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2025-09-17refs/files: catch conflicts on case-insensitive file-systemsKarthik Nayak1-3/+18
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>
2025-07-23config: drop `git_config_get_int()` wrapperPatrick Steinhardt1-2/+2
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_get_int()`. All callsites are adjusted so that they use `repo_config_get_int(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>
2025-07-23config: drop `git_config_get_string()` 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_get_string()`. All callsites are adjusted so that they use `repo_config_get_string(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>
2025-07-23config: drop `git_config()` wrapperPatrick Steinhardt1-2/+2
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>
2025-07-16Merge branch 'ph/fetch-prune-optim'Junio C Hamano1-11/+8
"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
2025-07-15Merge branch 'ps/object-store'Junio C Hamano1-10/+11
Code clean-up around object access API. * ps/object-store: odb: rename `read_object_with_reference()` odb: rename `pretend_object_file()` odb: rename `has_object()` odb: rename `repo_read_object_file()` odb: rename `oid_object_info()` odb: trivial refactorings to get rid of `the_repository` odb: get rid of `the_repository` when handling submodule sources odb: get rid of `the_repository` when handling the primary source odb: get rid of `the_repository` in `for_each()` functions odb: get rid of `the_repository` when handling alternates odb: get rid of `the_repository` in `odb_mkstemp()` odb: get rid of `the_repository` in `assert_oid_type()` odb: get rid of `the_repository` in `find_odb()` odb: introduce parent pointers object-store: rename files to "odb.{c,h}" object-store: rename `object_directory` to `odb_source` object-store: rename `raw_object_store` to `object_database`
2025-07-08Merge branch 'kn/fetch-push-bulk-ref-update'Junio C Hamano1-54/+73
"git push" and "git fetch" are taught to update refs in batches to gain performance. * kn/fetch-push-bulk-ref-update: receive-pack: handle reference deletions separately refs/files: skip updates with errors in batched updates receive-pack: use batched reference updates send-pack: fix memory leak around duplicate refs fetch: use batched reference updates refs: add function to translate errors to strings
2025-07-01clean up interface for refs_warn_dangling_symrefsPhil Hord1-4/+1
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>
2025-07-01fetch-prune: optimize dangling-ref reportingPhil Hord1-10/+10
When pruning during `git fetch` we check each pruned ref against the ref_store one at a time to decide whether to report it as dangling. This causes every local ref to be scanned for each ref being pruned. If there are N refs in the repo and M refs being pruned, this code is O(M*N). However, `git remote prune` uses a very similar function that is only O(N*log(M)). Remove the wasteful ref scanning for each pruned ref and use the faster version already available in refs_warn_dangling_symrefs. Change the message to include the original refname since the message is no longer printed immediately after the line that did just print the refname. In a repo with 126,000 refs, where I was pruning 28,000 refs, this code made about 3.6 billion calls to strcmp and consumed 410 seconds of CPU. (Invariably in that time, my remote would timeout and the fetch would fail anyway.) After this change, the same operation completes in under a second. Signed-off-by: Phil Hord <phil.hord@gmail.com> Reviewed-by: Jacob Keller <jacob.e.keller@intel.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-01odb: rename `has_object()`Patrick Steinhardt1-8/+9
Rename `has_object()` to `odb_has_object()` to match other functions related to the object database and our modern coding guidelines. Introduce a compatibility wrapper so that any in-flight topics will continue to compile. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-01object-store: rename files to "odb.{c,h}"Patrick Steinhardt1-1/+1
In the preceding commits we have renamed the structures contained in "object-store.h" to `struct object_database` and `struct odb_backend`. As such, the code files "object-store.{c,h}" are confusingly named now. Rename them to "odb.{c,h}" accordingly. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-07-01object-store: rename `object_directory` to `odb_source`Patrick Steinhardt1-1/+1
