 1, NULL))
+	if (!resolve_ref_unsafe("HEAD", head_sha1, NULL, RESOLVE_REF_READING))
 		return error(_("Could not resolve HEAD commit\n"));
 
 	head_commit = lookup_commit(head_sha1);
@@ -912,7 +912,7 @@ static int rollback_single_pick(void)
 	if (!file_exists(git_path("CHERRY_PICK_HEAD")) &&
 	    !file_exists(git_path("REVERT_HEAD")))
 		return error(_("no cherry-pick or revert in progress"));
-	if (read_ref_full("HEAD", head_sha1, 0, NULL))
+	if (read_ref_full("HEAD", head_sha1, NULL, 0))
 		return error(_("cannot resolve HEAD"));
 	if (is_null_sha1(head_sha1))
 		return error(_("cannot abort from a branch yet to be born"));
diff --git a/transport-helper.c b/transport-helper.c
index 84c616f..8365441 100644
--- a/transport-helper.c
+++ b/transport-helper.c
@@ -889,7 +889,9 @@ static int push_refs_with_export(struct transport *transport,
 					int flag;
 
 					/* Follow symbolic refs (mainly for HEAD). */
-					name = resolve_ref_unsafe(ref->peer_ref->name, sha1, 1, &flag);
+					name = resolve_ref_unsafe(
+						 ref->peer_ref->name, sha1,
+						 &flag, RESOLVE_REF_READING);
 					if (!name || !(flag & REF_ISSYMREF))
 						name = ref->peer_ref->name;
 
diff --git a/transport.c b/transport.c
index 325f03e..3ba7bbf 100644
--- a/transport.c
+++ b/transport.c
@@ -168,7 +168,8 @@ static void set_upstreams(struct transport *transport, struct ref *refs,
 		/* Follow symbolic refs (mainly for HEAD). */
 		localname = ref->peer_ref->name;
 		remotename = ref->name;
-		tmp = resolve_ref_unsafe(localname, sha, 1, &flag);
+		tmp = resolve_ref_unsafe(localname, sha, &flag,
+					 RESOLVE_REF_READING);
 		if (tmp && flag & REF_ISSYMREF &&
 			starts_with(tmp, "refs/heads/"))
 			localname = tmp;
@@ -753,7 +754,7 @@ void transport_print_push_status(const char *dest, struct ref *refs,
 	unsigned char head_sha1[20];
 	char *head;
 
-	head = resolve_refdup("HEAD", head_sha1, 1, NULL);
+	head = resolve_refdup("HEAD", head_sha1, NULL, RESOLVE_REF_READING);
 
 	if (verbose) {
 		for (ref = refs; ref; ref = ref->next)
diff --git a/upload-pack.c b/upload-pack.c
index 01de944..3b51ccb 100644
--- a/upload-pack.c
+++ b/upload-pack.c
@@ -743,7 +743,7 @@ static int find_symref(const char *refname, const unsigned char *sha1, int flag,
 
 	if ((flag & REF_ISSYMREF) == 0)
 		return 0;
-	symref_target = resolve_ref_unsafe(refname, unused, 0, &flag);
+	symref_target = resolve_ref_unsafe(refname, unused, &flag, 0);
 	if (!symref_target || (flag & REF_ISSYMREF) == 0)
 		die("'%s' is a symref but it is not?", refname);
 	item = string_list_append(cb_data, refname);
diff --git a/wt-status.c b/wt-status.c
index 318a191..6819e2b 100644
--- a/wt-status.c
+++ b/wt-status.c
@@ -128,7 +128,7 @@ void wt_status_prepare(struct wt_status *s)
 	s->show_untracked_files = SHOW_NORMAL_UNTRACKED_FILES;
 	s->use_color = -1;
 	s->relative_paths = 1;
-	s->branch = resolve_refdup("HEAD", sha1, 0, NULL);
+	s->branch = resolve_refdup("HEAD", sha1, NULL, 0);
 	s->reference = "HEAD";
 	s->fp = stdout;
 	s->index_file = get_index_file();