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2025-11-06Merge branch 'pk/reflog-migrate-message-fix' into nextJunio C Hamano1-1/+1
Message fix. * pk/reflog-migrate-message-fix: refs: add missing space in messages
2025-11-05refs: add missing space in messagesPeter Krefting1-1/+1
Signed-off-by: Peter Krefting <peter@softwolves.pp.se> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04refs: rename 'pack_refs_opts' to 'refs_optimize_opts'Karthik Nayak1-2/+2
The previous commit removed all references to 'pack_refs()' within the refs subsystem. Continue this cleanup by also renaming 'pack_refs_opts' to 'refs_optimize_opts' and the respective flags accordingly. Keeping the naming consistent will make the code easier to maintain. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04refs: move to using the '.optimize' functionsKarthik Nayak1-10/+3
The `struct ref_store` variable exposes two ways to optimize a reftable backend: 1. pack_refs 2. optimize The former was specific to the 'files' + 'packed' refs backend. The latter is more generic and covers all backends. While the naming is different, both of these functions perform the same functionality. Consolidate this code to only maintain the 'optimize' functions. Do this by modifying the backends so that they exclusively implement the `optimize` callback, only. All users of the refs subsystem already use the 'optimize' function so there is no changes needed on the callee side. Finally, cleanup all references to the 'pack_refs' field of the structure and code around it. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04refs: don't store peeled object IDs for invalid tagsPatrick Steinhardt1-1/+2
Both the "files" and "reftable" backend store peeled object IDs for references that point to tags: - The "files" backend stores the value when packing refs, where each peeled object ID is prefixed with "^". - The "reftable" backend stores the value whenever writing a new reference that points to a tag via a special ref record type. Both of these backends use `peel_object()` to find the peeled object ID. But as explained in the preceding commit, that function does not detect the case where the tag's tagged object and its claimed type mismatch. The consequence of storing these bogus peeled object IDs is that we're less likely to detect such corruption in other parts of Git. git-for-each-ref(1) for example does not notice anymore that the tag is broken when using "--format=%(*objectname)" to dereference tags. One could claim that this is good, because it still allows us to mostly use the tag as intended. But the biggest problem here is that we now have different behaviour for such a broken tag depending on whether or not we have its peeled value in the refdb. Fix the issue by verifying the object type when peeling the object. If that verification fails we simply skip storing the peeled value in either of the reference formats. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04object: add flag to `peel_object()` to verify object typePatrick Steinhardt1-2/+2
When peeling a tag to a non-tag object we repeatedly call `parse_object()` on the tagged object until we find the first object that isn't a tag. While this feels sensible at first, there is a big catch here: `parse_object()` doesn't actually verify the type of the tagged object. The relevant code path here eventually ends up in `parse_tag_buffer()`. Here, we parse the various fields of the tag, including the "type". Once we've figured out the type and the tagged object ID, we call one of the `lookup_${type}()` functions for whatever type we have found. There is two possible outcomes in the successful case: 1. The object is already part of our cached objects. In that case we double-check whether the type we're trying to look up matches the type that was cached. 2. The object is _not_ part of our cached objects. In that case, we simply create a new object with the expected type, but we don't parse that object. In the first case we might notice type mismatches, but only in the case where our cache has the object with the correct type. In the second case, we'll blindly assume that the type is correct and then go with it. We'll only notice that the type might be wrong when we try to parse the object at a later point. Now arguably, we could change `parse_tag_buffer()` to verify the tagged object's type for us. But that would have the effect that such a tag cannot be parsed at all anymore, and we have a small bunch of tests for exactly this case that assert we still can open such tags. So this change does not feel like something we can retroactively tighten, even though one shouldn't ever hit such corrupted tags. Instead, add a new `flags` field to `peel_object()` that allows the caller to opt in to strict object verification. This will be wired up at a subset of callsites over the next few commits. Note that this change also inlines `deref_tag_noverify()`. There's only been two callsites of that function, the one we're changing and one in our test helpers. The latter callsite can trivially use `deref_tag()` instead, so by inlining the function we avoid having to pass down the flag. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04refs: drop infrastructure to peel via iteratorsPatrick Steinhardt1-24/+0
Now that the peeled object ID gets propagated via the `struct reference` there is no need anymore to call into the reference iterator itself to dereference an object. Remove this infrastructure. Most of the changes are straight-forward deletions of code. There is one exception though in `refs/packed-backend.c::write_with_updates()`. Here we stop peeling the iterator and instead just pass the peeled object ID of that iterator directly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04refs: expose peeled object ID via the iteratorPatrick Steinhardt1-0/+5
Both the "files" and "reftable" backend are able to store peeled values for tags in the respective formats. This allows for a more efficient lookup of the target object of such a tag without having to manually peel via the object database. The infrastructure to access these peeled object IDs is somewhat funky though. When iterating through objects, we store a pointer reference to the current iterator in a global variable. The callbacks invoked by that iterator are then expected to call `peel_iterated_oid()`, which checks whether the globally-stored iterator's current reference refers to the one handed into that function. If so, we ask the iterator to peel the object, otherwise we manually peel the object via the object database. Depending on global state like this is somewhat weird and also quite fragile. Introduce a new `struct reference::peeled_oid` field that can be populated by the reference backends. This field can be accessed via a new function `reference_get_peeled_oid()` that either uses that value, if set, or alternatively peels via the ODB. With this change we don't have to rely on global state anymore, but make the peeled object ID available to the callback functions directly. Adjust trivial callers that already have a `struct reference` available. Remaining callers will be adjusted in subsequent commits. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04refs: fully reset `struct ref_iterator::ref` on iterationPatrick Steinhardt1-0/+1
With the introduction of the `struct ref_iterator::ref` field it now is a whole lot easier to introduce new fields that become accessible to the caller without having to adapt every single callsite. But there's a downside: when a new field is introduced we always have to adapt all backends to set that field. This isn't something we can avoid in the general case: when the new field is expected to be populated by all backends we of course cannot avoid doing so. But new fields may be entirely optional, in which case we'd still have such churn. And furthermore, it is very easy right now to leak state from a previous iteration into the next iteration. Address this issue by ensuring that the reference backends all fully reset the field on every single iteration. This ensures that no state from previous iterations can leak into the next one. And it ensures that any newly introduced fields will be zeroed out by default. Note that we don't have to explicitly adapt the "files" backend, as it uses the `cache_ref_iterator` internally. Furthermore, other "wrapping" iterators like for example the `prefix_ref_iterator` copy around the whole reference, so these don't need to be adapted either. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04refs: introduce `.ref` field for the base iteratorPatrick Steinhardt1-6/+6
The base iterator has a couple of fields that tracks the name, target, object ID and flags for the current reference. Due to this design we have to create a new `struct reference` whenever we want to hand over that reference to the callback function, which is tedious and not very efficient. Convert the structure to instead contain a `struct reference` as member. This member is expected to be populated by the implementations of the iterator and is handed over to the callback directly. While at it, simplify `should_pack_ref()` to take a `struct reference` directly instead of passing its respective fields. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-10-15Merge branch 'ps/reflog-migrate-fixes' into maint-2.51Junio C Hamano1-9/+17
"git refs migrate" to migrate the reflog entries from a refs backend to another had a handful of bugs squashed. * ps/reflog-migrate-fixes: refs: fix invalid old object IDs when migrating reflogs refs: stop unsetting REF_HAVE_OLD for log-only updates refs/files: detect race when generating reflog entry for HEAD refs: fix identity for migrated reflogs ident: fix type of string length parameter builtin/reflog: implement subcommand to write new entries refs: export `ref_transaction_update_reflog()` builtin/reflog: improve grouping of subcommands Documentation/git-reflog: convert to use synopsis type
2025-10-13Merge branch 'kn/reftable-consistency-checks'Junio C Hamano1-6/+52
The reftable backend learned to sanity check its on-disk data more carefully. * kn/reftable-consistency-checks: refs/reftable: add fsck check for checking the table name reftable: add code to facilitate consistency checks fsck: order 'fsck_msg_type' alphabetically Documentation/fsck-msgids: remove duplicate msg id reftable: check for trailing newline in 'tables.list' refs: move consistency check msg to generic layer refs: remove unused headers
2025-10-07refs/reftable: add fsck check for checking the table nameKarthik Nayak1-5/+52
Add glue code in 'refs/reftable-backend.c' which calls the reftable library to perform the fsck checks. Here we also map the reftable errors to Git' fsck errors. Introduce a check to validate table names for a given reftable stack. Also add 'badReftableTableName' as a corresponding error within Git. The reftable specification mentions: It suggested to use ${min_update_index}-${max_update_index}-${random}.ref as a naming convention. So treat non-conformant file names as warnings. While adding the fsck header to 'refs/reftable-backend.c', modify the list to maintain lexicographical ordering. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-10-07refs: remove unused headersKarthik Nayak1-1/+0
In the 'refs/' namespace, some of the included header files are not needed, let's remove them. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-10-02Merge branch 'ms/refs-optimize'Junio C Hamano1-0/+7
"git refs optimize" is added for not very well explained reason despite it does the same thing as "git pack-refs"... * ms/refs-optimize: t: add test for git refs optimize subcommand t0601: refactor tests to be shareable builtin/refs: add optimize subcommand doc: pack-refs: factor out common options builtin/pack-refs: factor out core logic into a shared library builtin/pack-refs: convert to use the generic refs_optimize() API reftable-backend: implement 'optimize' action files-backend: implement 'optimize' action refs: add a generic 'optimize' API
2025-09-19reftable-backend: implement 'optimize' actionMeet Soni1-0/+7