The `object_directory` structure is used as an access point for a single object directory like ".git/objects". While the structure isn't yet fully self-contained, the intent is for it to eventually contain all information required to access objects in one specific location. While the name "object directory" is a good fit for now, this will change over time as we continue with the agenda to make pluggable object databases a thing. Eventually, objects may not be accessed via any kind of directory at all anymore, but they could instead be backed by any kind of durable storage mechanism. While it seems quite far-fetched for now, it is thinkable that eventually this might even be some form of a database, for example. As such, the current name of this structure will become worse over time as we evolve into the direction of pluggable ODBs. Immediate next steps will start to carve out proper self-contained object directories, which requires us to pass in these object directories as parameters. Based on our modern naming schema this means that those functions should then be named after their subsystem, which means that we would start to bake the current name into the codebase more and more. Let's preempt this by renaming the structure. There have been a couple alternatives that were discussed: - `odb_backend` was discarded because it led to the association that one object database has a single backend, but the model is that one alternate has one backend. Furthermore, "backend" is more about the actual backing implementation and less about the high-level concept. - `odb_alternate` was discarded because it is a bit of a stretch to also call the main object directory an "alternate". Instead, pick `odb_source` as the new name. It makes it sufficiently clear that there can be multiple sources and does not cause confusion when mixed with the already-existing "alternate" terminology. In the future, this change allows us to easily introduce for example a `odb_files_source` and other format-specific implementations. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-06-25Merge branch 'ps/maintenance-ref-lock'Junio C Hamano1-1/+1
"git maintenance" lacked the care "git gc" had to avoid holding onto the repository lock for too long during packing refs, which has been remedied. * ps/maintenance-ref-lock: builtin/maintenance: fix locking race when handling "gc" task builtin/gc: avoid global state in `gc_before_repack()` usage: allow dying without writing an error message builtin/maintenance: fix locking race with refs and reflogs tasks builtin/maintenance: split into foreground and background tasks builtin/maintenance: fix typedef for function pointers builtin/maintenance: extract function to run tasks builtin/maintenance: stop modifying global array of tasks builtin/maintenance: mark "--task=" and "--schedule=" as incompatible builtin/maintenance: centralize configuration of explicit tasks builtin/gc: drop redundant local variable builtin/gc: use designated field initializers for maintenance tasks
2025-06-03usage: allow dying without writing an error messagePatrick Steinhardt1-1/+1
Sometimes code wants to die in a situation where it already has written an error message. To use the same error code as `die()` we have to use `exit(128)`, which is easy to get wrong and leaves magic numbers all over our codebase. Teach `die_message_builtin()` to not print any error when passed a `NULL` pointer as error string. Like this, such users can now call `die(NULL)` to achieve the same result without any hardcoded error codes. Adapt a couple of builtins to use this new pattern to demonstrate that there is a need for such a helper. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-19fetch: use batched reference updatesKarthik Nayak1-54/+73
The reference updates performed as a part of 'git-fetch(1)', take place one at a time. For each reference update, a new transaction is created and committed. This is necessary to ensure we can allow individual updates to fail without failing the entire command. The command also supports an '--atomic' mode, which uses a single transaction to update all of the references. But this mode has an all-or-nothing approach, where if a single update fails, all updates would fail. In 23fc8e4f61 (refs: implement batch reference update support, 2025-04-08), we introduced a new mechanism to batch reference updates. Under the hood, this uses a single transaction to perform a batch of reference updates, while allowing only individual updates to fail. Utilize this newly introduced batch update mechanism in 'git-fetch(1)'. This provides a significant bump in performance, especially when dealing with repositories with large number of references. Adding support for batched updates is simply modifying the flow to also create a batch update transaction in the non-atomic flow. With the reftable backend there is a 22x performance improvement, when performing 'git-fetch(1)' with 10000 refs: Benchmark 1: fetch: many refs (refformat = reftable, refcount = 10000, revision = master) Time (mean ± σ): 3.403 s ± 0.775 s [User: 1.875 s, System: 1.417 s] Range (min … max): 2.454 s … 4.529 s 10 runs Benchmark 2: fetch: many refs (refformat = reftable, refcount = 10000, revision = HEAD) Time (mean ± σ): 154.3 ms ± 17.6 ms [User: 102.5 ms, System: 56.1 ms] Range (min … max): 145.2 ms … 220.5 ms 18 runs Summary fetch: many refs (refformat = reftable, refcount = 10000, revision = HEAD) ran 22.06 ± 5.62 times faster than fetch: many refs (refformat = reftable, refcount = 10000, revision = master) In similar conditions, the files backend sees a 1.25x performance improvement: Benchmark 1: fetch: many refs (refformat = files, refcount = 10000, revision = master) Time (mean ± σ): 605.5 ms ± 9.4 ms [User: 117.8 ms, System: 483.3 ms] Range (min … max): 595.6 ms … 621.5 ms 10 runs Benchmark 2: fetch: many refs (refformat = files, refcount = 10000, revision = HEAD) Time (mean ± σ): 485.8 ms ± 4.3 ms [User: 91.1 ms, System: 396.7 ms] Range (min … max): 477.6 ms … 494.3 ms 10 runs Summary fetch: many refs (refformat = files, refcount = 10000, revision = HEAD) ran 1.25 ± 0.02 times faster than fetch: many refs (refformat = files, refcount = 10000, revision = master) With this we'll either be using a regular transaction or a batch update transaction. This helps cleanup some code which is no longer needed as we'll now always have some type of 'ref_transaction' object being propagated. One big change is that earlier, each individual update would propagate a failure. Whereas now, the `ref_transaction_for_each_rejected_update` function is called at the end of the flow to capture the exit status for 'git-fetch(1)' and also to print F/D conflict errors. This does change the order of the errors being printed, but the behavior stays the same. Since transaction errors are now explicitly defined as part of 76e760b999 (refs: introduce enum-based transaction error types, 2025-04-08), utilize them and get rid of custom errors defined within 'builtin/fetch.c'. Signed-off-by: Karthik Nayak <karthik.188@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-15fetch: avoid unnecessary work when there is no current branchJohannes Schindelin1-1/+1
As pointed out by CodeQL, `branch_get()` may return `NULL`, in which case `branch_has_merge_config()` would return early, but we can even avoid enumerating the refs prefixes in that case, saving even more CPU cycles. Technically, we should enclose these two statements in an `if (branch) {...}` block, but the indentation is already quite deep, therefore I refrained from doing that. Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-15fetch: carefully clear local variable's address after useJohannes Schindelin1-0/+1
As pointed out by CodeQL, it is a potentially dangerous practice to store local variables' addresses in non-local structs. Yet this is exactly what happens with the `acked_commits` attribute that is used in `cmd_fetch()`: The pointer to a local variable is assigned to it. Now, it is Git's convention that `cmd_*()` functions are essentially only returning just before exiting the process, therefore there is little danger that this attribute is used after the code flow returns from that function. However, code in `cmd_*()` function is often so useful that it gets lifted into a library function, at which point this issue could become a real problem. Let's make sure to clear the `acked_commits` attribute out after it was used, and before the function returns (at which point the address would go stale). Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-05-12Merge branch 'ps/object-store-cleanup'Junio C Hamano1-8/+7
Further code clean-up in the object-store layer. * ps/object-store-cleanup: object-store: drop `repo_has_object_file()` treewide: convert users of `repo_has_object_file()` to `has_object()` object-store: allow fetching objects via `has_object()` object-store: move function declarations to their respective subsystems object-store: move and rename `odb_pack_keep()` object-store: drop `loose_object_path()` object-store: move `struct packed_git` into "packfile.h"
2025-04-29treewide: convert users of `repo_has_object_file()` to `has_object()`Patrick Steinhardt1-8/+7
As the comment of `repo_has_object_file()` and its `_with_flags()` variant tells us, these functions are considered to be deprecated in favor of `has_object()`. There are a couple of slight benefits in favor of the replacement: - The new function has a short-and-sweet name. - More explicit defaults: `has_object()` doesn't fetch missing objects via promisor remotes, and neither does it reload packfiles if an object wasn't found by default. This ensures that it becomes immediately obvious when a simple object existence check may result in expensive actions. Most importantly though, it is confusing that we have two sets of functions that ultimately do the same thing, but with different defaults. Start sunsetting `repo_has_object_file()` and its `_with_flags()` sibling by replacing all callsites with `has_object()`: - `repo_has_object_file(...)` is equivalent to `has_object(..., HAS_OBJECT_RECHECK_PACKED | HAS_OBJECT_FETCH_PROMISOR)`. - `repo_has_object_file_with_flags(..., OBJECT_INFO_QUICK | OBJECT_INFO_SKIP_FETCH_OBJECT)` is equivalent to `has_object(..., 0)`. - `repo_has_object_file_with_flags(..., OBJECT_INFO_SKIP_FETCH_OBJECT)` is equivalent to `has_object(..., HAS_OBJECT_RECHECK_PACKED)`. - `repo_has_object_file_with_flags(..., OBJECT_INFO_QUICK)` is equivalent to `has_object(..., HAS_OBJECT_FETCH_PROMISOR)`. The replacements should be functionally equivalent. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-24Merge branch 'ps/parse-options-integers'Junio C Hamano1-2/+8
