git/refs.c, branch v2.44.3

Merge branch 'ps/not-so-many-refs-are-special'

2024-01-30T00:03:00Z

Define "special ref" as a very narrow set that consists of FETCH_HEAD and MERGE_HEAD, and clarify everything else that used to be classified as such are actually just pseudorefs. * ps/not-so-many-refs-are-special: Documentation: add "special refs" to the glossary refs: redefine special refs refs: convert MERGE_AUTOSTASH to become a normal pseudo-ref sequencer: introduce functions to handle autostashes via refs refs: convert AUTO_MERGE to become a normal pseudo-ref sequencer: delete REBASE_HEAD in correct repo when picking commits sequencer: clean up pseudo refs with REF_NO_DEREF

Merge branch 'ps/worktree-refdb-initialization'

2024-01-26T16:54:46Z

Instead of manually creating refs/ hierarchy on disk upon a creation of a secondary worktree, which is only usable via the files backend, use the refs API to populate it. * ps/worktree-refdb-initialization: builtin/worktree: create refdb via ref backend worktree: expose interface to look up worktree by name builtin/worktree: move setup of commondir file earlier refs/files: skip creation of "refs/{heads,tags}" for worktrees setup: move creation of "refs/" into the files backend refs: prepare `refs_init_db()` for initializing worktree refs

refs: redefine special refs

2024-01-19T19:10:41Z

Now that our list of special refs really only contains refs which have actually-special semantics, let's redefine what makes a special ref. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

refs: convert MERGE_AUTOSTASH to become a normal pseudo-ref

2024-01-19T19:10:41Z

Similar to the preceding conversion of the AUTO_MERGE pseudo-ref, let's convert the MERGE_AUTOSTASH ref to become a normal pseudo-ref as well. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

refs: convert AUTO_MERGE to become a normal pseudo-ref

2024-01-19T19:10:41Z

In 70c70de616 (refs: complete list of special refs, 2023-12-14) we have inrtoduced a new `is_special_ref()` function that classifies some refs as being special. The rule is that special refs are exclusively read and written via the filesystem directly, whereas normal refs exclucsively go via the refs API. The intent of that commit was to record the status quo so that we know to route reads of such special refs consistently. Eventually, the list should be reduced to its bare minimum of refs which really are special, namely FETCH_HEAD and MERGE_HEAD. Follow up on this promise and convert the AUTO_MERGE ref to become a normal pseudo-ref by using the refs API to both read and write it instead of accessing the filesystem directly. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

Merge branch 'ps/refstorage-extension'

2024-01-16T18:11:57Z

Introduce a new extension "refstorage" so that we can mark a repository that uses a non-default ref backend, like reftable. * ps/refstorage-extension: t9500: write "extensions.refstorage" into config builtin/clone: introduce `--ref-format=` value flag builtin/init: introduce `--ref-format=` value flag builtin/rev-parse: introduce `--show-ref-format` flag t: introduce GIT_TEST_DEFAULT_REF_FORMAT envvar setup: introduce GIT_DEFAULT_REF_FORMAT envvar setup: introduce "extensions.refStorage" extension setup: set repository's formats on init setup: start tracking ref storage format refs: refactor logic to look up storage backends worktree: skip reading HEAD when repairing worktrees t: introduce DEFAULT_REPO_FORMAT prereq

refs: prepare `refs_init_db()` for initializing worktree refs

2024-01-08T21:17:30Z

The purpose of `refs_init_db()` is to initialize the on-disk files of a new ref database. The function is quite inflexible right now though, as callers can neither specify the `struct ref_store` nor can they pass any flags. Refactor the interface to accept both of these. This will be required so that we can start initializing per-worktree ref databases via the ref backend instead of open-coding the initialization in "worktree.c". Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

Merge branch 'ps/pseudo-refs'

2024-01-02T21:51:30Z

Assorted changes around pseudoref handling. * ps/pseudo-refs: bisect: consistently write BISECT_EXPECTED_REV via the refdb refs: complete list of special refs refs: propagate errno when reading special refs fails wt-status: read HEAD and ORIG_HEAD via the refdb

setup: start tracking ref storage format

2024-01-02T17:24:47Z

In order to discern which ref storage format a repository is supposed to use we need to start setting up and/or discovering the format. This needs to happen in two separate code paths. - The first path is when we create a repository via `init_db()`. When we are re-initializing a preexisting repository we need to retain the previously used ref storage format -- if the user asked for a different format then this indicates an error and we error out. Otherwise we either initialize the repository with the format asked for by the user or the default format, which currently is the "files" backend. - The second path is when discovering repositories, where we need to read the config of that repository. There is not yet any way to configure something other than the "files" backend, so we can just blindly set the ref storage format to this backend. Wire up this logic so that we have the ref storage format always readily available when needed. As there is only a single backend and because it is not configurable we cannot yet verify that this tracking works as expected via tests, but tests will be added in subsequent commits. To countermand this ommission now though, raise a BUG() in case the ref storage format is not set up properly in `ref_store_init()`. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

refs: refactor logic to look up storage backends

2024-01-02T17:24:47Z

In order to look up ref storage backends, we're currently using a linked list of backends, where each backend is expected to set up its `next` pointer to the next ref storage backend. This is kind of a weird setup as backends need to be aware of other backends without much of a reason. Refactor the code so that the array of backends is centrally defined in "refs.c", where each backend is now identified by an integer constant. Expose functions to translate from those integer constants to the name and vice versa, which will be required by subsequent patches. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano