Optimize unnecessary full-tree diff away from "git log -L" machinery.
* sg/line-log-tree-diff-optim:
line-log: avoid unnecessary full tree diffs
line-log: extract pathspec parsing from line ranges into a helper function
With rename detection enabled the line-level log is able to trace the
evolution of line ranges across whole-file renames [1]. Alas, to
achieve that it uses the diff machinery very inefficiently, making the
operation very slow [2]. And since rename detection is enabled by
default, the line-level log is very slow by default.
When the line-level log processes a commit with rename detection
enabled, it currently does the following (see queue_diffs()):
1. Computes a full tree diff between the commit and (one of) its
parent(s), i.e. invokes diff_tree_oid() with an empty
'diffopt->pathspec'.
2. Checks whether any paths in the line ranges were modified.
3. Checks whether any modified paths in the line ranges are missing
in the parent commit's tree.
4. If there is such a missing path, then calls diffcore_std() to
figure out whether the path was indeed renamed based on the
previously computed full tree diff.
5. Continues doing stuff that are unrelated to the slowness.
So basically the line-level log computes a full tree diff for each
commit-parent pair in step (1) to be used for rename detection in step
(4) in the off chance that an interesting path is missing from the
parent.
Avoid these expensive and mostly unnecessary full tree diffs by
limiting the diffs to paths in the line ranges. This is much cheaper,
and makes step (2) unnecessary. If it turns out that an interesting
path is missing from the parent, then fall back and compute a full
tree diff, so the rename detection will still work.
Care must be taken when to update the pathspec used to limit the diff
in case of renames. A path might be renamed on one branch and
modified on several parallel running branches, and while processing
commits on these branches the line-level log might have to alternate
between looking at a path's new and old name. However, at any one
time there is only a single 'diffopt->pathspec'.
So add a step (0) to the above to ensure that the paths in the
pathspec match the paths in the line ranges associated with the
currently processed commit, and re-parse the pathspec from the paths
in the line ranges if they differ.
The new test cases include a specially crafted piece of history with
two merged branches and two files, where each branch modifies both
files, renames on of them, and then modifies both again. Then two
separate 'git log -L' invocations check the line-level log of each of
those two files, which ensures that at least one of those invocations
have to do that back-and-forth between the file's old and new name (no
matter which branch is traversed first). 't/t4211-line-log.sh'
already contains two tests involving renames, they don't don't trigger
this back-and-forth.
Avoiding these unnecessary full tree diffs can have huge impact on
performance, especially in big repositories with big trees and mergy
history. Tracing the evolution of a function through the whole
history:
# git.git
$ time git --no-pager log -L:read_alternate_refs:sha1-file.c v2.23.0
Before:
real 0m8.874s
user 0m8.816s
sys 0m0.057s
After:
real 0m2.516s
user 0m2.456s
sys 0m0.060s
# linux.git
$ time ~/src/git/git --no-pager log \
-L:build_restore_work_registers:arch/mips/mm/tlbex.c v5.2
Before:
real 3m50.033s
user 3m48.041s
sys 0m0.300s
After:
real 0m2.599s
user 0m2.466s
sys 0m0.157s
That's just over 88x speedup.
[1] Line-level log's rename following is quite similar to 'git log
--follow path', with the notable differences that it does handle
multiple paths at once as well, and that it doesn't show the
commit performing the rename if it's an exact rename.
[2] This slowness might not have been apparent initially, because back
when the line-level log feature was introduced rename detection
was not yet enabled by default; 12da1d1f6f (Implement line-history
search (git log -L), 2013-03-28) and 5404c116aa (diff: activate
diff.renames by default, 2016-02-25).
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A helper function to parse the paths involved in the line ranges and
to turn them into a pathspec will be useful in the next patch.
Signed-off-by: SZEDER Gábor <szeder.dev@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"git merge-recursive" backend recently learned a new heuristics to
infer file movement based on how other files in the same directory
moved. As this is inherently less robust heuristics than the one
based on the content similarity of the file itself (rather than
based on what its neighbours are doing), it sometimes gives an
outcome unexpected by the end users. This has been toned down to
leave the renamed paths in higher/conflicted stages in the index so
that the user can examine and confirm the result.
