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2020-05-13Merge branch 'tb/shallow-cleanup'Libravatar Junio C Hamano1-0/+1
Code cleanup. * tb/shallow-cleanup: shallow: use struct 'shallow_lock' for additional safety shallow.h: document '{commit,rollback}_shallow_file' shallow: extract a header file for shallow-related functions commit: make 'commit_graft_pos' non-static
2020-05-08Merge branch 'jt/commit-graph-plug-memleak'Libravatar Junio C Hamano1-11/+11
Fix a leak noticed by fuzzer. * jt/commit-graph-plug-memleak: commit-graph: avoid memory leaks
2020-05-05Merge branch 'tb/commit-graph-perm-bits'Libravatar Junio C Hamano1-2/+10
Some of the files commit-graph subsystem keeps on disk did not correctly honor the core.sharedRepository settings and some were left read-write. * tb/commit-graph-perm-bits: commit-graph.c: make 'commit-graph-chain's read-only commit-graph.c: ensure graph layers respect core.sharedRepository commit-graph.c: write non-split graphs as read-only lockfile.c: introduce 'hold_lock_file_for_update_mode' tempfile.c: introduce 'create_tempfile_mode'
2020-05-04commit-graph: avoid memory leaksLibravatar Jonathan Tan1-11/+11
A fuzzer running on the entry point provided by fuzz-commit-graph.c revealed a memory leak when parse_commit_graph() creates a struct bloom_filter_settings and then returns early due to error. Fix that error by always freeing that struct first (if it exists) before returning early due to error. While making that change, I also noticed another possible memory leak - when the BLOOMDATA chunk is provided but not BLOOMINDEXES. Also fix that error. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Reviewed-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 Hamano1-0/+14
"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
2020-05-01Merge branch 'gs/commit-graph-path-filter'Libravatar Junio C Hamano1-6/+207
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-fd-exhaustion-fix'Libravatar Junio C Hamano1-13/+8
The commit-graph code exhausted file descriptors easily when it does not have to. * tb/commit-graph-fd-exhaustion-fix: commit-graph: close descriptors after mmap commit-graph.c: gracefully handle file descriptor exhaustion t/test-lib.sh: make ULIMIT_FILE_DESCRIPTORS available to tests commit-graph.c: don't use discarded graph_name in error
2020-05-01Merge branch 'tb/commit-graph-split-strategy'Libravatar Junio C Hamano1-47/+84
"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
2020-04-30shallow: extract a header file for shallow-related functionsLibravatar Taylor Blau1-0/+1
There are many functions in commit.h that are more related to shallow repositories than they are to any sort of generic commit machinery. Likely this began when there were only a few shallow-related functions, and commit.h seemed a reasonable enough place to put them. But, now there are a good number of shallow-related functions, and placing them all in 'commit.h' doesn't make sense. This patch extracts a 'shallow.h', which takes all of the declarations from 'commit.h' for functions which already exist in 'shallow.c'. We will bring the remaining shallow-related functions defined in 'commit.c' in a subsequent patch. For now, move only the ones that already are implemented in 'shallow.c', and update the necessary includes. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-29Revert "commit-graph.c: introduce '--[no-]check-oids'"Libravatar Junio C Hamano1-1/+1
This reverts commit 7a9ce0269bc0f4ef230f930b3910b70ac3142552, which has not yet gained consensus.
