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2021-09-20Merge branch 'tb/multi-pack-bitmaps'Libravatar Junio C Hamano1-22/+0
The reachability bitmap file used to be generated only for a single pack, but now we've learned to generate bitmaps for history that span across multiple packfiles. * tb/multi-pack-bitmaps: (29 commits) pack-bitmap: drop bitmap_index argument from try_partial_reuse() pack-bitmap: drop repository argument from prepare_midx_bitmap_git() p5326: perf tests for MIDX bitmaps p5310: extract full and partial bitmap tests midx: respect 'GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP' t7700: update to work with MIDX bitmap test knob t5319: don't write MIDX bitmaps in t5319 t5310: disable GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP t0410: disable GIT_TEST_MULTI_PACK_INDEX_WRITE_BITMAP t5326: test multi-pack bitmap behavior t/helper/test-read-midx.c: add --checksum mode t5310: move some tests to lib-bitmap.sh pack-bitmap: write multi-pack bitmaps pack-bitmap: read multi-pack bitmaps pack-bitmap.c: avoid redundant calls to try_partial_reuse pack-bitmap.c: introduce 'bitmap_is_preferred_refname()' pack-bitmap.c: introduce 'nth_bitmap_object_oid()' pack-bitmap.c: introduce 'bitmap_num_objects()' midx: avoid opening multiple MIDXs when writing midx: close linked MIDXs, avoid leaking memory ...
2021-09-01midx: avoid opening multiple MIDXs when writingLibravatar Taylor Blau1-22/+0
Opening multiple instance of the same MIDX can lead to problems like two separate packed_git structures which represent the same pack being added to the repository's object store. The above scenario can happen because prepare_midx_pack() checks if `m->packs[pack_int_id]` is NULL in order to determine if a pack has been opened and installed in the repository before. But a caller can construct two copies of the same MIDX by calling get_multi_pack_index() and load_multi_pack_index() since the former manipulates the object store directly but the latter is a lower-level routine which allocates a new MIDX for each call. So if prepare_midx_pack() is called on multiple MIDXs with the same pack_int_id, then that pack will be installed twice in the object store's packed_git pointer. This can lead to problems in, for e.g., the pack-bitmap code, which does something like the following (in pack-bitmap.c:open_pack_bitmap()): struct bitmap_index *bitmap_git = ...; for (p = get_all_packs(r); p; p = p->next) { if (open_pack_bitmap_1(bitmap_git, p) == 0) ret = 0; } which is a problem if two copies of the same pack exist in the packed_git list because pack-bitmap.c:open_pack_bitmap_1() contains a conditional like the following: if (bitmap_git->pack || bitmap_git->midx) { /* ignore extra bitmap file; we can only handle one */ warning("ignoring extra bitmap file: %s", packfile->pack_name); close(fd); return -1; } Avoid this scenario by not letting write_midx_internal() open a MIDX that isn't also pointed at by the object store. So long as this is the case, other routines should prefer to open MIDXs with get_multi_pack_index() or reprepare_packed_git() instead of creating instances on their own. Because get_multi_pack_index() returns `r->object_store->multi_pack_index` if it is non-NULL, we'll only have one instance of a MIDX open at one time, avoiding these problems. To encourage this, drop the `struct multi_pack_index *` parameter from `write_midx_internal()`, and rely instead on the `object_dir` to find (or initialize) the correct MIDX instance. Likewise, replace the call to `close_midx()` with `close_object_store()`, since we're about to replace the MIDX with a new one and should invalidate the object store's memory of any MIDX that might have existed beforehand. Note that this now forbids passing object directories that don't belong to alternate repositories over `--object-dir`, since before we would have happily opened a MIDX in any directory, but now restrict ourselves to only those reachable by `r->objects->multi_pack_index` (and alternate MIDXs that we can see by walking the `next` pointer). As far as I can tell, supporting arbitrary directories with `--object-dir` was a historical accident, since even the documentation says `<alt>` when referring to the value passed to this option. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-30commit-graph: show "unexpected subcommand" errorLibravatar Ævar Arnfjörð Bjarmason1-0/+1
Bring the "commit-graph" command in line with the error output and general pattern in cmd_multi_pack_index(). Let's test for that output, and also cover the same potential bug as was fixed in the multi-pack-index command in 88617d11f9d (multi-pack-index: fix potential segfault without sub-command, 2021-07-19). Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-30commit-graph: show usage on "commit-graph [write|verify] garbage"Libravatar Ævar Arnfjörð Bjarmason1-0/+4
