git/builtin/diff.c, branch v2.50.0

hash: stop depending on `the_repository` in `null_oid()`

2025-03-10T20:16:20Z

The `null_oid()` function returns the object ID that only consists of zeroes. Naturally, this ID also depends on the hash algorithm used, as the number of zeroes is different between SHA1 and SHA256. Consequently, the function returns the hash-algorithm-specific null object ID. This is currently done by depending on `the_hash_algo`, which implicitly makes us depend on `the_repository`. Refactor the function to instead pass in the hash algorithm for which we want to retrieve the null object ID. Adapt callsites accordingly by passing in `the_repository`, thus bubbling up the dependency on that global variable by one layer. There are a couple of trivial exceptions for subsystems that already got rid of `the_repository`. These subsystems instead use the repository that is available via the calling context: - "builtin/grep.c" - "grep.c" - "refs/debug.c" There are also two non-trivial exceptions: - "diff-no-index.c": Here we know that we may not have a repository initialized at all, so we cannot rely on `the_repository`. Instead, we adapt `diff_no_index()` to get a `struct git_hash_algo` as parameter. The only caller is located in "builtin/diff.c", where we know to call `repo_set_hash_algo()` in case we're running outside of a Git repository. Consequently, it is fine to continue passing `the_repository->hash_algo` even in this case. - "builtin/ls-files.c": There is an in-flight patch series that drops `USE_THE_REPOSITORY_VARIABLE` in this file, which causes a semantic conflict because we use `null_oid()` in `show_submodule()`. The value is passed to `repo_submodule_init()`, which may use the object ID to resolve a tree-ish in the superproject from which we want to read the submodule config. As such, the object ID should refer to an object in the superproject, and consequently we need to use its hash algorithm. This means that we could in theory just not bother about this edge case at all and just use `the_repository` in "diff-no-index.c". But doing so would feel misdesigned. Remove the `USE_THE_REPOSITORY_VARIABLE` preprocessor define in "hash.c". Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

global: mark code units that generate warnings with `-Wsign-compare`

2024-12-06T11:20:02Z

Mark code units that generate warnings with `-Wsign-compare`. This allows for a structured approach to get rid of all such warnings over time in a way that can be easily measured. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

global: drop `UNLEAK()` annotation

2024-11-20T23:23:46Z

There are two users of `UNLEAK()` left in our codebase: - In "builtin/clone.c", annotating the `repo` variable. That leak has already been fixed though as you can see in the context, where we do know to free `repo_to_free`. - In "builtin/diff.c", to unleak entries of the `blob[]` array. That leak has also been fixed, because the entries we assign to that array come from `rev.pending.objects`, and we do eventually release `rev`. This neatly demonstrates one of the issues with `UNLEAK()`: it is quite easy for the annotation to become stale. A second issue is that its whole intent is to paper over leaks. And while that has been a necessary evil in the past, because Git was leaking left and right, it isn't really much of an issue nowadays where our test suite has no known leaks anymore. Remove the last two users of this macro. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

Merge branch 'jc/pass-repo-to-builtins'

2024-09-23T17:35:09Z

The convention to calling into built-in command implementation has been updated to pass the repository, if known, together with the prefix value. * jc/pass-repo-to-builtins: add: pass in repo variable instead of global the_repository builtin: remove USE_THE_REPOSITORY for those without the_repository builtin: remove USE_THE_REPOSITORY_VARIABLE from builtin.h builtin: add a repository parameter for builtin functions

Merge branch 'jc/range-diff-lazy-setup'

2024-09-16T21:22:55Z

Code clean-up. * jc/range-diff-lazy-setup: remerge-diff: clean up temporary objdir at a central place remerge-diff: lazily prepare temporary objdir on demand

builtin: remove USE_THE_REPOSITORY_VARIABLE from builtin.h

2024-09-13T21:32:24Z

Instead of including USE_THE_REPOSITORY_VARIABLE by default on every builtin, remove it from builtin.h and add it to all the builtins that include builtin.h (by definition, that means all builtins/*.c). Also, remove the include statement for repository.h since it gets brought in through builtin.h. The next step will be to migrate each builtin from having to use the_repository. Signed-off-by: John Cai Signed-off-by: Junio C Hamano

builtin: add a repository parameter for builtin functions

2024-09-13T21:27:08Z

In order to reduce the usage of the global the_repository, add a parameter to builtin functions that will get passed a repository variable. This commit uses UNUSED on most of the builtin functions, as subsequent commits will modify the actual builtins to pass the repository parameter down. Signed-off-by: John Cai Signed-off-by: Junio C Hamano

builtin/diff: free symmetric diff members

2024-08-14T17:08:02Z

We populate a `struct symdiff` in case the user has requested a symmetric diff. Part of this is to populate a `skip` bitmap that indicates which commits shall be ignored in the diff. But while this bitmap is dynamically allocated, we never free it. Fix this by introducing and calling a new `symdiff_release()` function that does this for us. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

remerge-diff: clean up temporary objdir at a central place

2024-08-09T22:42:40Z

After running a diff between two things, or a series of diffs while walking the history, the diff computation is concluded by a call to diff_result_code() to extract the exit status of the diff machinery. The function can work on "struct diffopt", but all the callers historically and currently pass "struct diffopt" that is embedded in the "struct rev_info" that is used to hold the remerge_diff bit and the remerge_objdir variable that points at the temporary object directory in use. Redefine diff_result_code() to take the whole "struct rev_info" to give it an access to these members related to remerge-diff, so that it can get rid of the temporary object directory for any and all callers that used the feature. We can lose the equivalent code to do so from the code paths for individual commands, diff-tree, diff, and log. Signed-off-by: Junio C Hamano

builtin/diff: explicitly set hash algo when there is no repo

2024-05-07T05:50:49Z

The git-diff(1) command can be used outside repositories to diff two files with each other. But even if there is no repository we will end up hashing the files that we are diffing so that we can print the "index" line: ``` diff --git a/a b/b index 7898192..6178079 100644 --- a/a +++ b/b @@ -1 +1 @@ -a +b ``` We implicitly use SHA1 to calculate the hash here, which is because `the_repository` gets initialized with SHA1 during the startup routine. We are about to stop doing this though such that `the_repository` only ever has a hash function when it was properly initialized via a repo's configuration. To give full control to our users, we would ideally add a new switch to git-diff(1) that allows them to specify the hash function when executed outside of a repository. But for now, we only convert the code to make this explicit such that we can stop setting the default hash algorithm for `the_repository`. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano