[PATCH v2 00/27] Clean up update-refs --stdin and implement ref_transaction

This is v2 of this patch series.  See also [1] for more context.

Thanks to Brad, Junio, and Johan for their feedback on v1 [2]. I think I have addressed all of your points.

Changes relative to v1:

* Rename the functions associated with ref_transactions to be more
  reminiscent of database transactions:

  * create_ref_transaction() -> ref_transaction_begin()
  * free_ref_transaction() -> ref_transaction_rollback()
  * queue_update_ref() -> ref_transaction_update()
  * queue_create_ref() -> ref_transaction_create()
  * queue_delete_ref() -> ref_transaction_delete()
  * commit_ref_transaction() -> ref_transaction_commit()

* Change ref_transaction_commit() to also free the transaction, so the
  user doesn't have to think about memory resources at all.

* Fix backwards compatibility of "git update-ref --stdin -z"'s
  handling of the "create" command: allow <newvalue> to be the empty
  string, treating it the same zeros.  But deprecate this usage.

* Rebased to current master (there were no conflicts).

[1] http://article.gmane.org/gmane.comp.version-control.git/243726 [2] http://thread.gmane.org/gmane.comp.version-control.git/243731

Michael Haggerty (27):
  t1400: Fix name and expected result of one test
  t1400: Provide more usual input to the command
  parse_arg(): Really test that argument is properly terminated
  t1400: Add some more tests involving quoted arguments
  refs.h: Rename the action_on_err constants
  update_refs(): Fix constness
  update-ref --stdin: Read the whole input at once
  parse_cmd_verify(): Copy old_sha1 instead of evaluating <oldvalue>
    twice
  update-ref.c: Extract a new function, parse_refname()
  update-ref --stdin: Improve error messages for invalid values
  update-ref --stdin: Make error messages more consistent
  update-ref --stdin: Simplify error messages for missing oldvalues
  t1400: Test that stdin -z update treats empty <newvalue> as zeros
  update-ref.c: Extract a new function, parse_next_sha1()
  update-ref --stdin -z: Deprecate interpreting the empty string as
    zeros
  t1400: Test one mistake at a time
  update-ref --stdin: Improve the error message for unexpected EOF
  update-ref --stdin: Harmonize error messages
  refs: Add a concept of a reference transaction
  update-ref --stdin: Reimplement using reference transactions
  refs: Remove API function update_refs()
  struct ref_update: Rename field "ref_name" to "refname"
  struct ref_update: Store refname as a FLEX_ARRAY.
  ref_transaction_commit(): Introduce temporary variables
  struct ref_update: Add a lock member
  struct ref_update: Add type field
  ref_transaction_commit(): Work with transaction->updates in place

 Documentation/git-update-ref.txt       |  18 +-
 builtin/checkout.c                     |   2 +-
 builtin/clone.c                        |   9 +-
 builtin/merge.c                        |   6 +-
 builtin/notes.c                        |   6 +-
 builtin/reset.c                        |   6 +-
 builtin/update-ref.c                   | 425 ++++++++++++++++++++-------------
 contrib/examples/builtin-fetch--tool.c |   3 +-
 notes-cache.c                          |   2 +-
 notes-utils.c                          |   3 +-
 refs.c                                 | 192 +++++++++++----
 refs.h                                 |  94 ++++++--
 t/t1400-update-ref.sh                  | 100 +++++---
 13 files changed, 582 insertions(+), 284 deletions(-)