To make the new generic `optimize` API fully functional, provide an implementation for the 'reftable' reference backend. For the reftable backend, the 'optimize' action is to compact its tables. The existing `reftable_be_pack_refs()` function already provides this logic, so the new `reftable_be_optimize()` function simply calls it. Wire up the new function to the `optimize` slot in the reftable backend's virtual table. Mentored-by: Patrick Steinhardt <ps@pks.im> Mentored-by: shejialuo <shejialuo@gmail.com> Signed-off-by: Meet Soni <meetsoni3017@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-29Merge branch 'jk/no-clobber-dangling-symref-with-fetch'Junio C Hamano1-3/+27
"git fetch" can clobber a symref that is dangling when the remote-tracking HEAD is set to auto update, which has been corrected. * jk/no-clobber-dangling-symref-with-fetch: refs: do not clobber dangling symrefs t5510: prefer "git -C" to subshell for followRemoteHEAD tests t5510: stop changing top-level working directory t5510: make confusing config cleanup more explicit
2025-08-29Merge branch 'ps/reftable-libgit2-cleanup'Junio C Hamano1-11/+12
Code clean-ups. * ps/reftable-libgit2-cleanup: refs/reftable: always reload stacks when creating lock reftable: don't second-guess errors from flock interface reftable/stack: handle outdated stacks when compacting reftable/stack: allow passing flags to `reftable_stack_add()` reftable/stack: fix compiler warning due to missing braces reftable/stack: reorder code to avoid forward declarations reftable/writer: drop Git-specific `QSORT()` macro reftable/writer: fix type used for number of records
2025-08-21Merge branch 'ps/remote-rename-fix'Junio C Hamano1-1/+1
"git remote rename origin upstream" failed to move origin/HEAD to upstream/HEAD when origin/HEAD is unborn and performed other renames extremely inefficiently, which has been corrected. * ps/remote-rename-fix: builtin/remote: only iterate through refs that are to be renamed builtin/remote: rework how remote refs get renamed builtin/remote: determine whether refs need renaming early on builtin/remote: fix sign comparison warnings refs: simplify logic when migrating reflog entries refs: pass refname when invoking reflog entry callback
2025-08-21Merge branch 'ps/reflog-migrate-fixes'Junio C Hamano1-9/+17
"git refs migrate" to migrate the reflog entries from a refs backend to another had a handful of bugs squashed. * ps/reflog-migrate-fixes: refs: fix invalid old object IDs when migrating reflogs refs: stop unsetting REF_HAVE_OLD for log-only updates refs/files: detect race when generating reflog entry for HEAD refs: fix identity for migrated reflogs ident: fix type of string length parameter builtin/reflog: implement subcommand to write new entries refs: export `ref_transaction_update_reflog()` builtin/reflog: improve grouping of subcommands Documentation/git-reflog: convert to use synopsis type
2025-08-19refs: do not clobber dangling symrefsJeff King1-3/+27
When given an expected "before" state, the ref-writing code will avoid overwriting any ref that does not match that expected state. We use the null oid as a sentinel value for "nothing should exist", and likewise that is the sentinel value we get when trying to read a ref that does not exist. But there's one corner case where this is ambiguous: dangling symrefs. Trying to read them will yield the null oid, but there is potentially something of value there: the dangling symref itself. For a normal recursive write, this is OK. Imagine we have a symref "FOO_HEAD" that points to a ref "refs/heads/bar" that does not exist, and we try to write to it with a create operation like: oid=$(git rev-parse HEAD) ;# or whatever git symbolic-ref FOO_HEAD refs/heads/bar echo "create FOO_HEAD $oid" | git update-ref --stdin The attempt to resolve FOO_HEAD will actually resolve "bar", yielding the null oid. That matches our expectation, and the write proceeds. This is correct, because we are not writing FOO_HEAD at all, but writing its destination "bar", which in fact does not exist. But what if the operation asked not to dereference symrefs? Like this: echo "create FOO_HEAD $oid" | git update-ref --no-deref --stdin Resolving FOO_HEAD would still result in a null oid, and the write will proceed. But it will overwrite FOO_HEAD itself, removing the fact that it ever pointed to "bar". This case is a little esoteric; we are clobbering a symref with a no-deref write of a regular ref value. But the same problem occurs when writing symrefs. For example: echo "symref-create FOO_HEAD refs/heads/other" | git update-ref --no-deref --stdin The "create" operation asked us to create FOO_HEAD only if it did not exist. But we silently overwrite the existing value. You can trigger this without using update-ref via the fetch followRemoteHEAD code. In "create" mode, it should not overwrite an existing value. But if you manually create a symref pointing to a value that does not yet exist (either via symbolic-ref or with "remote add -m"), create mode will happily overwrite it. Instead, we should detect this case and refuse to write. The correct specification to overwrite FOO_HEAD in this case is to provide an expected target ref value, like: echo "symref-update FOO_HEAD refs/heads/other ref refs/heads/bar" | git update-ref --no-deref --stdin Note that the non-symref "update" directive does not allow you to do this (you can only specify an oid). This is a weakness in the update-ref interface, and you'd have to overwrite unconditionally, like: echo "update FOO_HEAD $oid" | git update-ref --no-deref --stdin Likewise other symref operations like symref-delete do not accept the "ref" keyword. You should be able to do: echo "symref-delete FOO_HEAD ref refs/heads/bar" but cannot (and can only delete unconditionally). This patch doesn't address those gaps. We may want to do so in a future patch for completeness, but it's not clear if anybody actually wants to perform those operations. The symref update case (specifically, via followRemoteHEAD) is what I ran into in the wild. The code for the fix is relatively straight-forward given the discussion above. But note that we have to implement it independently for the files and reftable backends. The "old oid" checks happen as part of the locking process, which is implemented separately for each system. We may want to factor this out somehow, but it's beyond the scope of this patch. (Another curiosity is that the messages in the reftable code are marked for translation, but the ones in the files backend are not. I followed local convention in each case, but we may want to harmonize this at some point). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12refs/reftable: always reload stacks when creating lockPatrick Steinhardt1-11/+12