Change the parse_options() invocation in the commit-graph code to error on unknown leftover argv elements, in addition to the existing and implicit erroring via parse_options() on unknown options. We'd already error in cmd_commit_graph() on e.g.: git commit-graph unknown verify git commit-graph --unknown verify But here we're calling parse_options() twice more for the "write" and "verify" subcommands. We did not do the same checking for leftover argv elements there. As a result we'd silently accept garbage in these subcommands, let's not do that. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-30commit-graph: early exit to "usage" on !argcLibravatar Ævar Arnfjörð Bjarmason1-6/+7
Rather than guarding all of the !argc with an additional "if" arm let's do an early goto to "usage". This also makes it clear that "save_commit_buffer" is not needed in this case. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-30commit-graph: use parse_options_concat()Libravatar Ævar Arnfjörð Bjarmason1-16/+21
Make use of the parse_options_concat() so we don't need to copy/paste common options like --object-dir. This is inspired by a similar change to "checkout" in 2087182272 (checkout: split options[] array in three pieces, 2019-03-29), and the same pattern in the multi-pack-index command, see 60ca94769ce (builtin/multi-pack-index.c: split sub-commands, 2021-03-30). A minor behavior change here is that now we're going to list both --object-dir and --progress first, before we'd list --progress along with other options. Co-authored-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-30commit-graph: remove redundant handling of -hLibravatar Ævar Arnfjörð Bjarmason1-4/+0
If we don't handle the -h option here like most parse_options() users we'll fall through and it'll do the right thing for us. I think this code added in 4ce58ee38d (commit-graph: create git-commit-graph builtin, 2018-04-02) was always redundant, parse_options() did this at the time, and the commit-graph code never used PARSE_OPT_NO_INTERNAL_HELP. We don't need a test for this, it's tested by the t0012-help.sh test added in d691551192a (t0012: test "-h" with builtins, 2017-05-30). Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-30commit-graph: define common usage with a macroLibravatar Ævar Arnfjörð Bjarmason1-14/+17
Share the usage message between these three variables by using a macro. Before this new options needed to copy/paste the usage information, see e.g. 809e0327f5 (builtin/commit-graph.c: introduce '--max-new-filters=<n>', 2020-09-18). See b25b727494f (builtin/multi-pack-index.c: define common usage with a macro, 2021-03-30) for another use of this pattern (but on-list this one came first). Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Reviewed-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-06builtin/*: update usage formatLibravatar ZheNing Hu1-3/+3
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>
2020-09-30assert PARSE_OPT_NONEG in parse-options callbacksLibravatar Jeff King1-0/+2
In the spirit of 517fe807d6 (assert NOARG/NONEG behavior of parse-options callbacks, 2018-11-05), let's cover some parse-options callbacks which expect to be used with PARSE_OPT_NONEG but don't explicitly assert that this is the case. These callbacks are all used correctly in the current code, but this will help document their expectations and future-proof the code. As a bonus, it also silences -Wunused-parameters (these were added since the initial sweep of 517fe807d6, and we can't yet turn on -Wunused-parameters to remind people because it has too many existing false positives). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18commit-graph: introduce 'commitGraph.maxNewFilters'Libravatar Taylor Blau1-0/+14
Introduce a configuration variable to specify a default value for the recently-introduce '--max-new-filters' option of 'git commit-graph write'. Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18builtin/commit-graph.c: introduce '--max-new-filters=<n>'Libravatar Taylor Blau1-2/+25
Introduce a command-line flag to specify the maximum number of new Bloom filters that a 'git commit-graph write' is willing to compute from scratch. Prior to this patch, a commit-graph write with '--changed-paths' would compute Bloom filters for all selected commits which haven't already been computed (i.e., by a previous commit-graph write with '--split' such that a roll-up or replacement is performed). This behavior can cause prohibitively-long commit-graph writes for a variety of reasons: * There may be lots of filters whose diffs take a long time to generate (for example, they have close to the maximum number of changes, diffing itself takes a long time, etc). * Old-style commit-graphs (which encode filters with too many entries as not having been computed at all) cause us to waste time recomputing filters that appear to have not been computed only to discover that they are too-large. This can make the upper-bound of the time it takes for 'git commit-graph write --changed-paths' to be rather unpredictable. To make this command behave more predictably, introduce '--max-new-filters=<n>' to allow computing at most '<n>' Bloom filters from scratch. This lets "computing" already-known filters proceed quickly, while bounding the number of slow tasks that Git is willing to do. Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-17commit-graph: rename 'split_commit_graph_opts'Libravatar Taylor Blau1-10/+10
