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2022-01-05Merge branch 'pw/diff-color-moved-fix'Libravatar Junio C Hamano1-245/+186
Correctness and performance update to "diff --color-moved" feature. * pw/diff-color-moved-fix: diff --color-moved: intern strings diff: use designated initializers for emitted_diff_symbol diff --color-moved-ws=allow-indentation-change: improve hash lookups diff --color-moved: stop clearing potential moved blocks diff --color-moved: shrink potential moved blocks as we go diff --color-moved: unify moved block growth functions diff --color-moved: call comparison function directly diff --color-moved-ws=allow-indentation-change: simplify and optimize diff: simplify allow-indentation-change delta calculation diff --color-moved: avoid false short line matches and bad zebra coloring diff --color-moved=zebra: fix alternate coloring diff --color-moved: rewind when discarding pmb diff --color-moved: factor out function diff --color-moved: clear all flags on blocks that are too short diff --color-moved: add perf tests
2021-12-09diff --color-moved: intern stringsLibravatar Phillip Wood1-78/+96
Taking inspiration from xdl_classify_record() assign an id to each addition and deletion such that lines that match for the current --color-moved-ws mode share the same unique id. This reduces the number of hash lookups a little (calculating the ids still involves one hash lookup per line) but the main benefit is that when growing blocks of potentially moved lines we can replace string comparisons which involve chasing a pointer with a simple integer comparison. On a large diff this commit reduces the time to run 'diff --color-moved' by 37% compared to the previous commit and 31% compared to master, for 'diff --color-moved-ws=allow-indentation-change' the reduction is 28% compared to the previous commit and 96% compared to master. There is little change in the performance of 'git log --patch' as the diffs are smaller. Test HEAD^ HEAD --------------------------------------------------------------------------------------------------------------- 4002.1: diff --no-color-moved --no-color-moved-ws large change 0.38(0.33+0.05) 0.38(0.33+0.05) +0.0% 4002.2: diff --color-moved --no-color-moved-ws large change 0.88(0.81+0.06) 0.55(0.50+0.04) -37.5% 4002.3: diff --color-moved-ws=allow-indentation-change large change 0.85(0.79+0.06) 0.61(0.54+0.06) -28.2% 4002.4: log --no-color-moved --no-color-moved-ws 1.16(1.07+0.08) 1.15(1.09+0.05) -0.9% 4002.5: log --color-moved --no-color-moved-ws 1.31(1.22+0.08) 1.29(1.19+0.09) -1.5% 4002.6: log --color-moved-ws=allow-indentation-change 1.32(1.24+0.08) 1.31(1.18+0.13) -0.8% Test master HEAD --------------------------------------------------------------------------------------------------------------- 4002.1: diff --no-color-moved --no-color-moved-ws large change 0.38 (0.33+0.05) 0.38(0.33+0.05) +0.0% 4002.2: diff --color-moved --no-color-moved-ws large change 0.80 (0.75+0.04) 0.55(0.50+0.04) -31.2% 4002.3: diff --color-moved-ws=allow-indentation-change large change 14.20(14.15+0.05) 0.61(0.54+0.06) -95.7% 4002.4: log --no-color-moved --no-color-moved-ws 1.15 (1.05+0.09) 1.15(1.09+0.05) +0.0% 4002.5: log --color-moved --no-color-moved-ws 1.30 (1.19+0.11) 1.29(1.19+0.09) -0.8% 4002.6: log --color-moved-ws=allow-indentation-change 1.70 (1.63+0.06) 1.31(1.18+0.13) -22.9% Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff: use designated initializers for emitted_diff_symbolLibravatar Phillip Wood1-1/+3
This makes it clearer which fields are being explicitly initialized and will simplify the next commit where we add a new field to the struct. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved-ws=allow-indentation-change: improve hash lookupsLibravatar Phillip Wood1-46/+19