2020-04-29commit-graph.c: make 'commit-graph-chain's read-onlyLibravatar Taylor Blau1-1/+2
In a previous commit, we made incremental graph layers read-only by using 'git_mkstemp_mode' with permissions '0444'. There is no reason that 'commit-graph-chain's should be modifiable by the user, since they are generated at a temporary location and then atomically renamed into place. To ensure that these files are read-only, too, use 'hold_lock_file_for_update_mode' with the same read-only permission bits, and let the umask and 'adjust_shared_perm' take care of the rest. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-29commit-graph.c: ensure graph layers respect core.sharedRepositoryLibravatar Taylor Blau1-0/+6
Non-layered commit-graphs use 'adjust_shared_perm' to make the commit-graph file readable (or not) to a combination of the user, group, and others. Call 'adjust_shared_perm' for split-graph layers to make sure that these also respect 'core.sharedRepository'. The 'commit-graph-chain' file already respects this configuration since it uses 'hold_lock_file_for_update' (which calls 'adjust_shared_perm' eventually in 'create_tempfile_mode'). Suggested-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-29commit-graph.c: write non-split graphs as read-onlyLibravatar Taylor Blau1-1/+2
In the previous commit, Git learned 'hold_lock_file_for_update_mode' to allow the caller to specify the permission bits (prior to further adjustment by the umask and shared repository permissions) used when acquiring a temporary file. Use this in the commit-graph machinery for writing a non-split graph to acquire an opened temporary file with permissions read-only permissions to match the split behavior. (In the split case, Git uses git_mkstemp_mode' for each of the commit-graph layers with permission bits '0444'). One can notice this discrepancy when moving a non-split graph to be part of a new chain. This causes a commit-graph chain where all layers have read-only permission bits, except for the base layer, which is writable for the current user. Resolve this discrepancy by using the new 'hold_lock_file_for_update_mode' and passing the desired permission bits. Doing so causes some test fallout in t5318 and t6600. In t5318, this occurs in tests that corrupt a commit-graph file by writing into it. For these, 'chmod u+w'-ing the file beforehand resolves the issue. The additional spot in 'corrupt_graph_verify' is necessary because of the extra 'git commit-graph write' beforehand (which *does* rewrite the commit-graph file). In t6600, this is caused by copying a read-only commit-graph file into place and then trying to replace it. For these, make these files writable. 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>
2020-04-28Merge 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
2020-04-24commit-graph: close descriptors after mmapLibravatar Jeff King1-10/+5
We don't ever refer to the descriptor after mmap-ing it. And keeping it open means we can run out of descriptors in degenerate cases (e.g., thousands of split chain files). Let's close it as soon as possible. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-23commit-graph.c: gracefully handle file descriptor exhaustionLibravatar Taylor Blau1-2/+2
When writing a layered commit-graph, the commit-graph machinery uses 'commit_graph_filenames_after' and 'commit_graph_hash_after' to keep track of the layers in the chain that we are in the process of writing. When the number of commit-graph layers shrinks, we initialize all entries in the aforementioned arrays, because we know the structure of the new commit-graph chain immediately (since there are no new layers, there are no unknown hash values). But when the number of commit-graph layers grows (i.e., that 'num_commit_graphs_after > num_commit_graphs_before'), then we leave some entries in the filenames and hashes arrays as uninitialized, because we will fill them in later as those values become available. For instance, we rely on 'write_commit_graph_file's to store the filename and hash of the last layer in the new chain, which is the one that it is responsible for writing. But, it's possible that 'write_commit_graph_file' may fail, e.g., from file descriptor exhaustion. In this case it is possible that 'git_mkstemp_mode' will fail, and that function will return early *before* setting the values for the last commit-graph layer's filename and hash. This causes a number of upleasant side-effects. For instance, trying to 'free()' each entry in 'ctx->commit_graph_filenames_after' (and similarly for the hashes array) causes us to 'free()' uninitialized memory, since the area is allocated with 'malloc()' and is therefore subject to contain garbage (which is left alone when 'write_commit_graph_file' returns early). This can manifest in other issues, like a general protection fault, and/or leaving a stray 'commit-graph-chain.lock' around after the process dies. (The reasoning for this is still a mystery to me, since we'd otherwise usually expect the kernel to run tempfile.c's 'atexit()' handlers in the case of a normal death...) To resolve this, initialize the memory with 'CALLOC_ARRAY' so that uninitialized entries are filled with zeros, and can thus be 'free()'d as a noop instead of causing a fault. Helped-by: Jeff King <peff@peff.net> Helped-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-23commit-graph.c: don't use discarded graph_name in errorLibravatar Taylor Blau1-1/+1
