git/shallow.c, branch v2.36.2

shallow: reset commit grafts when shallow is reset

2022-03-18T00:44:38Z

When reset_repository_shallow() is called, Git clears its cache of shallow information, so that if shallow information is re-requested, Git will read fresh data from disk instead of reusing its stale cached data. However, the cache of commit grafts is not likewise cleared, even though there are commit grafts created from shallow information. This means that if on-disk shallow information were to be updated and then a commit-graft-using codepath were run (for example, a revision walk), Git would be using stale commit graft information. This can be seen from the test in this patch, in which Git performs a revision walk (to check for changed submodules) after a fetch with --update-shallow. Therefore, clear the cache of commit grafts whenever reset_repository_shallow() is called. Signed-off-by: Jonathan Tan Signed-off-by: Junio C Hamano

git-rev-list: add --exclude-first-parent-only flag

2022-01-12T19:08:42Z

It is useful to know when a branch first diverged in history from some integration branch in order to be able to enumerate the user's local changes. However, these local changes can include arbitrary merges, so it is necessary to ignore this merge structure when finding the divergence point. In order to do this, teach the "rev-list" family to accept "--exclude-first-parent-only", which restricts the traversal of excluded commits to only follow first parent links. -A-----E-F-G--main \ / / B-C-D--topic In this example, the goal is to return the set {B, C, D} which represents a topic branch that has been merged into main branch. `git rev-list topic ^main` will end up returning no commits since excluding main will end up traversing the commits on topic as well. `git rev-list --exclude-first-parent-only topic ^main` however will return {B, C, D} as desired. Add docs for the new flag, and clarify the doc for --first-parent to indicate that it applies to traversing the set of included commits only. Signed-off-by: Jerry Zhang Signed-off-by: Junio C Hamano

commit_graft_pos(): take an oid instead of a bare hash

2021-01-28T19:21:07Z

All of our callers have an object_id, and are just dereferencing the hash field to pass to us. Let's take the actual object_id instead. We still access the hash to pass to hash_pos, but it's a step in the right direction. This makes the callers slightly simpler, but also gets rid of the untyped pointer, as well as the now-inaccurate name "sha1". Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

Merge branch 'sg/commit-graph-cleanups' into master

2020-07-30T20:20:30Z

The changed-path Bloom filter is improved using ideas from an independent implementation. * sg/commit-graph-cleanups: commit-graph: simplify write_commit_graph_file() #2 commit-graph: simplify write_commit_graph_file() #1 commit-graph: simplify parse_commit_graph() #2 commit-graph: simplify parse_commit_graph() #1 commit-graph: clean up #includes diff.h: drop diff_tree_oid() & friends' return value commit-slab: add a function to deep free entries on the slab commit-graph-format.txt: all multi-byte numbers are in network byte order commit-graph: fix parsing the Chunk Lookup table tree-walk.c: don't match submodule entries for 'submod/anything'

commit-slab: add a function to deep free entries on the slab

2020-06-08T19:28:49Z

clear_##slabname() frees only the memory allocated for a commit slab itself, but entries in the commit slab might own additional memory outside the slab that should be freed as well. We already have (at least) one such commit slab, and this patch series is about to add one more. To free all additional memory owned by entries on the commit slab the user of such a slab could iterate over all commits it knows about, peek whether there is a valid entry associated with each commit, and free the additional memory, if any. Or it could rely on intimate knowledge about the internals of the commit slab implementation, and could itself iterate directly through all entries in the slab, and free the additional memory. Or it could just leak the additional memory... Introduce deep_clear_##slabname() to allow releasing memory owned by commit slab entries by invoking the 'void free_fn(elemtype *ptr)' function specified as parameter for each entry in the slab. Use it in get_shallow_commits() in 'shallow.c' to replace an open-coded iteration over a commit slab's entries. Signed-off-by: SZEDER Gábor Signed-off-by: Derrick Stolee Signed-off-by: Junio C Hamano

Merge branch 'tb/shallow-cleanup'

2020-05-13T19:19:18Z

Code cleanup. * tb/shallow-cleanup: shallow: use struct 'shallow_lock' for additional safety shallow.h: document '{commit,rollback}_shallow_file' shallow: extract a header file for shallow-related functions commit: make 'commit_graft_pos' non-static

Merge branch 'tb/reset-shallow'

2020-05-01T20:39:51Z

Fix in-core inconsistency after fetching into a shallow repository that broke the code to write out commit-graph. * tb/reset-shallow: shallow.c: use '{commit,rollback}_shallow_file' t5537: use test_write_lines and indented heredocs for readability

shallow: use struct 'shallow_lock' for additional safety

2020-04-30T21:19:13Z

In previous patches, the functions 'commit_shallow_file' and 'rollback_shallow_file' were introduced to reset the shallowness validity checks on a repository after potentially modifying '.git/shallow'. These functions can be made safer by wrapping the 'struct lockfile *' in a new type, 'shallow_lock', so that they cannot be called with a raw lock (and potentially misused by other code that happens to possess a lockfile, but has nothing to do with shallowness). This patch introduces that type as a thin wrapper around 'struct lockfile', and updates the two aforementioned functions and their callers to use it. Suggested-by: Junio C Hamano Helped-by: Jonathan Nieder Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano

shallow: extract a header file for shallow-related functions

2020-04-30T21:19:13Z

There are many functions in commit.h that are more related to shallow repositories than they are to any sort of generic commit machinery. Likely this began when there were only a few shallow-related functions, and commit.h seemed a reasonable enough place to put them. But, now there are a good number of shallow-related functions, and placing them all in 'commit.h' doesn't make sense. This patch extracts a 'shallow.h', which takes all of the declarations from 'commit.h' for functions which already exist in 'shallow.c'. We will bring the remaining shallow-related functions defined in 'commit.c' in a subsequent patch. For now, move only the ones that already are implemented in 'shallow.c', and update the necessary includes. Signed-off-by: Taylor Blau Signed-off-by: Junio C Hamano

shallow.c: use '{commit,rollback}_shallow_file'

2020-04-24T20:56:39Z

In bd0b42aed3 (fetch-pack: do not take shallow lock unnecessarily, 2019-01-10), the author noted that 'is_repository_shallow' produces visible side-effect(s) by setting 'is_shallow' and 'shallow_stat'. This is a problem for e.g., fetching with '--update-shallow' in a shallow repository with 'fetch.writeCommitGraph' enabled, since the update to '.git/shallow' will cause Git to think that the repository isn't shallow when it is, thereby circumventing the commit-graph compatibility check. This causes problems in shallow repositories with at least shallow refs that have at least one ancestor (since the client won't have those objects, and therefore can't take the reachability closure over commits when writing a commit-graph). Address this by introducing thin wrappers over 'commit_lock_file' and 'rollback_lock_file' for use specifically when the lock is held over '.git/shallow'. These wrappers (appropriately called 'commit_shallow_file' and 'rollback_shallow_file') call into their respective functions in 'lockfile.h', but additionally reset validity checks used by the shallow machinery. Replace each instance of 'commit_lock_file' and 'rollback_lock_file' with 'commit_shallow_file' and 'rollback_shallow_file' when the lock being held is over the '.git/shallow' file. As a result, 'prune_shallow' can now only be called once (since 'check_shallow_file_for_update' will die after calling 'reset_repository_shallow'). But, this is OK since we only call 'prune_shallow' at most once per process. Helped-by: Jonathan Tan Helped-by: Junio C Hamano Signed-off-by: Taylor Blau Reviewed-by: Jonathan Tan Signed-off-by: Junio C Hamano