Update parse-options API to catch mistakes to pass address of an integral variable of a wrong type/size. * ps/parse-options-integers: parse-options: detect mismatches in integer signedness parse-options: introduce precision handling for `OPTION_UNSIGNED` parse-options: introduce precision handling for `OPTION_INTEGER` parse-options: rename `OPT_MAGNITUDE()` to `OPT_UNSIGNED()` parse-options: support unit factors in `OPT_INTEGER()` global: use designated initializers for options parse: fix off-by-one for minimum signed values
2025-04-24Merge branch 'ps/object-file-cleanup'Junio C Hamano1-1/+1
Code clean-up. * ps/object-file-cleanup: object-store: merge "object-store-ll.h" and "object-store.h" object-store: remove global array of cached objects object: split out functions relating to object store subsystem object-file: drop `index_blob_stream()` object-file: split up concerns of `HASH_*` flags object-file: split out functions relating to object store subsystem object-file: move `xmmap()` into "wrapper.c" object-file: move `git_open_cloexec()` to "compat/open.c" object-file: move `safe_create_leading_directories()` into "path.c" object-file: move `mkdir_in_gitdir()` into "path.c"
2025-04-24Merge branch 'ps/object-file-cleanup' into ps/object-store-cleanupJunio C Hamano1-1/+1
* ps/object-file-cleanup: object-store: merge "object-store-ll.h" and "object-store.h" object-store: remove global array of cached objects object: split out functions relating to object store subsystem object-file: drop `index_blob_stream()` object-file: split up concerns of `HASH_*` flags object-file: split out functions relating to object store subsystem object-file: move `xmmap()` into "wrapper.c" object-file: move `git_open_cloexec()` to "compat/open.c" object-file: move `safe_create_leading_directories()` into "path.c" object-file: move `mkdir_in_gitdir()` into "path.c"
2025-04-17Merge branch 'jk/fetch-follow-remote-head-fix'Junio C Hamano1-25/+11
"git fetch [<remote>]" with only the configured fetch refspec should be the only thing to update refs/remotes/<remote>/HEAD, but the code was overly eager to do so in other cases. * jk/fetch-follow-remote-head-fix: fetch: make set_head() call easier to read fetch: don't ask for remote HEAD if followRemoteHEAD is "never" fetch: only respect followRemoteHEAD with configured refspecs
2025-04-17global: use designated initializers for optionsPatrick Steinhardt1-2/+8
While we expose macros for most of our different option types understood by the "parse-options" subsystem, not every combination of fields that has one as that would otherwise quickly lead to an explosion of macros. Instead, we just initialize structures manually for those variants of fields that don't have a macro. Callsites that open-code these structure initialization don't use designated initializers though and instead just provide values for each of the fields that they want to initialize. This has three significant downsides: - Callsites need to specify all values up to the last field that they care about. This often includes fields that should simply be left at their default zero-initialized state, which adds distraction. - Any reader not deeply familiar with the layout of the structure has a hard time figuring out what the respective initializers mean. - Reordering or introducing new fields in the middle of the structure is impossible without adapting all callsites. Convert all sites to instead use designated initializers, which we have started using in our codebase quite a while ago. This allows us to skip any default-initialized fields, gives the reader context by specifying the field names and allows us to reorder or introduce new fields where we want to. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-16Merge branch 'kn/non-transactional-batch-updates'Junio C Hamano1-1/+1
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()
2025-04-16Merge branch 'jt/ref-transaction-abort-fix'Junio C Hamano1-1/+8
A ref transaction corner case fix. * jt/ref-transaction-abort-fix: builtin/fetch: avoid aborting closed reference transaction
2025-04-15Merge branch 'jt/clone-guess-remote-head-fix'Junio C Hamano1-1/+1
"git clone" still gave the message about the default branch name; this message has been turned into an advice message that can be turned off. * jt/clone-guess-remote-head-fix: advice: allow disabling default branch name advice builtin/clone: suppress unexpected default branch advice remote: allow `guess_remote_head()` to suppress advice
2025-04-15object-store: merge "object-store-ll.h" and "object-store.h"Patrick Steinhardt1-1/+1
The "object-store-ll.h" header has been introduced to keep transitive header dependendcies and compile times at bay. Now that we have created a new "object-store.c" file though we can easily move the last remaining additional bit of "object-store.h", the `odb_path_map`, out of the header. Do so. As the "object-store.h" header is now equivalent to its low-level alternative we drop the latter and inline it into the former. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-09fetch: make set_head() call easier to readJeff King1-4/+5
We ignore any error returned from set_head(), but 638060dcb9 (fetch set_head: refactor to use remote directly, 2025-01-26) left its call in a noop "if" conditional as a sort of note-to-self. When c834d1a7ce (fetch: only respect followRemoteHEAD with configured refspecs, 2025-03-18) added a "do_set_head" flag, it was rolled into the same conditional, putting set_head() on the right-hand side of a short-circuit AND. That's not wrong, but it really hides the point of the line, which is (maybe) calling the function. Instead, let's have a full if() block for the flag, and then our comment (with some rewording) will be sufficient to clarify the error handling. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-04-08refs: introduce enum-based transaction error typesKarthik Nayak1-1/+1
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>
2025-03-25remote: allow `guess_remote_head()` to suppress adviceJustin Tobler1-1/+1
The `repo_default_branch_name()` invoked through `guess_remote_head()` is configured to always display the default branch advice message. Adapt `guess_remote_head()` to accept flags and convert the `all` parameter to a flag. Add the `REMOTE_GUESS_HEAD_QUIET` flag to to enable suppression of advice messages. Call sites are updated accordingly. Signed-off-by: Justin Tobler <jltobler@gmail.com> Acked-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-21builtin/fetch: avoid aborting closed reference transactionJustin Tobler1-1/+8
As part of the reference transaction commit phase, the transaction is set to a closed state regardless of whether it was successful of not. Attempting to abort a closed transaction via `ref_transaction_abort()` results in a `BUG()`. In c92abe71df (builtin/fetch: fix leaking transaction with `--atomic`, 2024-08-22), logic to free a transaction after the commit phase is moved to the centralized exit path. In cases where the transaction commit failed, this results in a closed transaction being aborted and signaling a bug. Free the transaction and set it to NULL when the commit fails. This allows the exit path to correctly handle the error without attempting to abort the transaction. Signed-off-by: Justin Tobler <jltobler@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-21refspec: replace `refspec_item_init()` with fetch/push variantsTaylor Blau1-1/+1
For similar reasons as in the previous refactoring of `refspec_init()` into `refspec_init_fetch()` and `refspec_init_push()`, apply the same refactoring to `refspec_item_init()`. Signed-off-by: Taylor Blau <me@ttaylorr.com> Acked-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-18fetch: don't ask for remote HEAD if followRemoteHEAD is "never"Jeff King1-4/+2
When we are going to consider updating the refs/remotes/*/HEAD symref, we have to ask the remote side where its HEAD points. But if we know that the feature is disabled by config, we don't need to bother! This saves a little bit of work and network communication for the server. And even a little bit of effort on the client, as our local set_head() function did a bit of work matching the remote HEAD before realizing that we're not going to do anything with it. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-18fetch: only respect followRemoteHEAD with configured refspecsJeff King1-19/+6
