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2019-12-01Merge branch 'jk/cleanup-object-parsing-and-fsck'Libravatar Junio C Hamano1-5/+28
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 ...
2019-11-10Merge branch 'pw/post-commit-from-sequencer'Libravatar Junio C Hamano1-0/+24
"rebase -i" ceased to run post-commit hook by mistake in an earlier update, which has been corrected. * pw/post-commit-from-sequencer: sequencer: run post-commit hook move run_commit_hook() to libgit and use it there sequencer.h fix placement of #endif t3404: remove uneeded calls to set_fake_editor t3404: set $EDITOR in subshell t3404: remove unnecessary subshell
2019-10-28commit, tag: don't set parsed bit for parse failuresLibravatar Jeff King1-1/+13
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>
2019-10-21parse_commit_buffer(): treat lookup_tree() failure as parse errorLibravatar Jeff King1-1/+7
If parsing a commit yields a valid tree oid, but we've seen that same oid as a non-tree in the same process, the resulting commit struct will end up with a NULL tree pointer, but not otherwise report a parsing failure. That's perhaps convenient for callers which want to operate on even partially corrupt commits (e.g., by still looking at the parents). But it leaves a potential trap for most callers, who now have to manually check for a NULL tree. Most do not, and it's likely that there are possible segfaults lurking. I say "possible" because there are many candidates, and I don't think it's worth following through on reproducing them when we can just fix them all in one spot. And certainly we _have_ seen real-world cases, such as the one fixed by 806278dead (commit-graph.c: handle corrupt/missing trees, 2019-09-05). Note that we can't quite drop the check in the caller added by that commit yet, as there's some subtlety with repeated parsings (which will be addressed in a future commit). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-21parse_commit_buffer(): treat lookup_commit() failure as parse errorLibravatar Jeff King1-3/+8
While parsing the parents of a commit, if we are able to parse an actual oid but lookup_commit() fails on it (because we previously saw it in this process as a different object type), we silently omit the parent and do not report any error to the caller. The caller has no way of knowing this happened, because even an empty parent list is a valid parse result. As a result, it's possible to fool our "rev-list" connectivity check into accepting a corrupted set of objects. There's a test for this case already in t6102, but unfortunately it has a slight error. It creates a broken commit with a parent line pointing to a blob, and then checks that rev-list notices the problem in two cases: 1. the "lone" case: we traverse the broken commit by itself (here we try to actually load the blob from disk and find out that it's not a commit) 2. the "seen" case: we parse the blob earlier in the process, and then when calling lookup_commit() we realize immediately that it's not a commit The "seen" variant for this test mistakenly parsed another commit instead of the blob, meaning that we were actually just testing the "lone" case again. Changing that reveals the breakage (and shows that this fixes it). Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-16move run_commit_hook() to libgit and use it thereLibravatar Phillip Wood1-0/+24
This function was declared in commit.h but was implemented in builtin/commit.c so was not part of libgit. Move it to libgit so we can use it in the sequencer. This simplifies the implementation of run_prepare_commit_msg_hook() and will be used in the next commit. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-10-07Merge branch 'tb/commit-graph-harden'Libravatar Junio C Hamano1-1/+2
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
2019-09-30Merge branch 'mh/release-commit-memory-fix'Libravatar Junio C Hamano1-1/+1
Leakfix. * mh/release-commit-memory-fix: commit: free the right buffer in release_commit_memory
2019-09-09commit-graph.c: handle corrupt/missing treesLibravatar Taylor Blau1-1/+2