When writing a commit-graph layer, we do so in a temporary file which is renamed into place. If we fail to create a temporary file, for e.g., because we have too many open files, then 'git_mkstemp_mode' sets the pattern to the empty string, in which case we get an error something along the lines of: error: unable to create '' It's not useful to show the pattern here at all, since we (1) know the pattern is well-formed, and (2) would have already shown the dirname when trying to create the leading directories. So, replace this error with something friendlier. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-16tests: write commit-graph with Bloom filtersLibravatar Derrick Stolee1-0/+14
The GIT_TEST_COMMIT_GRAPH environment variable updates the commit- graph file whenever "git commit" is run, ensuring that we always have an updated commit-graph throughout the test suite. The GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS environment variable was introduced to write the changed-path Bloom filters whenever "git commit-graph write" is run. However, the GIT_TEST_COMMIT_GRAPH trick doesn't launch a separate process and instead writes it directly. To expand the number of tests that have commits in the commit-graph file, add a helper method that computes the commit-graph and place that helper inside "git commit" and "git merge". In the helper method, check GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS to ensure we are writing changed-path Bloom filters whenever possible. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-04-15commit-graph.c: introduce '--[no-]check-oids'Libravatar Taylor Blau1-1/+1
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 Blau1-26/+33
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 Blau1-14/+39
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 Blau1-7/+12
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>
2020-04-06commit-graph: reuse existing Bloom filters during writeLibravatar Garima Singh1-3/+3
Add logic to a) parse Bloom filter information from the commit graph file and, b) re-use existing Bloom filters. See Documentation/technical/commit-graph-format for the format in which the Bloom filter information is written to the commit graph file. To read Bloom filter for a given commit with lexicographic position 'i' we need to: 1. Read BIDX[i] which essentially gives us the starting index in BDAT for filter of commit i+1. It is essentially the index past the end of the filter of commit i. It is called end_index in the code. 2. For i>0, read BIDX[i-1] which will give us the starting index in BDAT for filter of commit i. It is called the start_index in the code. For the first commit, where i = 0, Bloom filter data starts at the beginning, just past the header in the BDAT chunk. Hence, start_index will be 0. 3. The length of the filter will be end_index - start_index, because BIDX[i] gives the cumulative 8-byte words including the ith commit's filter. We toggle whether Bloom filters should be recomputed based on the compute_if_not_present flag. 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: write Bloom filters to commit graph fileLibravatar Garima Singh1-1/+112
Update the technical documentation for commit-graph-format with the formats for the Bloom filter index (BIDX) and Bloom filter data (BDAT) chunks. Write the computed Bloom filters information to the commit graph file using this format. 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>
2020-03-30commit-graph: examine commits by generation numberLibravatar Garima Singh1-3/+30
When running 'git commit-graph write --changed-paths', we sort the commits by pack-order to save time when computing the changed-paths bloom filters. This does not help when finding the commits via the '--reachable' flag. If not using pack-order, then sort by generation number before examining the diff. Commits with similar generation are more likely to have many trees in common, making the diff faster. On the Linux kernel repository, this change reduced the computation time for 'git commit-graph write --reachable --changed-paths' from 3m00s to 1m37s. Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-30commit-graph: examine changed-path objects in pack orderLibravatar Jeff King1-3/+35
Looking at the diff of commit objects in pack order is much faster than in sha1 order, as it gives locality to the access of tree deltas (whereas sha1 order is effectively random). Unfortunately the commit-graph code sorts the commits (several times, sometimes as an oid and sometimes a pointer-to-commit), and we ultimately traverse in sha1 order. Instead, let's remember the position at which we see each commit, and traverse in that order when looking at bloom filters. This drops my time for "git commit-graph write --changed-paths" in linux.git from ~4 minutes to ~1.5 minutes. Probably the "--reachable" code path would want something similar. Or alternatively, we could use a different data structure (either a hash, or maybe even just a bit in "struct commit") to keep track of which oids we've seen, etc instead of sorting. And then we could keep the original order. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-30commit-graph: compute Bloom filters for changed pathsLibravatar Garima Singh1-1/+31
Add new COMMIT_GRAPH_WRITE_CHANGED_PATHS flag that makes Git compute Bloom filters for the paths that changed between a commit and it's first parent, for each commit in the commit-graph. This computation is done on a commit-by-commit basis. We will write these Bloom filters to the commit-graph file, to store this data on disk, in the next change in this series. 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>
