kernel/git - git - PowerEL Git System

Commit Graph

Author	SHA1	Message	Date
Junio C Hamano	dbd5e0a186	Revert "commit-graph.c: introduce '--[no-]check-oids'" This reverts commit `7a9ce0269b`, which has not yet gained consensus.	5 years ago
Taylor Blau	7a9ce0269b	commit-graph.c: introduce '--[no-]check-oids' 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>	5 years ago
Taylor Blau	6830c36077	commit-graph.h: replace 'commit_hex' with 'commits' 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>	5 years ago
Taylor Blau	8a6ac287b2	builtin/commit-graph.c: introduce split strategy 'replace' 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>	5 years ago
Taylor Blau	fdbde82fe5	builtin/commit-graph.c: introduce split strategy 'no-merge' 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>	5 years ago
Taylor Blau	4f027355f6	builtin/commit-graph.c: support for '--split[=<strategy>]' 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>	5 years ago
Garima Singh	d5b873c832	commit-graph: add GIT_TEST_COMMIT_GRAPH_CHANGED_PATHS test flag 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>	5 years ago
Garima Singh	d38e07b8c4	commit-graph: add --changed-paths option to write subcommand 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>	5 years ago
Derrick Stolee	b09b785c78	commit-graph: fix buggy --expire-time option 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>	5 years ago
Alexandr Miloslavskiy	3d7747e318	real_path: remove unsafe API 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>	5 years ago
Taylor Blau	a7df60cac8	commit-graph.h: use odb in 'load_commit_graph_one_fd_st' 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>	5 years ago
Taylor Blau	ad2dd5bb63	commit-graph.c: remove path normalization, comparison 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>	5 years ago
Taylor Blau	13c2499249	commit-graph.h: store object directory in 'struct commit_graph' 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>	5 years ago
Taylor Blau	0bd52e27e3	commit-graph.h: store an odb in 'struct write_commit_graph_context' 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>	5 years ago
Derrick Stolee	4bd0593e0f	test-tool: use 'read-graph' helper 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>	5 years ago
SZEDER Gábor	8b656572ca	builtin/commit-graph.c: remove subcommand-less usage string 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>	5 years ago
Garima Singh	0bd7f578b2	commit-graph: emit trace2 cmd_mode for each sub-command 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>	6 years ago
Garima Singh	7371612255	commit-graph: add --[no-]progress to write and verify 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>	6 years ago
Jeff King	dd2e50a84e	commit-graph: turn off save_commit_buffer 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>	6 years ago
SZEDER Gábor	7c5c9b9c57	commit-graph: error out on invalid commit oids in 'write --stdin-commits' 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>	6 years ago
SZEDER Gábor	39d8831856	commit-graph: turn a group of write-related macro flags into an enum 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>	6 years ago
Derrick Stolee	135a712375	commit-graph: add --split option to builtin Add a new "--split" option to the 'git commit-graph write' subcommand. This option allows the optional behavior of writing a commit-graph chain. The current behavior will add a tip commit-graph containing any commits that are not in the existing commit-graph or commit-graph chain. Later changes will allow merging the chain and expiring out-dated files. Add a new test script (t5324-split-commit-graph.sh) that demonstrates this behavior. Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Derrick Stolee	3da4b609bb	commit-graph: verify chains with --shallow mode If we wrote a commit-graph chain, we only modified the tip file in the chain. It is valuable to verify what we wrote, but not waste time checking files we did not write. Add a '--shallow' option to the 'git commit-graph verify' subcommand and check that it does not read the base graph in a two-file chain. Making the verify subcommand read from a chain of commit-graphs takes some rearranging of the builtin code. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Derrick Stolee	c2bc6e6ab0	commit-graph: create options for split files The split commit-graph feature is now fully implemented, but needs some more run-time configurability. Allow direct callers to 'git commit-graph write --split' to specify the values used in the merge strategy and the expire time. Update the documentation to specify these values. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Derrick Stolee	5af8039452	commit-graph: collapse parameters into flags The write_commit_graph() and write_commit_graph_reachable() methods currently take two boolean parameters: 'append' and 'report_progress'. As we update these methods, adding more parameters this way becomes cluttered and hard to maintain. Collapse these parameters into a 'flags' parameter, and adjust the callers to provide flags as necessary. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Derrick Stolee	e103f7276f	commit-graph: return with errors during write The write_commit_graph() method uses die() to report failure and exit when confronted with an unexpected condition. This use of die() in a library function is incorrect and is now replaced by error() statements and an int return type. Return zero on success and a negative value on failure. Now that we use 'goto cleanup' to jump to the terminal condition on an error, we have new paths that could lead to uninitialized values. New initializers are added to correct for this. The builtins 'commit-graph', 'gc', and 'commit' call these methods, so update them to check the return value. Test that 'git commit-graph write' returns a proper error code when hitting a failure condition in write_commit_graph(). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Ævar Arnfjörð Bjarmason	7b8ce9c673	commit-graph verify: detect inability to read the graph Change "commit-graph verify" to error on open() failures other than ENOENT. As noted in the third paragraph of `283e68c72f` ("commit-graph: add 'verify' subcommand", 2018-06-27) and the test it added it's intentional that "commit-graph verify" doesn't error out when the file doesn't exist. But let's not be overly promiscuous in what we accept. If we can't read the file for other reasons, e.g. permission errors, bad file descriptor etc. we'd like to report an error to the user. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Ævar Arnfjörð Bjarmason	67a530fab3	commit-graph: don't pass filename to load_commit_graph_one_fd_st() An earlier change implemented load_commit_graph_one_fd_st() in a way that was bug-compatible with earlier code in terms of the "graph file %s is too small" error message printing out the path to the commit-graph (".git/objects/info/commit-graph"). But change that, because: * A function that takes an already-open file descriptor also needing the filename isn't very intuitive. * The vast majority of errors we might emit when loading the graph come from parse_commit_graph(), which doesn't report the filename. Let's not do that either in this case for consistency. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Ævar Arnfjörð Bjarmason	61df89c8e5	commit-graph: don't early exit(1) on e.g. "git status" Make the commit-graph loading code work as a library that returns an error code instead of calling exit(1) when the commit-graph is corrupt. This means that e.g. "status" will now report commit-graph corruption as an "error: [...]" at the top of its output, but then proceed to work normally. This required splitting up the load_commit_graph_one() function so that the code that deals with open()-ing and stat()-ing the graph can now be called independently as open_commit_graph(). This is needed because "commit-graph verify" where the graph doesn't exist isn't an error. See the third paragraph in `283e68c72f` ("commit-graph: add 'verify' subcommand", 2018-06-27). There's a bug in that logic where we conflate the intended ENOENT with other errno values (e.g. EACCES), but this change doesn't address that. That'll be addressed in a follow-up change. I'm then splitting most of the logic out of load_commit_graph_one() into load_commit_graph_one_fd_st(), which allows for providing an existing file descriptor and stat information to the loading code. This isn't strictly needed, but it would be redundant and confusing to open() and stat() the file twice for some of the codepaths, this allows for calling open_commit_graph() followed by load_commit_graph_one_fd_st(). The "graph_file" still needs to be passed to that function for the the "graph file %s is too small" error message. This leaves load_commit_graph_one() unused by everything except the internal prepare_commit_graph_one() function, so let's mark it as "static". If someone needs it in the future we can remove the "static" attribute. I could also rewrite its sole remaining user ("prepare_commit_graph_one()") to use load_commit_graph_one_fd_st() instead, but let's leave it at this. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
SZEDER Gábor	5af7417bd8	commit-graph: rename "large edges" to "extra edges" The optional 'Large Edge List' chunk of the commit graph file stores parent information for commits with more than two parents, and the names of most of the macros, variables, struct fields, and functions related to this chunk contain the term "large edges", e.g. write_graph_chunk_large_edges(). However, it's not a really great term, as the edges to the second and subsequent parents stored in this chunk are not any larger than the edges to the first and second parents stored in the "main" 'Commit Data' chunk. It's the number of edges, IOW number of parents, that is larger compared to non-merge and "regular" two-parent merge commits. And indeed, two functions in 'commit-graph.c' have a local variable called 'num_extra_edges' that