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2020-12-08Merge branch 'ma/grep-init-default'Libravatar Junio C Hamano1-1/+0
Code clean-up. * ma/grep-init-default: MyFirstObjectWalk: drop `init_walken_defaults()` grep: copy struct in one fell swoop grep: use designated initializers for `grep_defaults` grep: don't set up a "default" repo for grep
2020-11-21grep: use designated initializers for `grep_defaults`Libravatar Martin Ågren1-1/+0
In 15fabd1bbd ("builtin/grep.c: make configuration callback more reusable", 2012-10-09), we learned to fill a `static struct grep_opt grep_defaults` which we can use as a blueprint for other such structs. At the time, we didn't consider designated initializers to be widely useable, but these days, we do. (See, e.g., cbc0f81d96 ("strbuf: use designated initializers in STRBUF_INIT", 2017-07-10).) Use designated initializers to let the compiler set up the struct and so that we don't need to remember to call `init_grep_defaults()`. Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-21grep: don't set up a "default" repo for grepLibravatar Martin Ågren1-1/+1
`init_grep_defaults()` fills a `static struct grep_opt grep_defaults`. This struct is then used by `grep_init()` as a blueprint for other such structs. Notably, `grep_init()` takes a `struct repo *` and assigns it into the target struct. As a result, it is unnecessary for us to take a `struct repo *` in `init_grep_defaults()` as well. We assign it into the default struct and never look at it again. And in light of how we return early if we have already set up the default struct, it's not just unnecessary, but is also a bit confusing: If we are called twice and with different repos, is it a bug or a feature that we ignore the second repo? Drop the repo parameter for `init_grep_defaults()`. Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-11Use new HASHMAP_INIT macro to simplify hashmap initializationLibravatar Elijah Newren1-8/+1
Now that hashamp has lazy initialization and a HASHMAP_INIT macro, hashmaps allocated on the stack can be initialized without a call to hashmap_init() and in some cases makes the code a bit shorter. Convert some callsites over to take advantage of this. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-02hashmap: provide deallocation function namesLibravatar Elijah Newren1-1/+1
hashmap_free(), hashmap_free_entries(), and hashmap_free_() have existed for a while, but aren't necessarily the clearest names, especially with hashmap_partial_clear() being added to the mix and lazy-initialization now being supported. Peff suggested we adopt the following names[1]: - hashmap_clear() - remove all entries and de-allocate any hashmap-specific data, but be ready for reuse - hashmap_clear_and_free() - ditto, but free the entries themselves - hashmap_partial_clear() - remove all entries but don't deallocate table - hashmap_partial_clear_and_free() - ditto, but free the entries This patch provides the new names and converts all existing callers over to the new naming scheme. [1] https://lore.kernel.org/git/20201030125059.GA3277724@coredump.intra.peff.net/ Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-30drop unused argc parametersLibravatar Jeff King1-3/+3
Many functions take an argv/argc pair, but never actually look at argc. This makes it useless at best (we use the NULL sentinel in argv to find the end of the array), and misleading at worst (what happens if the argc count does not match the argv NULL?). In each of these instances, the argv NULL does match the argc count, so there are no bugs here. But let's tighten the interfaces to make it harder to get wrong (and to reduce some -Wunused-parameter complaints). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-29Merge branch 'tb/bloom-improvements'Libravatar Junio C Hamano1-5/+2
"git commit-graph write" learned to limit the number of bloom filters that are computed from scratch with the --max-new-filters option. * tb/bloom-improvements: commit-graph: introduce 'commitGraph.maxNewFilters' builtin/commit-graph.c: introduce '--max-new-filters=<n>' commit-graph: rename 'split_commit_graph_opts' bloom: encode out-of-bounds filters as non-empty bloom/diff: properly short-circuit on max_changes bloom: use provided 'struct bloom_filter_settings' bloom: split 'get_bloom_filter()' in two commit-graph.c: store maximum changed paths commit-graph: respect 'commitGraph.readChangedPaths' t/helper/test-read-graph.c: prepare repo settings commit-graph: pass a 'struct repository *' in more places t4216: use an '&&'-chain commit-graph: introduce 'get_bloom_filter_settings()'
2020-09-18Merge branch 'mf/submodule-summary-with-correct-repository'Libravatar Junio C Hamano1-9/+9
"git diff/show" on a change that involves a submodule used to read the information on commits in the submodule from a wrong repository and gave a wrong information when the commit-graph is involved. * mf/submodule-summary-with-correct-repository: submodule: use submodule repository when preparing summary revision: use repository from rev_info when parsing commits
2020-09-17bloom: split 'get_bloom_filter()' in twoLibravatar Taylor Blau1-1/+1
'get_bloom_filter' takes a flag to control whether it will compute a Bloom filter if the requested one is missing. In the next patch, we'll add yet another parameter to this method, which would force all but one caller to specify an extra 'NULL' parameter at the end. Instead of doing this, split 'get_bloom_filter' into two functions: 'get_bloom_filter' and 'get_or_compute_bloom_filter'. The former only looks up a Bloom filter (and does not compute one if it's missing, thus dropping the 'compute_if_not_present' flag). The latter does compute missing Bloom filters, with an additional parameter to store whether or not it needed to do so. This simplifies many call-sites, since the majority of existing callers to 'get_bloom_filter' do not want missing Bloom filters to be computed (so they can drop the parameter entirely and use the simpler version of the function). While we're at it, instrument the new 'get_or_compute_bloom_filter()' with counters in the 'write_commit_graph_context' struct which store the number of filters that we did and didn't compute, as well as filters that were truncated. It would be nice to drop the 'compute_if_not_present' flag entirely, since all remaining callers of 'get_or_compute_bloom_filter' pass it as '1', but this will change in a future patch and hence cannot be removed. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-09Merge branch 'jt/interpret-branch-name-fallback'Libravatar Junio C Hamano1-1/+2