* en/merge-directory-renames:
merge-recursive: switch directory rename detection default
merge-recursive: give callers of handle_content_merge() access to contents
merge-recursive: track information associated with directory renames
t6043: fix copied test description to match its purpose
merge-recursive: switch from (oid,mode) pairs to a diff_filespec
merge-recursive: cleanup handle_rename_* function signatures
merge-recursive: track branch where rename occurred in rename struct
merge-recursive: remove ren[12]_other fields from rename_conflict_info
merge-recursive: shrink rename_conflict_info
merge-recursive: move some struct declarations together
merge-recursive: use 'ci' for rename_conflict_info variable name
merge-recursive: rename locals 'o' and 'a' to 'obuf' and 'abuf'
merge-recursive: rename diff_filespec 'one' to 'o'
merge-recursive: rename merge_options argument from 'o' to 'opt'
Use 'unsigned short' for mode, like diff_filespec does
struct diff_filespec defines mode to be an 'unsigned short'. Several
other places in the API which we'd like to interact with using a
diff_filespec used a plain unsigned (or unsigned int). This caused
problems when taking addresses, so switch to unsigned short.
Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
When "-L" is in use, we ignore any diff output format that the user
provides to us, and just always print a patch (with extra context lines
covering the whole area of interest). It's not entirely clear what we
should do with all formats (e.g., should "--stat" show just the diffstat
of the touched lines, or the stat for the whole file?).
But "-s" is pretty clear: the user probably wants to see just the
commits that touched those lines, without any diff at all. Let's at
least make that work.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff and textconv code has so widespread use that it's hard to simply
update their api and all call sites at once because it would result in
a big patch. For now reduce the_index references to two places:
diff_setup() and fill_textconv().
Signed-off-by: Nguyễn Thái Ngọc Duy <pclouds@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Parsing of -L[<N>][,[<M>]] parameters "git blame" and "git log"
take has been tweaked.
* is/parsing-line-range:
log: prevent error if line range ends past end of file
blame: prevent error if range ends past end of file
Add a repository argument to allow the callers of deref_tag
to be more specific about which repository to act on. This is a small
mechanical change; it doesn't change the implementation to handle
repositories other than the_repository yet.
As with the previous commits, use a macro to catch callers passing a
repository other than the_repository at compile time.
Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
If the -L option is used to specify a line range in git log, and the end
of the range is past the end of the file, git will fail with a fatal
error. This commit prevents such behaviour - instead we perform the log
for existing lines within the specified range.
This commit also fixes a corner case where -L ,-n:file would be treated
as a log over the whole file. Now we treat this as -L 1,-n:file and
blame the first line of the file instead.
Signed-off-by: Isabella Stephens <istephens@atlassian.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The code has been taught to use the duplicated information stored
in the commit-graph file to learn the tree object name for a commit
to avoid opening and parsing the commit object when it makes sense
to do so.
* ds/lazy-load-trees:
coccinelle: avoid wrong transformation suggestions from commit.cocci
commit-graph: lazy-load trees for commits
treewide: replace maybe_tree with accessor methods
commit: create get_commit_tree() method
treewide: rename tree to maybe_tree
In anticipation of making trees load lazily, create a Coccinelle
script (contrib/coccinelle/commit.cocci) to ensure that all
references to the 'maybe_tree' member of struct commit are either
mutations or accesses through get_commit_tree() or
get_commit_tree_oid().
Apply the Coccinelle script to create the rest of the patch.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Using the commit-graph file to walk commit history removes the large
cost of parsing commits during the walk. This exposes a performance
issue: lookup_tree() takes a large portion of the computation time,
even when Git never uses those trees.
In anticipation of lazy-loading these trees, rename the 'tree' member
of struct commit to 'maybe_tree'. This serves two purposes: it hints
at the future role of possibly being NULL even if the commit has a
valid tree, and it allows for unambiguous transformation from simple
member access (i.e. commit->maybe_tree) to method access.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert get_tree_entry and find_tree_entry to take pointers to struct
object_id.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Rename C++ keyword in order to bring the codebase closer to being able
to be compiled with a C++ compiler.
Signed-off-by: Brandon Williams <bmwill@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
A common pattern to free a piece of memory and assign NULL to the
pointer that used to point at it has been replaced with a new
FREE_AND_NULL() macro.