Apply similar treatment as in the previous commit to handle an unchecked call to 'get_commit_tree_oid()'. Previously, a NULL return value from this function would be immediately dereferenced with '->hash', and then cause a segfault. Before dereferencing to access the 'hash' member, check the return value of 'get_commit_tree_oid()' to make sure that it is not NULL. To make this check correct, a related change is also needed in 'commit.c', which is to check the return value of 'get_commit_tree' before taking its address. If 'get_commit_tree' returns NULL, we encounter an undefined behavior when taking the address of the return value of 'get_commit_tree' and then taking '->object.oid'. (On my system, this is memory address 0x8, which is obviously wrong). Fix this by making sure that 'get_commit_tree' returns something non-NULL before digging through a structure that is not there, thus preventing a segfault down the line in the commit graph code. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-08-26commit: free the right buffer in release_commit_memoryLibravatar Mike Hommey1-1/+1
The index field in the commit object is used to find the buffer corresponding to that commit in the buffer_slab. Resetting it first means free_commit_buffer is not going to free the right buffer. Signed-off-by: Mike Hommey <mh@glandium.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-07-29Merge branch 'ds/close-object-store' into maintLibravatar Junio C Hamano1-1/+1
The commit-graph file is now part of the "files that the runtime may keep open file descriptors on, all of which would need to be closed when done with the object store", and the file descriptor to an existing commit-graph file now is closed before "gc" finalizes a new instance to replace it. * ds/close-object-store: packfile: rename close_all_packs to close_object_store packfile: close commit-graph in close_all_packs commit-graph: use raw_object_store when closing commit-graph: extract write_commit_graph_file() commit-graph: extract copy_oids_to_commits() commit-graph: extract count_distinct_commits() commit-graph: extract fill_oids_from_all_packs() commit-graph: extract fill_oids_from_commit_hex() commit-graph: extract fill_oids_from_packs() commit-graph: create write_commit_graph_context commit-graph: remove Future Work section commit-graph: collapse parameters into flags commit-graph: return with errors during write commit-graph: fix the_repository reference
2019-07-09Merge branch 'jk/oidhash'Libravatar Junio C Hamano1-3/+2
Code clean-up to remove hardcoded SHA-1 hash from many places. * jk/oidhash: hashmap: convert sha1hash() to oidhash() hash.h: move object_id definition from cache.h khash: rename oid helper functions khash: drop sha1-specific map types pack-bitmap: convert khash_sha1 maps into kh_oid_map delta-islands: convert island_marks khash to use oids khash: rename kh_oid_t to kh_oid_set khash: drop broken oid_map typedef object: convert create_object() to use object_id object: convert internal hash_obj() to object_id object: convert lookup_object() to use object_id object: convert lookup_unknown_object() to use object_id pack-objects: convert locate_object_entry_hash() to object_id pack-objects: convert packlist_find() to use object_id pack-bitmap-write: convert some helpers to use object_id upload-pack: rename a "sha1" variable to "oid" describe: fix accidental oid/hash type-punning
2019-07-09Merge branch 'ds/commit-graph-write-refactor'Libravatar Junio C Hamano1-1/+1
Renamed from commit-graph-format-v2 and changed scope. * ds/commit-graph-write-refactor: commit-graph: extract write_commit_graph_file() commit-graph: extract copy_oids_to_commits() commit-graph: extract count_distinct_commits() commit-graph: extract fill_oids_from_all_packs() commit-graph: extract fill_oids_from_commit_hex() commit-graph: extract fill_oids_from_packs() commit-graph: create write_commit_graph_context commit-graph: remove Future Work section commit-graph: collapse parameters into flags commit-graph: return with errors during write commit-graph: fix the_repository reference
2019-06-20object: convert create_object() to use object_idLibravatar Jeff King1-2/+1
There are no callers left of create_object() that aren't just passing us the "hash" member of a "struct object_id". Let's take the whole struct, which gets us closer to removing all raw sha1 variables. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-06-20object: convert lookup_object() to use object_idLibravatar Jeff King1-1/+1
There are no callers left of lookup_object() that aren't just passing us the "hash" member of a "struct object_id". Let's take the whole struct, which gets us closer to removing all raw sha1 variables. It also matches the existing conversions of lookup_blob(), etc. The conversions of callers were done by hand, but they're all mechanical one-liners. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-13commit-graph: fix the_repository referenceLibravatar Derrick Stolee1-1/+1