refer to the same thing, and this "extra edges" term is much better at describing these edges. So let's rename all these references to "large edges" in macro, variable, function, etc. names to "extra edges". There is a GRAPH_OCTOPUS_EDGES_NEEDED macro as well; for the sake of consistency rename it to GRAPH_EXTRA_EDGES_NEEDED. We can do so safely without causing any incompatibility issues, because the term "large edges" doesn't come up in the file format itself in any form (the chunk's magic is {'E', 'D', 'G', 'E'}, there is no 'L' in there), but only in the specification text. The string "large edges", however, does come up in the output of 'git commit-graph read' and in tests looking at its input, but that command is explicitly documented as debugging aid, so we can change its output and the affected tests safely. Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	6 years ago
Martin Ågren	0bfb48e672	builtin/commit-graph.c: UNLEAK variables `graph_verify()`, `graph_read()` and `graph_write()` do the hard work of `cmd_commit_graph()`. As soon as these return, so does `cmd_commit_graph()`. `strbuf_getline()` may allocate memory in the strbuf, yet return EOF. We need to release the strbuf or UNLEAK it. Go for the latter since we are close to returning from `graph_write()`. `graph_write()` also fails to free the strings in the string list. They have been added to the list with `strdup_strings` set to 0. We could flip `strdup_strings` before clearing the list, which is our usual hack in situations like this. But since we are about to exit, let's just UNLEAK the whole string list instead. UNLEAK `graph` in `graph_verify`. While at it, and for consistency, UNLEAK in `graph_read()` as well, and remove an unnecessary UNLEAK just before dying. Signed-off-by: Martin Ågren <martin.agren@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Ævar Arnfjörð Bjarmason	7b0f229222	commit-graph write: add progress output Before this change the "commit-graph write" command didn't report any progress. On my machine this command takes more than 10 seconds to write the graph for linux.git, and around 1m30s on the 2015-04-03-1M-git.git[1] test repository (a test case for a large monorepository). Furthermore, since the gc.writeCommitGraph setting was added in `d5d5d7b641` ("gc: automatically write commit-graph files", 2018-06-27), there was no indication at all from a "git gc" run that anything was different. This why one of the progress bars being added here uses start_progress() instead of start_delayed_progress(), so that it's guaranteed to be seen. E.g. on my tiny 867 commit dotfiles.git repository: $ git -c gc.writeCommitGraph=true gc Enumerating objects: 2821, done. [...] Computing commit graph generation numbers: 100% (867/867), done. On larger repositories, such as linux.git the delayed progress bar(s) will kick in, and we'll show what's going on instead of, as was previously happening, printing nothing while we write the graph: $ git -c gc.writeCommitGraph=true gc [...] Annotating commits in commit graph: 1565573, done. Computing commit graph generation numbers: 100% (782484/782484), done. Note that here we don't show "Finding commits for commit graph", this is because under "git gc" we seed the search with the commit references in the repository, and that set is too small to show any progress, but would e.g. on a smaller repo such as git.git with --stdin-commits: $ git rev-list --all \| git -c gc.writeCommitGraph=true write --stdin-commits Finding commits for commit graph: 100% (162576/162576), done. Computing commit graph generation numbers: 100% (162576/162576), done. With --stdin-packs we don't show any estimation of how much is left to do. This is because we might be processing more than one pack. We could be less lazy here and show progress, either by detecting that we're only processing one pack, or by first looping over the packs to discover how many commits they have. I don't see the point in doing that work. So instead we get (on 2015-04-03-1M-git.git): $ echo pack-<HASH>.idx \| git -c gc.writeCommitGraph=true --exec-path=$PWD commit-graph write --stdin-packs Finding commits for commit graph: 13064614, done. Annotating commits in commit graph: 3001341, done. Computing commit graph generation numbers: 100% (1000447/1000447), done. No GC mode uses --stdin-packs. It's what they use at Microsoft to manually compute the generation numbers for their collection of large packs which are never coalesced. The reason we need a "report_progress" variable passed down from "git gc" is so that we don't report this output when we're running in the process "git gc --auto" detaches from the terminal. Since we write the commit graph from the "git gc" process itself (as opposed to what we do with say the "git repack" phase), we'd end up writing the output to .git/gc.log and reporting it to the user next time as part of the "The last gc run reported the following[...]" error, see `329e6e8794` ("gc: save log from daemonized gc --auto and print