* ab/free-and-null:
*.[ch] refactoring: make use of the FREE_AND_NULL() macro
coccinelle: make use of the "expression" FREE_AND_NULL() rule
coccinelle: add a rule to make "expression" code use FREE_AND_NULL()
coccinelle: make use of the "type" FREE_AND_NULL() rule
coccinelle: add a rule to make "type" code use FREE_AND_NULL()
git-compat-util: add a FREE_AND_NULL() wrapper around free(ptr); ptr = NULL
Replace occurrences of `free(ptr); ptr = NULL` which weren't caught by
the coccinelle rule. These fall into two categories:
- free/NULL assignments one after the other which coccinelle all put
on one line, which is functionally equivalent code, but very ugly.
- manually spotted occurrences where the NULL assignment isn't right
after the free() call.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Apply the result of the just-added coccinelle rule. This manually
excludes a few occurrences, mostly things that resulted in many
FREE_AND_NULL() on one line, that'll be manually fixed in a subsequent
change.
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The command-line parsing of "git log -L" copied internal data
structures using incorrect size on ILP32 systems.
* vn/line-log-memcpy-size-fix:
line-log: use COPY_ARRAY to fix mis-sized memcpy
The code to parse "git log -L..." command line was buggy when there
are many ranges specified with -L; overrun of the allocated buffer
has been fixed.
* ax/line-log-range-merge-fix:
line-log.c: prevent crash during union of too many ranges
This memcpy meant to get the sizeof a "struct range", not a
"range_set", as the former is what our array holds. Rather
than swap out the types, let's convert this site to
COPY_ARRAY, which avoids the problem entirely (and confirms
that the src and dst types match).
Note for curiosity's sake that this bug doesn't trigger on
I32LP64 systems, but does on ILP32 systems. The mistaken
"struct range_set" has two ints and a pointer. That's 16
bytes on LP64, or 12 on ILP32. The correct "struct range"
type has two longs, which is also 16 on LP64, but only 8 on
ILP32.
Likewise an IL32P64 system would experience the bug.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The existing implementation of range_set_union does not correctly
reallocate memory, leading to a heap overflow when it attempts to union
more than 24 separate line ranges.
For struct range_set *out to grow correctly it must have out->nr set to
the current size of the buffer when it is passed to range_set_grow.
However, the existing implementation of range_set_union only updates
out->nr at the end of the function, meaning that it is always zero
before this. This results in range_set_grow never growing the buffer, as
well as some of the union logic itself being incorrect as !out->nr is
always true.
The reason why 24 is the limit is that the first allocation of size 1
ends up allocating a buffer of size 24 (due to the call to alloc_nr in
ALLOC_GROW). This goes some way to explain why this hasn't been
caught before.
Fix the problem by correctly updating out->nr after reallocating the
range_set. As this results in out->nr containing the same value as the
variable o, replace o with out->nr as well.
Finally, add a new test to help prevent the problem reoccurring in the
future. Thanks to Vegard Nossum for writing the test.
Signed-off-by: Allan Xavier <allan.x.xavier@oracle.com>
Reviewed-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Apply the semantic patch contrib/coccinelle/qsort.cocci to the code
base, replacing calls of qsort(3) with QSORT. The resulting code is
shorter and supports empty arrays with NULL pointers.
Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The commands in the "log/diff" family have had an FILE* pointer in the
data structure they pass around for a long time, but some codepaths
used to always write to the standard output. As a preparatory step
to make "git format-patch" available to the internal callers, these
codepaths have been updated to consistently write into that FILE*
instead.
* js/log-to-diffopt-file:
mingw: fix the shortlog --output=<file> test
diff: do not color output when --color=auto and --output=<file> is given
t4211: ensure that log respects --output=<file>
shortlog: respect the --output=<file> setting
format-patch: use stdout directly
format-patch: avoid freopen()
format-patch: explicitly switch off color when writing to files
shortlog: support outputting to streams other than stdout
graph: respect the diffopt.file setting
line-log: respect diffopt's configured output file stream
log-tree: respect diffopt's configured output file stream
log: prepare log/log-tree to reuse the diffopt.close_file attribute
Now that this struct's sha1 member is called "oid", update the comment
and the sha1_valid member to be called "oid_valid" instead. The
following Coccinelle semantic patch was used to implement this, followed
by the transformations in object_id.cocci:
@@
struct diff_filespec o;
@@
- o.sha1_valid
+ o.oid_valid
@@
struct diff_filespec *p;
@@
- p->sha1_valid
+ p->oid_valid
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert struct diff_filespec's sha1 member to use a struct object_id
called "oid" instead. The following Coccinelle semantic patch was used
to implement this, followed by the transformations in object_id.cocci:
@@
struct diff_filespec o;
@@
- o.sha1
+ o.oid.hash
@@
struct diff_filespec *p;
@@
- p->sha1
+ p->oid.hash
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The diff machinery can optionally output to a file stream other than
stdout, by overriding diffopt.file. In such a case, the rest of the
log tree machinery should also write to that stream.