2020-03-30commit-graph: define and use MAX_NUM_CHUNKSLibravatar Garima Singh1-2/+3
This is a minor cleanup to make it easier to change the number of chunks being written to the commit graph. Reviewed-by: Jakub Narębski <jnareb@gmail.com> Signed-off-by: Garima Singh <garima.singh@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-03-05Merge branch 'rs/commit-graph-code-simplification'Libravatar Junio C Hamano1-6/+2
Code simplfication. * rs/commit-graph-code-simplification: commit-graph: use progress title directly
2020-02-27commit-graph: use progress title directlyLibravatar René Scharfe1-6/+2
merge_commit_graphs() copies the (translated) progress message into a strbuf and passes the copy to start_delayed_progress() at each loop iteration. The latter function takes a string pointer, so let's avoid the detour and hand the string to it directly. That's shorter, simpler and slightly more efficient. Signed-off-by: René Scharfe <l.s.r@web.de> Acked-by: Derrick Stolee <dstolee@microsoft.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 Blau1-11/+10
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 Blau1-28/+19
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 Blau1-17/+21
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 Blau1-25/+16
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>
2020-01-06Merge branch 'ds/commit-graph-set-size-mult'Libravatar Junio C Hamano1-1/+3
The code to write split commit-graph file(s) upon fetching computed bogus value for the parameter used in splitting the resulting files, which has been corrected. * ds/commit-graph-set-size-mult: commit-graph: prefer default size_mult when given zero
2020-01-02commit-graph: prefer default size_mult when given zeroLibravatar Derrick Stolee1-1/+3
In 50f26bd ("fetch: add fetch.writeCommitGraph config setting", 2019-09-02), the fetch builtin added the capability to write a commit-graph using the "--split" feature. This feature creates multiple commit-graph files, and those can merge based on a set of "split options" including a size multiple. The default size multiple is 2, which intends to provide a log_2 N depth of the commit-graph chain where N is the number of commits. However, I noticed during dogfooding that my commit-graph chains were becoming quite large when left only to builds by 'git fetch'. It turns out that in split_graph_merge_strategy(), we default the size_mult variable to 2 except we override it with the context's split_opts if they exist. In builtin/fetch.c, we create such a split_opts, but do not populate it with values. This problem is due to two failures: 1. It is unclear that we can add the flag COMMIT_GRAPH_WRITE_SPLIT with a NULL split_opts. 2. If we have a non-NULL split_opts, then we override the default values even if a zero value is given. Correct both of these issues. First, do not override size_mult when the options provide a zero value. Second, stop creating a split_opts in the fetch builtin. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-12-10Merge branch 'ds/commit-graph-delay-gen-progress'Libravatar Junio C Hamano1-1/+1
One kind of progress messages were always given during commit-graph generation, instead of following the "if it takes more than two seconds, show progress" pattern, which has been corrected. * ds/commit-graph-delay-gen-progress: commit-graph: use start_delayed_progress() progress: create GIT_PROGRESS_DELAY
2019-12-01Merge branch 'en/doc-typofix'Libravatar Junio C Hamano1-1/+1
Docfix. * en/doc-typofix: Fix spelling errors in no-longer-updated-from-upstream modules multimail: fix a few simple spelling errors sha1dc: fix trivial comment spelling error Fix spelling errors in test commands Fix spelling errors in messages shown to users Fix spelling errors in names of tests Fix spelling errors in comments of testcases Fix spelling errors in code comments Fix spelling errors in documentation outside of Documentation/ Documentation: fix a bunch of typos, both old and new
2019-12-01Merge branch 'jk/cleanup-object-parsing-and-fsck'Libravatar Junio C Hamano1-3/+0
Crufty code and logic accumulated over time around the object parsing and low-level object access used in "git fsck" have been cleaned up. * jk/cleanup-object-parsing-and-fsck: (23 commits) fsck: accept an oid instead of a "struct tree" for fsck_tree() fsck: accept an oid instead of a "struct commit" for fsck_commit() fsck: accept an oid instead of a "struct tag" for fsck_tag() fsck: rename vague "oid" local variables fsck: don't require an object struct in verify_headers() fsck: don't require an object struct for fsck_ident() fsck: drop blob struct from fsck_finish() fsck: accept an oid instead of a "struct blob" for fsck_blob() fsck: don't require an object struct for report() fsck: only require an oid for skiplist functions fsck: only provide oid/type in fsck_error callback fsck: don't require object structs for display functions fsck: use oids rather than objects for object_name API fsck_describe_object(): build on our get_object_name() primitive fsck: unify object-name code fsck: require an actual buffer for non-blobs fsck: stop checking tag->tagged fsck: stop checking commit->parent counts fsck: stop checking commit->tree value commit, tag: don't set parsed bit for parse failures ...