The parse_commit_buffer() method takes a repository pointer, so it should not refer to the_repository anymore. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-05-09Merge branch 'tb/unexpected'Libravatar Junio C Hamano1-3/+3
Code tightening against a "wrong" object appearing where an object of a different type is expected, instead of blindly assuming that the connection between objects are correctly made. * tb/unexpected: rev-list: detect broken root trees rev-list: let traversal die when --missing is not in use get_commit_tree(): return NULL for broken tree list-objects.c: handle unexpected non-tree entries list-objects.c: handle unexpected non-blob entries t: introduce tests for unexpected object types t: move 'hex2oct' into test-lib-functions.sh
2019-04-16commit.c: add repo_get_commit_tree()Libravatar Nguyễn Thái Ngọc Duy1-2/+3
Remove the implicit dependency on the_repository in this function. It will be used in sha1-name.c functions when they are updated to take any 'struct repository'. get_commit_tree() remains as a compat wrapper, to be slowly replaced later. Any access to "maybe_tree" field directly will result in _broken_ code after running through commit.cocci because we can't know what is the right repository to use. the_repository would be correct most of the time. But we're relying less and less on the_repository and that assumption may no longer be true. The transformation now is more of a poor man replacement for a C++ compiler catching access to private fields. Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-16commit.cocci: refactor code, avoid double rewriteLibravatar Nguyễn Thái Ngọc Duy1-2/+7
"maybe" pointer in 'struct commit' is tricky because it can be lazily initialized to take advantage of commit-graph if available. This makes it not safe to access directly. This leads to a rule in commit.cocci to rewrite 'x->maybe_tree' to 'get_commit_tree(x)'. But that rule alone could lead to incorrectly rewrite assignments, e.g. from x->maybe_tree = yes to get_commit_tree(x) = yes Because of this we have a second rule to revert this effect. Szeder found out that we could do better by performing the assignment rewrite rule first, then the remaining is read-only access and handled by the current first rule. For this to work, we need to transform "x->maybe_tree = y" to something that does NOT contain "x->maybe_tree" to avoid the original first rule. This is where set_commit_tree() comes in. Helped-by: SZEDER Gábor <szeder.dev@gmail.com> Helped-by: Johannes Schindelin <Johannes.Schindelin@gmx.de> Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-04-10get_commit_tree(): return NULL for broken treeLibravatar Jeff King1-3/+3
Return NULL from 'get_commit_tree()' when a commit's root tree is corrupt, doesn't exist, or points to an object which is not a tree. In [1], this situation became a BUG(), but it can certainly occur in cases which are not a bug in Git, for e.g., if a caller manually crafts a commit whose tree is corrupt in any of the above ways. Note that the expect_failure test in t6102 triggers this BUG(), but we can't flip it to expect_success yet. Solving this problem actually reveals a second bug. [1]: 7b8a21dba1 (commit-graph: lazy-load trees for commits, 2018-04-06) Co-authored-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2019-02-05Merge branch 'sb/more-repo-in-api'Libravatar Junio C Hamano1-17/+24
The in-core repository instances are passed through more codepaths. * sb/more-repo-in-api: (23 commits) t/helper/test-repository: celebrate independence from the_repository path.h: make REPO_GIT_PATH_FUNC repository agnostic commit: prepare free_commit_buffer and release_commit_memory for any repo commit-graph: convert remaining functions to handle any repo submodule: don't add submodule as odb for push submodule: use submodule repos for object lookup pretty: prepare format_commit_message to handle arbitrary repositories commit: prepare logmsg_reencode to handle arbitrary repositories commit: prepare repo_unuse_commit_buffer to handle any repo commit: prepare get_commit_buffer to handle any repo commit-reach: prepare in_merge_bases[_many] to handle any repo commit-reach: prepare get_merge_bases to handle any repo commit-reach.c: allow get_merge_bases_many_0 to handle any repo commit-reach.c: allow remove_redundant to handle any repo commit-reach.c: allow merge_bases_many to handle any repo commit-reach.c: allow paint_down_to_common to handle any repo commit: allow parse_commit* to handle any repo object: parse_object to honor its repository argument object-store: prepare has_{sha1, object}_file to handle any repo object-store: prepare read_object_file to deal with any repo ...