Currently, there is no user of the line level log that wants to
redirect output to a file. Therefore, one might argue that it is
superfluous to support that now. However, it is better to be
consistent now, rather than to face hard-to-debug problems later.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
These callers appear to expect that deref_tag() is to peel one layer
of a tag, but the function does not work that way; it has its own
loop to unwrap tags until an object that is not a tag appears.
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Each of these cases can be converted to use ALLOC_ARRAY or
REALLOC_ARRAY, which has two advantages:
1. It automatically checks the array-size multiplication
for overflow.
2. It always uses sizeof(*array) for the element-size,
so that it can never go out of sync with the declared
type of the array.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
There are many manual argv allocations that predate the
argv_array API. Switching to that API brings a few
advantages:
1. We no longer have to manually compute the correct final
array size (so it's one less thing we can screw up).
2. In many cases we had to make a separate pass to count,
then allocate, then fill in the array. Now we can do it
in one pass, making the code shorter and easier to
follow.
3. argv_array handles memory ownership for us, making it
more obvious when things should be free()d and and when
not.
Most of these cases are pretty straightforward. In some, we
switch from "run_command_v" to "run_command" which lets us
directly use the argv_array embedded in "struct
child_process".
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Convert all instances of get_object_hash to use an appropriate reference
to the hash member of the oid member of struct object. This provides no
functional change, as it is essentially a macro substitution.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
Convert most instances where the sha1 member of struct object is
dereferenced to use get_object_hash. Most instances that are passed to
functions that have versions taking struct object_id, such as
get_sha1_hex/get_oid_hex, or instances that can be trivially converted
to use struct object_id instead, are not converted.
Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net>
Signed-off-by: Jeff King <peff@peff.net>
When we call into xdiff to perform a diff, we generally lose
the return code completely. Typically by ignoring the return
of our xdi_diff wrapper, but sometimes we even propagate
that return value up and then ignore it later. This can
lead to us silently producing incorrect diffs (e.g., "git
log" might produce no output at all, not even a diff header,
for a content-level diff).
In practice this does not happen very often, because the
typical reason for xdiff to report failure is that it
malloc() failed (it uses straight malloc, and not our
xmalloc wrapper). But it could also happen when xdiff
triggers one our callbacks, which returns an error (e.g.,
outf() in builtin/rerere.c tries to report a write failure
in this way). And the next patch also plans to add more
failure modes.
Let's notice an error return from xdiff and react
appropriately. In most of the diff.c code, we can simply
die(), which matches the surrounding code (e.g., that is
what we do if we fail to load a file for diffing in the
first place). This is not that elegant, but we are probably
better off dying to let the user know there was a problem,
rather than simply generating bogus output.
We could also just die() directly in xdi_diff, but the
callers typically have a bit more context, and can provide a
better message (and if we do later decide to pass errors up,
we're one step closer to doing so).
There is one interesting case, which is in diff_grep(). Here
if we cannot generate the diff, there is nothing to match,
and we silently return "no hits". This is actually what the
existing code does already, but we make it a little more
explicit.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
"color.diff.plain" was a misnomer; give it 'color.diff.context' as
a more logical synonym.
* jk/color-diff-plain-is-context:
diff.h: rename DIFF_PLAIN color slot to DIFF_CONTEXT
diff: accept color.diff.context as a synonym for "plain"
The latter is a much more descriptive name (and we support
"color.diff.context" now). This also updates the name of any
local variables which were used to store the color.
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The old message did not mention the :regex:file form.
To avoid overly long lines, split the message into two lines (in case
item->string is long, it will be the only part truncated in a narrow
terminal).
Signed-off-by: Matthieu Moy <Matthieu.Moy@imag.fr>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
The `filepair` is assigned new memory with any iteration via
process_diff_filepair, so free it before the current iteration ends.
Signed-off-by: Stefan Beller <sbeller@google.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
