Commit Graph

515 Commits

Author SHA1 Message Date
Junio C Hamano
0e07c1cd83 Merge branch 'jk/cleanup-object-parsing-and-fsck'
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
  ...
2019-12-01 09:04:28 -08:00
Junio C Hamano
5c8c0a0d78 Merge branch 'pw/post-commit-from-sequencer'
"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
2019-11-10 18:02:12 +09:00
Jeff King
228c78fbd4 commit, tag: don't set parsed bit for parse failures
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>
2019-10-28 14:04:49 +09:00
Jeff King
12736d2f02 parse_commit_buffer(): treat lookup_tree() failure as parse error
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>
2019-10-21 11:15:23 +09:00
Jeff King
c78fe00459 parse_commit_buffer(): treat lookup_commit() failure as parse error
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>
2019-10-21 11:15:23 +09:00
Phillip Wood
49697cb721 move run_commit_hook() to libgit and use it there
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>
2019-10-16 10:30:51 +09:00
Junio C Hamano
80693e3f09 Merge branch 'tb/commit-graph-harden'
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
2019-10-07 11:32:58 +09:00
Junio C Hamano
21ce0b48f3 Merge branch 'mh/release-commit-memory-fix'
Leakfix.

* mh/release-commit-memory-fix:
  commit: free the right buffer in release_commit_memory
2019-09-30 13:19:25 +09:00
Taylor Blau
806278dead commit-graph.c: handle corrupt/missing trees
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>
2019-09-09 10:55:59 -07:00
Mike Hommey
9784f97321 commit: free the right buffer in release_commit_memory
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>
2019-08-26 10:53:25 -07:00
Junio C Hamano
dea6737bb7 Merge branch 'ds/close-object-store' into maint
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
2019-07-29 12:38:22 -07:00
Junio C Hamano
a7db4c193d Merge branch 'jk/oidhash'
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
2019-07-09 15:25:43 -07:00
Junio C Hamano
e1168940ce Merge branch 'ds/commit-graph-write-refactor'
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
2019-07-09 15:25:36 -07:00
Jeff King
a378509e1c object: convert create_object() to use object_id
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>
2019-06-20 10:20:51 -07:00
Jeff King
d0229abd93 object: convert lookup_object() to use object_id
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>
2019-06-20 10:18:09 -07:00
Derrick Stolee
c7944050af commit-graph: fix the_repository reference
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>
2019-05-13 11:52:19 +09:00
Junio C Hamano
ea2dab1abb Merge branch 'tb/unexpected'
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
2019-05-09 00:37:25 +09:00
Nguyễn Thái Ngọc Duy
301b8c7f40 commit.c: add repo_get_commit_tree()
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>
2019-04-16 18:56:51 +09:00
Nguyễn Thái Ngọc Duy
a133c40b23 commit.cocci: refactor code, avoid double rewrite
"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>
2019-04-16 18:56:51 +09:00
Jeff King
834876630b get_commit_tree(): return NULL for broken tree
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>
2019-04-10 12:59:39 +09:00
Junio C Hamano
b99a579f8e Merge branch 'sb/more-repo-in-api'
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
  ...
2019-02-05 14:26:09 -08:00
Stefan Beller
6a7895fd8a commit: prepare free_commit_buffer and release_commit_memory for any repo
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>
2018-12-28 10:06:33 -08:00
Junio C Hamano
6d2035ee60 Merge branch 'jk/verify-sig-merge-into-void'
"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
2018-11-18 18:23:54 +09:00
Junio C Hamano
62ca33e02a Merge branch 'ds/reachable-topo-order'
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
2018-11-18 18:23:52 +09:00
Stefan Beller
70315373ae commit: prepare repo_unuse_commit_buffer to handle any repo
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-14 17:22:40 +09:00
Stefan Beller
07de3fd840 commit: prepare get_commit_buffer to handle any repo
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2018-11-14 17:22:40 +09:00
Stefan Beller
9e5252abd1 commit: allow parse_commit* to handle any repo
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>
2018-11-14 17:22:40 +09:00
Jeff King
edc4d47d54 merge: extract verify_merge_signature() helper
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>
2018-11-07 10:11:09 +09:00
Derrick Stolee
5284fc5cc9 commit/revisions: bookkeeping before refactoring
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>
2018-11-02 12:14:22 +09:00
Junio C Hamano
0293121717 Merge branch 'pk/rebase-in-c-4-opts'
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"
2018-11-02 11:04:55 +09:00
Junio C Hamano
6d8f8ebb74 Merge branch 'ds/commit-graph-with-grafts'
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
2018-10-16 16:15:59 +09:00
Pratik Karki
103148aad8 merge-base --fork-point: extract libified function
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>
2018-10-11 14:12:45 +09:00
Junio C Hamano
769af0fd9e Merge branch 'jk/cocci'
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
2018-09-17 13:53:57 -07:00
Junio C Hamano
fba9654364 Merge branch 'jk/trailer-fixes'
"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
2018-09-17 13:53:54 -07:00
Junio C Hamano
1b7a91da71 Merge branch 'ds/reachable'
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
2018-09-17 13:53:52 -07:00
Junio C Hamano
0a866db570 Merge branch 'ds/commit-graph-lockfile-fix'
"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
2018-09-04 14:31:39 -07:00
Derrick Stolee
091f4cf358 commit: don't use generation numbers if not needed
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>
2018-08-30 11:17:57 -07:00
Jeff King
9001dc2a74 convert "oidcmp() != 0" to "!oideq()"
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>
2018-08-29 11:32:49 -07:00
Junio C Hamano
1392c5d289 Merge branch 'js/larger-timestamps'
Portability fix.

* js/larger-timestamps:
  commit: use timestamp_t for author_date_slab
2018-08-27 14:33:44 -07:00
Jeff King
66e83d9b41 append_signoff: use size_t for string offsets
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>
2018-08-23 10:08:51 -07:00
Derrick Stolee
1820703045 commit: use timestamp_t for author_date_slab
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>
2018-08-21 14:08:18 -07:00
Derrick Stolee
20fd6d5799 commit-graph: not compatible with grafts
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>
2018-08-21 10:22:51 -07:00
Junio C Hamano
78a72ad4f8 Merge branch 'jt/commit-graph-per-object-store'
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
2018-08-02 15:30:47 -07:00
Junio C Hamano
3a2a1dc170 Merge branch 'sb/object-store-lookup'
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
  ...
2018-08-02 15:30:42 -07:00
Junio C Hamano
b006f01ab5 Merge branch 'ds/commit-graph-fsck'
"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
  ...
2018-08-02 15:30:40 -07:00
Junio C Hamano
37aac3e408 Merge branch 'bc/object-id'
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
2018-08-02 15:30:39 -07:00
Derrick Stolee
5227c38566 commit-reach: move walk methods from commit.c
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>
2018-07-20 15:38:54 -07:00
Junio C Hamano
00624d608c Merge branch 'sb/object-store-grafts'
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
2018-07-18 12:20:28 -07:00
Jonathan Tan
dade47c06c commit-graph: add repo arg to graph readers
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>
2018-07-17 15:47:48 -07:00
Junio C Hamano
8295296458 Merge branch 'ds/commit-graph-fsck' into jt/commit-graph-per-object-store
* 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
  ...
2018-07-17 15:46:19 -07:00