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2021-01-25packfile: prepare for the existence of '*.rev' filesTaylor Blau1-0/+1
Specify the format of the on-disk reverse index 'pack-*.rev' file, as well as prepare the code for the existence of such files. The reverse index maps from pack relative positions (i.e., an index into the array of object which is sorted by their offsets within the packfile) to their position within the 'pack-*.idx' file. Today, this is done by building up a list of (off_t, uint32_t) tuples for each object (the off_t corresponding to that object's offset, and the uint32_t corresponding to its position in the index). To convert between pack and index position quickly, this array of tuples is radix sorted based on its offset. This has two major drawbacks: First, the in-memory cost scales linearly with the number of objects in a pack. Each 'struct revindex_entry' is sizeof(off_t) + sizeof(uint32_t) + padding bytes for a total of 16. To observe this, force Git to load the reverse index by, for e.g., running 'git cat-file --batch-check="%(objectsize:disk)"'. When asking for a single object in a fresh clone of the kernel, Git needs to allocate 120+ MB of memory in order to hold the reverse index in memory. Second, the cost to sort also scales with the size of the pack. Luckily, this is a linear function since 'load_pack_revindex()' uses a radix sort, but this cost still must be paid once per pack per process. As an example, it takes ~60x longer to print the _size_ of an object as it does to print that entire object's _contents_: Benchmark #1: git.compile cat-file --batch <obj Time (mean ± σ): 3.4 ms ± 0.1 ms [User: 3.3 ms, System: 2.1 ms] Range (min … max): 3.2 ms … 3.7 ms 726 runs Benchmark #2: git.compile cat-file --batch-check="%(objectsize:disk)" <obj Time (mean ± σ): 210.3 ms ± 8.9 ms [User: 188.2 ms, System: 23.2 ms] Range (min … max): 193.7 ms … 224.4 ms 13 runs Instead, avoid computing and sorting the revindex once per process by writing it to a file when the pack itself is generated. The format is relatively straightforward. It contains an array of uint32_t's, the length of which is equal to the number of objects in the pack. The ith entry in this table contains the index position of the ith object in the pack, where "ith object in the pack" is determined by pack offset. One thing that the on-disk format does _not_ contain is the full (up to) eight-byte offset corresponding to each object. This is something that the in-memory revindex contains (it stores an off_t in 'struct revindex_entry' along with the same uint32_t that the on-disk format has). Omit it in the on-disk format, since knowing the index position for some object is sufficient to get a constant-time lookup in the pack-*.idx file to ask for an object's offset within the pack. This trades off between the on-disk size of the 'pack-*.rev' file for runtime to chase down the offset for some object. Even though the lookup is constant time, the constant is heavier, since it can potentially involve two pointer walks in v2 indexes (one to access the 4-byte offset table, and potentially a second to access the double wide offset table). Consider trying to map an object's pack offset to a relative position within that pack. In a cold-cache scenario, more page faults occur while switching between binary searching through the reverse index and searching through the *.idx file for an object's offset. Sure enough, with a cold cache (writing '3' into '/proc/sys/vm/drop_caches' after 'sync'ing), printing out the entire object's contents is still marginally faster than printing its size: Benchmark #1: git.compile cat-file --batch-check="%(objectsize:disk)" <obj >/dev/null Time (mean ± σ): 22.6 ms ± 0.5 ms [User: 2.4 ms, System: 7.9 ms] Range (min … max): 21.4 ms … 23.5 ms 41 runs Benchmark #2: git.compile cat-file --batch <obj >/dev/null Time (mean ± σ): 17.2 ms ± 0.7 ms [User: 2.8 ms, System: 5.5 ms] Range (min … max): 15.6 ms … 18.2 ms 45 runs (Numbers taken in the kernel after cheating and using the next patch to generate a reverse index). There are a couple of approaches to improve cold cache performance not pursued here: - We could include the object offsets in the reverse index format. Predictably, this does result in fewer page faults, but it triples the size of the file, while simultaneously duplicating a ton of data already available in the .idx file. (This was the original way I implemented the format, and it did show `--batch-check='%(objectsize:disk)'` winning out against `--batch`.) On the other hand, this increase in size also results in a large block-cache footprint, which could potentially hurt other workloads. - We could store the mapping from pack to index position in more cache-friendly way, like constructing a binary search tree from the table and writing the values in breadth-first order. This would result in much better locality, but the price you pay is trading O(1) lookup in 'pack_pos_to_index()' for an O(log n) one (since you can no longer directly index the table). So, neither of these approaches are taken here. (Thankfully, the format is versioned, so we are free to pursue these in the future.) But, cold cache performance likely isn't interesting outside of one-off cases like asking for the size of an object directly. In real-world usage, Git is often performing many operations in the revindex (i.e., asking about many objects rather than a single one). The trade-off is worth it, since we will avoid the vast majority of the cost of generating the revindex that the extra pointer chase will look like noise in the following patch's benchmarks. This patch describes the format and prepares callers (like in pack-revindex.c) to be able to read *.rev files once they exist. An implementation of the writer will appear in the next patch, and callers will gradually begin to start using the writer in the patches that follow after that. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-25Merge branch 'tb/pack-revindex-api'Junio C Hamano2-14/+25
Abstract accesses to in-core revindex that allows enumerating objects stored in a packfile in the order they appear in the pack, in preparation for introducing an on-disk precomputed revindex. * tb/pack-revindex-api: (21 commits) for_each_object_in_pack(): clarify pack vs index ordering pack-revindex.c: avoid direct revindex access in 'offset_to_pack_pos()' pack-revindex: hide the definition of 'revindex_entry' pack-revindex: remove unused 'find_revindex_position()' pack-revindex: remove unused 'find_pack_revindex()' builtin/gc.c: guess the size of the revindex for_each_object_in_pack(): convert to new revindex API unpack_entry(): convert to new revindex API packed_object_info(): convert to new revindex API retry_bad_packed_offset(): convert to new revindex API get_delta_base_oid(): convert to new revindex API rebuild_existing_bitmaps(): convert to new revindex API try_partial_reuse(): convert to new revindex API get_size_by_pos(): convert to new revindex API show_objects_for_type(): convert to new revindex API bitmap_position_packfile(): convert to new revindex API check_object(): convert to new revindex API write_reused_pack_verbatim(): convert to new revindex API write_reused_pack_one(): convert to new revindex API write_reuse_object(): convert to new revindex API ...
2021-01-25Merge branch 'cc/write-promisor-file'Junio C Hamano1-5/+3
A bit of code refactoring. * cc/write-promisor-file: pack-write: die on error in write_promisor_file() fetch-pack: refactor writing promisor file fetch-pack: rename helper to create_promisor_file()
2021-01-25Merge branch 'ab/mailmap'Junio C Hamano5-18/+6
Clean-up docs, codepaths and tests around mailmap. * ab/mailmap: (22 commits) shortlog: remove unused(?) "repo-abbrev" feature mailmap doc + tests: document and test for case-insensitivity mailmap tests: add tests for empty "<>" syntax mailmap tests: add tests for whitespace syntax mailmap tests: add a test for comment syntax mailmap doc + tests: add better examples & test them tests: refactor a few tests to use "test_commit --append" test-lib functions: add an --append option to test_commit test-lib functions: add --author support to test_commit test-lib functions: document arguments to test_commit test-lib functions: expand "test_commit" comment template mailmap: test for silent exiting on missing file/blob mailmap tests: get rid of overly complex blame fuzzing mailmap tests: add a test for "not a blob" error mailmap tests: remove redundant entry in test mailmap tests: improve --stdin tests mailmap tests: modernize syntax & test idioms mailmap tests: use our preferred whitespace syntax mailmap doc: start by mentioning the comment syntax check-mailmap doc: note config options ...
2021-01-25Merge branch 'ps/fetch-atomic'Junio C Hamano1-57/+167
"git fetch" learns to treat ref updates atomically in all-or-none fashion, just like "git push" does, with the new "--atomic" option. * ps/fetch-atomic: fetch: implement support for atomic reference updates fetch: allow passing a transaction to `s_update_ref()` fetch: refactor `s_update_ref` to use common exit path fetch: use strbuf to format FETCH_HEAD updates fetch: extract writing to FETCH_HEAD
2021-01-25Merge branch 'jc/deprecate-pack-redundant'Junio C Hamano1-0/+13
Warn loudly when the "pack-redundant" command, which has been left stale with almost unusable performance issues, gets used, as we no longer want to recommend its use (instead just "repack -d" instead). * jc/deprecate-pack-redundant: pack-redundant: gauge the usage before proposing its removal
2021-01-25Merge branch 'ab/branch-sort'Junio C Hamano3-4/+6
The implementation of "git branch --sort" wrt the detached HEAD display has always been hacky, which has been cleaned up. * ab/branch-sort: branch: show "HEAD detached" first under reverse sort branch: sort detached HEAD based on a flag ref-filter: move ref_sorting flags to a bitfield ref-filter: move "cmp_fn" assignment into "else if" arm ref-filter: add braces to if/else if/else chain branch tests: add to --sort tests branch: change "--local" to "--list" in comment
2021-01-25Merge branch 'ma/more-opaque-lock-file'Junio C Hamano1-4/+4
Code clean-up. * ma/more-opaque-lock-file: read-cache: try not to peek into `struct {lock_,temp}file` refs/files-backend: don't peek into `struct lock_file` midx: don't peek into `struct lock_file` commit-graph: don't peek into `struct lock_file` builtin/gc: don't peek into `struct lock_file`
2021-01-25Merge branch 'ab/mktag'Junio C Hamano2-167/+80
"git mktag" validates its input using its own rules before writing a tag object---it has been updated to share the logic with "git fsck". * ab/mktag: (23 commits) mktag: add a --[no-]strict option mktag: mark strings for translation mktag: convert to parse-options mktag: allow omitting the header/body \n separator mktag: allow turning off fsck.extraHeaderEntry fsck: make fsck_config() re-usable mktag: use fsck instead of custom verify_tag() mktag: use puts(str) instead of printf("%s\n", str) mktag: remove redundant braces in one-line body "if" mktag: use default strbuf_read() hint mktag tests: test verify_object() with replaced objects mktag tests: improve verify_object() test coverage mktag tests: test "hash-object" compatibility mktag tests: stress test whitespace handling mktag tests: run "fsck" after creating "mytag" mktag tests: don't create "mytag" twice mktag tests: don't redirect stderr to a file needlessly mktag tests: remove needless SHA-1 hardcoding mktag tests: use "test_commit" helper mktag tests: don't needlessly use a subshell ...
2021-01-23sparse-checkout: load sparse-checkout patternsDerrick Stolee1-5/+0
A future feature will want to load the sparse-checkout patterns into a pattern_list, but the current mechanism to do so is a bit complicated. This is made difficult due to needing to find the sparse-checkout file in different ways throughout the codebase. The logic implemented in the new get_sparse_checkout_patterns() was duplicated in populate_from_existing_patterns() in unpack-trees.c. Use the new method instead, keeping the logic around handling the struct unpack_trees_options. The callers to get_sparse_checkout_filename() in builtin/sparse-checkout.c manipulate the sparse-checkout file directly, so it is not appropriate to replace logic in that file with get_sparse_checkout_patterns(). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-23cache-tree: clean up cache_tree_update()Derrick Stolee1-3/+0
Make the method safer by allocating a cache_tree member for the given index_state if it is not already present. This is preferrable to a BUG() statement or returning with an error because future callers will want to populate an empty cache-tree using this method. Callers can also remove their conditional allocations of cache_tree. Also drop local variables that can be found directly from the 'istate' parameter. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-23ls-files.c: add --deduplicate optionZheNing Hu1-3/+28
During a merge conflict, the name of a file may appear multiple times in "git ls-files" output, once for each stage. If you use both `--delete` and `--modify` at the same time, the output may mention a deleted file twice. When none of the '-t', '-u', or '-s' options is in use, these duplicate entries do not add much value to the output. Introduce a new '--deduplicate' option to suppress them. Signed-off-by: ZheNing Hu <adlternative@gmail.com> [jc: extended doc and rewritten commit log] Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-23ls_files.c: consolidate two for loops into oneZheNing Hu1-36/+27
This will make it easier to show only one entry per filename in the next step. Signed-off-by: ZheNing Hu <adlternative@gmail.com> [jc: corrected the log message] Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-23ls_files.c: bugfix for --deleted and --modifiedZheNing Hu1-4/+7
This situation may occur in the original code: lstat() failed but we use `&st` to feed ie_modified() later. Therefore, we can directly execute show_ce without the judgment of ie_modified() when lstat() has failed. Signed-off-by: ZheNing Hu <adlternative@gmail.com> [jc: fixed misindented code] Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-22builtin/pack-objects.c: avoid iterating all refsJacob Vosmaer1-5/+3
In git-pack-objects, we iterate over all the tags if the --include-tag option is passed on the command line. For some reason this uses for_each_ref which is expensive if the repo has many refs. We should use for_each_tag_ref instead. Because the add_ref_tag callback will now only visit tags we simplified it a bit. The motivation for this change is that we observed performance issues with a repository on gitlab.com that has 500,000 refs but only 2,000 tags. The fetch traffic on that repo is dominated by CI, and when we changed CI to fetch with 'git fetch --no-tags' we saw a dramatic change in the CPU profile of git-pack-objects. This lead us to this particular ref walk. More details in: https://gitlab.com/gitlab-com/gl-infra/scalability/-/issues/746#note_483546598 Signed-off-by: Jacob Vosmaer <jacob@gitlab.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-21use delete_refs when deleting tags or branchesPhil Hord2-29/+62
'git tag -d' accepts one or more tag refs to delete, but each deletion is done by calling `delete_ref` on each argv. This is very slow when removing from packed refs. Use delete_refs instead so all the removals can be done inside a single transaction with a single update. Do the same for 'git branch -d'. Since delete_refs performs all the packed-refs delete operations inside a single transaction, if any of the deletes fail then all them will be skipped. In practice, none of them should fail since we verify the hash of each one before calling delete_refs, but some network error or odd permissions problem could have different results after this change. Also, since the file-backed deletions are not performed in the same transaction, those could succeed even when the packed-refs transaction fails. After deleting branches, remove the branch config only if the branch ref was removed and was not subsequently added back in. A manual test deleting 24,000 tags took about 30 minutes using delete_ref. It takes about 5 seconds using delete_refs. Acked-by: Elijah Newren <newren@gmail.com> Signed-off-by: Phil Hord <phil.hord@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-21refs: switch peel_ref() to peel_iterated_oid()Jeff King4-5/+5
The peel_ref() interface is confusing and error-prone: - it's typically used by ref iteration callbacks that have both a refname and oid. But since they pass only the refname, we may load the ref value from the filesystem again. This is inefficient, but also means we are open to a race if somebody simultaneously updates the ref. E.g., this: int some_ref_cb(const char *refname, const struct object_id *oid, ...) { if (!peel_ref(refname, &peeled)) printf("%s peels to %s", oid_to_hex(oid), oid_to_hex(&peeled); } could print nonsense. It is correct to say "refname peels to..." (you may see the "before" value or the "after" value, either of which is consistent), but mentioning both oids may be mixing before/after values. Worse, whether this is possible depends on whether the optimization to read from the current iterator value kicks in. So it is actually not possible with: for_each_ref(some_ref_cb); but it _is_ possible with: head_ref(some_ref_cb); which does not use the iterator mechanism (though in practice, HEAD should never peel to anything, so this may not be triggerable). - it must take a fully-qualified refname for the read_ref_full() code path to work. Yet we routinely pass it partial refnames from callbacks to for_each_tag_ref(), etc. This happens to work when iterating because there we do not call read_ref_full() at all, and only use the passed refname to check if it is the same as the iterator. But the requirements for the function parameters are quite unclear. Instead of taking a refname, let's instead take an oid. That fixes both problems. It's a little funny for a "ref" function not to involve refs at all. The key thing is that it's optimizing under the hood based on having access to the ref iterator. So let's change the name to make it clear why you'd want this function versus just peel_object(). There are two other directions I considered but rejected: - we could pass the peel information into the each_ref_fn callback. However, we don't know if the caller actually wants it or not. For packed-refs, providing it is essentially free. But for loose refs, we actually have to peel the object, which would be wasteful in most cases. We could likewise pass in a flag to the callback indicating whether the peeled information is known, but that complicates those callbacks, as they then have to decide whether to manually peel themselves. Plus it requires changing the interface of every callback, whether they care about peeling or not, and there are many of them. - we could make a function to return the peeled value of the current iterated ref (computing it if necessary), and BUG() otherwise. I.e.: int peel_current_iterated_ref(struct object_id *out); Each of the current callers is an each_ref_fn callback, so they'd mostly be happy. But: - we use those callbacks with functions like head_ref(), which do not use the iteration code. So we'd need to handle the fallback case there, anyway. - it's possible that a caller would want to call into generic code that sometimes is used during iteration and sometimes not. This encapsulates the logic to do the fast thing when possible, and fallback when necessary. The implementation is mostly obvious, but I want to call out a few things in the patch: - the test-tool coverage for peel_ref() is now meaningless, as it all collapses to a single peel_object() call (arguably they were pretty uninteresting before; the tricky part of that function is the fast-path we see during iteration, but these calls didn't trigger that). I've just dropped it entirely, though note that some other tests relied on the tags we created; I've moved that creation to the tests where it matters. - we no longer need to take a ref_store parameter, since we'd never look up a ref now. We do still rely on a global "current iterator" variable which _could_ be kept per-ref-store. But in practice this is only useful if there are multiple recursive iterations, at which point the more appropriate solution is probably a stack of iterators. No caller used the actual ref-store parameter anyway (they all call the wrapper that passes the_repository). - the original only kicked in the optimization when the "refname" pointer matched (i.e., not string comparison). We do likewise with the "oid" parameter here, but fall back to doing an actual oideq() call. This in theory lets us kick in the optimization more often, though in practice no current caller cares. It should never be wrong, though (peeling is a property of an object, so two refs pointing to the same object would peel identically). - the original took care not to touch the peeled out-parameter unless we found something to put in it. But no caller cares about this, and anyway, it is enforced by peel_object() itself (and even in the optimized iterator case, that's where we eventually end up). We can shorten the code and avoid an extra copy by just passing the out-parameter through the stack. Signed-off-by: Jeff King <peff@peff.net> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-20maintenance: set log.excludeDecoration durin prefetchDerrick Stolee1-0/+6
The 'prefetch' task fetches refs from all remotes and places them in the refs/prefetch/<remote>/ refspace. As this task is intended to run in the background, this allows users to keep their local data very close to the remote servers' data while not updating the users' understanding of the remote refs in refs/remotes/<remote>/. However, this can clutter 'git log' decorations with copies of the refs with the full name 'refs/prefetch/<remote>/<branch>'. The log.excludeDecoration config option was added in a6be5e67 (log: add log.excludeDecoration config option, 2020-05-16) for exactly this purpose. Ensure we set this only for users that would benefit from it by assigning it at the beginning of the prefetch task. Other alternatives would be during 'git maintenance register' or 'git maintenance start', but those might assign the config even when the prefetch task is disabled by existing config. Further, users could run 'git maintenance run --task=prefetch' using their own scripting or scheduling. This provides the best coverage to automatically update the config when valuable. It is improbable, but possible, that users might want to run the prefetch task _and_ see these refs in their log decorations. This seems incredibly unlikely to me, but users can always opt-in on a command-by-command basis using --decorate-refs=refs/prefetch/. Test that this works in a few cases. In particular, ensure that our assignment of log.excludeDecoration=refs/prefetch/ is additive to other existing exclusions. Further, ensure we do not add multiple copies in multiple runs. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-15Merge branch 'ds/for-each-repo-noopfix'Junio C Hamano1-0/+7
