From: phillip.wood123@gmail.com Date: Tue, 07 May 2024 15:50:05 GMT Subject: Re: [PATCH v8 0/8] refs: add support for transactional symref updates Message-ID: <9d4c4850-6d73-472c-9ab1-fe5f6f4657d8@gmail.com> In-Reply-To: <20240507125859.132116-1-knayak@gitlab.com> Hi Karthik On 07/05/2024 13:58, Karthik Nayak wrote: > Changes since v6: > * Made the check for old/new oid & target more stricter by removing > the exception for null oid's. > * Extracted `ref_update_check_old_target` and `original_update_refname` > to refs.c > * ^This allowed us to generalize the error messages for non-matching > old_target values between files and reftable backend. > * Better line wrapping in code. > * Fixed some grammar in commit messages. Thanks for re-rolling - these changes address all of my comments on v6 and the range-diff below looks good. Best Wishes Phillip > Range diff against v6: > > 1: a354190905 ! 1: defc1b3521 refs: accept symref values in `ref_transaction_update()` > @@ refs.c: struct ref_update *ref_transaction_add_update( > if (transaction->state != REF_TRANSACTION_OPEN) > BUG("update called for transaction that is not open"); > > -+ if (old_oid && !is_null_oid(old_oid) && old_target) > ++ if (old_oid && old_target) > + BUG("only one of old_oid and old_target should be non NULL"); > -+ if (new_oid && !is_null_oid(new_oid) && new_target) > ++ if (new_oid && new_target) > + BUG("only one of new_oid and new_target should be non NULL"); > + > FLEX_ALLOC_STR(update, refname, refname); > 2: 0d9c5b9804 = 2: 54bb78a27c files-backend: extract out `create_symref_lock()` > 3: e0219ffd31 = 3: c16b7c5da0 refs: support symrefs in 'reference-transaction' hook > -: ---------- > 4: 2d268f12cc refs: move `original_update_refname` to 'refs.c' > 4: b22c59c722 ! 5: 7db3a2245f refs: add support for transactional symref updates > @@ Commit message > updates. While this is exposed to users via 'git-update-ref' and its > '--stdin' mode, it is also used internally within various commands. > > - However, we never supported transactional updates of symrefs. Let's add > - support for symrefs in both the 'files' and the 'reftable' backend. > + However, we do not support transactional updates of symrefs. This commit > + adds support for symrefs in both the 'files' and the 'reftable' backend. > > Here, we add and use `ref_update_has_null_new_value()`, a helper > function which is used to check if there is a new_value in a reference > update. The new value could either be a symref target `new_target` or a > OID `new_oid`. > > - With this, now transactional updates (verify, create, delete, update) > - can be used for: > + We also add another common function `ref_update_check_old_target` which > + will be used to check if the update's old_target corresponds to a > + reference's current target. > + > + Now transactional updates (verify, create, delete, update) can be used > + for: > - regular refs > - symbolic refs > - conversion of regular to symbolic refs and vice versa > @@ refs.c: int ref_transaction_update(struct ref_transaction *transaction, > > ref_transaction_add_update(transaction, refname, flags, > new_oid, old_oid, new_target, > -@@ refs.c: int copy_existing_ref(const char *oldref, const char *newref, const char *logmsg > - { > - return refs_copy_existing_ref(get_main_ref_store(the_repository), oldref, newref, logmsg); > +@@ refs.c: const char *ref_update_original_update_refname(struct ref_update *update) > + return update->refname; > } > -+ > + > +int ref_update_has_null_new_value(struct ref_update *update) > +{ > + return !update->new_target && is_null_oid(&update->new_oid); > +} > - > - ## refs/files-backend.c ## > -@@ refs/files-backend.c: static const char *original_update_refname(struct ref_update *update) > - return update->refname; > - } > - > -+/* > -+ * Check whether the old_target values stored in update are consistent > -+ * with current_target, which is the symbolic reference's current value. > -+ * If everything is OK, return 0; otherwise, write an error message to > -+ * err and return -1. > -+ */ > -+static int check_old_target(struct ref_update *update, > -+ const char *current_target, > -+ struct strbuf *err) > ++ > ++int ref_update_check_old_target(const char *referent, struct ref_update *update, > ++ struct strbuf *err) > +{ > + if (!update->old_target) > + BUG("called without old_target set"); > + > -+ if (!strcmp(update->old_target, current_target)) > ++ if (!strcmp(referent, update->old_target)) > + return 0; > + > -+ if (!strcmp(current_target, "")) > -+ strbuf_addf(err, "cannot lock ref '%s': " > ++ if (!strcmp(referent, "")) > ++ strbuf_addf(err, "verifying symref target: '%s': " > + "reference is missing but expected %s", > -+ original_update_refname(update), > ++ ref_update_original_update_refname(update), > + update->old_target); > + else > -+ strbuf_addf(err, "cannot lock ref '%s': " > ++ strbuf_addf(err, "verifying symref target: '%s': " > + "is at %s but expected %s", > -+ original_update_refname(update), > -+ current_target, update->old_target); > -+ > ++ ref_update_original_update_refname(update), > ++ referent, update->old_target); > + return -1; > +} > -+ > - /* > - * Check whether the REF_HAVE_OLD and old_oid values stored in update > - * are consistent with oid, which is the reference's current value. If > + > + ## refs/files-backend.c ## > +@@ refs/files-backend.c: static int split_symref_update(struct ref_update *update, > + > + new_update = ref_transaction_add_update( > + transaction, referent, new_flags, > +- &update->new_oid, &update->old_oid, > +- NULL, NULL, update->msg); > ++ update->new_target ? NULL : &update->new_oid, > ++ update->old_target ? NULL : &update->old_oid, > ++ update->new_target, update->old_target, update->msg); > + > + new_update->parent_update = update; > + > @@ refs/files-backend.c: static int lock_ref_for_update(struct files_ref_store *refs, > > files_assert_main_repository(refs, "lock_ref_for_update"); > @@ refs/files-backend.c: static int lock_ref_for_update(struct files_ref_store *ref > + } > + > + if (update->old_target) { > -+ if (check_old_target(update, referent.buf, err)) { > ++ if (ref_update_check_old_target(referent.buf, update, err)) { > + ret = TRANSACTION_GENERIC_ERROR; > + goto out; > + } > @@ refs/files-backend.c: static int lock_ref_for_update(struct files_ref_store *ref > + * be set for symrefs, but we're strict about its usage. > + */ > + if (update->old_target) { > -+ if (check_old_target(update, referent.buf, err)) { > ++ if (ref_update_check_old_target(referent.buf, update, err)) { > + ret = TRANSACTION_GENERIC_ERROR; > + goto out; > + } > @@ refs/files-backend.c: static int lock_ref_for_update(struct files_ref_store *ref > - !(update->flags & REF_DELETING) && > - !(update->flags & REF_LOG_ONLY)) { > + if (update->new_target && !(update->flags & REF_LOG_ONLY)) { > -+ if (create_symref_lock(refs, lock, update->refname, update->new_target, err)) { > ++ if (create_symref_lock(refs, lock, update->refname, > ++ update->new_target, err)) { > + ret = TRANSACTION_GENERIC_ERROR; > + goto out; > + } > @@ refs/files-backend.c: static int files_transaction_finish(struct ref_store *ref_ > if (commit_ref(lock)) { > > ## refs/refs-internal.h ## > -@@ refs/refs-internal.h: void base_ref_store_init(struct ref_store *refs, struct repository *repo, > +@@ refs/refs-internal.h: struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_stor > */ > - struct ref_store *maybe_debug_wrap_ref_store(const char *gitdir, struct ref_store *store); > + const char *ref_update_original_update_refname(struct ref_update *update); > > +/* > + * Helper function to check if the new value is null, this > @@ refs/refs-internal.h: void base_ref_store_init(struct ref_store *refs, struct re > + * ref or a symbolic ref. > + */ > +int ref_update_has_null_new_value(struct ref_update *update); > ++ > ++/* > ++ * Check whether the old_target values