In the subsequent commit, additional options will be added to the commit-graph API which have nothing to do with splitting. Rename the 'split_commit_graph_opts' structure to the more-generic 'commit_graph_opts' to encompass both. Likewise, rename the 'flags' member to instead be 'split_flags' to clarify that it only has to do with the behavior implied by '--split'. Suggested-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-09commit-graph: pass a 'struct repository *' in more placesLibravatar Taylor Blau1-1/+1
In a future commit, some commit-graph internals will want access to 'r->settings', but we only have the 'struct object_directory *' corresponding to that repository. Add an additional parameter to pass the repository around in more places. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-30Merge branch 'ds/commit-graph-bloom-updates' into masterLibravatar Junio C Hamano1-1/+4
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
2020-07-15Merge branch 'tb/commit-graph-no-check-oids' into masterLibravatar Junio C Hamano1-3/+1
Fix to the code to produce progress bar, which is new in the upcoming release. * tb/commit-graph-no-check-oids: commit-graph: fix "Collecting commits from input" progress line
2020-07-15commit-graph: fix "Collecting commits from input" progress lineLibravatar SZEDER Gábor1-3/+1
To display a progress line while reading commits from standard input and looking them up, 5b6653e523 (builtin/commit-graph.c: dereference tags in builtin, 2020-05-13) should have added a pair of start_delayed_progress() and stop_progress() calls around the loop reading stdin. Alas, the stop_progress() call ended up at the wrong place, after write_commit_graph(), which does all the commit-graph computation and writing, and has several progress lines of its own. Consequently, that new Collecting commits from input: 1234 progress line is overwritten by the first progress line shown by write_commit_graph(), and its final "done" line is shown last, after everything is finished: $ { sleep 3 ; git rev-list -3 HEAD ; sleep 1 ; } | ~/src/git/git commit-graph write --stdin-commits Expanding reachable commits in commit graph: 873402, done. Writing out commit graph in 4 passes: 100% (3493608/3493608), done. Collecting commits from input: 3, done. Furthermore, that stop_progress() call was added after the 'cleanup' label, where that loop reading stdin jumps in case of an error. In case of invalid input this then results in the "done" line shown after the error message: $ { sleep 3 ; git rev-list -3 HEAD ; echo junk ; } | ~/src/git/git commit-graph write --stdin-commits error: unexpected non-hex object ID: junk Collecting commits from input: 3, done. Move that stop_progress() call to the right place. While at it, drop the unnecessary 'if (progress)' condition protecting the stop_progress() call, because that function is prepared to handle a NULL progress struct. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Reviewed-by: Derrick Stolee <stolee@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-07-01commit-graph: persist existence of changed-pathsLibravatar Derrick Stolee1-1/+4
The changed-path Bloom filters were released in v2.27.0, but have a significant drawback. A user can opt-in to writing the changed-path filters using the "--changed-paths" option to "git commit-graph write" but the next write will drop the filters unless that option is specified. This becomes even more important when considering the interaction with gc.writeCommitGraph (on by default) or fetch.writeCommitGraph (part of features.experimental). These config options trigger commit-graph writes that the user did not signal, and hence there is no --changed-paths option available. Allow a user that opts-in to the changed-path filters to persist the property of "my commit-graph has changed-path filters" automatically. A user can drop filters using the --no-changed-paths option. In the process, we need to be extremely careful to match the Bloom filter settings as specified by the commit-graph. This will allow future versions of Git to customize these settings, and the version with this change will persist those settings as commit-graphs are rewritten on top. Use the trace2 API to signal the settings used during the write, and check that output in a test after manually adjusting the correct bytes in the commit-graph file. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-06-17object: drop parsed_object_pool->commit_countLibravatar Abhishek Kumar1-1/+1
14ba97f8 (alloc: allow arbitrary repositories for alloc functions, 2018-05-15) introduced parsed_object_pool->commit_count to keep count of commits per repository and was used to assign commit->index. However, commit-slab code requires commit->index values to be unique and a global count would be correct, rather than a per-repo count. Let's introduce a static counter variable, `parsed_commits_count` to keep track of parsed commits so far. As commit_count has no use anymore, let's also drop it from the struct. Signed-off-by: Abhishek Kumar <abhishekkumar8222@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-18commit-graph: drop COMMIT_GRAPH_WRITE_CHECK_OIDS flagLibravatar Taylor Blau1-7/+8