As libxdiff does not have a whitespace flag to ignore the indentation the code for --color-moved-ws=allow-indentation-change uses XDF_IGNORE_WHITESPACE and then filters out any hash lookups where there are non-indentation changes. This filtering is inefficient as we have to perform another string comparison. By using the offset data that we have already computed to skip the indentation we can avoid using XDF_IGNORE_WHITESPACE and safely remove the extra checks which improves the performance by 11% and paves the way for the elimination of string comparisons in the next commit. This change slightly increases the run time of other --color-moved modes. This could be avoided by using different comparison functions for the different modes but after the next two commits there is no measurable benefit in doing so. There is a change in behavior for lines that begin with a form-feed or vertical-tab character. Since b46054b374 ("xdiff: use git-compat-util", 2019-04-11) xdiff does not treat '\f' or '\v' as whitespace characters. This means that lines starting with those characters are never considered to be blank and never match a line that does not start with the same character. After this patch a line matching "^[\f\v\r]*[ \t]*$" is considered to be blank by --color-moved-ws=allow-indentation-change and lines beginning "^[\f\v\r]*[ \t]*" can match another line if the suffixes match. This changes the output of git show for d18f76dccf ("compat/regex: use the regex engine from gawk for compat", 2010-08-17) as some lines in the pre-image before a moved block that contain '\f' are now considered moved as well as they match a blank line before the moved lines in the post-image. This commit updates one of the tests to reflect this change. Test HEAD^ HEAD -------------------------------------------------------------------------------------------------------------- 4002.1: diff --no-color-moved --no-color-moved-ws large change 0.38(0.33+0.05) 0.38(0.33+0.05) +0.0% 4002.2: diff --color-moved --no-color-moved-ws large change 0.86(0.82+0.04) 0.88(0.84+0.04) +2.3% 4002.3: diff --color-moved-ws=allow-indentation-change large change 0.97(0.94+0.03) 0.86(0.81+0.05) -11.3% 4002.4: log --no-color-moved --no-color-moved-ws 1.16(1.07+0.09) 1.16(1.06+0.09) +0.0% 4002.5: log --color-moved --no-color-moved-ws 1.32(1.26+0.06) 1.33(1.27+0.05) +0.8% 4002.6: log --color-moved-ws=allow-indentation-change 1.35(1.29+0.06) 1.33(1.24+0.08) -1.5% Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: stop clearing potential moved blocksLibravatar Phillip Wood1-11/+0
moved_block_clear() was introduced in 74d156f4a1 ("diff --color-moved-ws: fix double free crash", 2018-10-04) to free the memory that was allocated when initializing a potential moved block. However since 21536d077f ("diff --color-moved-ws: modify allow-indentation-change", 2018-11-23) initializing a potential moved block no longer allocates any memory. Up until the last commit we were relying on moved_block_clear() to set the `match` pointer to NULL when a block stopped matching, but since that commit we do not clear a moved block that does not match so it does not make sense to clear them elsewhere. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: shrink potential moved blocks as we goLibravatar Phillip Wood1-36/+8
Rather than setting `match` to NULL and then looping over the list of potential matched blocks for a second time to remove blocks with no matches just filter out the blocks with no matches as we go. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: unify moved block growth functionsLibravatar Phillip Wood1-29/+12
After the last two commits pmb_advance_or_null() and pmb_advance_or_null_multi_match() differ only in the comparison they perform. Lets simplify the code by combining them into a single function. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: call comparison function directlyLibravatar Phillip Wood1-4/+7
This change will allow us to easily combine pmb_advance_or_null() and pmb_advance_or_null_multi_match() in the next commit. Calling xdiff_compare_lines() directly rather than using a function pointer from the hash map has little effect on the run time. Test HEAD^ HEAD ------------------------------------------------------------------------------------------------------------- 4002.1: diff --no-color-moved --no-color-moved-ws large change 0.38(0.35+0.03) 0.38(0.32+0.06) +0.0% 4002.2: diff --color-moved --no-color-moved-ws large change 0.87(0.83+0.04) 0.87(0.80+0.06) +0.0% 4002.3: diff --color-moved-ws=allow-indentation-change large change 0.97(0.92+0.04) 0.97(0.93+0.04) +0.0% 4002.4: log --no-color-moved --no-color-moved-ws 1.17(1.06+0.10) 1.16(1.10+0.05) -0.9% 4002.5: log --color-moved --no-color-moved-ws 1.32(1.24+0.08) 1.31(1.22+0.09) -0.8% 4002.6: log --color-moved-ws=allow-indentation-change 1.36(1.25+0.10) 1.35(1.25+0.10) -0.7% Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved-ws=allow-indentation-change: simplify and optimizeLibravatar Phillip Wood1-50/+20