The new followRemoteHEAD feature is triggered for almost every fetch, causing us to ask the server about the remote "HEAD" and to consider updating our local tracking HEAD symref. This patch limits the feature only to the case when we are fetching a remote using its configured refspecs (typically into its refs/remotes/ hierarchy). There are two reasons for this. One is efficiency. E.g., the fixes in 6c915c3f85 (fetch: do not ask for HEAD unnecessarily, 2024-12-06) and 20010b8c20 (fetch: avoid ls-refs only to ask for HEAD symref update, 2025-03-08) were aimed at reducing the work we do when we would not be able to update HEAD anyway. But they do not quite cover all cases. The remaining one is: git fetch origin refs/heads/foo:refs/remotes/origin/foo which _sometimes_ can update HEAD, but usually not. And that leads us to the second point, which is being simple and explainable. The code for updating the tracking HEAD symref requires both that we learned which ref the remote HEAD points at, and that the server advertised that ref to us. But because the v2 protocol narrows the server's advertisement, the command above would not typically update HEAD at all, unless it happened to point to the "foo" branch. Or even weirder, it probably _would_ update if the server is very old and supports only the v0 protocol, which always gives a full advertisement. This creates confusing behavior for the user: sometimes we may try to update HEAD and sometimes not, depending on vague rules. One option here would be to loosen the update code to accept the remote HEAD even if the server did not advertise that ref. I think that could work, but it may also lead to interesting corner cases (e.g., creating a dangling symref locally, even though the branch is not unborn on the server, if we happen not to have fetched it). So let's instead simplify the rules: we'll only consider updating the tracking HEAD symref when we're doing a full fetch of the remote's configured refs. This is easy to implement; we can just set a flag at the moment we realize we're using the configured refspecs. And we can drop the special case code added by 6c915c3f85 and 20010b8c20, since this covers those cases. The existing tests from those commits still pass. In t5505, an incidental call to "git fetch <remote> <refspec>" updated HEAD, which caused us to adjust the test in 3f763ddf28 (fetch: set remote/HEAD if it does not exist, 2024-11-22). We can now adjust that back to how it was before the feature was added. Even though t5505 is incidentally testing our new desired behavior, we'll add an explicit test in t5510 to make sure it is covered. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-10fetch: use ref prefix list to skip ls-refsJeff King1-20/+7
In git-fetch we have an optimization to avoid issuing an ls-refs command to the server if we don't care about the value of any refs (e.g., because we are fetching exact object ids), saving a round-trip to the server. This comes from e70a3030e7 (fetch: do not list refs if fetching only hashes, 2018-09-27). It uses an explicit flag "must_list_refs" to decide when we need to do so. That was needed back then, because the list of ref-prefixes was not always complete. If it was empty, it did not necessarily mean that we were not interested in any refs). But that is no longer the case; an empty list of prefixes means that we truly do not care about any refs. And so rather than an explicit flag, we can just check whether we are interested in any ref prefixes. This simplifies the code slightly, as there is now a single source of truth for the decision. It also fixes a bug in / optimizes a very unlikely case, which is: git fetch $remote ^foo $oid I.e., a negative refspec combined with an exact oid fetch. This is somewhat nonsense, in that there are no positive refspecs mentioning refs to countermand with the negative one. But we should be able to do this without issuing an ls-refs command (excluding "foo" from the empty set will obviously still be the empty set). However, the current code does not do so. The negative refspec is not counted as a noop in un-setting the must_list_refs flag (hardly the fault of e70a3030e7, as negative refspecs did not appear until much later). But by using the prefix list as a source of truth, this naturally just works; the negative refspec does not add a prefix to ask about, and hence does not trigger the ls-refs call. This is esoteric enough that I didn't bother adding a test. The real value here is in the code simplification. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-10fetch: avoid ls-refs only to ask for HEAD symref updateJeff King1-3/+2
When we fetch from a configured remote, we may try to update the local refs/remotes/<origin>/HEAD, and so we ask the server to advertise its HEAD to us. But if we aren't otherwise asking about any refs at all, then we know this HEAD update can never happen! To consider a new value for HEAD, the set_head() function uses guess_remote_head(). And even if it sees an explicit symref value for HEAD, it will only report that as a match if we also saw that remote ref advertised, and it mapped to a local tracking ref via get_fetch_map(). In other words, a fetch like this: git fetch origin $exact_oid:refs/heads/foo can never update HEAD, because we will never have fetched (nor even see the advertisement for) the ref that HEAD points to. Currently the command above will still call ls-refs to ask about the HEAD, even though it is pointless. This patch teaches it to skip the ls-refs call entirely in this case, which avoids a round-trip to the server. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-10fetch: stop protecting additions to ref-prefix listJeff King1-6/+4