When creating a new addition via either `reftable_stack_new_addition()` or its convenince wrapper `reftable_stack_add()` we: 1. Create the "tables.list.lock" file. 2. Verify that the current version of the "tables.list" file is up-to-date. 3. Write the new table records if so. By default, the second step would cause us to bail out if we see that there has been a concurrent write to the stack that made our in-memory copy of the stack out-of-date. This is a safety mechanism to not write records to the stack based on outdated information. The downside though is that concurrent writes may now cause us to bail out, which is not a good user experience. In addition, this isn't even necessary for us, as Git knows to perform all checks for the old state of references under the lock. (Well, in all except one case: when we expire the reflog we first create the log iterator before we create the lock, but this ordering is fixed as part of this commit.) Consequently, most writers pass the `REFTABLE_STACK_NEW_ADDITION_RELOAD` flag. The effect of this flag is that we reload the stack after having acquired the lock in case the stack is out-of-date. This plugs the race with concurrent writers, but we continue performing the verifications of the expected old state to catch actual conflicts in the references we are about to write. Adapt the remaining callsites that don't yet pass this flag to do so. While at it, drop a needless manual reload. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-12reftable/stack: allow passing flags to `reftable_stack_add()`Patrick Steinhardt1-4/+4
The `reftable_stack_add()` function is a simple wrapper to lock the stack, add records to it via a callback and then commit the result. One problem with it though is that it doesn't accept any flags for creating the addition. This makes it impossible to automatically reload the stack in case it was modified before we managed to lock the stack. Add a `flags` field to plug this gap and pass it through accordingly. For now this new flag won't be used by us, but it will be used by libgit2. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-06refs: pass refname when invoking reflog entry callbackPatrick Steinhardt1-1/+1
With `refs_for_each_reflog_ent()` callers can iterate through all the reflog entries for a given reference. The callback that is being invoked for each such entry does not receive the name of the reference that we are currently iterating through. This isn't really a limiting factor, as callers can simply pass the name via the callback data. But this layout sometimes does make for a bit of an awkward calling pattern. One example: when iterating through all reflogs, and for each reflog we iterate through all refnames, we have to do some extra book keeping to track which reference name we are currently yielding reflog entries for. Change the signature of the callback function so that the reference name of the reflog gets passed through to it. Adapt callers accordingly and start using the new parameter in trivial cases. The next commit will refactor the reference migration logic to make use of this parameter so that we can simplify its logic a bit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-06refs: fix invalid old object IDs when migrating reflogsPatrick Steinhardt1-0/+14
When migrating reflog entries between different storage formats we end up with invalid old object IDs for the migrated entries: instead of writing the old object ID of the to-be-migrated entry, we end up with the all-zeroes object ID. The root cause of this issue is that we don't know to use the old object ID provided by the caller. Instead, we manually resolve the old object ID by resolving the current value of its matching reference. But as that reference does not yet exist in the target ref storage we always end up resolving it to all-zeroes. This issue got unnoticed as there is no user-facing command that would even show the old object ID. While `git log -g` knows to show the new object ID, we don't have any formatting directive to show the old object ID. Fix the bug by introducing a new flag `REF_LOG_USE_PROVIDED_OIDS`. If set, backends are instructed to use the old and new object IDs provided by the caller, without doing any manual resolving. Set this flag in `ref_transaction_update_reflog()`. Amend our tests in t1460-refs-migrate to use our test tool to read reflog entries. This test tool prints out both old and new object ID of each reflog entry, which fixes the test gap. Furthermore it also prints the full identity used to write the reflog, which provides test coverage for the previous commit in this patch series that fixed the identity for migrated reflogs. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-06refs: stop unsetting REF_HAVE_OLD for log-only updatesPatrick Steinhardt1-9/+3
The `REF_HAVE_OLD` flag indicates whether a given ref update has its old object ID set. If so, the value of that field is used to verify whether the current state of the reference matches this expected state. It is thus an important part of mitigating races with a concurrent process that updates the same set of references. When writing reflogs though we explicitly unset that flag. This is a sensible thing to do: the old state of reflog entry updates may not necessarily match the current on-disk state of its accompanying ref, but it's only intended to signal what old object ID we want to write into the new reflog entry. For example when migrating refs we end up writing many reflog entries for a single reference, and most likely those reflog entries will have many different old object IDs. But unsetting this flag also removes a useful signal, namely that the caller _did_ provide an old object ID for a given reflog entry. This signal will become useful in a subsequent commit, where we add a new flag that tells the transaction to use the provided old and new object IDs to write a reflog entry. The `REF_HAVE_OLD` flag is then used as a signal to verify that the caller really did provide an old object ID. Stop unsetting the flag so that we can use it as this described signal in a subsequent commit. Skip checking the old object ID for log-only updates so that we don't expect it to match the current on-disk state. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-04Merge branch 'ps/config-wo-the-repository'Junio C Hamano1-1/+1