Since 7c5c9b9c57 (commit-graph: error out on invalid commit oids in 'write --stdin-commits', 2019-08-05), the commit-graph builtin dies on receiving non-commit OIDs as input to '--stdin-commits'. This behavior can be cumbersome to work around in, say, the case of piping 'git for-each-ref' to 'git commit-graph write --stdin-commits' if the caller does not want to cull out non-commits themselves. In this situation, it would be ideal if 'git commit-graph write' wrote the graph containing the inputs that did pertain to commits, and silently ignored the remainder of the input. Some options have been proposed to the effect of '--[no-]check-oids' which would allow callers to have the commit-graph builtin do just that. After some discussion, it is difficult to imagine a caller who wouldn't want to pass '--no-check-oids', suggesting that we should get rid of the behavior of complaining about non-commit inputs altogether. If callers do wish to retain this behavior, they can easily work around this change by doing the following: git for-each-ref --format='%(objectname) %(objecttype) %(*objecttype)' | awk ' !/commit/ { print "not-a-commit:"$1 } /commit/ { print $1 } ' | git commit-graph write --stdin-commits To make it so that valid OIDs that refer to non-existent objects are indeed an error after loosening the error handling, perform an extra lookup to make sure that object indeed exists before sending it to the commit-graph internals. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-18builtin/commit-graph.c: dereference tags in builtinLibravatar Taylor Blau1-3/+21
When given a list of commits, the commit-graph machinery calls 'lookup_commit_reference_gently()' on each element in the set and treats the resulting set of OIDs as the base over which to close for reachability. In an earlier collection of commits, the 'git commit-graph write --reachable' case made the inner-most call to 'lookup_commit_reference_gently()' by peeling references before they were passed over to the commit-graph internals. Do the analog for 'git commit-graph write --stdin-commits' by calling 'lookup_commit_reference_gently()' outside of the commit-graph machinery, making the inner-most call a noop. Since this may incur additional processing time, surround 'read_one_commit' with a progress meter to provide output to the caller. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-18builtin/commit-graph.c: extract 'read_one_commit()'Libravatar Taylor Blau1-29/+29
With either '--stdin-commits' or '--stdin-packs', the commit-graph builtin will read line-delimited input, and interpret it either as a series of commit OIDs, or pack names. In a subsequent commit, we will begin handling '--stdin-commits' differently by processing each line as it comes in, instead of in one shot at the end. To make adequate room for this additional logic, split the '--stdin-commits' case from '--stdin-packs' by only storing the input when '--stdin-packs' is given. In the case of '--stdin-commits', feed each line to a new 'read_one_commit' helper, which (for now) will merely call 'parse_oid_hex'. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-05-01Merge branch 'gs/commit-graph-path-filter'Libravatar Junio C Hamano1-2/+8
Introduce an extension to the commit-graph to make it efficient to check for the paths that were modified at each commit using Bloom filters. * gs/commit-graph-path-filter: bloom: ignore renames when computing changed paths commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag t4216: add end to end tests for git log with Bloom filters revision.c: add trace2 stats around Bloom filter usage revision.c: use Bloom filters to speed up path based revision walks commit-graph: add --changed-paths option to write subcommand commit-graph: reuse existing Bloom filters during write commit-graph: write Bloom filters to commit graph file commit-graph: examine commits by generation number commit-graph: examine changed-path objects in pack order commit-graph: compute Bloom filters for changed paths diff: halt tree-diff early after max_changes bloom.c: core Bloom filter implementation for changed paths. bloom.c: introduce core Bloom filter constructs bloom.c: add the murmur3 hash implementation commit-graph: define and use MAX_NUM_CHUNKS
2020-05-01Merge branch 'tb/commit-graph-split-strategy'Libravatar Junio C Hamano1-7/+45
"git commit-graph write" learned different ways to write out split files. * tb/commit-graph-split-strategy: Revert "commit-graph.c: introduce '--[no-]check-oids'" commit-graph.c: introduce '--[no-]check-oids' commit-graph.h: replace 'commit_hex' with 'commits' oidset: introduce 'oidset_size' builtin/commit-graph.c: introduce split strategy 'replace' builtin/commit-graph.c: introduce split strategy 'no-merge' builtin/commit-graph.c: support for '--split[=<strategy>]' t/helper/test-read-graph.c: support commit-graph chains
2020-04-29Revert "commit-graph.c: introduce '--[no-]check-oids'"Libravatar Junio C Hamano1-8/+3
This reverts commit 7a9ce0269bc0f4ef230f930b3910b70ac3142552, which has not yet gained consensus.
