438 Commits

Author SHA1 Message Date
Junio C Hamano
f1ee3dec94 Merge branch 'ps/refs-for-each' into jch
Code refactoring around refs-for-each-* API functions.

* ps/refs-for-each:
  refs: replace `refs_for_each_fullref_in()`
  refs: replace `refs_for_each_namespaced_ref()`
  refs: replace `refs_for_each_glob_ref()`
  refs: replace `refs_for_each_glob_ref_in()`
  refs: replace `refs_for_each_rawref_in()`
  refs: replace `refs_for_each_rawref()`
  refs: replace `refs_for_each_ref_in()`
  refs: improve verification for-each-ref options
  refs: generalize `refs_for_each_fullref_in_prefixes()`
  refs: generalize `refs_for_each_namespaced_ref()`
  refs: speed up `refs_for_each_glob_ref_in()`
  refs: introduce `refs_for_each_ref_ext`
  refs: rename `each_ref_fn`
  refs: rename `do_for_each_ref_flags`
  refs: move `do_for_each_ref_flags` further up
  refs: move `refs_head_ref_namespaced()`
  refs: remove unused `refs_for_each_include_root_ref()`
2026-03-04 10:53:11 -08:00
Junio C Hamano
1d0a2acb78 Merge branch 'kn/ref-location'
Allow the directory in which reference backends store their data to
be specified.

* kn/ref-location:
  refs: add GIT_REFERENCE_BACKEND to specify reference backend
  refs: allow reference location in refstorage config
  refs: receive and use the reference storage payload
  refs: move out stub modification to generic layer
  refs: extract out `refs_create_refdir_stubs()`
  setup: don't modify repo in `create_reference_database()`
2026-03-04 10:52:59 -08:00
Karthik Nayak
4ffbb02ee4 refs: extract out refs_create_refdir_stubs()
For Git to recognize a directory as a Git directory, it requires the
directory to contain:

  1. 'HEAD' file
  2. 'objects/' directory
  3. 'refs/' directory

Here, #1 and #3 are part of the reference storage mechanism,
specifically the files backend. Since then, newer backends such as the
reftable backend have moved to using their own path ('reftable/') for
storing references. But to ensure Git still recognizes the directory as
a Git directory, we create stubs.

There are two locations where we create stubs:

- In 'refs/reftable-backend.c' when creating the reftable backend.
- In 'clone.c' before spawning transport helpers.

In a following commit, we'll add another instance. So instead of
repeating the code, let's extract out this code to
`refs_create_refdir_stubs()` and use it.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-25 09:27:12 -08:00
Patrick Steinhardt
1dd4f1e43f refs: replace refs_for_each_fullref_in()
Replace calls to `refs_for_each_fullref_in()` with the newly introduced
`refs_for_each_ref_ext()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:19 -08:00
Patrick Steinhardt
96c35a9ba5 refs: replace refs_for_each_namespaced_ref()
Replace calls to `refs_for_each_namespaced_ref()` with the newly
introduced `refs_for_each_ref_ext()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:19 -08:00
Patrick Steinhardt
3fc1ad03c6 refs: replace refs_for_each_glob_ref()
Replace calls to `refs_for_each_glob_ref()` with the newly introduced
`refs_for_each_ref_ext()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:19 -08:00
Patrick Steinhardt
4091d29893 refs: replace refs_for_each_glob_ref_in()
Replace calls to `refs_for_each_glob_ref_in()` with the newly introduced
`refs_for_each_ref_ext()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:19 -08:00
Patrick Steinhardt
5ef6d593f1 refs: replace refs_for_each_rawref_in()
Replace calls to `refs_for_each_rawref_in()` with the newly introduced
`refs_for_each_ref_ext()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:19 -08:00
Patrick Steinhardt
67034081ad refs: replace refs_for_each_rawref()
Replace calls to `refs_for_each_rawref()` with the newly introduced
`refs_for_each_ref_ext()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
00be226f1f refs: replace refs_for_each_ref_in()
Replace calls to `refs_for_each_ref_in()` with the newly introduced
`refs_for_each_ref_ext()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
f503bb7dc9 refs: generalize refs_for_each_fullref_in_prefixes()
The function `refs_for_each_fullref_in_prefixes()` can be used to
iterate over all references part of any of the user-provided prefixes.
In contrast to the `prefix` parameter of `refs_for_each_ref_ext()` it
knows to handle the case well where multiple of the passed-in prefixes
start with a common prefix by computing longest common prefixes and then
iterating over those.