"git status" has trouble showing where it came from by interpreting reflog entries that recordcertain events, e.g. "checkout @{u}", and gives a hard/fatal error. Even though it inherently is impossible to give a correct answer because the reflog entries lose some information (e.g. "@{u}" does not record what branch the user was on hence which branch 'the upstream' needs to be computed, and even if the record were available, the relationship between branches may have changed), at least hide the error to allow "status" show its output. * jt/interpret-branch-name-fallback: wt-status: tolerate dangling marks refs: move dwim_ref() to header file sha1-name: replace unsigned int with option struct
2020-09-09Merge branch 'so/separate-field-for-m-and-diff-merges'Libravatar Junio C Hamano1-0/+6
Internal API clean-up to handle two options "diff-index" and "log" have, which happen to share the same short form, more sensibly. * so/separate-field-for-m-and-diff-merges: revision: add separate field for "-m" of "diff-index -m"
2020-09-09commit-graph: introduce 'get_bloom_filter_settings()'Libravatar Taylor Blau1-4/+1
Many places in the code often need a pointer to the commit-graph's 'struct bloom_filter_settings', in which case they often take the value from the top-most commit-graph. In the non-split case, this works as expected. In the split case, however, things get a little tricky. Not all layers in a chain of incremental commit-graphs are required to themselves have Bloom data, and so whether or not some part of the code uses Bloom filters depends entirely on whether or not the top-most level of the commit-graph chain has Bloom filters. This has been the behavior since Bloom filters were introduced, and has been codified into the tests since a759bfa9ee (t4216: add end to end tests for git log with Bloom filters, 2020-04-06). In fact, t4216.130 requires that Bloom filters are not used in exactly the case described earlier. There is no reason that this needs to be the case, since it is perfectly valid for commits in an earlier layer to have Bloom filters when commits in a newer layer do not. Since Bloom settings are guaranteed in practice to be the same for any layer in a chain that has Bloom data, it is sufficient to traverse the '->base_graph' pointer until either (1) a non-null 'struct bloom_filter_settings *' is found, or (2) until we are at the root of the commit-graph chain. Introduce a 'get_bloom_filter_settings()' function that does just this, and use it instead of purely dereferencing the top-most graph's '->bloom_filter_settings' pointer. While we're at it, add an additional test in t5324 to guard against code in the commit-graph writing machinery that doesn't correctly handle a NULL 'struct bloom_filter *'. Co-authored-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-02sha1-name: replace unsigned int with option structLibravatar Jonathan Tan1-1/+2
In preparation for a future patch adding a boolean parameter to repo_interpret_branch_name(), which might be easily confused with an existing unsigned int parameter, refactor repo_interpret_branch_name() to take an option struct instead of the unsigned int parameter. The static function interpret_branch_mark() is also updated to take the option struct in preparation for that future patch, since it will also make use of the to-be-introduced boolean parameter. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-31Merge branch 'jk/rev-input-given-fix'Libravatar Junio C Hamano1-5/+11
Feeding "$ZERO_OID" to "git log --ignore-missing --stdin", and running "git log --ignore-missing $ZERO_OID" fell back to start digging from HEAD; it has been corrected to become a no-op, like "git log --tags=no-tag-matches-this-pattern" does. * jk/rev-input-given-fix: revision: set rev_input_given in handle_revision_arg()
2020-08-31revision: add separate field for "-m" of "diff-index -m"Libravatar Sergey Organov1-0/+6
Add separate 'match_missing' field for diff-index to use and set it when we encounter "-m" option. This field won't then be cleared when another meaning of "-m" is reverted (e.g., by "--no-diff-merges"), nor it will be affected by future option(s) that might drive 'ignore_merges' field. Use this new field from diff-lib:do_oneway_diff() instead of reusing 'ignore_merges' field. Signed-off-by: Sergey Organov <sorganov@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-26revision: set rev_input_given in handle_revision_arg()Libravatar Jeff King1-5/+11
Commit 7ba826290a (revision: add rev_input_given flag, 2017-08-02) added a flag to rev_info to tell whether we got any revision arguments. As explained there, this is necessary because some revision arguments may not produce any pending traversal objects, but should still inhibit default behaviors (e.g., a glob that matches nothing). However, it only set the flag in the globbing code, but not for revisions we get on the command-line or via stdin. This leads to two problems: - the command-line code keeps its own separate got_rev_arg flag; this isn't wrong, but it's confusing and an extra maintenance burden - even specifically-named rev arguments might end up not adding any pending objects: if --ignore-missing is set, then specifying a missing object is a noop rather than an error. And that leads to some user-visible bugs: - when deciding whether a default rev like "HEAD" should kick in, we check both got_rev_arg and rev_input_given. That means that "--ignore-missing $ZERO_OID" works on the command-line (where we