"git for-each-repo --config=<var> <cmd>" should not run <cmd> for any repository when the configuration variable <var> is not defined even once. * ds/for-each-repo-noopfix: for-each-repo: do nothing on empty config
2021-01-15Merge branch 'ds/maintenance-part-4'Junio C Hamano1-27/+395
Follow-up on the "maintenance part-3" which introduced scheduled maintenance tasks to support platforms whose native scheduling methods are not 'cron'. * ds/maintenance-part-4: maintenance: use Windows scheduled tasks maintenance: use launchctl on macOS maintenance: include 'cron' details in docs maintenance: extract platform-specific scheduling
2021-01-15Merge branch 'en/stash-apply-sparse-checkout'Junio C Hamano1-49/+116
"git stash" did not work well in a sparsely checked out working tree. * en/stash-apply-sparse-checkout: stash: fix stash application in sparse-checkouts stash: remove unnecessary process forking t7012: add a testcase demonstrating stash apply bugs in sparse checkouts
2021-01-15Merge branch 'zh/arg-help-format'Junio C Hamano7-61/+61
Clean up option descriptions in "git cmd --help". * zh/arg-help-format: builtin/*: update usage format parse-options: format argh like error messages
2021-01-15Merge branch 'rs/rebase-commit-validation'Junio C Hamano1-1/+3
Diagnose command line error of "git rebase" early. * rs/rebase-commit-validation: rebase: verify commit parameter
2021-01-15Merge branch 'ma/sha1-is-a-hash'Junio C Hamano2-3/+3
Retire more names with "sha1" in it. * ma/sha1-is-a-hash: hash-lookup: rename from sha1-lookup sha1-lookup: rename `sha1_pos()` as `hash_pos()` object-file.c: rename from sha1-file.c object-name.c: rename from sha1-name.c
2021-01-15Merge branch 'bc/rev-parse-path-format'Junio C Hamano1-12/+94
"git rev-parse" can be explicitly told to give output as absolute or relative path with the `--path-format=(absolute|relative)` option. * bc/rev-parse-path-format: rev-parse: add option for absolute or relative path formatting abspath: add a function to resolve paths with missing components
2021-01-13builtin/gc.c: guess the size of the revindexTaylor Blau1-1/+1
'estimate_repack_memory()' takes into account the amount of memory required to load the reverse index in memory by multiplying the assumed number of objects by the size of the 'revindex_entry' struct. Prepare for hiding the definition of 'struct revindex_entry' by removing a 'sizeof()' of that type from outside of pack-revindex.c. Instead, guess that one off_t and one uint32_t are required per object. Strictly speaking, this is a worse guess than asking for 'sizeof(struct revindex_entry)' directly, since the true size of this struct is 16 bytes with padding on the end of the struct in order to align the offset field. But, this is an approximation anyway, and it does remove a use of the 'struct revindex_entry' from outside of pack-revindex internals. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-13check_object(): convert to new revindex APITaylor Blau1-4/+4
Replace direct accesses to the revindex with calls to 'offset_to_pack_pos()' and 'pack_pos_to_index()'. Since this caller already had some error checking (it can jump to the 'give_up' label if it encounters an error), we can easily check whether or not the provided offset points to an object in the given pack. This error checking existed prior to this patch, too, since the caller checks whether the return value from 'find_pack_revindex()' was NULL or not. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-13write_reused_pack_verbatim(): convert to new revindex APITaylor Blau1-1/+1
Replace a direct access to the revindex array with 'pack_pos_to_offset()'. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-13write_reused_pack_one(): convert to new revindex APITaylor Blau1-4/+10
Replace direct revindex accesses with calls to 'pack_pos_to_offset()' and 'pack_pos_to_index()'. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-13write_reuse_object(): convert to new revindex APITaylor Blau1-4/+9
First replace 'find_pack_revindex()' with its replacement 'offset_to_pack_pos()'. This prevents any bogus OFS_DELTA that may make its way through until 'write_reuse_object()' from causing a bad memory read (if 'revidx' is 'NULL') Next, replace a direct access of '->nr' with the wrapper function 'pack_pos_to_index()'. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12fetch-pack: refactor writing promisor fileChristian Couder1-5/+3
Let's replace the 2 different pieces of code that write a promisor file in 'builtin/repack.c' and 'fetch-pack.c' with a new function called 'write_promisor_file()' in 'pack-write.c' and 'pack.h'. This might also help us in the future, if we want to put back the ref names and associated hashes that were in the promisor files we are repacking in 'builtin/repack.c' as suggested by a NEEDSWORK comment just above the code we are refactoring. Signed-off-by: Christian Couder <chriscool@tuxfamily.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12shortlog: remove unused(?) "repo-abbrev" featureÆvar Arnfjörð Bjarmason5-18/+6
Remove support for the magical "repo-abbrev" comment in .mailmap files. This was added to .mailmap parsing in [1], as a generalized feature of the git-shortlog Perl script added earlier in [2]. There was no documentation or tests for this feature, and I don't think it's used in practice anymore. What it did was to allow you to specify a single string to be search-replaced with "/.../" in the .mailmap file. E.g. for linux.git's current .mailmap: git archive --remote=git@gitlab.com:linux-kernel/linux.git \ HEAD -- .mailmap | grep -a repo-abbrev # repo-abbrev: /pub/scm/linux/kernel/git/ Then when running e.g.: git shortlog --merges --author=Linus -1 v5.10-rc7..v5.10 | grep Merge We'd emit (the [...] is mine): Merge tag [...]git://git.kernel.org/.../tip/tip But will now emit: Merge tag [...]git.kernel.org/pub/scm/linux/kernel/git/tip/tip I think at this point this is just a historical artifact we can get rid of. It was initially meant for Linus's own use when we integrated the Perl script[2], but since then it seems he's stopped using it. Digging through Linus's release announcements on the LKML[3] the last release I can find that made use of this output is Linux 2.6.25-rc6 back in March 2008[4]. Later on Linus started using --no-merges[5], and nowadays seems to prefer some custom not-quite-shortlog format of merges from lieutenants[6]. You will still see it on linux.git if you run "git shortlog" manually yourself with --merges, with this removed you can still get the same output with: git log --pretty=fuller v5.10-rc7..v5.10 | sed 's!/pub/scm/linux/kernel/git/!/.../!g' | git shortlog Arguably we should do the same for the search-replacing of "[PATCH]" at the beginning with "". That seems to be another relic of a bygone era when linux.git patches would have their E-Mail subject lines applied as-is by "git am" or whatever. But we documented that feature in "git-shortlog(1)", and it seems more widely applicable than something purely kernel-specific. 1. 7595e2ee6ef (git-shortlog: make common repository prefix configurable with .mailmap, 2006-11-25) 2. fa375c7f1b6 (Add git-shortlog perl script, 2005-06-04) 3. https://lore.kernel.org/lkml/ 4. https://lore.kernel.org/lkml/alpine.LFD.1.00.0803161651350.3020@woody.linux-foundation.org/ 5. https://lore.kernel.org/lkml/BANLkTinrbh7Xi27an3uY7pDWrNKhJRYmEA@mail.gmail.com/ 6. https://lore.kernel.org/lkml/CAHk-=wg1+kf1AVzXA-RQX0zjM6t9J2Kay9xyuNqcFHWV-y5ZYw@mail.gmail.com/ Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12fetch: implement support for atomic reference updatesPatrick Steinhardt1-5/+41
When executing a fetch, then git will currently allocate one reference transaction per reference update and directly commit it. This means that fetches are non-atomic: even if some of the reference updates fail, others may still succeed and modify local references. This is fine in many scenarios, but this strategy has its downsides. - The view of remote references may be inconsistent and may show a bastardized state of the remote repository. - Batching together updates may improve performance in certain scenarios. While the impact probably isn't as pronounced with loose references, the upcoming reftable backend may benefit as it needs to write less files in case the update is batched. - The reference-update hook is currently being executed twice per updated reference. While this doesn't matter when there is no such hook, we have seen severe performance regressions when doing a git-fetch(1) with reference-transaction hook when the remote repository has hundreds of thousands of references. Similar to `git push --atomic`, this commit thus introduces atomic fetches. Instead of allocating one reference transaction per updated reference, it causes us to only allocate a single transaction and commit it as soon as all updates were received. If locking of any reference fails, then we abort the complete transaction and don't update any reference, which gives us an all-or-nothing fetch. Note that this may not completely fix the first of above downsides, as the consistent view also depends on the server-side. If the server doesn't have a consistent view of its own references during the reference negotiation phase, then the client would get the same inconsistent view the server has. This is a separate problem though and, if it actually exists, can be fixed at a later point. This commit also changes the way we write FETCH_HEAD in case `--atomic` is passed. Instead of writing changes as we go, we need to accumulate all changes first and only commit them at the end when we know that all reference updates succeeded. Ideally, we'd just do so via a temporary file so that we don't need to carry all updates in-memory. This isn't trivially doable though considering the `--append` mode, where we do not truncate the file but simply append to it. And given that we support concurrent processes appending to FETCH_HEAD at the same time without any loss of data, seeding the temporary file with current contents of FETCH_HEAD initially and then doing a rename wouldn't work either. So this commit implements the simple strategy of buffering all changes and appending them to the file on commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12fetch: allow passing a transaction to `s_update_ref()`Patrick Steinhardt1-20/+31
The handling of ref updates is completely handled by `s_update_ref()`, which will manage the complete lifecycle of the reference transaction. This is fine right now given that git-fetch(1) does not support atomic fetches, so each reference gets its own transaction. It is quite inflexible though, as `s_update_ref()` only knows about a single reference update at a time, so it doesn't allow us to alter the strategy. This commit prepares `s_update_ref()` and its only caller `update_local_ref()` to allow passing an external transaction. If none is given, then the existing behaviour is triggered which creates a new transaction and directly commits it. Otherwise, if the caller provides a transaction, then we only queue the update but don't commit it. This optionally allows the caller to manage when a transaction will be committed. Given that `update_local_ref()` is always called with a `NULL` transaction for now, no change in behaviour is expected from this change. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12fetch: refactor `s_update_ref` to use common exit pathPatrick Steinhardt1-18/+25
The cleanup code in `s_update_ref()` is currently duplicated for both succesful and erroneous exit paths. This commit refactors the function to have a shared exit path for both cases to remove the duplication. Suggested-by: Christian Couder <christian.couder@gmail.com> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12fetch: use strbuf to format FETCH_HEAD updatesPatrick Steinhardt1-5/+11