stored in update are consistent > ++ * with the referent, which is the symbolic reference's current value. > ++ * If everything is OK, return 0; otherwise, write an error message to > ++ * err and return -1. > ++ */ > ++int ref_update_check_old_target(const char *referent, struct ref_update *update, > ++ struct strbuf *err); > + > #endif /* REFS_REFS_INTERNAL_H */ > > @@ refs/reftable-backend.c: static int reftable_be_transaction_prepare(struct ref_s > */ > - if (u->flags & REF_HAVE_OLD && !oideq(¤t_oid, &u->old_oid)) { > + if (u->old_target) { > -+ if (strcmp(referent.buf, u->old_target)) { > -+ if (!strcmp(referent.buf, "")) > -+ strbuf_addf(err, "verifying symref target: '%s': " > -+ "reference is missing but expected %s", > -+ original_update_refname(u), > -+ u->old_target); > -+ else > -+ strbuf_addf(err, "verifying symref target: '%s': " > -+ "is at %s but expected %s", > -+ original_update_refname(u), > -+ referent.buf, u->old_target); > ++ if (ref_update_check_old_target(referent.buf, u, err)) { > + ret = -1; > + goto done; > + } > + } else if ((u->flags & REF_HAVE_OLD) && !oideq(¤t_oid, &u->old_oid)) { > if (is_null_oid(&u->old_oid)) > strbuf_addf(err, _("cannot lock ref '%s': " > - "reference already exists"), > + "reference already exists"), > @@ refs/reftable-backend.c: static int write_transaction_table(struct reftable_writer *writer, void *cb_data > * - `core.logAllRefUpdates` tells us to create the reflog for > * the given ref. > */ > - if (u->flags & REF_HAVE_NEW && !(u->type & REF_ISSYMREF) && is_null_oid(&u->new_oid)) { > -+ if ((u->flags & REF_HAVE_NEW) && !(u->type & REF_ISSYMREF) && ref_update_has_null_new_value(u)) { > ++ if ((u->flags & REF_HAVE_NEW) && > ++ !(u->type & REF_ISSYMREF) && > ++ ref_update_has_null_new_value(u)) { > struct reftable_log_record log = {0}; > struct reftable_iterator it = {0}; > > @@ refs/reftable-backend.c: static int write_transaction_table(struct reftable_writ > + fill_reftable_log_record(log); > + log->update_index = ts; > + log->refname = xstrdup(u->refname); > -+ memcpy(log->value.update.new_hash, u->new_oid.hash, GIT_MAX_RAWSZ); > -+ memcpy(log->value.update.old_hash, tx_update->current_oid.hash, GIT_MAX_RAWSZ); > ++ memcpy(log->value.update.new_hash, > ++ u->new_oid.hash, GIT_MAX_RAWSZ); > ++ memcpy(log->value.update.old_hash, > ++ tx_update->current_oid.hash, GIT_MAX_RAWSZ); > + log->value.update.message = > + xstrndup(u->msg, arg->refs->write_options.block_size / 2); > + } > 5: 636bf5ce98 = 6: 354ebbe17f refs: use transaction in `refs_create_symref()` > 6: 07fb23374f = 7: c8a23b3454 refs: rename `refs_create_symref()` to `refs_update_symref()` > 7: 5c05813bcc = 8: fa1b8f445b refs: remove `create_symref` and associated dead code > > > Karthik Nayak (8): > refs: accept symref values in `ref_transaction_update()` > files-backend: extract out `create_symref_lock()` > refs: support symrefs in 'reference-transaction' hook > refs: move `original_update_refname` to 'refs.c' > refs: add support for transactional symref updates > refs: use transaction in `refs_create_symref()` > refs: rename `refs_create_symref()` to `refs_update_symref()` > refs: remove `create_symref` and associated dead code > > Documentation/githooks.txt | 14 ++- > branch.c | 2 +- > builtin/branch.c | 2 +- > builtin/fast-import.c | 5 +- > builtin/fetch.c | 2 +- > builtin/receive-pack.c | 1 + > builtin/replace.c | 2 +- > builtin/tag.c | 1 + > builtin/update-ref.c | 1 + > builtin/worktree.c | 2 +- > refs.c | 119 ++++++++++++++---- > refs.h | 20 ++- > refs/debug.c | 13 -- > refs/files-backend.c | 208 +++++++++++++++++-------------- > refs/packed-backend.c | 1 - > refs/refs-internal.h | 40 +++++- > refs/reftable-backend.c | 183 +++++++++------------------ > sequencer.c | 9 +- > t/helper/test-ref-store.c | 2 +- > t/t0610-reftable-basics.sh | 2 +- > t/t1416-ref-transaction-hooks.sh | 23 ++++ > walker.c | 2 +- > 22 files changed, 374 insertions(+), 280 deletions(-) >