set got_rev_arg) but not on --stdin (where we don't) - when rev-list decides whether it should complain that it wasn't given a starting point, it relies on rev_input_given. So it can't even get the command-line "--ignore-missing $ZERO_OID" right Let's consistently set the flag if we got any revision argument. That lets us clean up the redundant got_rev_arg, and fixes both of those bugs (but note there are three new tests: we'll confirm the already working git-log command-line case). A few implementation notes: - conceptually we want to set the flag whenever handle_revision_arg() finds an actual revision arg ("handles" it, you might say). But it covers a ton of cases with early returns. Rather than annotating each one, we just wrap it and use its success exit-code to set the flag in one spot. - the new rev-list test is in t6018, which is titled to cover globs. This isn't exactly a glob, but it made sense to stick it with the other tests that handle the "even though we got a rev, we have no pending objects" case, which are globs. - the tests check for the oid of a missing object, which it's pretty clear --ignore-missing should ignore. You can see the same behavior with "--ignore-missing a-ref-that-does-not-exist", because --ignore-missing treats them both the same. That's perhaps less clearly correct, and we may want to change that in the future. But the way the code and tests here are written, we'd continue to do the right thing even if it does. Reported-by: Bryan Turner <bturner@atlassian.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-17Merge branch 'so/log-diff-merges-opt'Libravatar Junio C Hamano1-1/+8
Earlier, to countermand the implicit "-m" option when the "--first-parent" option is used with "git log", we added the "--[no-]diff-merges" option in the jk/log-fp-implies-m topic. To leave the door open to allow the "--diff-merges" option to take values that instructs how patches for merge commits should be computed (e.g. "cc"? "-p against first parent?"), redefine "--diff-merges" to take non-optional value, and implement "off" that means the same thing as "--no-diff-merges". * so/log-diff-merges-opt: t/t4013: add test for --diff-merges=off doc/git-log: describe --diff-merges=off revision: change "--diff-merges" option to require parameter
2020-08-17Merge branch 'jk/log-fp-implies-m'Libravatar Junio C Hamano1-3/+7
"git log --first-parent -p" showed patches only for single-parent commits on the first-parent chain; the "--first-parent" option has been made to imply "-m". Use "--no-diff-merges" to restore the previous behaviour to omit patches for merge commits. * jk/log-fp-implies-m: doc/git-log: clarify handling of merge commit diffs doc/git-log: move "-t" into diff-options list doc/git-log: drop "-r" diff option doc/git-log: move "Diff Formatting" from rev-list-options log: enable "-m" automatically with "--first-parent" revision: add "--no-diff-merges" option to counteract "-m" log: drop "--cc implies -m" logic
2020-08-17Merge branch 'al/bisect-first-parent'Libravatar Junio C Hamano1-3/+0
"git bisect" learns the "--first-parent" option to find the first breakage along the first-parent chain. * al/bisect-first-parent: bisect: combine args passed to find_bisection() bisect: introduce first-parent flag cmd_bisect__helper: defer parsing no-checkout flag rev-list: allow bisect and first-parent flags t6030: modernize "git bisect run" tests
2020-08-11revision: change "--diff-merges" option to require parameterLibravatar Sergey Organov1-1/+8
--diff-merges=off is the only accepted form for now, a synonym for --no-diff-merges. This patch is a preparation for adding more values, as well as supporting --diff-merges=<parent>, where <parent> is single parent number to output diff against. Signed-off-by: Sergey Organov <sorganov@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-10Merge branch 'so/rev-parser-errormessage-fix'Libravatar Junio C Hamano1-1/+1
Error message fix. * so/rev-parser-errormessage-fix: revision: fix die() message for "--unpacked="
2020-08-10Merge branch 'jk/compiler-fixes-and-workarounds'Libravatar Junio C Hamano1-5/+3
Small fixes and workarounds. * jk/compiler-fixes-and-workarounds: revision: avoid leak when preparing bloom filter for "/" revision: avoid out-of-bounds read/write on empty pathspec config: work around gcc-10 -Wstringop-overflow warning
2020-08-10Merge branch 'jk/strvec'Libravatar Junio C Hamano1-10/+10
The argv_array API is useful for not just managing argv but any "vector" (NULL-terminated array) of strings, and has seen adoption to a certain degree. It has been renamed to "strvec" to reduce the barrier to adoption. * jk/strvec: strvec: rename struct fields strvec: drop argv_array compatibility layer strvec: update documention to avoid argv_array strvec: fix indentation in renamed calls strvec: convert remaining callers away from argv_array name strvec: convert more callers away from argv_array name strvec: convert builtin/ callers away from argv_array name quote: rename sq_dequote_to_argv_array to mention strvec strvec: rename files from argv-array to strvec argv-array: rename to strvec argv-array: use size_t for count and alloc
2020-08-07rev-list: allow bisect and first-parent flagsLibravatar Aaron Lipman1-3/+0
Add first_parent_only parameter to find_bisection(), removing the barrier that prevented combining the --bisect and --first-parent flags when using git rev-list Based-on-patch-by: Tiago Botelho <tiagonbotelho@hotmail.com> Signed-off-by: Aaron Lipman <alipman88@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-04revision: fix die() message for "--unpacked="Libravatar Sergey Organov1-1/+1
Get rid of the trailing dot and mark for translation. Signed-off-by: Sergey Organov <sorganov@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-04revision: avoid leak when preparing bloom filter for "/"Libravatar Jeff King1-0/+1