2019-11-27commit-graph: use start_delayed_progress()Libravatar Derrick Stolee1-1/+1
When writing a commit-graph, we show progress along several commit walks. When we use start_delayed_progress(), the progress line will only appear if that step takes a decent amount of time. However, one place was missed: computing generation numbers. This is normally a very fast operation as all commits have been parsed in a previous step. But, this is showing up for all users no matter how few commits are being added. The tests that check for the progress output have already been updated to use GIT_PROGRESS_DELAY=0 to force the expected output. Helped-by: Jeff King <peff@peff.net> Reported-by: ryenus <ryenus@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-10Fix spelling errors in code commentsLibravatar Elijah Newren1-1/+1
Reported-by: Jens Schleusener <Jens.Schleusener@fossies.org> Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-11-04Merge branch 'ds/commit-graph-on-fetch'Libravatar Junio C Hamano1-4/+7
Regression fix. * ds/commit-graph-on-fetch: commit-graph: fix writing first commit-graph during fetch t5510-fetch.sh: demonstrate fetch.writeCommitGraph bug
2019-10-28commit, tag: don't set parsed bit for parse failuresLibravatar Jeff King1-3/+0
If we can't parse a commit, then parse_commit() will return an error code. But it _also_ sets the "parsed" flag, which tells us not to bother trying to re-parse the object. That means that subsequent parses have no idea that the information in the struct may be bogus. I.e., doing this: parse_commit(commit); ... if (parse_commit(commit) < 0) die("commit is broken"); will never trigger the die(). The second parse_commit() will see the "parsed" flag and quietly return success. There are two obvious ways to fix this: 1. Stop setting "parsed" until we've successfully parsed. 2. Keep a second "corrupt" flag to indicate that we saw an error (and when the parsed flag is set, return 0/-1 depending on the corrupt flag). This patch does option 1. The obvious downside versus option 2 is that we might continually re-parse a broken object. But in practice, corruption like this is rare, and we typically die() or return an error in the caller. So it's OK not to worry about optimizing for corruption. And it's much simpler: we don't need to use an extra bit in the object struct, and callers which check the "parsed" flag don't need to learn about the corrupt bit, too. There's no new test here, because this case is already covered in t5318. Note that we do need to update the expected message there, because we now detect the problem in the return from "parse_commit()", and not with a separate check for a NULL tree. In fact, we can now ditch that explicit tree check entirely, as we're covered robustly by this change (and the previous recent change to treat a NULL tree as a parse error). We'll also give tags the same treatment. I don't know offhand of any cases where the problem can be triggered (it implies somebody ignoring a parse error earlier in the process), but consistently returning an error should cause the least surprise. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-25commit-graph: fix writing first commit-graph during fetchLibravatar Derrick Stolee1-4/+7
The previous commit includes a failing test for an issue around fetch.writeCommitGraph and fetching in a repo with a submodule. Here, we fix that bug and set the test to "test_expect_success". The problem arises with this set of commands when the remote repo at <url> has a submodule. Note that --recurse-submodules is not needed to demonstrate the bug. $ git clone <url> test $ cd test $ git -c fetch.writeCommitGraph=true fetch origin Computing commit graph generation numbers: 100% (12/12), done. BUG: commit-graph.c:886: missing parent <hash1> for commit <hash2> Aborted (core dumped) As an initial fix, I converted the code in builtin/fetch.c that calls write_commit_graph_reachable() to instead launch a "git commit-graph write --reachable --split" process. That code worked, but is not how we want the feature to work long-term. That test did demonstrate that the issue must be something to do with internal state of the 'git fetch' process. The write_commit_graph() method in commit-graph.c ensures the commits we plan to write are "closed under reachability" using close_reachable(). This method walks from the input commits, and uses the UNINTERESTING flag to mark which commits have already been visited. This allows the walk to take O(N) time, where N is the number of commits, instead of O(P) time, where P is the number of paths. (The number of paths can be exponential in the number of commits.) However, the UNINTERESTING flag is used in lots of places in the codebase. This flag usually means some barrier to stop a commit walk, such as in revision-walking to compare histories. It is not often cleared after the walk completes because the starting points of those walks do not have the UNINTERESTING flag, and clear_commit_marks() would stop immediately. This is happening during a 'git fetch' call with a remote. The fetch negotiation is comparing the remote refs with the local refs and marking some commits as UNINTERESTING. I tested running clear_commit_marks_many() to clear the UNINTERESTING flag inside close_reachable(), but the tips did not have the flag, so that did nothing. It turns out that the calculate_changed_submodule_paths() method is at fault. Thanks, Peff, for pointing out this detail! More specifically, for each submodule, the collect_changed_submodules() runs a revision walk to essentially do file-history on the list of submodules. That revision walk marks commits UNININTERESTING if they are simplified away by not changing the submodule. Instead, I finally arrived on the conclusion that I should use a flag that is not used in any other part of the code. In commit-reach.c, a number of flags were defined for commit walk algorithms. The REACHABLE flag seemed like it made the most sense, and it seems it was not actually used in the file. The REACHABLE flag was used in early versions of commit-reach.c, but was removed by 4fbcca4 (commit-reach: make can_all_from_reach... linear, 2018-07-20). Add the REACHABLE flag to commit-graph.c and use it instead of UNINTERESTING in close_reachable(). This fixes the bug in manual testing. Reported-by: Johannes Schindelin <johannes.schindelin@gmx.de> Helped-by: Jeff King <peff@peff.net> 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>
2019-10-09Merge branch 'ah/cleanups'Libravatar Junio C Hamano1-2/+3
Miscellaneous code clean-ups. * ah/cleanups: git_mkstemps_mode(): replace magic numbers with computed value wrapper: use a loop instead of repetitive statements diffcore-break: use a goto instead of a redundant if statement commit-graph: remove a duplicate assignment
2019-10-07Merge branch 'tb/commit-graph-harden'Libravatar Junio C Hamano1-2/+9
The code to parse and use the commit-graph file has been made more robust against corrupted input. * tb/commit-graph-harden: commit-graph.c: handle corrupt/missing trees commit-graph.c: handle commit parsing errors t/t5318: introduce failing 'git commit-graph write' tests
2019-10-07Merge branch 'gs/commit-graph-progress'Libravatar Junio C Hamano1-2/+4
* gs/commit-graph-progress: commit-graph: add --[no-]progress to write and verify
2019-10-07Merge branch 'rs/commit-graph-use-list-count'Libravatar Junio C Hamano1-11/+6
Code cleanup. * rs/commit-graph-use-list-count: commit-graph: use commit_list_count()
2019-10-07Merge branch 'jk/disable-commit-graph-during-upload-pack'Libravatar Junio C Hamano1-3/+15
The "upload-pack" (the counterpart of "git fetch") needs to disable commit-graph when responding to a shallow clone/fetch request, but the way this was done made Git panic, which has been corrected. * jk/disable-commit-graph-during-upload-pack: upload-pack: disable commit graph more gently for shallow traversal commit-graph: bump DIE_ON_LOAD check to actual load-time