2020-04-28Merge branch 'ds/commit-graph-expiry-fix'Libravatar Junio C Hamano1-1/+1
"git commit-graph write --expire-time=<timestamp>" did not use the given timestamp correctly, which has been corrected. * ds/commit-graph-expiry-fix: commit-graph: fix buggy --expire-time option
2020-04-15commit-graph.c: introduce '--[no-]check-oids'Libravatar Taylor Blau1-3/+8
When operating on a stream of commit OIDs on stdin, 'git commit-graph write' checks that each OID refers to an object that is indeed a commit. This is convenient to make sure that the given input is well-formed, but can sometimes be undesirable. For example, server operators may wish to feed the refnames that were updated during a push to 'git commit-graph write --input=stdin-commits', and silently discard refs that don't point at commits. This can be done by combing the output of 'git for-each-ref' with '--format %(*objecttype)', but this requires opening up a potentially large number of objects. Instead, it is more convenient to feed the updated refs to the commit-graph machinery, and let it throw out refs that don't point to commits. Introduce '--[no-]check-oids' to make such a behavior possible. With '--check-oids' (the default behavior to retain backwards compatibility), 'git commit-graph write' will barf on a non-commit line in its input. With 'no-check-oids', such lines will be silently ignored, making the above possible by specifying this option. No matter which is supplied, 'git commit-graph write' retains the behavior from the previous commit of rejecting non-OID inputs like "HEAD" and "refs/heads/foo" as before. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-15commit-graph.h: replace 'commit_hex' with 'commits'Libravatar Taylor Blau1-3/+16
The 'write_commit_graph()' function takes in either a string list of pack indices, or a string list of hexadecimal commit OIDs. These correspond to the '--stdin-packs' and '--stdin-commits' mode(s) from 'git commit-graph write'. Using a string_list of hexadecimal commit IDs is not the most efficient use of memory, since we can instead use the 'struct oidset', which is more well-suited for this case. This has another benefit which will become apparent in the following commit. This is that we are about to disambiguate the kinds of errors we produce with '--stdin-commits' into "non-hex input" and "hex-input, but referring to a non-commit object". By having 'write_commit_graph' take in a 'struct oidset *' of commits, we place the burden on the caller (in this case, the builtin) to handle the first case, and the commit-graph machinery can handle the second case. Suggested-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-15builtin/commit-graph.c: introduce split strategy 'replace'Libravatar Taylor Blau1-0/+2
When using split commit-graphs, it is sometimes useful to completely replace the commit-graph chain with a new base. For example, consider a scenario in which a repository builds a new commit-graph incremental for each push. Occasionally (say, after some fixed number of pushes), they may wish to rebuild the commit-graph chain with all reachable commits. They can do so with $ git commit-graph write --reachable but this removes the chain entirely and replaces it with a single commit-graph in 'objects/info/commit-graph'. Unfortunately, this means that the next push will have to move this commit-graph into the first layer of a new chain, and then write its new commits on top. Avoid such copying entirely by allowing the caller to specify that they wish to replace the entirety of their commit-graph chain, while also specifying that the new commit-graph should become the basis of a fresh, length-one chain. This addresses the above situation by making it possible for the caller to instead write: $ git commit-graph write --reachable --split=replace which writes a new length-one chain to 'objects/info/commit-graphs', making the commit-graph incremental generated by the subsequent push relatively cheap by avoiding the aforementioned copy. In order to do this, remove an assumption in 'write_commit_graph_file' that chains are always at least two incrementals long. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-15builtin/commit-graph.c: introduce split strategy 'no-merge'Libravatar Taylor Blau1-1/+6
In the previous commit, we laid the groundwork for supporting different splitting strategies. In this commit, we introduce the first splitting strategy: 'no-merge'. Passing '--split=no-merge' is useful for callers which wish to write a new incremental commit-graph, but do not want to spend effort condensing the incremental chain [1]. Previously, this was possible by passing '--size-multiple=0', but this no longer the case following 63020f175f (commit-graph: prefer default size_mult when given zero, 2020-01-02). When '--split=no-merge' is given, the commit-graph machinery will never condense an existing chain, and it will always write a new incremental. [1]: This might occur when, for example, a server administrator running some program after each push may want to ensure that each job runs proportional in time to the size of the push, and does not "jump" when the commit-graph machinery decides to trigger a merge. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-15builtin/commit-graph.c: support for '--split[=<strategy>]'Libravatar Taylor Blau1-4/+22