If we're given an empty pathspec, we refuse to set up bloom filters, as described in f3c2a36810 (revision: empty pathspecs should not use Bloom filters, 2020-07-01). But before the empty string check, we drop any trailing slash by allocating a new string without it. So a pathspec consisting only of "/" will allocate that string, but then still cause us to bail, leaking the new string. Let's make sure to free it. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-08-04revision: avoid out-of-bounds read/write on empty pathspecLibravatar Jeff King1-5/+2
Running t4216 with ASan results in it complaining of an out-of-bounds read in prepare_to_use_bloom_filter(). The issue is this code to strip a trailing slash: last_index = pi->len - 1; if (pi->match[last_index] == '/') { because we have no guarantee that pi->len isn't zero. This can happen if the pathspec is ".", as we translate that to an empty string. And if that read of random memory does trigger the conditional, we'd then do an out-of-bounds write: path_alloc = xstrdup(pi->match); path_alloc[last_index] = '\0'; Let's make sure to check the length before subtracting. Note that for an empty pathspec, we'd end up bailing from the function a few lines later, which makes it tempting to just: if (!pi->len) return; early here. But our code here is stripping a trailing slash, and we need to check for emptiness after stripping that slash, too. So we'd have two blocks, which would require repeating some cleanup code. Instead, just skip the trailing-slash for an empty string. Setting last_index at all in the case is awkward since it will have a nonsense value (and it uses an "int", which is a too-small type for a string anyway). So while we're here, let's: - drop last_index entirely; it's only used in two spots right next to each other and writing out "pi->len - 1" in both is actually easier to follow - use xmemdupz() to duplicate the string. This is slightly more efficient, but more importantly makes the intent more clear by allocating the correct-sized substring in the first place. It also eliminates any question of whether path_alloc is as long as pi->match (which it would not be if pi->match has any embedded NULs, though in practice this is probably impossible). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30strvec: rename struct fieldsLibravatar Jeff King1-2/+2
The "argc" and "argv" names made sense when the struct was argv_array, but now they're just confusing. Let's rename them to "nr" (which we use for counts elsewhere) and "v" (which is rather terse, but reads well when combined with typical variable names like "args.v"). Note that we have to update all of the callers immediately. Playing tricks with the preprocessor is hard here, because we wouldn't want to rewrite unrelated tokens. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30Merge branch 'ds/commit-graph-bloom-updates' into masterLibravatar Junio C Hamano1-19/+44
Updates to the changed-paths bloom filter. * ds/commit-graph-bloom-updates: commit-graph: check all leading directories in changed path Bloom filters revision: empty pathspecs should not use Bloom filters revision.c: fix whitespace commit-graph: check chunk sizes after writing commit-graph: simplify chunk writes into loop commit-graph: unify the signatures of all write_graph_chunk_*() functions commit-graph: persist existence of changed-paths bloom: fix logic in get_bloom_filter() commit-graph: change test to die on parse, not load commit-graph: place bloom_settings in context
2020-07-30Merge branch 'sg/commit-graph-cleanups' into masterLibravatar Junio C Hamano1-6/+3
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'
2020-07-29revision: add "--no-diff-merges" option to counteract "-m"Libravatar Jeff King1-3/+7
The "-m" option sets revs->ignore_merges to "0", but there's no way to undo it. This probably isn't something anybody overly cares about, since "1" is already the default, but it will serve as an escape hatch when we flip the default for ignore_merges to "0" in more situations. We'll also add a few extra niceties: - initialize the value to "-1" to indicate "not set", and then resolve it to the normal 0/1 bool in setup_revisions(). This lets any tweak functions, as well as setup_revisions() itself, avoid clobbering the user's preference (which until now they couldn't actually express). - since we now have --no-diff-merges, let's add the matching --diff-merges, which is just a synonym for "-m". Then we don't even need to document --no-diff-merges separately; it countermands the long form of "-m" in the usual way. The new test shows that this behaves just the same as the current behavior without "-m". Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28strvec: convert remaining callers away from argv_array nameLibravatar Jeff King1-7/+7
We eventually want to drop the argv_array name and just use strvec consistently. There's no particular reason we have to do it all at once, or care about interactions between converted and unconverted bits. Because of our preprocessor compat layer, the names are interchangeable to the compiler (so even a definition and declaration using different names is OK). This patch converts all of the remaining files, as the resulting diff is reasonably sized. The conversion was done purely mechanically with: git ls-files '*.c' '*.h' | xargs perl -i -pe ' s/ARGV_ARRAY/STRVEC/g; s/argv_array/strvec/g; ' We'll deal with any indentation/style fallouts separately. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-28strvec: rename files from argv-array to strvecLibravatar Jeff King1-1/+1
This requires updating #include lines across the code-base, but that's all fairly mechanical, and was done with: git ls-files '*.c' '*.h' | xargs perl -i -pe 's/argv-array.h/strvec.h/' Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-09Merge branch 'rs/line-log-until' into masterLibravatar Junio C Hamano1-1/+2
"git log -Lx,y:path --before=date" lost track of where the range should be because it didn't take the changes made by the youngest commits that are omitted from the output into account. * rs/line-log-until: revision: disable min_age optimization with line-log
2020-07-06Merge branch 'es/get-worktrees-unsort'Libravatar Junio C Hamano1-2/+2
