git/pack.h, branch v2.50.0

pack-write: stop depending on `the_repository` and `the_hash_algo`

2025-03-10T20:16:18Z

There are a couple of functions in "pack-write.c" that implicitly depend on `the_repository` or `the_hash_algo`. Remove this dependency by injecting the repository via a parameter and adapt callers accordingly. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano

Merge branch 'kn/pack-write-with-reduced-globals'

2025-02-03T18:23:34Z

Code clean-up. * kn/pack-write-with-reduced-globals: pack-write: pass hash_algo to internal functions pack-write: pass hash_algo to `write_rev_file()` pack-write: pass hash_algo to `write_idx_file()` pack-write: pass repository to `index_pack_lockfile()` pack-write: pass hash_algo to `fixup_pack_header_footer()`

Merge branch 'jk/pack-header-parse-alignment-fix'

2025-01-28T21:02:23Z

It was possible for "git unpack-objects" and "git index-pack" to make an unaligned access, which has been corrected. * jk/pack-header-parse-alignment-fix: index-pack, unpack-objects: use skip_prefix to avoid magic number index-pack, unpack-objects: use get_be32() for reading pack header parse_pack_header_option(): avoid unaligned memory writes packfile: factor out --pack_header argument parsing bswap.h: squelch potential sparse -Wcast-truncate warnings

pack-write: pass hash_algo to `write_rev_file()`

2025-01-21T20:36:34Z

The `write_rev_file()` function uses the global `the_hash_algo` variable to access the repository's hash_algo. To avoid global variable usage, pass a hash_algo from the layers above. Also modify children functions `write_rev_file_order()` and `write_rev_header()` to accept 'the_hash_algo'. Altough the layers above could have access to the hash_algo internally, simply pass in `the_hash_algo`. This avoids any compatibility issues and bubbles up global variable usage to upper layers which can be eventually resolved. However, in `midx-write.c`, since all usage of global variables is removed, don't reintroduce them and instead use the `repo` available in the context. Signed-off-by: Karthik Nayak Signed-off-by: Junio C Hamano

pack-write: pass hash_algo to `write_idx_file()`

2025-01-21T20:36:34Z

The `write_idx_file()` function uses the global `the_hash_algo` variable to access the repository's hash_algo. To avoid global variable usage, pass a hash_algo from the layers above. Since `stage_tmp_packfiles()` also resides in 'pack-write.c' and calls `write_idx_file()`, update it to accept a `struct git_hash_algo` as a parameter and pass it through to the callee. Altough the layers above could have access to the hash_algo internally, simply pass in `the_hash_algo`. This avoids any compatibility issues and bubbles up global variable usage to upper layers which can be eventually resolved. Signed-off-by: Karthik Nayak Signed-off-by: Junio C Hamano

pack-write: pass repository to `index_pack_lockfile()`

2025-01-21T20:36:34Z

The `index_pack_lockfile()` function uses the global `the_repository` variable to access the repository. To avoid global variable usage, pass the repository from the layers above. Altough the layers above could have access to the repository internally, simply pass in `the_repository`. This avoids any compatibility issues and bubbles up global variable usage to upper layers which can be eventually resolved. Signed-off-by: Karthik Nayak Signed-off-by: Junio C Hamano

pack-write: pass hash_algo to `fixup_pack_header_footer()`

2025-01-21T20:36:34Z

The `fixup_pack_header_footer()` function uses the global `the_hash_algo` variable to access the repository's hash function. To avoid global variable usage, pass a hash_algo from the layers above. Altough the layers above could have access to the hash_algo internally, simply pass in `the_hash_algo`. This avoids any compatibility issues and bubbles up global variable usage to upper layers which can be eventually resolved. Signed-off-by: Karthik Nayak Signed-off-by: Junio C Hamano

index-pack, unpack-objects: use get_be32() for reading pack header

2025-01-21T16:42:56Z

Both of these commands read the incoming pack into a static unsigned char buffer in BSS, and then parse it by casting the start of the buffer to a struct pack_header. This can result in SIGBUS on some platforms if the compiler doesn't place the buffer in a position that is properly aligned for 4-byte integers. This reportedly happens with unpack-objects (but not index-pack) on sparc64 when compiled with clang (but not gcc). But we are definitely in the wrong in both spots; since the buffer's type is unsigned char, we can't depend on larger alignment. When it works it is only because we are lucky. We'll fix this by switching to get_be32() to read the headers (just like the last few commits similarly switched us to put_be32() for writing into the same buffer). It would be nice to factor this out into a common helper function, but the interface ends up quite awkward. Either the caller needs to hardcode how many bytes we'll need, or it needs to pass us its fill()/use() functions as pointers. So I've just fixed both spots in the same way; this is not code that is likely to be repeated a third time (most of the pack reading code uses an mmap'd buffer, which should be properly aligned). I did make one tweak to the shared code: our pack_version_ok() macro expects us to pass the big-endian value we'd get by casting. We can introduce a "native" variant which uses the host integer ordering. Reported-by: Koakuma Signed-off-by: Jeff King Signed-off-by: Junio C Hamano

config: make `delta_base_cache_limit` a non-global variable

2024-12-03T23:21:55Z

The `delta_base_cache_limit` variable is a global config variable used by multiple subsystems. Let's make this non-global, by adding this variable independently to the subsystems where it is used. First, add the setting to the `repo_settings` struct, this provides access to the config in places where the repository is available. Use this in `packfile.c`. In `index-pack.c` we add it to the `pack_idx_option` struct and its constructor. While the repository struct is available here, it may not be set because `git index-pack` can be used without a repository. In `gc.c` add it to the `gc_config` struct and also the constructor function. The gc functions currently do not have direct access to a repository struct. These changes are made to remove the usage of `delta_base_cache_limit` as a global variable in `packfile.c`. This brings us one step closer to removing the `USE_THE_REPOSITORY_VARIABLE` definition in `packfile.c` which we complete in the next patch. Signed-off-by: Karthik Nayak Signed-off-by: Junio C Hamano

pack-write: fix return parameter of `write_rev_file_order()`

2024-09-30T18:23:08Z

While the return parameter of `write_rev_file_order()` is a string constant, the function may indeed return an allocated string when its first parameter is a `NULL` pointer. This makes for a confusing calling convention, where callers need to be aware of these intricate ownership rules and cast away the constness to free the string in some cases. Adapt the function and its caller `write_rev_file()` to always return an allocated string and adapt callers to always free the return value. Note that this requires us to also adapt `rename_tmp_packfile()`, which compares the pointers to packfile data with each other. Now that the path of the reverse index file gets allocated unconditionally the check will always fail. This is fixed by using strcmp(3P) instead, which also feels way less fragile. Signed-off-by: Patrick Steinhardt Signed-off-by: Junio C Hamano