This commit refactors `append_fetch_head()` to use a `struct strbuf` for formatting the update which we're about to append to the FETCH_HEAD file. While the refactoring doesn't have much of a benefit right now, it serves as a preparatory step to implement atomic fetches where we need to buffer all updates to FETCH_HEAD and only flush them out if all reference updates succeeded. No change in behaviour is expected from this commit. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-12fetch: extract writing to FETCH_HEADPatrick Steinhardt1-29/+79
When performing a fetch with the default `--write-fetch-head` option, we write all updated references to FETCH_HEAD while the updates are performed. Given that updates are not performed atomically, it means that we we write to FETCH_HEAD even if some or all of the reference updates fail. Given that we simply update FETCH_HEAD ad-hoc with each reference, the logic is completely contained in `store_update_refs` and thus quite hard to extend. This can already be seen by the way we skip writing to the FETCH_HEAD: instead of having a conditional which simply skips writing, we instead open "/dev/null" and needlessly write all updates there. We are about to extend git-fetch(1) to accept an `--atomic` flag which will make the fetch an all-or-nothing operation with regards to the reference updates. This will also require us to make the updates to FETCH_HEAD an all-or-nothing operation, but as explained doing so is not easy with the current layout. This commit thus refactors the wa we write to FETCH_HEAD and pulls out the logic to open, append to, commit and close the file. While this may seem rather over-the top at first, pulling out this logic will make it a lot easier to update the code in a subsequent commit. It also allows us to easily skip writing completely in case `--no-write-fetch-head` was passed. Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-07for-each-repo: do nothing on empty configDerrick Stolee1-0/+7
'git for-each-repo --config=X' should return success without calling any subcommands when the config key 'X' has no value. The current implementation instead segfaults. A user could run into this issue if they used 'git maintenance start' to initialize their cron schedule using 'git for-each-repo --config=maintenance.repo ...' but then using 'git maintenance unregister' to remove the config option. (Note: 'git maintenance stop' would remove the config _and_ remove the cron schedule.) Add a simple test to ensure this works. Use 'git help --no-such-option' as the potential subcommand to ensure that we will hit a failure if the subcommand is ever run. Reported-by: Andreas Bühmann <dev@uuml.de> Helped-by: Eric Sunshine <sunshine@sunshineco.com> Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-07branch: sort detached HEAD based on a flagÆvar Arnfjörð Bjarmason1-0/+2
Change the ref-filter sorting of detached HEAD to check the FILTER_REFS_DETACHED_HEAD flag, instead of relying on the ref description filled-in by get_head_description() to start with "(", which in turn we expect to ASCII-sort before any other reference. For context, we'd like the detached line to appear first at the start of "git branch -l", e.g.: $ git branch -l * (HEAD detached at <hash>) master This doesn't change that, but improves on a fix made in 28438e84e04 (ref-filter: sort detached HEAD lines firstly, 2019-06-18) and gives the Chinese translation the ability to use its preferred punctuation marks again. In Chinese the fullwidth versions of punctuation like "()" are typically written as (U+FF08 fullwidth left parenthesis), (U+FF09 fullwidth right parenthesis) instead[1]. This form is used in both po/zh_{CN,TW}.po in most cases where "()" is translated in a string. Aside from that improvement to the Chinese translation, it also just makes for cleaner code that we mark any special cases in the ref_array we're sorting with flags and make the sort function aware of them, instead of piggy-backing on the general-case of strcmp() doing the right thing. As seen in the amended tests this made reverse sorting a bit more consistent. Before this we'd sometimes sort this message in the middle, now it's consistently at the beginning or end, depending on whether we're doing a normal or reverse sort. Having it at the end doesn't make much sense either, but at least it behaves consistently now. A follow-up commit will make this behavior under reverse sorting even better. I'm removing the "TRANSLATORS" comments that were in the old code while I'm at it. Those were added in d4919bb288e (ref-filter: move get_head_description() from branch.c, 2017-01-10). I think it's obvious from context, string and translation memory in typical translation tools that these are the same or similar string. 1. https://en.wikipedia.org/wiki/Chinese_punctuation#Marks_similar_to_European_punctuation Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-07ref-filter: move ref_sorting flags to a bitfieldÆvar Arnfjörð Bjarmason3-3/+3
Change the reverse/ignore_case/version sort flags in the ref_sorting struct into a bitfield. Having three of them was already a bit unwieldy, but it would be even more so if another flag needed a function like ref_sorting_icase_all() introduced in 76f9e569adb (ref-filter: apply --ignore-case to all sorting keys, 2020-05-03). A follow-up change will introduce such a flag, so let's move this over to a bitfield. Instead of using the usual '#define' pattern I'm using the "enum" pattern from builtin/rebase.c's b4c8eb024af (builtin rebase: support --quiet, 2018-09-04). Perhaps there's a more idiomatic way of doing the "for each in list amend mask" pattern than this "mask/on" variable combo. This function doesn't allow us to e.g. do any arbitrary changes to the bitfield for multiple flags, but I think in this case that's fine. The common case is that we're calling this with a list of one. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-06Merge branch 'es/worktree-repair-both-moved'Junio C Hamano1-1/+1