2018-12-28commit: prepare free_commit_buffer and release_commit_memory for any repoLibravatar Stefan Beller1-5/+4
Pass the object pool to free_commit_buffer and release_commit_memory, such that we can eliminate access to 'the_repository'. Also remove the TODO in release_commit_memory, as commit->util was removed in 9d2c97016f (commit.h: delete 'util' field in struct commit, 2018-05-19) Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-18Merge branch 'jk/verify-sig-merge-into-void'Libravatar Junio C Hamano1-0/+26
"git merge" and "git pull" that merges into an unborn branch used to completely ignore "--verify-signatures", which has been corrected. * jk/verify-sig-merge-into-void: pull: handle --verify-signatures for unborn branch merge: handle --verify-signatures for unborn branch merge: extract verify_merge_signature() helper
2018-11-18Merge branch 'ds/reachable-topo-order'Libravatar Junio C Hamano1-5/+4
The revision walker machinery learned to take advantage of the commit generation numbers stored in the commit-graph file. * ds/reachable-topo-order: t6012: make rev-list tests more interesting revision.c: generation-based topo-order algorithm commit/revisions: bookkeeping before refactoring revision.c: begin refactoring --topo-order logic test-reach: add rev-list tests test-reach: add run_three_modes method prio-queue: add 'peek' operation
2018-11-14commit: prepare repo_unuse_commit_buffer to handle any repoLibravatar Stefan Beller1-2/+4
Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-14commit: prepare get_commit_buffer to handle any repoLibravatar Stefan Beller1-3/+5
Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-14commit: allow parse_commit* to handle any repoLibravatar Stefan Beller1-7/+11
Just like the previous commit, parse_commit and friends are used a lot and are found in new patches, so we cannot change their signature easily. Re-introduce these function prefixed with 'repo_' that take a repository argument and keep the original as a shallow macro. Signed-off-by: Stefan Beller <sbeller@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-07merge: extract verify_merge_signature() helperLibravatar Jeff King1-0/+26
The logic to implement "merge --verify-signatures" is inline in cmd_merge(), but this site misses some cases. Let's extract the logic into a function so we can call it from more places. We'll move it to commit.[ch], since one of the callers (git-pull) is outside our source file. This function isn't all that general (after all, its main function is to exit the program) but it's not worth trying to fix that. The heavy lifting is done by check_commit_signature(), and our purpose here is just sharing the die() logic. We'll mark it with a comment to make that clear. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-02commit/revisions: bookkeeping before refactoringLibravatar Derrick Stolee1-5/+4
There are a few things that need to move around a little before making a big refactoring in the topo-order logic: 1. We need access to record_author_date() and compare_commits_by_author_date() in revision.c. These are used currently by sort_in_topological_order() in commit.c. 2. Moving these methods to commit.h requires adding an author_date_slab declaration to commit.h. Consumers will need their own implementation. 3. The add_parents_to_list() method in revision.c performs logic around the UNINTERESTING flag and other special cases depending on the struct rev_info. Allow this method to ignore a NULL 'list' parameter, as we will not be populating the list for our walk. Also rename the method to the slightly more generic name process_parents() to make clear that this method does more than add to a list (and no list is required anymore). Helped-by: Jeff King <peff@peff.net> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-02Merge branch 'pk/rebase-in-c-4-opts'Libravatar Junio C Hamano1-0/+82
Rewrite "git rebase" in C. * pk/rebase-in-c-4-opts: builtin rebase: support --root builtin rebase: add support for custom merge strategies builtin rebase: support `fork-point` option merge-base --fork-point: extract libified function builtin rebase: support --rebase-merges[=[no-]rebase-cousins] builtin rebase: support `--allow-empty-message` option builtin rebase: support `--exec` builtin rebase: support `--autostash` option builtin rebase: support `-C` and `--whitespace=<type>` builtin rebase: support `--gpg-sign` option builtin rebase: support `--autosquash` builtin rebase: support `keep-empty` option builtin rebase: support `ignore-date` option builtin rebase: support `ignore-whitespace` option builtin rebase: support --committer-date-is-author-date builtin rebase: support --rerere-autoupdate builtin rebase: support --signoff builtin rebase: allow selecting the rebase "backend"