API cleanup for get_worktrees() * es/get-worktrees-unsort: worktree: drop get_worktrees() unused 'flags' argument worktree: drop get_worktrees() special-purpose sorting option
2020-07-06revision: disable min_age optimization with line-logLibravatar René Scharfe1-1/+2
If one of the options --before, --min-age or --until is given, limit_list() filters out younger commits early on. Line-log needs all those commits to trace the movement of line ranges, though. Skip this optimization if both are used together. Reported-by: Мария Долгополова <dolgopolovamariia@gmail.com> Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01commit-graph: check all leading directories in changed path Bloom filtersLibravatar SZEDER Gábor1-9/+37
The file 'dir/subdir/file' can only be modified if its leading directories 'dir' and 'dir/subdir' are modified as well. So when checking modified path Bloom filters looking for commits modifying a path with multiple path components, then check not only the full path in the Bloom filters, but all its leading directories as well. Take care to check these paths in "deepest first" order, because it's the full path that is least likely to be modified, and the Bloom filter queries can short circuit sooner. This can significantly reduce the average false positive rate, by about an order of magnitude or three(!), and can further speed up pathspec-limited revision walks. The table below compares the average false positive rate and runtime of git rev-list HEAD -- "$path" before and after this change for 5000+ randomly* selected paths from each repository: Average false Average Average positive rate runtime runtime before after before after difference ------------------------------------------------------------------ git 3.220% 0.7853% 0.0558s 0.0387s -30.6% linux 2.453% 0.0296% 0.1046s 0.0766s -26.8% tensorflow 2.536% 0.6977% 0.0594s 0.0420s -29.2% *Path selection was done with the following pipeline: git ls-tree -r --name-only HEAD | sort -R | head -n 5000 The improvements in runtime are much smaller than the improvements in average false positive rate, as we are clearly reaching diminishing returns here. However, all these timings depend on that accessing tree objects is reasonably fast (warm caches). If we had a partial clone and the tree objects had to be fetched from a promisor remote, e.g.: $ git clone --filter=tree:0 --bare file://.../webkit.git webkit.notrees.git $ git -C webkit.git -c core.modifiedPathBloomFilters=1 \ commit-graph write --reachable $ cp webkit.git/objects/info/commit-graph webkit.notrees.git/objects/info/ $ git -C webkit.notrees.git -c core.modifiedPathBloomFilters=1 \ rev-list HEAD -- "$path" then checking all leading path component can reduce the runtime from over an hour to a few seconds (and this is with the clone and the promisor on the same machine). This adjusts the tracing values in t4216-log-bloom.sh, which provides a concrete way to notice the improvement. Helped-by: Taylor Blau <me@ttaylorr.com> Helped-by: René Scharfe <l.s.r@web.de> Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01revision: empty pathspecs should not use Bloom filtersLibravatar Taylor Blau1-0/+4
The prepare_to_use_bloom_filter() method was not intended to be called on an empty pathspec. However, 'git log -- .' and 'git log' are subtly different: the latter reports all commits while the former will simplify commits that do not change the root tree. This means that the path used to construct the bloom_key might be empty, and that value is not added to the Bloom filter during construction. That means that the results are likely incorrect! To resolve the issue, be careful about the length of the path and stop filling Bloom filters. To be completely sure we do not use them, drop the pointer to the bloom_filter_settings from the commit-graph. That allows our test to look at the trace2 logs to verify no Bloom filter statistics are reported. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01revision.c: fix whitespaceLibravatar Derrick Stolee1-4/+4
Here, four spaces were used instead of tab characters. Reported-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01bloom: fix logic in get_bloom_filter()Libravatar Derrick Stolee1-7/+0
The get_bloom_filter() method is a bit complicated in some parts where it does not need to be. In particular, it needs to return a NULL filter only when compute_if_not_present is zero AND the filter data cannot be loaded from a commit-graph file. This currently happens by accident because the commit-graph does not load changed-path Bloom filters from an existing commit-graph when writing a new one. This will change in a later patch. Also clean up some style issues while we are here. One side-effect of returning a NULL filter is that the filters that are reported as "too large" will now be reported as NULL insead of length zero. This case was not properly covered before, so add a test. Further, remote the counting of the zero-length filters from revision.c and the trace2 logs. Helped-by: René Scharfe <l.s.r@web.de> Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-24revision: use repository from rev_info when parsing commitsLibravatar Michael Forney1-9/+9
This is needed when repo_init_revisions() is called with a repository that is not the_repository to ensure appropriate repository is used in repo_parse_commit_internal(). If the wrong repository is used, a fatal error is the commit-graph machinery occurs: fatal: invalid commit position. commit-graph is likely corrupt Since revision.c was the only user of the parse_commit_gently compatibility define, remove it from commit.h. Signed-off-by: Michael Forney <mforney@mforney.org> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-22worktree: drop get_worktrees() unused 'flags' argumentLibravatar Eric Sunshine1-2/+2
get_worktrees() accepts a 'flags' argument, however, there are no existing flags (the lone flag GWT_SORT_LINKED was recently retired) and no behavior which can be tweaked. Therefore, drop the 'flags' argument. Signed-off-by: Eric Sunshine <sunshine@sunshineco.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-17commit-graph: minimize commit_graph_data_slab accessLibravatar Abhishek Kumar1-4/+8