The config API had a set of convenience wrapper functions that implicitly use the_repository instance; they have been removed and inlined at the calling sites. * ps/config-wo-the-repository: (21 commits) config: fix sign comparison warnings config: move Git config parsing into "environment.c" config: remove unused `the_repository` wrappers config: drop `git_config_set_multivar()` wrapper config: drop `git_config_get_multivar_gently()` wrapper config: drop `git_config_set_multivar_in_file_gently()` wrapper config: drop `git_config_set_in_file_gently()` wrapper config: drop `git_config_set()` wrapper config: drop `git_config_set_gently()` wrapper config: drop `git_config_set_in_file()` wrapper config: drop `git_config_get_bool()` wrapper config: drop `git_config_get_ulong()` wrapper config: drop `git_config_get_int()` wrapper config: drop `git_config_get_string()` wrapper config: drop `git_config_get_string()` wrapper config: drop `git_config_get_string_multi()` wrapper config: drop `git_config_get_value()` wrapper config: drop `git_config_get_value()` wrapper config: drop `git_config_get()` wrapper config: drop `git_config_clear()` wrapper ...
2025-07-23config: drop `git_config()` wrapperPatrick Steinhardt1-1/+1
In 036876a1067 (config: hide functions using `the_repository` by default, 2024-08-13) we have moved around a bunch of functions in the config subsystem that depend on `the_repository`. Those function have been converted into mere wrappers around their equivalent function that takes in a repository as parameter, and the intent was that we'll eventually remove those wrappers to make the dependency on the global repository variable explicit at the callsite. Follow through with that intent and remove `git_config()`. All callsites are adjusted so that they use `repo_config(the_repository, ...)` instead. While some callsites might already have a repository available, this mechanical conversion is the exact same as the current situation and thus cannot cause any regression. Those sites should eventually be cleaned up in a later patch series. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-15refs: selectively set prefix in the seek functionsKarthik Nayak1-7/+14
The ref iterator exposes a `ref_iterator_seek()` function. The name suggests that this would seek the iterator to a specific reference in some ways similar to how `fseek()` works for the filesystem. However, the function actually sets the prefix for refs iteration. So further iteration would only yield references which match the particular prefix. This is a bit confusing. Let's add a 'flags' field to the function, which when set with the 'REF_ITERATOR_SEEK_SET_PREFIX' flag, will set the prefix for the iteration in-line with the existing behavior. Otherwise, the reference backends will simply seek to the specified reference and clears any previously set prefix. This allows users to start iteration from a specific reference. In the packed and reftable backend, since references are available in a sorted list, the changes are simply setting the prefix if needed. The changes on the files-backend are a little more involved, since the files backend uses the 'ref-cache' mechanism. We move out the existing logic within `cache_ref_iterator_seek()` to `cache_ref_iterator_set_prefix()` which is called when the 'REF_ITERATOR_SEEK_SET_PREFIX' flag is set. We then parse the provided seek string and set the required levels and their indexes to ensure that seeking is possible. Helped-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-16Merge branch 'kn/non-transactional-batch-updates'Junio C Hamano1-248/+254
Updating multiple references have only been possible in all-or-none fashion with transactions, but it can be more efficient to batch multiple updates even when some of them are allowed to fail in a best-effort manner. A new "best effort batches of updates" mode has been introduced. * kn/non-transactional-batch-updates: update-ref: add --batch-updates flag for stdin mode refs: support rejection in batch updates during F/D checks refs: implement batch reference update support refs: introduce enum-based transaction error types refs/reftable: extract code from the transaction preparation refs/files: remove duplicate duplicates check refs: move duplicate refname update check to generic layer refs/files: remove redundant check in split_symref_update()
2025-04-08refs: support rejection in batch updates during F/D checksKarthik Nayak1-3/+8
The `refs_verify_refnames_available()` is used to batch check refnames for F/D conflicts. While this is the more performant alternative than its individual version, it does not provide rejection capabilities on a single update level. For batched updates, this would mean a rejection of the entire transaction whenever one reference has a F/D conflict. Modify the function to call `ref_transaction_maybe_set_rejected()` to check if a single update can be rejected. Since this function is only internally used within 'refs/' and we want to pass in a `struct ref_transaction *` as a variable. We also move and mark `refs_verify_refnames_available()` to 'refs-internal.h' to be an internal function. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08refs: implement batch reference update supportKarthik Nayak1-1/+11