When using the ref-prefix feature of protocol v2, a client which sends no prefixes at all will get the full advertisement. And so the code in git-fetch was historically loose about setting up that list based on our refspecs. There were cases where we needed to know about some refs, so we just didn't add anything to the ref-prefix list. And hence further code, like that for tag-following and updating origin/HEAD, had to be careful about adding to an empty list. E.g., see the bug fixed by bd52d9a058 (fetch: fix following tags when fetching specific OID, 2025-03-07). But the previous commit removed the last such case, and now we know an empty ref-prefix list (at least inside git-fetch's do_fetch() function) means that we really don't need to see any refs. So we can drop those extra conditionals. This simplifies the code a little. But it also means that some cases can now use ref prefixes when they would not otherwise. As the test shows, fetching an exact oid into a local ref can now avoid enumerating all of the refs. The refspec itself doesn't need to know about any remote refs, and the tag auto-following can just ask about refs/tags/. The same is true for asking about HEAD to update the local origin/HEAD. I didn't add a test for that yet, though, as we can optimize it even further. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-10fetch: ask server to advertise HEAD for config-less fetchJeff King1-0/+8
If we're not given any refspecs (either on the command line or via config) and we have no branch merge config, then we fetch the remote HEAD into our local FETCH_HEAD. In that case we do not send any ref-prefix option to the server at all, and we see the full advertisement. But this is sub-optimal. We only care about HEAD, so we can just ask for that, and ignore all of the other refs. The new test demonstrates a case where we see fewer refs (in this case only one less, but in theory we could be ignoring millions of them). This also removes the only case where we care about seeing some refs from the other side, but don't add anything to the ref_prefixes list. Cleaning this up means one less maintenance burden. Before this patch, any code which wanted to add to the list had to make sure the list was not empty, since an empty list meant "ask for everything". Now it really means "we are not interested in any refs". This should let us optimize a few more cases in subsequent patches. Note that we'll add "HEAD" to the list of prefixes, and later code for updating "refs/remotes/<remote>/HEAD" may likewise do so. In theory this could cause duplicates in the list, but in practice these can't both trigger. We hit our new case only if there are no refspecs, and the "<remote>/HEAD" feature is enabled only when we are fetching from a remote with configured refspecs. We could be defensive with a flag, but it didn't seem worth it to me (the absolute worse case is a useless redundant ref-prefix line sent to the server). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-03-10Merge branch 'tb/fetch-follow-tags-fix'Junio C Hamano1-1/+3
* tb/fetch-follow-tags-fix: fetch: fix following tags when fetching specific OID
2025-03-07fetch: fix following tags when fetching specific OIDTaylor Blau1-1/+3
In 3f763ddf28 (fetch: set remote/HEAD if it does not exist, 2024-11-22), unconditionally adds "HEAD" to the list of ref prefixes we send to the server. This breaks a core assumption that the list of prefixes we send to the server is complete. We must either send all prefixes we care about, or none at all (in the latter case the server then advertises everything). The tag following code is careful to only add "refs/tags/" to the list of prefixes if there are already entries in the prefix list. But because the new code from 3f763ddf28 runs after the tag code, and because it unconditionally adds to the prefix list, we may end up with a prefix list that _should_ have "refs/tags/" in it, but doesn't. When that is the case, the server does not advertise any tags, and our auto-following breaks because we never learned about any tags in the first place. Fix this by only adding "HEAD" to the ref prefixes when we know that we are already limiting the advertisement. In either case we'll learn about HEAD (either through the limited advertisement, or implicitly through a full advertisement). Reported-by: Igor Todorovski <itodorov@ca.ibm.com> Co-authored-by: Jeff King <peff@peff.net> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-27fetch set_head: fix non-mirror remotes in bare repositoriesBence Ferdinandy1-5/+5