In an earlier patch, multiple struct acccesses to `graph_pos` and `generation` were auto-converted to multiple method calls. Since the values are fixed and commit-slab access costly, we would be better off with storing the values as a local variable and reusing it. Signed-off-by: Abhishek Kumar <abhishekkumar8222@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-17commit: move members graph_pos, generation to a slabLibravatar Abhishek Kumar1-8/+8
We remove members `graph_pos` and `generation` from the struct commit. The default assignments in init_commit_node() are no longer valid, which is fine as the slab helpers return appropriate default values and the assignments are removed. We will replace existing use of commit->generation and commit->graph_pos by commit_graph_data_slab helpers using `contrib/coccinelle/commit.cocci'. Signed-off-by: Abhishek Kumar <abhishekkumar8222@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-08Merge branch 'ds/line-log-on-bloom'Libravatar Junio C Hamano1-7/+36
"git log -L..." now takes advantage of the "which paths are touched by this commit?" info stored in the commit-graph system. * ds/line-log-on-bloom: line-log: integrate with changed-path Bloom filters line-log: try to use generation number-based topo-ordering line-log: more responsive, incremental 'git log -L' t4211-line-log: add tests for parent oids line-log: remove unused fields from 'struct line_log_data'
2020-06-08diff.h: drop diff_tree_oid() & friends' return valueLibravatar SZEDER Gábor1-6/+3
ll_diff_tree_oid() has only ever returned 0 [1], so it's return value is basically useless. It's only caller diff_tree_oid() has only ever returned the return value of ll_diff_tree_oid() as-is [2], so its return value is just as useless. Most of diff_tree_oid()'s callers simply ignore its return value, except: - diff_root_tree_oid() is a thin wrapper around diff_tree_oid() and returns with its return value, but all of diff_root_tree_oid()'s callers ignore its return value. - rev_compare_tree() and rev_same_tree_as_empty() do look at the return value in a condition, but, since the return value is always 0, the former's < 0 condition is never fulfilled, while the latter's >= 0 condition is always fulfilled. So let's drop the return value of ll_diff_tree_oid(), diff_tree_oid() and diff_root_tree_oid(), and drop those conditions from rev_compare_tree() and rev_same_tree_as_empty() as well. [1] ll_diff_tree_oid() and its ancestors have been returning only 0 ever since it was introduced as diff_tree() in 9174026cfe (Add "diff-tree" program to show which files have changed between two trees., 2005-04-09). [2] diff_tree_oid() traces back to diff-tree.c:main() in 9174026cfe as well. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11line-log: integrate with changed-path Bloom filtersLibravatar Derrick Stolee1-1/+4
The previous changes to the line-log machinery focused on making the first result appear faster. This was achieved by no longer walking the entire commit history before returning the early results. There is still another way to improve the performance: walk most commits much faster. Let's use the changed-path Bloom filters to reduce time spent computing diffs. Since the line-log computation requires opening blobs and checking the content-diff, there is still a lot of necessary computation that cannot be replaced with changed-path Bloom filters. The part that we can reduce is most effective when checking the history of a file that is deep in several directories and those directories are modified frequently. In this case, the computation to check if a commit is TREESAME to its first parent takes a large fraction of the time. That is ripe for improvement with changed-path Bloom filters. We must ensure that prepare_to_use_bloom_filters() is called in revision.c so that the bloom_filter_settings are loaded into the struct rev_info from the commit-graph. Of course, some cases are still forbidden, but in the line-log case the pathspec is provided in a different way than normal. Since multiple paths and segments could be requested, we compute the struct bloom_key data dynamically during the commit walk. This could likely be improved, but adds code complexity that is not valuable at this time. There are two cases to care about: merge commits and "ordinary" commits. Merge commits have multiple parents, but if we are TREESAME to our first parent in every range, then pass the blame for all ranges to the first parent. Ordinary commits have the same condition, but each is done slightly differently in the process_ranges_[merge|ordinary]_commit() methods. By checking if the changed-path Bloom filter can guarantee TREESAME, we can avoid that tree-diff cost. If the filter says "probably changed", then we need to run the tree-diff and then the blob-diff if there was a real edit. The Linux kernel repository is a good testing ground for the performance improvements claimed here. There are two different cases to test. The first is the "entire history" case, where we output the entire history to /dev/null to see how long it would take to compute the full line-log history. The second is the "first result" case, where we find how long it takes to show the first value, which is an indicator of how quickly a user would see responses when waiting at a terminal. To test, I selected the paths that were changed most frequently in the top 10,000 commits using this command (stolen from StackOverflow [1]): git log --pretty=format: --name-only -n 10000 | sort | \ uniq -c | sort -rg | head -10 which results in 121 MAINTAINERS 63 fs/namei.c 60 arch/x86/kvm/cpuid.c 59 fs/io_uring.c 58 arch/x86/kvm/vmx/vmx.c 51 arch/x86/kvm/x86.c 45 arch/x86/kvm/svm.c 42 fs/btrfs/disk-io.c 42 Documentation/scsi/index.rst (along with a bogus first result). It appears that the path arch/x86/kvm/svm.c was renamed, so we ignore