Git supports making reference updates with or without transactions. Updates with transactions are generally better optimized. But transactions are all or nothing. This means, if a user wants to batch updates to take advantage of the optimizations without the hard requirement that all updates must succeed, there is no way currently to do so. Particularly with the reftable backend where batching multiple reference updates is more efficient than performing them sequentially. Introduce batched update support with a new flag, 'REF_TRANSACTION_ALLOW_FAILURE'. Batched updates while different from transactions, use the transaction infrastructure under the hood. When enabled, this flag allows individual reference updates that would typically cause the entire transaction to fail due to non-system-related errors to be marked as rejected while permitting other updates to proceed. System errors referred by 'REF_TRANSACTION_ERROR_GENERIC' continue to result in the entire transaction failing. This approach enhances flexibility while preserving transactional integrity where necessary. The implementation introduces several key components: - Add 'rejection_err' field to struct `ref_update` to track failed updates with failure reason. - Add a new struct `ref_transaction_rejections` and a field within `ref_transaction` to this struct to allow quick iteration over rejected updates. - Modify reference backends (files, packed, reftable) to handle partial transactions by using `ref_transaction_set_rejected()` instead of failing the entire transaction when `REF_TRANSACTION_ALLOW_FAILURE` is set. - Add `ref_transaction_for_each_rejected_update()` to let callers examine which updates were rejected and why. This foundational change enables batched update support throughout the reference subsystem. A following commit will expose this capability to users by adding a `--batch-updates` flag to 'git-update-ref(1)', providing both a user-facing feature and a testable implementation. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08refs: introduce enum-based transaction error typesKarthik Nayak1-32/+32
Replace preprocessor-defined transaction errors with a strongly-typed enum `ref_transaction_error`. This change: - Improves type safety and function signature clarity. - Makes error handling more explicit and discoverable. - Maintains existing error cases, while adding new error cases for common scenarios. This refactoring paves the way for more comprehensive error handling which we will utilize in the upcoming commits to add batch reference update support. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08refs/reftable: extract code from the transaction preparationKarthik Nayak1-226/+237
Extract the core logic for preparing individual reference updates from `reftable_be_transaction_prepare()` into `prepare_single_update()`. This dedicated function now handles all validation and preparation steps for each reference update in the transaction, including object ID verification, HEAD reference handling, and symref processing. The refactoring consolidates all reference update validation into a single logical block, which improves code maintainability and readability. More importantly, this restructuring lays the groundwork for implementing batched reference update support in the reftable backend, which will be introduced in a followup commit. No functional changes are included in this commit - it is purely a code reorganization to support future enhancements. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08refs: move duplicate refname update check to generic layerKarthik Nayak1-37/+17
Move the tracking of refnames in `affected_refnames` from individual backends into the generic layer in 'refs.c'. This centralizes the duplicate refname detection that was previously handled separately by each backend. Make some changes to accommodate this move: - Add a `string_list` field `refnames` to `ref_transaction` to contain all the references in a transaction. This field is updated whenever a new update is added via `ref_transaction_add_update`, so manual additions in reference backends are dropped. - Modify the backends to use this field internally as needed. The backends need to check if an update for refname already exists when splitting symrefs or adding an update for 'HEAD'. - In the reftable backend, within `reftable_be_transaction_prepare()`, move the `string_list_has_string()` check above `ref_transaction_add_update()`. Since `ref_transaction_add_update()` automatically adds the refname to `transaction->refnames`, performing the check after will always return true, so we perform the check before adding the update. This helps reduce duplication of functionality between the backends and makes it easier to make changes in a more centralized manner. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Acked-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-29Merge branch 'ps/refname-avail-check-optim'Junio C Hamano1-37/+47
The code paths to check whether a refname X is available (by seeing if another ref X/Y exists, etc.) have been optimized. * ps/refname-avail-check-optim: refs: reuse iterators when determining refname availability refs/iterator: implement seeking for files iterators refs/iterator: implement seeking for packed-ref iterators refs/iterator: implement seeking for ref-cache iterators refs/iterator: implement seeking for reftable iterators refs/iterator: implement seeking for merged iterators refs/iterator: provide infrastructure to re-seek iterators refs/iterator: separate lifecycle from iteration refs: stop re-verifying common prefixes for availability refs/files: batch refname availability checks for initial transactions refs/files: batch refname availability checks for normal transactions refs/reftable: batch refname availability checks refs: introduce function to batch refname availability checks builtin/update-ref: skip ambiguity checks when parsing object IDs object-name: allow skipping ambiguity checks in `get_oid()` family object-name: introduce `repo_get_oid_with_flags()`
2025-03-12refs/iterator: implement seeking for reftable iteratorsPatrick Steinhardt1-5/+30