If we already have a block of potentially moved lines then as we move down the diff we need to check if the next line of each potentially moved line matches the current line of the diff. The implementation of --color-moved-ws=allow-indentation-change was needlessly performing this check on all the lines in the diff that matched the current line rather than just the current line. To exacerbate the problem finding all the other lines in the diff that match the current line involves a fuzzy lookup so we were wasting even more time performing a second comparison to filter out the non-matching lines. Fixing this reduces time to run git diff --color-moved-ws=allow-indentation-change v2.28.0 v2.29.0 by 93% compared to master and simplifies the code. Test HEAD^ HEAD --------------------------------------------------------------------------------------------------------------- 4002.1: diff --no-color-moved --no-color-moved-ws large change 0.38 (0.35+0.03) 0.38(0.35+0.03) +0.0% 4002.2: diff --color-moved --no-color-moved-ws large change 0.86 (0.80+0.06) 0.87(0.83+0.04) +1.2% 4002.3: diff --color-moved-ws=allow-indentation-change large change 19.01(18.93+0.06) 0.97(0.92+0.04) -94.9% 4002.4: log --no-color-moved --no-color-moved-ws 1.16 (1.06+0.09) 1.17(1.06+0.10) +0.9% 4002.5: log --color-moved --no-color-moved-ws 1.32 (1.25+0.07) 1.32(1.24+0.08) +0.0% 4002.6: log --color-moved-ws=allow-indentation-change 1.71 (1.64+0.06) 1.36(1.25+0.10) -20.5% Test master HEAD --------------------------------------------------------------------------------------------------------------- 4002.1: diff --no-color-moved --no-color-moved-ws large change 0.38 (0.33+0.05) 0.38(0.35+0.03) +0.0% 4002.2: diff --color-moved --no-color-moved-ws large change 0.80 (0.75+0.04) 0.87(0.83+0.04) +8.7% 4002.3: diff --color-moved-ws=allow-indentation-change large change 14.20(14.15+0.05) 0.97(0.92+0.04) -93.2% 4002.4: log --no-color-moved --no-color-moved-ws 1.15 (1.05+0.09) 1.17(1.06+0.10) +1.7% 4002.5: log --color-moved --no-color-moved-ws 1.30 (1.19+0.11) 1.32(1.24+0.08) +1.5% 4002.6: log --color-moved-ws=allow-indentation-change 1.70 (1.63+0.06) 1.36(1.25+0.10) -20.0% Helped-by: Jeff King <peff@peff.net> Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff: simplify allow-indentation-change delta calculationLibravatar Phillip Wood1-11/+2
Now that we reliably end a block when the sign changes we don't need the whitespace delta calculation to rely on the sign. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: avoid false short line matches and bad zebra coloringLibravatar Phillip Wood1-6/+11
When marking moved lines it is possible for a block of potential matched lines to extend past a change in sign when there is a sequence of added lines whose text matches the text of a sequence of deleted and added lines. Most of the time either `match` will be NULL or `pmb_advance_or_null()` will fail when the loop encounters a change of sign but there are corner cases where `match` is non-NULL and `pmb_advance_or_null()` successfully advances the moved block despite the change in sign. One consequence of this is highlighting a short line as moved when it should not be. For example -moved line # Correctly highlighted as moved +short line # Wrongly highlighted as moved context +moved line # Correctly highlighted as moved +short line context -short line The other consequence is coloring a moved addition following a moved deletion in the wrong color. In the example below the first "+moved line 3" should be highlighted as newMoved not newMovedAlternate. -moved line 1 # Correctly highlighted as oldMoved -moved line 2 # Correctly highlighted as oldMovedAlternate +moved line 3 # Wrongly highlighted as newMovedAlternate context # Everything else is highlighted correctly +moved line 2 +moved line 3 context +moved line 1 -moved line 3 These false matches are more likely when using --color-moved-ws with the exception of --color-moved-ws=allow-indentation-change which ties the sign of the current whitespace delta to the sign of the line to avoid this problem. The fix is to check that the sign of the new line being matched is the same as the sign of the line that started the block of potential matches. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved=zebra: fix alternate coloringLibravatar Phillip Wood1-2/+2