that entry. This leaves the following results for the real command time: | | Entire History | First Result | | Path | Before | After | Before | After | |------------------------------|--------|--------|--------|--------| | MAINTAINERS | 4.26 s | 3.87 s | 0.41 s | 0.39 s | | fs/namei.c | 1.99 s | 0.99 s | 0.42 s | 0.21 s | | arch/x86/kvm/cpuid.c | 5.28 s | 1.12 s | 0.16 s | 0.09 s | | fs/io_uring.c | 4.34 s | 0.99 s | 0.94 s | 0.27 s | | arch/x86/kvm/vmx/vmx.c | 5.01 s | 1.34 s | 0.21 s | 0.12 s | | arch/x86/kvm/x86.c | 2.24 s | 1.18 s | 0.21 s | 0.14 s | | fs/btrfs/disk-io.c | 1.82 s | 1.01 s | 0.06 s | 0.05 s | | Documentation/scsi/index.rst | 3.30 s | 0.89 s | 1.46 s | 0.03 s | It is worth noting that the least speedup comes for the MAINTAINERS file which is * edited frequently, * low in the directory heirarchy, and * quite a large file. All of those points lead to spending more time doing the blob diff and less time doing the tree diff. Still, we see some improvement in that case and significant improvement in other cases. A 2-4x speedup is likely the more typical case as opposed to the small 5% change for that file. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11line-log: try to use generation number-based topo-orderingLibravatar SZEDER Gábor1-5/+6
The previous patch made it possible to perform line-level filtering during history traversal instead of in an expensive preprocessing step, but it still requires some simpler preprocessing steps, notably topo-ordering. However, nowadays we have commit-graphs storing generation numbers, which make it possible to incrementally traverse the history in topological order, without the preparatory limit_list() and sort_in_topological_order() steps; see b45424181e (revision.c: generation-based topo-order algorithm, 2018-11-01). This patch combines the two, so we can do both the topo-ordering and the line-level filtering during history traversal, eliminating even those simpler preprocessing steps, and thus further reducing the delay before showing the first commit modifying the given line range. The 'revs->limited' flag plays the central role in this, because, due to limitations of the current implementation, the generation number-based topo-ordering is only enabled when this flag remains unset. Line-level log, however, always sets this flag in setup_revisions() ever since the feature was introduced in 12da1d1f6f (Implement line-history search (git log -L), 2013-03-28). The reason for setting 'limited' is unclear, though, because the line-level log itself doesn't directly depend on it, and it doesn't affect how the limit_list() function limits the revision range. However, there is an indirect dependency: the line-level log requires topo-ordering, and the "traditional" sort_in_topological_order() requires an already limited commit list since e6c3505b44 (Make sure we generate the whole commit list before trying to sort it topologically, 2005-07-06). The new, generation numbers-based topo-ordering doesn't require a limited commit list anymore. So don't set 'revs->limited' for line-level log, unless it is really necessary, namely: - The user explicitly requested parent rewriting, because that is still done in the line_log_filter() preprocessing step (see previous patch), which requires sort_in_topological_order() and in turn limit_list() as well. - A commit-graph file is not available or it doesn't yet contain generation numbers. In these cases we had to fall back on sort_in_topological_order() and in turn limit_list(). The existing condition with generation_numbers_enabled() has already ensured that the 'limited' flag is set in these cases; this patch just makes sure that the line-level log sets 'revs->topo_order' before that condition. While the reduced delay before showing the first commit is measurable in git.git, it takes a bigger repository to make it clearly noticable. In both cases below the line ranges were chosen so that they were modified rather close to the starting revisions, so the effect of this change is most noticable. # git.git $ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0 Before: real 0m0.107s user 0m0.091s sys 0m0.013s After: real 0m0.058s user 0m0.050s sys 0m0.005s # linux.git $ time git --no-pager log \ -L:build_restore_work_registers:arch/mips/mm/tlbex.c -1 v5.2 Before: real 0m1.129s user 0m1.061s sys 0m0.069s After: real 0m0.096s user 0m0.087s sys 0m0.009s Additional testing by Derrick Stolee: Since this patch improves the performance for the first result, I repeated the experiment from the previous patch on the Linux kernel repository, reporting real time here: Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null Before: 0.71 s After: 0.05 s Now, we have dropped the full topo-order of all ~910,000 commits before reporting the first result. The remaining performance improvements then are: 1. Update the parent-rewriting logic to be incremental similar to how "git log --graph" behaves. 2. Use changed-path Bloom filters to reduce the time spend in the tree-diff to see if the path(s) changed. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-11line-log: more responsive, incremental 'git log -L'Libravatar SZEDER Gábor1-1/+26