Implement seeking of reftable iterators. As the low-level reftable iterators already support seeking this change is straight-forward. Two notes though: - We do not support seeking on reflog iterators. It is unclear what seeking would even look like in this context, as you typically would want to seek to a specific entry in the reflog for a specific ref. There is currently no use case for this, but if one arises in the future, we can still implement seeking at that later point. - We start to check whether `reftable_stack_init_ref_iterator()` is successful. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-12refs/iterator: separate lifecycle from iterationPatrick Steinhardt1-26/+8
The ref and reflog iterators have their lifecycle attached to iteration: once the iterator reaches its end, it is automatically released and the caller doesn't have to care about that anymore. When the iterator should be released before it has been exhausted, callers must explicitly abort the iterator via `ref_iterator_abort()`. This lifecycle is somewhat unusual in the Git codebase and creates two problems: - Callsites need to be very careful about when exactly they call `ref_iterator_abort()`, as calling the function is only valid when the iterator itself still is. This leads to somewhat awkward calling patterns in some situations. - It is impossible to reuse iterators and re-seek them to a different prefix. This feature isn't supported by any iterator implementation except for the reftable iterators anyway, but if it was implemented it would allow us to optimize cases where we need to search for specific references repeatedly by reusing internal state. Detangle the lifecycle from iteration so that we don't deallocate the iterator anymore once it is exhausted. Instead, callers are now expected to always call a newly introduce `ref_iterator_free()` function that deallocates the iterator and its internal state. Note that the `dir_iterator` is somewhat special because it does not implement the `ref_iterator` interface, but is only used to implement other iterators. Consequently, we have to provide `dir_iterator_free()` instead of `dir_iterator_release()` as the allocated structure itself is managed by the `dir_iterator` interfaces, as well, and not freed by `ref_iterator_free()` like in all the other cases. While at it, drop the return value of `ref_iterator_abort()`, which wasn't really required by any of the iterator implementations anyway. Furthermore, stop calling `base_ref_iterator_free()` in any of the backends, but instead call it in `ref_iterator_free()`. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-12refs/reftable: batch refname availability checksPatrick Steinhardt1-6/+9
Refactor the "reftable" backend to batch the availability check for refnames. This does not yet have an effect on performance as `refs_verify_refnames_available()` effectively still performs the availability check for each refname individually. But this will be optimized in subsequent commits, where we learn to optimize some parts of the logic when checking multiple refnames for availability. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-05Merge branch 'ps/path-sans-the-repository'Junio C Hamano1-5/+5
The path.[ch] API takes an explicit repository parameter passed throughout the callchain, instead of relying on the_repository singleton instance. * ps/path-sans-the-repository: path: adjust last remaining users of `the_repository` environment: move access to "core.sharedRepository" into repo settings environment: move access to "core.hooksPath" into repo settings repo-settings: introduce function to clear struct path: drop `git_path()` in favor of `repo_git_path()` rerere: let `rerere_path()` write paths into a caller-provided buffer path: drop `git_common_path()` in favor of `repo_common_path()` worktree: return allocated string from `get_worktree_git_dir()` path: drop `git_path_buf()` in favor of `repo_git_path_replace()` path: drop `git_pathdup()` in favor of `repo_git_path()` path: drop unused `strbuf_git_path()` function path: refactor `repo_submodule_path()` family of functions submodule: refactor `submodule_to_gitdir()` to accept a repo path: refactor `repo_worktree_path()` family of functions path: refactor `repo_git_path()` family of functions path: refactor `repo_common_path()` family of functions
2025-02-28path: adjust last remaining users of `the_repository`Patrick Steinhardt1-5/+5
With the preceding refactorings we now only have a couple of implicit users of `the_repository` left in the "path" subsystem, all of which depend on global state via `calc_shared_perm()`. Make the dependency on `the_repository` explicit by passing the repo as a parameter instead and adjust callers accordingly. Note that this change bubbles up into a couple of subsystems that were previously declared as free from `the_repository`. Instead of marking all of them as `the_repository`-dependent again, we instead use the repository that is available in the calling context. There are three exceptions though with "copy.c", "pack-write.c" and "tempfile.c". Adjusting these would require us to adapt callsites all over the place, so this is left for a future iteration. Mark "path.c" as free from `the_repository`. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-02-14Merge branch 'kn/reflog-migration-fix-followup'Junio C Hamano1-6/+16
Code clean-up. * kn/reflog-migration-fix-followup: reftable: prevent 'update_index' changes after adding records refs: use 'uint64_t' for 'ref_update.index' refs: mark `ref_transaction_update_reflog()` as static
2025-02-03Merge branch 'kn/reflog-migration-fix-fix'Junio C Hamano1-10/+10
Fix bugs in an earlier attempt to fix "git refs migration". * kn/reflog-migration-fix-fix: refs/reftable: fix uninitialized memory access of `max_index` reftable: write correct max_update_index to header
2025-01-27refs/reftable: fix uninitialized memory access of `max_index`Karthik Nayak1-3/+3