While we could move this logic into `refs_for_each_ref_ext()`, this one
feels somewhat special as we perform multiple iterations. But what we
_can_ do is to generalize how this function works: instead of accepting
only a small handful of parameters, we can have it accept the full
options structure.

One obvious exception is that the caller must not provide a prefix via
the options. But this case can be easily detected.

Refactor the code accordingly.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
5387919327 refs: generalize refs_for_each_namespaced_ref()
The function `refs_for_each_namespaced_ref()` iterates through all
references that are part of the current ref namespace. This namespace
can be configured by setting the `GIT_NAMESPACE` environment variable
and is then retrieved by calling `get_git_namespace()`.

If a namespace is configured, then we:

  - Obviously only yield refs that exist in this namespace.

  - Rewrite exclude patterns so that they work for the given namespace,
    if any namespace is currently configured.

Port this logic to `refs_for_each_ref_ext()` by adding a new `namespace`
field to the options structure. This gives callers more flexibility as
they can decide by themselves whether they want to use the globally
configured or an arbitrary other namespace.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
daf01b1366 refs: speed up refs_for_each_glob_ref_in()
The function `refs_for_each_glob_ref_in()` can be used to iterate
through all refs in a specific prefix with globbing. The logic to handle
this is currently hosted by `refs_for_each_glob_ref_in()`, which sets up
a callback function that knows to filter out refs that _don't_ match the
given globbing pattern.

The way we do this is somewhat inefficient though: even though the
function is expected to only yield refs in the given prefix, we still
end up iterating through _all_ references, regardless of whether or not
their name matches the given prefix.

Extend `refs_for_each_ref_ext()` so that it can handle patterns and
adapt `refs_for_each_glob_ref_in()` to use it. This means we continue to
use the same callback-based infrastructure to filter individual refs via
the globbing pattern, but we can now also use the other functionality of
the `_ext()` variant.

Most importantly, this means that we now properly handle the prefix.
This results in a performance improvement when using a prefix where a
significant majority of refs exists outside of the prefix. The following
benchmark is an extreme case, with 1 million refs that exist outside the
prefix and a single ref that exists inside it:

    Benchmark 1: git rev-parse --branches=refs/heads/* (rev = HEAD~)
      Time (mean ± σ):     115.9 ms ±   0.7 ms    [User: 113.0 ms, System: 2.4 ms]
      Range (min … max):   114.9 ms … 117.8 ms    25 runs

    Benchmark 2: git rev-parse --branches=refs/heads/* (rev = HEAD)
      Time (mean ± σ):       1.1 ms ±   0.1 ms    [User: 0.3 ms, System: 0.7 ms]
      Range (min … max):     1.0 ms …   2.3 ms    2092 runs

    Summary
      git rev-parse --branches=refs/heads/* (rev = HEAD) ran
      107.01 ± 6.49 times faster than git rev-parse --branches=refs/heads/* (rev = HEAD~)

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
aefcc9b367 refs: introduce refs_for_each_ref_ext
In the refs subsystem we have a proliferation of functions that all
iterate through references. (Almost) all of these functions internally
call `do_for_each_ref()` and provide slightly different arguments so
that one can control different aspects of its behaviour. This approach
doesn't really scale: every time there is a slightly different use case
for iterating through refs we create another new function.

This combinatorial explosion doesn't make a lot of sense: it leads to
confusing interfaces and heightens the maintenance burden.

Refactor the code to become more composable by:

  - Exposing `do_for_each_ref()` as `refs_for_each_ref_ext()`.

  - Introducing an options structure that lets the caller control
    individual options.