The current line-level log implementation performs a preprocessing step in prepare_revision_walk(), during which the line_log_filter() function filters and rewrites history to keep only commits modifying the given line range. This preprocessing affects both responsiveness and correctness: - Git doesn't produce any output during this preprocessing step. Checking whether a commit modified the given line range is somewhat expensive, so depending on the size of the given revision range this preprocessing can result in a significant delay before the first commit is shown. - Limiting the number of displayed commits (e.g. 'git log -3 -L...') doesn't limit the amount of work during preprocessing, because that limit is applied during history traversal. Alas, by that point this expensive preprocessing step has already churned through the whole revision range to find all commits modifying the revision range, even though only a few of them need to be shown. - It rewrites parents, with no way to turn it off. Without the user explicitly requesting parent rewriting any parent object ID shown should be that of the immediate parent, just like in case of a pathspec-limited history traversal without parent rewriting. However, after that preprocessing step rewrote history, the subsequent "regular" history traversal (i.e. get_revision() in a loop) only sees commits modifying the given line range. Consequently, it can only show the object ID of the last ancestor that modified the given line range (which might happen to be the immediate parent, but many-many times it isn't). This patch addresses both the correctness and, at least for the common case, the responsiveness issues by integrating line-level log filtering into the regular revision walking machinery: - Make process_ranges_arbitrary_commit(), the static function in 'line-log.c' deciding whether a commit modifies the given line range, public by removing the static keyword and adding the 'line_log_' prefix, so it can be called from other parts of the revision walking machinery. - If the user didn't explicitly ask for parent rewriting (which, I believe, is the most common case): - Call this now-public function during regular history traversal, namely from get_commit_action() to ignore any commits not modifying the given line range. Note that while this check is relatively expensive, it must be performed before other, much cheaper conditions, because the tracked line range must be adjusted even when the commit will end up being ignored by other conditions. - Skip the line_log_filter() call, i.e. the expensive preprocessing step, in prepare_revision_walk(), because, thanks to the above points, the revision walking machinery is now able to filter out commits not modifying the given line range while traversing history. This way the regular history traversal sees the unmodified history, and is therefore able to print the object ids of the immediate parents of the listed commits. The eliminated preprocessing step can greatly reduce the delay before the first commit is shown, see the numbers below. - However, if the user did explicitly ask for parent rewriting via '--parents' or a similar option, then stick with the current implementation for now, i.e. perform that expensive filtering and history rewriting in the preprocessing step just like we did before, leaving the initial delay as long as it was. I tried to integrate line-level log filtering with parent rewriting into the regular history traversal, but, unfortunately, several subtleties resisted... :) Maybe someday we'll figure out how to do that, but until then at least the simple and common (i.e. without parent rewriting) 'git log -L:func:file' commands can benefit from the reduced delay. This change makes the failing 'parent oids without parent rewriting' test in 't4211-line-log.sh' succeed. The reduced delay is most noticable when there's a commit modifying the line range near the tip of a large-ish revision range: # no parent rewriting requested, no commit-graph present $ time git --no-pager log -L:read_alternate_refs:sha1-file.c -1 v2.23.0 Before: real 0m9.570s user 0m9.494s sys 0m0.076s After: real 0m0.718s user 0m0.674s sys 0m0.044s A significant part of the remaining delay is spent reading and parsing commit objects in limit_list(). With the help of the commit-graph we can eliminate most of that reading and parsing overhead, so here are the timing results of the same command as above, but this time using the commit-graph: Before: real 0m8.874s user 0m8.816s sys 0m0.057s After: real 0m0.107s user 0m0.091s sys 0m0.013s The next patch will further reduce the remaining delay. To be clear: this patch doesn't actually optimize the line-level log, but merely moves most of the work from the preprocessing step to the history traversal, so the commits modifying the line range can be shown as soon as they are processed, and the traversal can be terminated as soon as the given number of commits are shown. Consequently, listing the full history of a line range, potentially all the way to the root commit, will take the same time as before (but at least the user might start reading the output earlier). Furthermore, if the most recent commit modifying the line range is far away from the starting revision, then that initial delay will still be significant. Additional testing by Derrick Stolee: In the Linux kernel repository, the MAINTAINERS file was changed ~3,500 times across the ~915,000 commits. In addition to that edit frequency, the file itself is quite large (~18,700 lines). This means that a significant portion of the computation is taken up by computing the patch-diff of the file. This patch improves the real time it takes to output the first result quite a bit: Command: git log -L 100,200:MAINTAINERS -n 1 >/dev/null Before: 3.88 s After: 0.71 s If we drop the "-n 1" in the command, then there is no change in end-to-end process time. This is because the command still needs to walk the entire commit history, which negates the point of this patch. This is expected. As a note for future reference, the ~4.3 seconds in the old code spends ~2.6 seconds computing the patch-diffs, and the rest of the time is spent walking commits and computing diffs for which paths changed at each commit. The changed-path Bloom filters could improve the end-to-end computation time (i.e. no "-n 1" in the command). Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-01Merge branch 'ds/blame-on-bloom'Libravatar Junio C Hamano1-1/+18
"git blame" learns to take advantage of the "changed-paths" Bloom filter stored in the commit-graph file. * ds/blame-on-bloom: test-bloom: check that we have expected arguments test-bloom: fix some whitespace issues blame: drop unused parameter from maybe_changed_path blame: use changed-path Bloom filters tests: write commit-graph with Bloom filters revision: complicated pathspecs disable filters