With '--split', the commit-graph machinery writes new commits in another incremental commit-graph which is part of the existing chain, and optionally decides to condense the chain into a single commit-graph. This is done to ensure that the asymptotic behavior of looking up a commit in an incremental chain is not dominated by the number of incrementals in that chain. It can be controlled by the '--max-commits' and '--size-multiple' options. In the next two commits, we will introduce additional splitting strategies that can exert additional control over: - when a split commit-graph is and isn't written, and - when the existing commit-graph chain is discarded completely and replaced with another graph To prepare for this, make '--split' take an optional strategy (as in '--split[=<strategy>]'), and add a new enum to describe which strategy is being used. For now, no strategies are given, and the only enumerated value is 'COMMIT_GRAPH_SPLIT_UNSPECIFIED', indicating the absence of a strategy. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flagLibravatar Garima Singh1-1/+2
Add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag to the test setup suite in order to toggle writing Bloom filters when running any of the git tests. If set to true, we will compute and write Bloom filters every time a test calls `git commit-graph write`, as if the `--changed-paths` option was passed in. The test suite passes when GIT_TEST_COMMIT_GRAPH and GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS are enabled. Helped-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-06commit-graph: add --changed-paths option to write subcommandLibravatar Garima Singh1-2/+7
Add --changed-paths option to git commit-graph write. This option will allow users to compute information about the paths that have changed between a commit and its first parent, and write it into the commit graph file. If the option is passed to the write subcommand we set the COMMIT_GRAPH_WRITE_BLOOM_FILTERS flag and pass it down to the commit-graph logic. Helped-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-01commit-graph: fix buggy --expire-time optionLibravatar Derrick Stolee1-1/+1
The commit-graph builtin has an --expire-time option that takes a datetime using OPT_EXPIRY_DATE(). However, the implementation inside expire_commit_graphs() was treating a non-zero value as a number of seconds to subtract from "now". Update t5323-split-commit-graph.sh to demonstrate the correct value of the --expire-time option by actually creating a crud .graph file with mtime earlier than the expire time. Instead of using a super- early time (1980) we use an explicit, and recent, time. Using test-tool chmtime to create two files on either end of an exact second, we create a test that catches this failure no matter the current time. Using a fixed date is more portable than trying to format a relative date string into the --expiry-date input. I noticed this when inspecting some Scalar repos that had an excess number of commit-graph files. In Scalar, we were using this second interpretation by using "--expire-time=3600" to mean "delete graphs older than one hour ago" to avoid deleting a commit-graph that a foreground process may be trying to load. Also I noticed that the help text was copied from the --max-commits option. Fix that help text. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-10real_path: remove unsafe APILibravatar Alexandr Miloslavskiy1-1/+4
Returning a shared buffer invites very subtle bugs due to reentrancy or multi-threading, as demonstrated by the previous patch. There was an unfinished effort to abolish this [1]. Let's finally rid of `real_path()`, using `strbuf_realpath()` instead. This patch uses a local `strbuf` for most places where `real_path()` was previously called. However, two places return the value of `real_path()` to the caller. For them, a `static` local `strbuf` was added, effectively pushing the problem one level higher: read_gitfile_gently() get_superproject_working_tree() [1] https://lore.kernel.org/git/1480964316-99305-1-git-send-email-bmwill@google.com/ Signed-off-by: Alexandr Miloslavskiy <alexandr.miloslavskiy@syntevo.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04commit-graph.h: use odb in 'load_commit_graph_one_fd_st'Libravatar Taylor Blau1-1/+1