This gives us a much better foundation to build on going forward.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
635f08b739 refs: rename each_ref_fn
Similar to the preceding commit, rename `each_ref_fn` to better match
our current best practices around how we name things.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
8f0720a5a7 refs: rename do_for_each_ref_flags
The enum `do_for_each_ref_flags` and its individual values don't match
to our current best practices when it comes to naming things. Rename it
to `refs_for_each_flag`.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:18 -08:00
Patrick Steinhardt
1c3aff34b8 refs: move do_for_each_ref_flags further up
Move the `do_for_each_ref_flags` enum further up. This prepares for
subsequent changes, where the flags will be used by more functions.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:17 -08:00
Patrick Steinhardt
7543920af2 refs: move refs_head_ref_namespaced()
The function `refs_head_ref_namespaced()` is somewhat special when
compared to most of the other functions that take a callback function:
while `refs_for_each_*()` functions yield multiple refs,
`refs_heasd_ref_namespaced()` will only yield at most the HEAD ref of
the current namespace. As such, the function is related to
`refs_head_ref()` and not to the for-each functions.

Move the function to be located next to `refs_head_ref()` to clarify.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:17 -08:00
Patrick Steinhardt
57fa3161a0 refs: remove unused refs_for_each_include_root_ref()
Remove the unused `refs_for_each_include_root_ref()` function.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-02-23 13:21:17 -08:00
Junio C Hamano
6176ee2349 Merge branch 'kn/ref-batch-output-error-reporting-fix'
A handful of code paths that started using batched ref update API
(after Git 2.51 or so) lost detailed error output, which have been
corrected.

* kn/ref-batch-output-error-reporting-fix:
  fetch: delay user information post committing of transaction
  receive-pack: utilize rejected ref error details
  fetch: utilize rejected ref error details
  update-ref: utilize rejected error details if available
  refs: add rejection detail to the callback function
  refs: skip to next ref when current ref is rejected
2026-02-09 12:09:10 -08:00
Karthik Nayak
be54b10fd7 refs: add rejection detail to the callback function
The previous commit started storing the rejection details alongside the
error code for rejected updates. Pass this along to the callback
function `ref_transaction_for_each_rejected_update()`. Currently the
field is unused, but will be integrated in the upcoming commits.

Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-01-25 22:27:33 -08:00
Patrick Steinhardt
ae38c3a359 refs/files: introduce function to perform normal ref checks
In a subsequent commit we'll introduce new generic checks for direct
refs. These checks will be independent of the actual backend.

Introduce a new function `refs_fsck_ref()` that will be used for this
purpose. At the current point in time it's still empty, but it will get
populated in a subsequent commit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-01-12 06:55:41 -08:00
Patrick Steinhardt
dcecffb616 refs/files: extract generic symref target checks
The consistency checks for the "files" backend contain a couple of
verifications for symrefs that verify generic properties of the target
reference. These properties need to hold for every backend, no matter
whether it's using the "files" or "reftable" backend.

Reimplementing these checks for every single backend doesn't really make
sense. Extract it into a generic `refs_fsck_symref()` function that can
be used by other backends, as well. The "reftable" backend will be wired
up in a subsequent commit.

While at it, improve the consistency checks so that we don't complain
about refs pointing to a non-ref target in case the target refname
format does not verify. Otherwise it's very likely that we'll generate
both error messages, which feels somewhat redundant in this case.

Note that the function has a couple of `UNUSED` parameters. These will
become referenced in a subsequent commit.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2026-01-12 06:55:40 -08:00
Karthik Nayak
f6c5ca387a refs: add a optimize_required field to struct ref_storage_be
To allow users of the refs namespace to check if the reference backend
requires optimization, add a new field `optimize_required` field to
`struct ref_storage_be`. This field is of type `optimize_required_fn`
which is also introduced in this commit.

Modify the debug, files, packed and reftable backend to implement this
field. A following commit will expose this via 'git pack-refs' and 'git
refs optimize'.

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>
2025-11-10 09:28:48 -08:00
Karthik Nayak
2cd99d9841 refs: rename 'pack_refs_opts' to 'refs_optimize_opts'
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>
2025-11-04 07:35:12 -08:00
Karthik Nayak
9b93ab8a9c refs: move to using the '.optimize' functions
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>
2025-11-04 07:35:12 -08:00
Patrick Steinhardt
705114772e refs: drop infrastructure to peel via iterators
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>
2025-11-04 07:32:25 -08:00
Patrick Steinhardt
f898661637 refs: expose peeled object ID via the iterator
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>
2025-11-04 07:32:25 -08:00
Patrick Steinhardt
eb2934d94b refs: refactor reference status flags
The reference flags encode information like whether or not a reference
is a symbolic reference or whether it may be broken. This information is
stored in a `int flags` bitfield, which is in conflict with our modern
best practices; we tend to use an unsigned integer to store flags.