2018-10-16Merge branch 'ds/commit-graph-with-grafts'Libravatar Junio C Hamano1-1/+1
The recently introduced commit-graph auxiliary data is incompatible with mechanisms such as replace & grafts that "breaks" immutable nature of the object reference relationship. Disable optimizations based on its use (and updating existing commit-graph) when these incompatible features are in use in the repository. * ds/commit-graph-with-grafts: commit-graph: close_commit_graph before shallow walk commit-graph: not compatible with uninitialized repo commit-graph: not compatible with grafts commit-graph: not compatible with replace objects test-repository: properly init repo commit-graph: update design document refs.c: upgrade for_each_replace_ref to be a each_repo_ref_fn callback refs.c: migrate internal ref iteration to pass thru repository argument
2018-10-11merge-base --fork-point: extract libified functionLibravatar Pratik Karki1-0/+81
We need this functionality in the builtin rebase. Note: to make this function truly reusable, we have to switch the call get_merges_many_dirty() to get_merges_many() because we want the commit flags to be reset (otherwise, subsequent get_merge_bases() calls would obtain incorrect results). This did not matter when the function was called in `git rev-parse --fork-point` because in that command, the process definitely did not traverse any commits before exiting. Signed-off-by: Pratik Karki <predatoramigo@gmail.com> Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-09-17Merge branch 'jk/cocci'Libravatar Junio C Hamano1-1/+1
spatch transformation to replace boolean uses of !hashcmp() to newly introduced oideq() is added, and applied, to regain performance lost due to support of multiple hash algorithms. * jk/cocci: show_dirstat: simplify same-content check read-cache: use oideq() in ce_compare functions convert hashmap comparison functions to oideq() convert "hashcmp() != 0" to "!hasheq()" convert "oidcmp() != 0" to "!oideq()" convert "hashcmp() == 0" to hasheq() convert "oidcmp() == 0" to oideq() introduce hasheq() and oideq() coccinelle: use <...> for function exclusion
2018-09-17Merge branch 'jk/trailer-fixes'Libravatar Junio C Hamano1-3/+3
"git interpret-trailers" and its underlying machinery had a buggy code that attempted to ignore patch text after commit log message, which triggered in various codepaths that will always get the log message alone and never get such an input. * jk/trailer-fixes: append_signoff: use size_t for string offsets sequencer: ignore "---" divider when parsing trailers pretty, ref-filter: format %(trailers) with no_divider option interpret-trailers: allow suppressing "---" divider interpret-trailers: tighten check for "---" patch boundary trailer: pass process_trailer_opts to trailer_info_get() trailer: use size_t for iterating trailer list trailer: use size_t for string offsets
2018-09-17Merge branch 'ds/reachable'Libravatar Junio C Hamano1-361/+0
The code for computing history reachability has been shuffled, obtained a bunch of new tests to cover them, and then being improved. * ds/reachable: commit-reach: correct accidental #include of C file commit-reach: use can_all_from_reach commit-reach: make can_all_from_reach... linear commit-reach: replace ref_newer logic test-reach: test commit_contains test-reach: test can_all_from_reach_with_flags test-reach: test reduce_heads test-reach: test get_merge_bases_many test-reach: test is_descendant_of test-reach: test in_merge_bases test-reach: create new test tool for ref_newer commit-reach: move can_all_from_reach_with_flags upload-pack: generalize commit date cutoff upload-pack: refactor ok_to_give_up() upload-pack: make reachable() more generic commit-reach: move commit_contains from ref-filter commit-reach: move ref_newer from remote.c commit.h: remove method declarations commit-reach: move walk methods from commit.c
2018-09-04Merge branch 'ds/commit-graph-lockfile-fix'Libravatar Junio C Hamano1-1/+4
"git merge-base" in 2.19-rc1 has performance regression when the (experimental) commit-graph feature is in use, which has been mitigated. * ds/commit-graph-lockfile-fix: commit: don't use generation numbers if not needed
2018-08-30commit: don't use generation numbers if not neededLibravatar Derrick Stolee1-1/+4
In 3afc679b "commit: use generations in paint_down_to_common()", the queue in paint_down_to_common() was changed to use a priority order based on generation number before commit date. This served two purposes: 1. When generation numbers are present, the walk guarantees correct topological relationships, regardless of clock skew in commit dates. 2. It enables short-circuiting the walk when the min_generation parameter is added in d7c1ec3e "commit: add short-circuit to paint_down_to_common()". This short-circuit helps commands like 'git branch --contains' from needing to walk to a merge base when we know the result is false. The commit message for 3afc679b includes the following sentence: This change does not affect the number of commits that are walked during the execution of paint_down_to_common(), only the order that those commits are inspected. This statement is incorrect. Because it changes the order in which the commits are inspected, it changes the order they are added to the queue, and hence can change the number of loops before the queue_has_nonstale() method returns true. This change makes a concrete difference depending on the topology of the commit graph. For instance, computing the merge-base between consecutive versions of the Linux kernel has no effect for versions after v4.9, but 'git merge-base v4.8 v4.9' presents a performance regression: v2.18.0: 0.122s v2.19.0-rc1: 0.547s HEAD: 0.127s To determine that this was simply an ordering issue, I inserted a counter within the while loop of paint_down_to_common() and found that the loop runs 167,468 times in v2.18.0 and 635,579 times in v2.19.0-rc1. The topology of this case can be described in a simplified way here: v4.9 | \ | \ v4.8 \ | \ \ | \ | ... A B | / / | / / |/__/ C Here, the "..." means "a very long line of commits". By generation number, A and B have generation one more than C. However, A and B have commit date higher than most of the commits reachable from v4.8. When the walk reaches v4.8, we realize that it has PARENT1 and PARENT2 flags, so everything it can reach is marked as STALE, including A. B has only the PARENT1 flag, so is not STALE. When paint_down_to_common() is run using compare_commits_by_commit_date, A and B are removed from the queue early and C is inserted into the queue. At this point, C and the rest of the queue entries are marked as STALE. The loop then terminates. When paint_down_to_common() is run using compare_commits_by_gen_then_commit_date, B is removed from the queue only after the many commits reachable from v4.8 are explored. This causes the loop to run longer. The reason for this regression is simple: the queue order is intended to not explore a commit until everything that _could_ reach that commit is explored. From the information gathered by the original ordering, we have no guarantee that there is not a commit D reachable from v4.8 that can also reach B. We gained absolute correctness in exchange for a performance regression. The performance regression is probably the worse option, since these incorrect results in paint_down_to_common() are rare. The topology required for the performance regression are less rare, but still require multiple merge commits where the parents differ greatly in generation number. In our example above, the commit A is as important as the commit B to demonstrate the problem, since otherwise the commit C will sit in the queue as non-stale just as long in both orders. The solution provided uses the min_generation parameter to decide if we should use generation numbers in our ordering. When min_generation is equal to zero, it means that the caller has no known cutoff for the walk, so we should rely on our commit-date heuristic as before; this is the case with merge_bases_many(). When min_generation is non-zero, then the caller knows a valuable cutoff for the short-circuit mechanism; this is the case with remove_redundant() and in_merge_bases_many(). Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-29convert "oidcmp() != 0" to "!oideq()"Libravatar Jeff King1-1/+1
This is the flip side of the previous two patches: checking for a non-zero oidcmp() can be more strictly expressed as inequality. Like those patches, we write "!= 0" in the coccinelle transformation, which covers by isomorphism the more common: if (oidcmp(E1, E2)) As with the previous two patches, this patch can be achieved almost entirely by running "make coccicheck"; the only differences are manual line-wrap fixes to match the original code. There is one thing to note for anybody replicating this, though: coccinelle 1.0.4 seems to miss the case in builtin/tag.c, even though it's basically the same as all the others. Running with 1.0.7 does catch this, so presumably it's just a coccinelle bug that was fixed in the interim. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-27Merge branch 'js/larger-timestamps'Libravatar Junio C Hamano1-1/+1
Portability fix. * js/larger-timestamps: commit: use timestamp_t for author_date_slab
2018-08-23append_signoff: use size_t for string offsetsLibravatar Jeff King1-3/+3