Apply a similar treatment as in the previous patch to pass a 'struct object_directory *' through the 'load_commit_graph_one_fd_st' initializer, too. This prevents a potential bug where a pointer comparison is made to a NULL 'g->odb', which would cause the commit-graph machinery to think that a pair of commit-graphs belonged to different alternates when in fact they do not (i.e., in the case of no '--object-dir'). Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04commit-graph.c: remove path normalization, comparisonLibravatar Taylor Blau1-1/+1
As of the previous patch, all calls to 'commit-graph.c' functions which perform path normalization (for e.g., 'get_commit_graph_filename()') are of the form 'ctx->odb->path', which is always in normalized form. Now that there are no callers passing non-normalized paths to these functions, ensure that future callers are bound by the same restrictions by making these functions take a 'struct object_directory *' instead of a 'const char *'. To match, replace all calls with arguments of the form 'ctx->odb->path' with 'ctx->odb' To recover the path, functions that perform path manipulation simply use 'odb->path'. Further, avoid string comparisons with arguments of the form 'odb->path', and instead prefer raw pointer comparisons, which accomplish the same effect, but are far less brittle. This has a pleasant side-effect of making these functions much more robust to paths that cannot be normalized by 'normalize_path_copy()', i.e., because they are outside of the current working directory. For example, prior to this patch, Valgrind reports that the following uninitialized memory read [1]: $ ( cd t && GIT_DIR=../.git valgrind git rev-parse HEAD^ ) because 'normalize_path_copy()' can't normalize '../.git' (since it's relative to but above of the current working directory) [2]. By using a 'struct object_directory *' directly, 'get_commit_graph_filename()' does not need to normalize, because all paths are relative to the current working directory since they are always read from the '->path' of an object directory. [1]: https://lore.kernel.org/git/20191027042116.GA5801@sigill.intra.peff.net. [2]: The bug here is that 'get_commit_graph_filename()' returns the result of 'normalize_path_copy()' without checking the return value. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04commit-graph.h: store object directory in 'struct commit_graph'Libravatar Taylor Blau1-1/+1
In a previous patch, the 'char *object_dir' in 'struct commit_graph' was replaced with a 'struct object_directory'. This patch applies the same treatment to 'struct commit_graph', which is another intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Instead of taking a 'char *object_dir', functions that construct a 'struct commit_graph' now take a 'struct object_directory *'. Any code that needs an object directory path use '->path' instead. This ensures that all calls to functions that perform path normalization are given arguments which do not themselves require normalization. This prepares those functions to drop their normalization entirely, which will occur in the subsequent patch. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-02-04commit-graph.h: store an odb in 'struct write_commit_graph_context'Libravatar Taylor Blau1-5/+28
There are lots of places in 'commit-graph.h' where a function either has (or almost has) a full 'struct object_directory *', accesses '->path', and then throws away the rest of the struct. This can cause headaches when comparing the locations of object directories across alternates (e.g., in the case of deciding if two commit-graph layers can be merged). These paths are normalized with 'normalize_path_copy()' which mitigates some comparison issues, but not all [1]. Replace usage of 'char *object_dir' with 'odb->path' by storing a 'struct object_directory *' in the 'write_commit_graph_context' structure. This is an intermediate step towards getting rid of all path normalization in 'commit-graph.c'. Resolving a user-provided '--object-dir' argument now requires that we compare it to the known alternates for equality. Prior to this patch, an unknown '--object-dir' argument would silently exit with status zero. This can clearly lead to unintended behavior, such as verifying commit-graphs that aren't in a repository's own object store (or one of its alternates), or causing a typo to mask a legitimate commit-graph verification failure. Make this error non-silent by 'die()'-ing when the given '--object-dir' does not match any known alternate object store. [1]: In my testing, for example, I can get one side of the commit-graph code to fill object_dir with "./objects" and the other with just "objects". Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-13test-tool: use 'read-graph' helperLibravatar Derrick Stolee1-68/+0
The 'git commit-graph read' subcommand is used in test scripts to check that the commit-graph contents match the expected data. Mostly, this helps check the header information and the list of chunks. Users do not need this information, so move the functionality to a test helper. Reported-by: Bryan Turner <bturner@atlassian.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-10Merge branch 'sg/commit-graph-usage-fix'Libravatar Junio C Hamano1-1/+0