Change the type of the field to be `unsigned`. While at it, refactor the
individual flags to be part of an `enum` instead of using preprocessor
defines.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04 07:32:25 -08:00
Patrick Steinhardt
bdbebe5714 refs: introduce wrapper struct for each_ref_fn
The `each_ref_fn` callback function type is used across our code base
for several different functions that iterate through reference. There's
a bunch of callbacks implementing this type, which makes any changes to
the callback signature extremely noisy. An example of the required churn
is e8207717f1 (refs: add referent to each_ref_fn, 2024-08-09): adding a
single argument required us to change 48 files.

It was already proposed back then [1] that we might want to introduce a
wrapper structure to alleviate the pain going forward. While this of
course requires the same kind of global refactoring as just introducing
a new parameter, it at least allows us to more change the callback type
afterwards by just extending the wrapper structure.

One counterargument to this refactoring is that it makes the structure
more opaque. While it is obvious which callsites need to be fixed up
when we change the function type, it's not obvious anymore once we use
a structure. That being said, we only have a handful of sites that
actually need to populate this wrapper structure: our ref backends,
"refs/iterator.c" as well as very few sites that invoke the iterator
callback functions directly.

Introduce this wrapper structure so that we can adapt the iterator
interfaces more readily.

[1]: <ZmarVcF5JjsZx0dl@tanuki>

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-11-04 07:32:24 -08:00
Junio C Hamano
db0babf9b2 Merge branch 'ms/refs-optimize'
"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
2025-10-02 12:26:12 -07:00
Junio C Hamano
96ed0a8906 Merge branch 'kn/refs-files-case-insensitive'
Deal more gracefully with directory / file conflicts when the files
backend is used for ref storage, by failing only the ones that are
involved in the conflict while allowing others.

* kn/refs-files-case-insensitive:
  refs/files: handle D/F conflicts during locking
  refs/files: handle F/D conflicts in case-insensitive FS
  refs/files: use correct error type when lock exists
  refs/files: catch conflicts on case-insensitive file-systems
2025-09-29 11:40:35 -07:00
Meet Soni
8dfe077fb6 refs: add a generic 'optimize' API
The existing `pack-refs` API is conceptually tied to the 'files'
backend, but its behavior is generic (e.g., it triggers compaction for
reftable). This naming is confusing.

Introduce a new generic refs_optimize() API that dispatches to a
backend-specific implementation via a new 'optimize' vtable method.

This lays the architectural groundwork for different reference backends
(like 'files' and 'reftable') to provide their own storage optimization
logic, which will be called from a single, generic entry point.

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>
2025-09-19 10:02:55 -07:00
Karthik Nayak
3c07063231 refs/files: catch conflicts on case-insensitive file-systems
During the 'prepare' phase of a reference transaction in the files
backend, we create the lock files for references to be created. When
using batched updates on case-insensitive filesystems, the entire
batched updates would be aborted if there are conflicting names such as:

  refs/heads/Foo
  refs/heads/foo

This affects all commands which were migrated to use batched updates in
Git 2.51, including 'git-fetch(1)' and 'git-receive-pack(1)'. Before
that, reference updates would be applied serially with one transaction
used per update. When users fetched multiple references on
case-insensitive systems, subsequent references would simply overwrite
any earlier references. So when fetching:

  refs/heads/foo: 5f34ec0bfeac225b1c854340257a65b106f70ea6
  refs/heads/Foo: ec3053b0977e83d9b67fc32c4527a117953994f3
  refs/heads/sample: 2eefd1150e06d8fca1ddfa684dec016f36bf4e56

The user would simply end up with:

  refs/heads/foo: ec3053b0977e83d9b67fc32c4527a117953994f3
  refs/heads/sample: 2eefd1150e06d8fca1ddfa684dec016f36bf4e56

This is buggy behavior since the user is never informed about the
overrides performed and missing references. Nevertheless, the user is
left with a working repository with a subset of the references. Since
Git 2.51, in such situations fetches would simply fail without updating
any references. Which is also buggy behavior and worse off since the
user is left without any references.