The append_signoff() function takes an "int" to specify the number of bytes to ignore. Most callers just pass 0, and the remainder use ignore_non_trailer() to skip over cruft. That function also returns an int, and uses them internally. On systems where size_t is larger than an int (i.e., most 64-bit systems), dealing with a ridiculously large commit message could end up overflowing an int, producing surprising results (e.g., returning a negative offset, which would cause us to look outside the original string). Let's consistently use size_t for these offsets through this whole stack. As a bonus, this makes the meaning of "ignore_footer" as an offset (and not a boolean) more clear. But while we're here, let's also document the interface. Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-21commit: use timestamp_t for author_date_slabLibravatar Derrick Stolee1-1/+1
The author_date_slab is used to store the author date of a commit when walking with the --author-date flag in rev-list or log. This was added as an 'unsigned long' in 81c6b38b "log: --author-date-order" Since 'unsigned long' is ambiguous in its bit-ness across platforms (64-bit in Linux, 32-bit in Windows, for example), most references to the author dates in commit.c were converted to timestamp_t in dddbad72 "timestamp_t: a new data type for timestamps" However, the slab definition was missed, leading to a mismatch in the data types in Windows. This would not reveal itself as a bug unless someone authors a commit after February 2106, but commits can store anything as their author date. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-21commit-graph: not compatible with graftsLibravatar Derrick Stolee1-1/+1
Augment commit_graph_compatible(r) to return false when the given repository r has commit grafts or is a shallow clone. Test that in these situations we ignore existing commit-graph files and we do not write new commit-graph files. Helped-by: Jakub Narebski <jnareb@gmail.com> Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-08-02Merge branch 'jt/commit-graph-per-object-store'Libravatar Junio C Hamano1-3/+3
The singleton commit-graph in-core instance is made per in-core repository instance. * jt/commit-graph-per-object-store: commit-graph: add repo arg to graph readers commit-graph: store graph in struct object_store commit-graph: add free_commit_graph commit-graph: add missing forward declaration object-store: add missing include commit-graph: refactor preparing commit graph
2018-08-02Merge branch 'sb/object-store-lookup'Libravatar Junio C Hamano1-30/+50
lookup_commit_reference() and friends have been updated to find in-core object for a specific in-core repository instance. * sb/object-store-lookup: (32 commits) commit.c: allow lookup_commit_reference to handle arbitrary repositories commit.c: allow lookup_commit_reference_gently to handle arbitrary repositories tag.c: allow deref_tag to handle arbitrary repositories object.c: allow parse_object to handle arbitrary repositories object.c: allow parse_object_buffer to handle arbitrary repositories commit.c: allow get_cached_commit_buffer to handle arbitrary repositories commit.c: allow set_commit_buffer to handle arbitrary repositories commit.c: migrate the commit buffer to the parsed object store commit-slabs: remove realloc counter outside of slab struct commit.c: allow parse_commit_buffer to handle arbitrary repositories tag: allow parse_tag_buffer to handle arbitrary repositories tag: allow lookup_tag to handle arbitrary repositories commit: allow lookup_commit to handle arbitrary repositories tree: allow lookup_tree to handle arbitrary repositories blob: allow lookup_blob to handle arbitrary repositories object: allow lookup_object to handle arbitrary repositories object: allow object_as_type to handle arbitrary repositories tag: add repository argument to deref_tag tag: add repository argument to parse_tag_buffer tag: add repository argument to lookup_tag ...
2018-08-02Merge branch 'ds/commit-graph-fsck'Libravatar Junio C Hamano1-2/+8
"git fsck" learns to make sure the optional commit-graph file is in a sane state. * ds/commit-graph-fsck: (23 commits) coccinelle: update commit.cocci commit-graph: update design document gc: automatically write commit-graph files commit-graph: add '--reachable' option commit-graph: use string-list API for input fsck: verify commit-graph commit-graph: verify contents match checksum commit-graph: test for corrupted octopus edge commit-graph: verify commit date commit-graph: verify generation number commit-graph: verify parent list commit-graph: verify root tree OIDs commit-graph: verify objects exist commit-graph: verify corrupt OID fanout and lookup commit-graph: verify required chunks are present commit-graph: verify catches corrupt signature commit-graph: add 'verify' subcommand commit-graph: load a root tree from specific graph commit: force commit to parse from object database commit-graph: parse commit from chosen graph ...