Message fix. * sg/commit-graph-usage-fix: builtin/commit-graph.c: remove subcommand-less usage string
2019-10-28builtin/commit-graph.c: remove subcommand-less usage stringLibravatar SZEDER Gábor1-1/+0
The first line in 'git commit-graph's usage string indicates that this command can be invoked without specifying a subcommand. However, this is not the case: $ git commit-graph usage: git commit-graph [--object-dir <objdir>] or: git commit-graph read [--object-dir <objdir>] [...] $ echo $? 129 Remove this line from the usage string. The synopsis in the manpage doesn't contain this line. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-15Merge branch 'gs/commit-graph-trace-with-cmd'Libravatar Junio C Hamano1-0/+6
Dev support. * gs/commit-graph-trace-with-cmd: commit-graph: emit trace2 cmd_mode for each sub-command
2019-10-07Merge branch 'gs/commit-graph-progress'Libravatar Junio C Hamano1-5/+14
* gs/commit-graph-progress: commit-graph: add --[no-]progress to write and verify
2019-10-07Merge branch 'jk/commit-graph-cleanup'Libravatar Junio C Hamano1-0/+2
A pair of small fixups to "git commit-graph" have been applied. * jk/commit-graph-cleanup: commit-graph: turn off save_commit_buffer commit-graph: don't show progress percentages while expanding reachable commits
2019-10-02commit-graph: emit trace2 cmd_mode for each sub-commandLibravatar Garima Singh1-0/+6
Emit trace2_cmd_mode() messages for each commit-graph sub-command. The commit graph commands were in flux when trace2 was making it's way to git. Now that we have enough sub-commands in commit-graph, we can label the various modes within them. Distinguishing between read, write and verify is a great start. Signed-off-by: Garima Singh <garima.singh@microsoft.com> Acked-by: Jeff Hostetler <jeffhost@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-18commit-graph: add --[no-]progress to write and verifyLibravatar Garima Singh1-5/+14
Add --[no-]progress to git commit-graph write and verify. The progress feature was introduced in 7b0f229 ("commit-graph write: add progress output", 2018-09-17) but the ability to opt-out was overlooked. Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-09-09commit-graph: turn off save_commit_bufferLibravatar Jeff King1-0/+2
The commit-graph tool may read a lot of commits, but it only cares about parsing their metadata (parents, trees, etc) and doesn't ever show the messages to the user. And so it should not need save_commit_buffer, which is meant for holding onto the object data of parsed commits so that we can show them later. In fact, it's quite harmful to do so. According to massif, the max heap of "git commit-graph write --reachable" in linux.git before/after this patch (removing the commit graph file in between) goes from ~1.1GB to ~270MB. Which isn't surprising, since the difference is about the sum of the uncompressed sizes of all commits in the repository, and this was equivalent to leaking them. This obviously helps if you're under memory pressure, but even without it, things go faster. My before/after times for that command (without massif) went from 12.521s to 11.874s, a speedup of ~5%. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-05commit-graph: error out on invalid commit oids in 'write --stdin-commits'Libravatar SZEDER Gábor1-1/+3
While 'git commit-graph write --stdin-commits' expects commit object ids as input, it accepts and silently skips over any invalid commit object ids, and still exits with success: # nonsense $ echo not-a-commit-oid | git commit-graph write --stdin-commits $ echo $? 0 # sometimes I forgot that refs are not good... $ echo HEAD | git commit-graph write --stdin-commits $ echo $? 0 # valid tree OID, but not a commit OID $ git rev-parse HEAD^{tree} | git commit-graph write --stdin-commits $ echo $? 0 $ ls -l .git/objects/info/commit-graph ls: cannot access '.git/objects/info/commit-graph': No such file or directory Check that all input records are indeed valid commit object ids and return with error otherwise, the same way '--stdin-packs' handles invalid input; see e103f7276f (commit-graph: return with errors during write, 2019-06-12). Note that it should only return with error when encountering an invalid commit object id coming from standard input. However, '--reachable' uses the same code path to process object ids pointed to by all refs, and that includes tag object ids as well, which should still be skipped over. Therefore add a new flag to 'enum commit_graph_write_flags' and a corresponding field to 'struct write_commit_graph_context', so we can differentiate between those two cases. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-05commit-graph: turn a group of write-related macro flags into an enumLibravatar SZEDER Gábor1-3/+3
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Acked-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>