The error is triggered in `lock_raw_ref()` where the files backend
attempts to create a lock file. When a lock file already exists the
function returns a 'REF_TRANSACTION_ERROR_GENERIC'. When this happens,
the entire batched updates, not individual operation, is aborted as if
it were in a transaction.

Change this to return 'REF_TRANSACTION_ERROR_CASE_CONFLICT' instead to
aid the batched update mechanism to simply reject such errors. The
change only affects batched updates since batched updates will reject
individual updates with non-generic errors. So specifically this would
only affect:

    1. git fetch
    2. git receive-pack
    3. git update-ref --batch-updates

This bubbles the error type up to `files_transaction_prepare()` which
tries to lock each reference update. So if the locking fails, we check
if the rejection type can be ignored, which is done by calling
`ref_transaction_maybe_set_rejected()`.

As the error type is now 'REF_TRANSACTION_ERROR_CASE_CONFLICT',
the specific reference update would simply be rejected, while other
updates in the transaction would continue to be applied. This allows
partial application of references in case-insensitive filesystems when
fetching colliding references.

While the earlier implementation allowed the last reference to be
applied overriding the initial references, this change would allow the
first reference to be applied while rejecting consequent collisions.
This should be an okay compromise since with the files backend, there is
no scenario possible where we would retain all colliding references.

Let's also be more proactive and notify users on case-insensitive
filesystems about such problems by providing a brief about the issue
while also recommending using the reftable backend, which doesn't have
the same issue.

Reported-by: Joe Drew <joe.drew@indexexchange.com>
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>
2025-09-17 09:19:07 -07:00
Junio C Hamano
9a85fa8406 Merge branch 'ps/remote-rename-fix'
"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
2025-08-21 13:46:58 -07:00
Junio C Hamano
c3c8b6910a Merge branch 'ps/reflog-migrate-fixes'
"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
2025-08-21 13:46:57 -07:00
Patrick Steinhardt
16c4fa26b9 builtin/remote: only iterate through refs that are to be renamed
When renaming a remote we also need to rename all references
accordingly. But while we only need to rename references that are
contained in the "refs/remotes/$OLDNAME/" namespace, we end up using
`refs_for_each_rawref()` that iterates through _all_ references. We know
to exit early in the callback in case we see an irrelevant reference,
but ultimately this is still a waste of compute as we knowingly iterate
through references that we won't ever care about.

Improve this by using `refs_for_each_rawref_in()`, which knows to only
iterate through (potentially broken) references in a given prefix.

The following benchmark renames a remote with a single reference in a
repository that has 100k unrelated references. This shows a sizeable
improvement with the "files" backend:

    Benchmark 1: rename remote (refformat = files, revision = HEAD~)
      Time (mean ± σ):      42.6 ms ±   0.9 ms    [User: 29.1 ms, System: 8.4 ms]
      Range (min … max):    40.1 ms …  43.3 ms    10 runs

    Benchmark 2: rename remote (refformat = files, revision = HEAD)
      Time (mean ± σ):      31.7 ms ±   4.0 ms    [User: 19.6 ms, System: 6.9 ms]
      Range (min … max):    27.1 ms …  36.0 ms    10 runs

    Summary
      rename remote (refformat = files, revision = HEAD) ran
        1.35 ± 0.17 times faster than rename remote (refformat = files, revision = HEAD~)

The "reftable" backend shows roughly the same absolute improvement, but
given that it's already significantly faster than the "files" backend
this translates to a much larger relative improvement:

    Benchmark 1: rename remote (refformat = reftable, revision = HEAD~)
      Time (mean ± σ):      18.2 ms ±   0.5 ms    [User: 12.7 ms, System: 3.0 ms]
      Range (min … max):    17.3 ms …  21.4 ms    110 runs

    Benchmark 2: rename remote (refformat = reftable, revision = HEAD)
      Time (mean ± σ):       8.8 ms ±   0.5 ms    [User: 3.8 ms, System: 2.9 ms]
      Range (min … max):     7.5 ms …   9.9 ms    167 runs

    Summary
      rename remote (refformat = reftable, revision = HEAD) ran
        2.07 ± 0.12 times faster than rename remote (refformat = reftable, revision = HEAD~)

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-06 14:19:30 -07:00
Patrick Steinhardt
b9fd73a234 refs: pass refname when invoking reflog entry callback
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>
2025-08-06 14:19:30 -07:00
Junio C Hamano
cf03815537 Merge branch 'ps/reflog-migrate-fixes' into ps/remote-rename-fix
* 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
2025-08-06 14:18:43 -07:00
Patrick Steinhardt
465eff81de refs: fix invalid old object IDs when migrating reflogs
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>
2025-08-06 07:36:31 -07:00
Patrick Steinhardt
1ffd2d4159 refs: export ref_transaction_update_reflog()
In a subsequent commit we'll add another user that wants to write reflog
entries. This requires them to call `ref_transaction_update_reflog()`,
but that function is local to "refs.c".