When migrating reflogs between reference backends, maintaining the original order of the reflog entries is crucial. To achieve this, an `index` field is stored within the `ref_update` struct that encodes the relative order of reflog entries. This field is used by the reftable backend as update index for the respective reflog entries to maintain that ordering. These update indices must be respected when writing table headers, which encode the minimum and maximum update index of contained records in the header and footer. This logic was added in commit bc67b4ab5f (reftable: write correct max_update_index to header, 2025-01-15), which started to use `reftable_writer_set_limits()` to propagate the mininum and maximum update index of all records contained in a ref transaction. However, we only set the maximum update index for the first transaction argument, even though there can be multiple such arguments. This is the case when we write to multiple stacks in a single transaction, e.g. when updating references in two different worktrees at once. Consequently, the update index for all but the first argument remain uninitialized, which may cause undefined behaviour. Fix this by moving the assignment of the maximum update index in `reftable_be_transaction_finish()` inside the loop, which ensures that all elements of the array are correctly initialized. Furthermore, initialize the `max_index` field to 0 when queueing a new transaction argument. This is not strictly necessary, as all elements of `write_transaction_table_arg.max_index` are now assigned correctly. However, this initialization is added for consistency and to safeguard against potential future changes that might inadvertently introduce uninitialized memory access. Reported-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22reftable: prevent 'update_index' changes after adding recordsKarthik Nayak1-5/+15
The function `reftable_writer_set_limits()` allows updating the 'min_update_index' and 'max_update_index' of a reftable writer. These values are written to both the writer's header and footer. Since the header is written during the first block write, any subsequent changes to the update index would create a mismatch between the header and footer values. The footer would contain the newer values while the header retained the original ones. To protect against this bug, prevent callers from updating these values after any record is written. To do this, modify the function to return an error whenever the limits are modified after any record adds. Check for record adds within `reftable_writer_set_limits()` by checking the `last_key` and `next` variable. The former is updated after each record added, but is reset at certain points. The latter is set after writing the first block. Modify all callers of the function to anticipate a return type and handle it accordingly. Add a unit test to also ensure the function returns the error as expected. Helped-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-22refs: use 'uint64_t' for 'ref_update.index'Karthik Nayak1-1/+1
The 'ref_update.index' variable is used to store an index for a given reference update. This index is used to order the updates in a predetermined order, while the default ordering is alphabetical as per the refname. For large repositories with millions of references, it should be safer to use 'uint64_t'. Let's do that. This also is applied for all other code sections where we store 'index' and pass it around. Reported-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-17Merge branch 'kn/reflog-migration-fix' into kn/reflog-migration-fix-followupJunio C Hamano1-10/+10
* kn/reflog-migration-fix: reftable: write correct max_update_index to header
2025-01-15reftable: write correct max_update_index to headerKarthik Nayak1-10/+10
In 297c09eabb (refs: allow multiple reflog entries for the same refname, 2024-12-16), the reftable backend learned to handle multiple reflog entries within the same transaction. This was done modifying the `update_index` for reflogs with multiple indices. During writing the logs, the `max_update_index` of the writer was modified to ensure the limits were raised to the modified `update_index`s. However, since ref entries are written before the modification to the `max_update_index`, if there are multiple blocks to be written, the reftable backend writes the header with the old `max_update_index`. When all logs are finally written, the footer will be written with the new `min_update_index`. This causes a mismatch between the header and the footer and causes the reftable file to be corrupted. The existing tests only spawn a single block and since headers are lazily written with the first block, the tests didn't capture this bug. To fix the issue, the appropriate `max_update_index` limit must be set even before the first block is written. Add a `max_index` field to the transaction which holds the `max_index` within all its updates, then propagate this value to the reftable backend, wherein this is used to the set the `max_update_index` correctly. Add a test which creates a few thousand reference updates with multiple reflog entries, which should trigger the bug. Reported-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-23Merge branch 'kn/reflog-migration'Junio C Hamano1-8/+45
"git refs migrate" learned to also migrate the reflog data across backends. * kn/reflog-migration: refs: mark invalid refname message for translation refs: add support for migrating reflogs refs: allow multiple reflog entries for the same refname refs: introduce the `ref_transaction_update_reflog` function refs: add `committer_info` to `ref_transaction_add_update()` refs: extract out refname verification in transactions refs/files: add count field to ref_lock refs: add `index` field to `struct ref_udpate` refs: include committer info in `ref_update` struct
2024-12-19Merge branch 'bf/set-head-symref'Junio C Hamano1-3/+9
When "git fetch $remote" notices that refs/remotes/$remote/HEAD is missing and discovers what branch the other side points with its HEAD, refs/remotes/$remote/HEAD is updated to point to it. * bf/set-head-symref: fetch set_head: handle mirrored bare repositories fetch: set remote/HEAD if it does not exist refs: add create_only option to refs_update_symref_extended refs: add TRANSACTION_CREATE_EXISTS error remote set-head: better output for --auto remote set-head: refactor for readability refs: atomically record overwritten ref in update_symref refs: standardize output of refs_read_symbolic_ref t/t5505-remote: test failure of set-head t/t5505-remote: set default branch to main