it next time", 2015-09-19). So we must keep track of whether or not we're running in that demonized mode, and if so print no progress. See [2] and subsequent replies for a discussion of an approach not taken in compute_generation_numbers(). I.e. we're saying "Computing commit graph generation numbers", even though on an established history we're mostly skipping over all the work we did in the past. This is similar to the white lie we tell in the "Writing objects" phase (not all are objects being written). Always showing progress is considered more important than accuracy. I.e. on a repository like 2015-04-03-1M-git.git we'd hang for 6 seconds with no output on the second "git gc" if no changes were made to any objects in the interim if we'd take the approach in [2]. 1. https://github.com/avar/2015-04-03-1M-git 2. <c6960252-c095-fb2b-e0bc-b1e6bb261614@gmail.com> (https://public-inbox.org/git/c6960252-c095-fb2b-e0bc-b1e6bb261614@gmail.com/) Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	d6538246d3	commit-graph: not compatible with replace objects Create new method commit_graph_compatible(r) to check if a given repository r is compatible with the commit-graph feature. Fill the method with a check to see if replace-objects exist. Test this interaction succeeds, including ignoring an existing commit-graph and failing to write a new commit-graph. However, we do ensure that we write a new commit-graph by setting read_replace_refs to 0, thereby ignoring the replace refs. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Jonathan Tan	c3756d5b7f	commit-graph: add free_commit_graph Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	59fb87701f	commit-graph: add '--reachable' option When writing commit-graph files, it can be convenient to ask for all reachable commits (starting at the ref set) in the resulting file. This is particularly helpful when writing to stdin is complicated, such as a future integration with 'git gc'. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	d88b14b3fd	commit-graph: use string-list API for input Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	283e68c72f	commit-graph: add 'verify' subcommand If the commit-graph file becomes corrupt, we need a way to verify that its contents match the object database. In the manner of 'git fsck' we will implement a 'git commit-graph verify' subcommand to report all issues with the file. Add the 'verify' subcommand to the 'commit-graph' builtin and its documentation. The subcommand is currently a no-op except for loading the commit-graph into memory, which may trigger run-time errors that would be caught by normal use. Add a simple test that ensures the command returns a zero error code. If no commit-graph file exists, this is an acceptable state. Do not report any errors. Helped-by: Ramsay Jones <ramsay@ramsayjones.plus.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	883e5c7fe9	commit-graph: UNLEAK before die() Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	7547b95b4f	commit-graph: implement "--append" option Teach git-commit-graph to add all commits from the existing commit-graph file to the file about to be written. This should be used when adding new commits without performing garbage collection. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	3d5df01b5e	commit-graph: build graph from starting commits Teach git-commit-graph to read commits from stdin when the --stdin-commits flag is specified. Commits reachable from these commits are added to the graph. This is a much faster way to construct the graph than inspecting all packed objects, but is restricted to known tips. For the Linux repository, 700,000+ commits were added to the graph file starting from 'master' in 7-9 seconds, depending on the number of packfiles in the repo (1, 24, or 120). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	049d51a2bb	commit-graph: read only from specific pack-indexes Teach git-commit-graph to inspect the objects only in a certain list of pack-indexes within the given pack directory. This allows updating the commit graph iteratively. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	2a2e32bdc5	commit-graph: implement git commit-graph read Teach git-commit-graph to read commit graph files and summarize their contents. Use the read subcommand to verify the contents of a commit graph file in the tests. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	f237c8b6fe	commit-graph: implement git-commit-graph write Teach git-commit-graph to write graph files. Create new test script to verify this command succeeds without failure. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago
Derrick Stolee	4ce58ee38d	commit-graph: create git-commit-graph builtin Teach git the 'commit-graph' builtin that will be used for writing and reading packed graph files. The current implementation is mostly empty, except for an '--object-dir' option. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>	7 years ago

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