Export the function to prepare for the change. While at it, drop the
`flags` field, as all callers are for now expected to use the same flags
anyway.

Signed-off-by: Patrick Steinhardt <ps@pks.im>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-08-06 07:36:29 -07:00
Junio C Hamano
8d9f536a51 Merge branch 'kn/for-each-ref-skip'
"git for-each-ref" learns "--start-after" option to help
applications that want to page its output.

* kn/for-each-ref-skip:
  ref-cache: set prefix_state when seeking
  for-each-ref: introduce a '--start-after' option
  ref-filter: remove unnecessary else clause
  refs: selectively set prefix in the seek functions
  ref-cache: remove unused function 'find_ref_entry()'
  refs: expose `ref_iterator` via 'refs.h'
2025-08-03 18:44:26 -07:00
Junio C Hamano
7b625c2a35 Merge branch 'ph/fetch-prune-optim'
"git fetch --prune" used to be O(n^2) expensive when there are many
refs, which has been corrected.

* ph/fetch-prune-optim:
  clean up interface for refs_warn_dangling_symrefs
  refs: remove old refs_warn_dangling_symref
  fetch-prune: optimize dangling-ref reporting
2025-07-16 09:42:27 -07:00
Karthik Nayak
2b4648b919 refs: selectively set prefix in the seek functions
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>
2025-07-15 11:54:20 -07:00
Karthik Nayak
6bde5d43b7 refs: expose ref_iterator via 'refs.h'
The `ref_iterator` is an internal structure to the 'refs/'
sub-directory, which allows iteration over refs. All reference iteration
is built on top of these iterators.

External clients of the 'refs' subsystem use the various
'refs_for_each...()' functions to iterate over refs. However since these
are wrapper functions, each combination of functionality requires a new
wrapper function. This is not feasible as the functions pile up with the
increase in requirements. Expose the internal reference iterator, so
advanced users can mix and match options as needed.

Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-15 11:54:19 -07:00
Phil Hord
87d8d8c5d0 clean up interface for refs_warn_dangling_symrefs
The refs_warn_dangling_symrefs interface is a bit fragile as it passes
in printf-formatting strings with expectations about the number of
arguments. This patch series made it worse by adding a 2nd positional
argument. But there are only two call sites, and they both use almost
identical display options.

Make this safer by moving the format strings into the function that uses
them to make it easier to see when the arguments don't match. Pass a
prefix string and a dry_run flag so the decision logic can be handled
where needed.

Signed-off-by: Phil Hord <phil.hord@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-01 18:42:25 -07:00
Phil Hord
0f84695499 refs: remove old refs_warn_dangling_symref
The dangling warning function that takes a single ref to search for
is no longer used.  Remove it.

Signed-off-by: Phil Hord <phil.hord@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-01 18:42:25 -07:00
Karthik Nayak
b3de3832ce refs: add function to translate errors to strings
The commit 76e760b999 (refs: introduce enum-based transaction error
types, 2025-04-08) introduced enum-based transaction error types. The
refs transaction logic was also modified to propagate these errors. For
clients of the ref transaction system, it would be beneficial to provide
human readable messages for these errors.

There is already an existing mapping in 'builtin/update-ref.c', move it
to 'refs.c' as `ref_transaction_error_msg()` and use the same within the
'builtin/update-ref.c'.

Helped-by: Junio C Hamano <gitster@pobox.com>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-19 11:06:31 -07:00
Junio C Hamano
47478802da Merge branch 'kn/non-transactional-batch-updates'
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()
2025-04-16 13:54:19 -07:00
Karthik Nayak
31726bb90d refs: support rejection in batch updates during F/D checks
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>
2025-04-08 07:57:21 -07:00