In b1b713f722 (fetch set_head: handle mirrored bare repositories, 2024-11-22) it was implicitly assumed that all remotes will be mirrors in a bare repository, thus fetching a non-mirrored remote could lead to HEAD pointing to a non-existent reference. Make sure we only overwrite HEAD if we are in a bare repository and fetching from a mirror. Otherwise, proceed as normally, and create refs/remotes/<nonmirrorremote>/HEAD instead. Reported-by: Christian Hesse <list@eworm.de> Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-27fetch set_head: refactor to use remote directlyBence Ferdinandy1-8/+7
As a preparatory step to use even more properties from the remote struct, refactor set_head to take the entire struct as a parameter, instead of the necessary bits. This also allows consolidating the use of gtransport->remote in set_head, making the access of the remote's properties consistent in the function. Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2025-01-06Merge branch 'bf/fetch-set-head-config'Junio C Hamano1-2/+2
A hotfix on an advice messagge added during this cycle. * bf/fetch-set-head-config: fetch: fix erroneous set_head advice message
2025-01-06fetch: fix erroneous set_head advice messageBence Ferdinandy1-2/+2
9e2b7005be (fetch set_head: add warn-if-not-$branch option, 2024-12-05) tried to expand the advice message for set_head with the new option, but unfortunately did not manage to add the right incantation. Fix the advice message with the correct usage of warn-if-not-$branch. Reported-by: Teng Long <dyroneteng@gmail.com> Signed-off-by: Bence Ferdinandy <bence@ferdinandy.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2024-12-23Merge branch 'ps/build-sign-compare'Junio C Hamano1-0/+3
Start working to make the codebase buildable with -Wsign-compare. * ps/build-sign-compare: t/helper: don't depend on implicit wraparound scalar: address -Wsign-compare warnings builtin/patch-id: fix type of `get_one_patchid()` builtin/blame: fix type of `length` variable when emitting object ID gpg-interface: address -Wsign-comparison warnings daemon: fix type of `max_connections` daemon: fix loops that have mismatching integer types global: trivial conversions to fix `-Wsign-compare` warnings pkt-line: fix -Wsign-compare warning on 32 bit platform csum-file: fix -Wsign-compare warning on 32-bit platform diff.h: fix index used to loop through unsigned integer config.mak.dev: drop `-Wno-sign-compare` global: mark code units that generate warnings with `-Wsign-compare` compat/win32: fix -Wsign-compare warning in "wWinMain()" compat/regex: explicitly ignore "-Wsign-compare" warnings git-compat-util: introduce macros to disable "-Wsign-compare" warnings
2024-12-19Merge branch 'bf/fetch-set-head-config'Junio C Hamano1-6/+55
"git fetch" honors "remote.<remote>.followRemoteHEAD" settings to tweak the remote-tracking HEAD in "refs/remotes/<remote>/HEAD". * bf/fetch-set-head-config: remote set-head: set followRemoteHEAD to "warn" if "always" fetch set_head: add warn-if-not-$branch option fetch set_head: move warn advice into advise_if_enabled fetch: add configuration for set_head behaviour
2024-12-19Merge branch 'jc/set-head-symref-fix'Junio C Hamano1-1/+19
"git fetch" from a configured remote learned to update a missing remote-tracking HEAD but it asked the remote about their HEAD even when it did not need to, which has been corrected. Incidentally, this also corrects "git fetch --tags $URL" which was broken by the new feature in an unspecified way. * jc/set-head-symref-fix: fetch: do not ask for HEAD unnecessarily
2024-12-19Merge branch 'bf/set-head-symref'Junio C Hamano1-0/+74
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
2024-12-07fetch: do not ask for HEAD unnecessarilyJunio C Hamano1-1/+19
In 3f763ddf28 (fetch: set remote/HEAD if it does not exist, 2024-11-22), git-fetch learned to opportunistically set $REMOTE/HEAD when fetching by always asking for remote HEAD, in the hope that it will help setting refs/remotes/<name>/HEAD if missing. But it is not needed to always ask for remote HEAD. When we are fetching from a remote, for which we have remote-tracking branches, we do need to know about HEAD. But if we are doing one-shot fetch, e.g., $ git fetch --tags https://github.com/git/git we do not even know what sub-hierarchy of refs/remotes/<remote>/ we need to adjust the remote HEAD for. There is no need to ask for HEAD in such a case. Incidentally, because the unconditional request to list "HEAD" affected the number of ref-prefixes requested in the ls-remote request, this affected how the requests for tags are added to the same ls-remote request, breaking "git fetch --tags $URL" performed against a URL that is not configured as a remote. Reported-by: Josh Steadmon <steadmon@google.com> [jc: tests are also borrowed from Josh's patch] Signed-off-by: Junio C Hamano <gitster@pobox.com>