2018-08-02Merge branch 'bc/object-id'Libravatar Junio C Hamano1-2/+2
Conversion from uchar[40] to struct object_id continues. * bc/object-id: pretty: switch hard-coded constants to the_hash_algo sha1-file: convert constants to uses of the_hash_algo log-tree: switch GIT_SHA1_HEXSZ to the_hash_algo->hexsz diff: switch GIT_SHA1_HEXSZ to use the_hash_algo builtin/merge-recursive: make hash independent builtin/merge: switch to use the_hash_algo builtin/fmt-merge-msg: make hash independent builtin/update-index: simplify parsing of cacheinfo builtin/update-index: convert to using the_hash_algo refs/files-backend: use the_hash_algo for writing refs sha1-name: use the_hash_algo when parsing object names strbuf: allocate space with GIT_MAX_HEXSZ commit: express tree entry constants in terms of the_hash_algo hex: switch to using the_hash_algo tree-walk: replace hard-coded constants with the_hash_algo cache: update object ID functions for the_hash_algo
2018-07-20commit-reach: move walk methods from commit.cLibravatar Derrick Stolee1-358/+0
There are several commit walks in the codebase. Group them together into a new commit-reach.c file and corresponding header. After we group these walks into one place, we can reduce duplicate logic by calling equivalent methods. The method declarations in commit.h are not touched by this commit and will be moved in a following commit. Many consumers need to point to commit-reach.h and that would bloat this commit. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-18Merge branch 'sb/object-store-grafts'Libravatar Junio C Hamano1-36/+41
The conversion to pass "the_repository" and then "a_repository" throughout the object access API continues. * sb/object-store-grafts: commit: allow lookup_commit_graft to handle arbitrary repositories commit: allow prepare_commit_graft to handle arbitrary repositories shallow: migrate shallow information into the object parser path.c: migrate global git_path_* to take a repository argument cache: convert get_graft_file to handle arbitrary repositories commit: convert read_graft_file to handle arbitrary repositories commit: convert register_commit_graft to handle arbitrary repositories commit: convert commit_graft_pos() to handle arbitrary repositories shallow: add repository argument to is_repository_shallow shallow: add repository argument to check_shallow_file_for_update shallow: add repository argument to register_shallow shallow: add repository argument to set_alternate_shallow_file commit: add repository argument to lookup_commit_graft commit: add repository argument to prepare_commit_graft commit: add repository argument to read_graft_file commit: add repository argument to register_commit_graft commit: add repository argument to commit_graft_pos object: move grafts to object parser object-store: move object access functions to object-store.h
2018-07-17commit-graph: add repo arg to graph readersLibravatar Jonathan Tan1-3/+3
Add a struct repository argument to the functions in commit-graph.h that read the commit graph. (This commit does not affect functions that write commit graphs.) Because the commit graph functions can now read the commit graph of any repository, the global variable core_commit_graph has been removed. Instead, the config option core.commitGraph is now read on the first time in a repository that a commit is attempted to be parsed using its commit graph. This commit includes a test that exercises the functionality on an arbitrary repository that is not the_repository. Signed-off-by: Jonathan Tan <jonathantanmy@google.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-07-17Merge branch 'ds/commit-graph-fsck' into jt/commit-graph-per-object-storeLibravatar Junio C Hamano1-2/+8
* ds/commit-graph-fsck: (23 commits) coccinelle: update commit.cocci commit-graph: update design document gc: automatically write commit-graph files commit-graph: add '--reachable' option commit-graph: use string-list API for input fsck: verify commit-graph commit-graph: verify contents match checksum commit-graph: test for corrupted octopus edge commit-graph: verify commit date commit-graph: verify generation number commit-graph: verify parent list commit-graph: verify root tree OIDs commit-graph: verify objects exist commit-graph: verify corrupt OID fanout and lookup commit-graph: verify required chunks are present commit-graph: verify catches corrupt signature commit-graph: add 'verify' subcommand commit-graph: load a root tree from specific graph commit: force commit to parse from object database commit-graph: parse commit from chosen graph ...