"git worktree repair" learned to deal with the case where both the repository and the worktree moved. * es/worktree-repair-both-moved: worktree: teach `repair` to fix multi-directional breakage
2021-01-06Merge branch 'fc/pull-merge-rebase'Junio C Hamano1-27/+43
When a user does not tell "git pull" to use rebase or merge, the command gives a loud message telling a user to choose between rebase or merge but creates a merge anyway, forcing users who would want to rebase to redo the operation. Fix an early part of this problem by tightening the condition to give the message---there is no reason to stop or force the user to choose between rebase or merge if the history fast-forwards. * fc/pull-merge-rebase: pull: display default warning only when non-ff pull: correct condition to trigger non-ff advice pull: get rid of unnecessary global variable pull: give the advice for choosing rebase/merge much later pull: refactor fast-forward check
2021-01-06Merge branch 'tb/pack-bitmap'Junio C Hamano1-1/+0
Various improvements to the codepath that writes out pack bitmaps. * tb/pack-bitmap: (24 commits) pack-bitmap-write: better reuse bitmaps pack-bitmap-write: relax unique revwalk condition pack-bitmap-write: use existing bitmaps pack-bitmap: factor out 'add_commit_to_bitmap()' pack-bitmap: factor out 'bitmap_for_commit()' pack-bitmap-write: ignore BITMAP_FLAG_REUSE pack-bitmap-write: build fewer intermediate bitmaps pack-bitmap.c: check reads more aggressively when loading pack-bitmap-write: rename children to reverse_edges t5310: add branch-based checks commit: implement commit_list_contains() bitmap: implement bitmap_is_subset() pack-bitmap-write: fill bitmap with commit history pack-bitmap-write: pass ownership of intermediate bitmaps pack-bitmap-write: reimplement bitmap writing ewah: add bitmap_dup() function ewah: implement bitmap_or() ewah: make bitmap growth less aggressive ewah: factor out bitmap growth rev-list: die when --test-bitmap detects a mismatch ...
2021-01-06branch: change "--local" to "--list" in commentÆvar Arnfjörð Bjarmason1-1/+1
There has never been a "git branch --local", this is just a typo for "--list". Fixes a comment added in 23e714df91c (branch: roll show_detached HEAD into regular ref_list, 2015-09-23). Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-06builtin/*: update usage formatZheNing Hu7-61/+61
According to the guidelines in parse-options.h, we should not end in a full stop or start with a capital letter. Fix old error and usage messages to match this expectation. Signed-off-by: ZheNing Hu <adlternative@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-06mktag: add a --[no-]strict optionÆvar Arnfjörð Bjarmason1-0/+9
Now that mktag has been migrated to use the fsck machinery to check its input, it makes sense to teach it to run in the equivalent of "git fsck"'s default mode. For cases where mktag is used to (re)create a tag object using data from an existing and malformed tag object, the validation may optionally have to be loosened. Teach the command to take the "--[no-]strict" option to do so. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-06builtin/gc: don't peek into `struct lock_file`Martin Ågren1-3/+3
A `struct lock_file` is pretty much just a wrapper around a tempfile. But it's easy enough to avoid relying on this. Use the wrappers that the lock file API provides rather than peeking at the temp file or even into *its* internals. Signed-off-by: Martin Ågren <martin.agren@gmail.com> Reviewed-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-05mktag: mark strings for translationÆvar Arnfjörð Bjarmason1-8/+8
Mark the errors mktag might emit for translation. This is a plumbing command, but the errors it emits are intended to be human-readable. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-05mktag: convert to parse-optionsÆvar Arnfjörð Bjarmason1-2/+12
Convert the "mktag" command to use parse-options.h instead of its own ad-hoc argc handling. This doesn't matter much in practice since it doesn't support any options, but removes another special-case in our codebase, and makes it easier to add options to it in the future. It does marginally improve the situation for programs that want to execute git commands in a consistent manner and e.g. always use --end-of-options. E.g. "gitaly" does that, and has a blacklist of built-ins that don't support --end-of-options. This is one less special case for it and other similar programs to support. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-05mktag: allow turning off fsck.extraHeaderEntryÆvar Arnfjörð Bjarmason1-1/+10
In earlier commits mktag learned to use the fsck machinery, at which point we needed to add fsck.extraHeaderEntry so it could be as strict about extra headers as it's been ever since it was implemented. But it's not nice to need to switch away from "mktag" to "hash-object" + manual "fsck" just because you'd like to have an extra header. So let's support turning it off by getting "fsck.*" variables from the config. Pedantically speaking it's still not possible to make "mktag" behave just like "hash-object -t tag" does, since we're unconditionally going to check the referenced object in verify_object_in_tag(), which is our own check, and not one that exists in fsck.c. But the spirit of "this works like fsck" is preserved, in that if you created such a tag with "hash-object" and did a full "fsck" on the repository it would also error out about that invalid object, it just wouldn't emit the same message as fsck does. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>