b0a2ba4776 ("diff --color-moved=zebra: be stricter with color alternation", 2018-11-23) sought to avoid using the alternate colors unless there are two adjacent moved blocks of the same sign. Unfortunately it contains two bugs that prevented it from fixing the problem properly. Firstly `last_symbol` is reset at the start of each iteration of the loop losing the symbol of the last line and secondly when deciding whether to use the alternate color it should be checking if the current line is the same sign of the last line, not a different sign. The combination of the two errors means that we still use the alternate color when we should do but we also use it when we shouldn't. This is most noticable when using --color-moved-ws=allow-indentation-change with hunks like -this line gets indented + this line gets indented where the post image is colored with newMovedAlternate rather than newMoved. While this does not matter much, the next commit will change the coloring to be correct in this case, so lets fix the bug here to make it clear why the output is changing and add a regression test. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: rewind when discarding pmbLibravatar Phillip Wood1-5/+23
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: factor out functionLibravatar Phillip Wood1-17/+34
This code is quite heavily indented and having it in its own function simplifies an upcoming change. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-12-09diff --color-moved: clear all flags on blocks that are too shortLibravatar Phillip Wood1-3/+3
If a block of potentially moved lines is not long enough then the DIFF_SYMBOL_MOVED_LINE flag is cleared on the matching lines so they are not marked as moved. To avoid problems when we start rewinding after an unsuccessful match in a couple of commits time make sure all the move related flags are cleared, not just DIFF_SYMBOL_MOVED_LINE. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-11-25run-command API users: use strvec_push(), not argv constructionLibravatar Ævar Arnfjörð Bjarmason1-6/+2
Change a pattern of hardcoding an "argv" array size, populating it and assigning to the "argv" member of "struct child_process" to instead use "strvec_push()" to add data to the "args" member. As noted in the preceding commit this moves us further towards being able to remove the "argv" member in a subsequent commit These callers could have used strvec_pushl(), but moving to strvec_push() makes the diff easier to read, and keeps the arguments aligned as before. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-27*.[ch] *_INIT macros: use { 0 } for a "zero out" idiomLibravatar Ævar Arnfjörð Bjarmason1-2/+2
In C it isn't required to specify that all members of a struct are zero'd out to 0, NULL or '\0', just providing a "{ 0 }" will accomplish that. Let's also change code that provided N zero'd fields to just provide one, and change e.g. "{ NULL }" to "{ 0 }" for consistency. I.e. even if the first member is a pointer let's use "0" instead of "NULL". The point of using "0" consistently is to pick one, and to not have the reader wonder why we're not using the same pattern everywhere. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-09-09diff: ignore sparse paths in diffstatLibravatar Derrick Stolee1-0/+8
The diff_populate_filespec() method is used to describe the diff after a merge operation is complete. In order to avoid expanding a sparse index, the reuse_worktree_file() needs to be adapted to ignore files that are outside of the sparse-checkout cone. The file names and OIDs used for this check come from the merged tree in the case of the ORT strategy, not the index, hence the ability to look into these paths without having already expanded the index. The work done by reuse_worktree_file() is only an optimization, and requires the file being on disk for it to be of any value. Thus, it is safe to exit the method early if we do not expect the file on disk. Signed-off-by: Derrick Stolee <dstolee@microsoft.com> Reviewed-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-08-06Merge branch 'ab/pickaxe-pcre2'Libravatar Junio C Hamano1-1/+1
* ab/pickaxe-pcre2: diff: --pickaxe-all typofix
2021-08-04diff: --pickaxe-all typofixLibravatar Bagas Sanjaya1-1/+1
When I was fixing fuzzies as I updating po/id.po for 2.33.0 l10n round, I noticed a triple-dash typo (--pickaxe-all) at diff.c, which according to git-diff(1) manpage, the correct option name should be --pickaxe-all. Fix the typo. Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com> Acked-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-28Merge branch 'en/rename-limits-doc'Libravatar Junio C Hamano1-2/+2
Documentation on "git diff -l<n>" and diff.renameLimit have been updated, and the defaults for these limits have been raised. * en/rename-limits-doc: rename: bump limit defaults yet again diffcore-rename: treat a rename_limit of 0 as unlimited doc: clarify documentation for rename/copy limits diff: correct warning message when renameLimit exceeded
2021-07-15rename: bump limit defaults yet againLibravatar Elijah Newren1-1/+1
These were last bumped in commit 92c57e5c1d29 (bump rename limit defaults (again), 2011-02-19), and were bumped both because processors had gotten faster, and because people were getting ugly merges that caused problems and reporting it to the mailing list (suggesting that folks were willing to spend more time waiting). Since that time: * Linus has continued recommending kernel folks to set diff.renameLimit=0 (maps to 32767, currently) * Folks with repositories with lots of renames were happy to set merge.renameLimit above 32767, once the code supported that, to get correct cherry-picks * Processors have gotten faster * It has been discovered that the timing methodology used last time probably used too large example files. The last point is probably worth explaining a bit more: * The "average" file size used appears to have been average blob size in the linux kernel history at the time (probably v2.6.25 or something close to it). * Since bigger files are modified more frequently, such a computation weights towards larger files. * Larger files may be more likely to be modified over time, but are not more likely to be renamed -- the mean and median blob size within a tree are a bit higher than the mean and median of blob sizes in the history leading up to that version for the linux kernel. * The mean blob size in v2.6.25 was half the average blob size in history leading to that point * The median blob size in v2.6.25 was about 40% of the mean blob size in v2.6.25. * Since the mean blob size is more than double the median blob size, any file as big as the mean will not be compared to any files of median size or less (because they'd be more than 50% dissimilar). * Since it is the number of files compared that provides the O(n^2) behavior, median-sized files should matter more than mean-sized ones. The combined effect of the above is that the file size used in past calculations was likely about 5x too large. Combine that with a CPU performance improvement of ~30%, and we can increase the limits by a factor of sqrt(5/(1-.3)) = 2.67, while keeping the original stated time limits. Keeping the same approximate time limit probably makes sense for diff.renameLimit (there is no progress feedback in e.g. git log -p), but the experience above suggests merge.renameLimit could be extended significantly. In fact, it probably would make sense to have an unlimited default setting for merge.renameLimit, but that would likely need to be coupled with changes to how progress is displayed. (See https://lore.kernel.org/git/YOx+Ok%2FEYvLqRMzJ@coredump.intra.peff.net/ for details in that area.) For now, let's just bump the approximate time limit from 10s to 1m. (Note: We do not want to use actual time limits, because getting results that depend on how loaded your system is that day feels bad, and because we don't discover that we won't get all the renames until after we've put in a lot of work rather than just upfront telling the user there are too many files involved.) Using the original time limit of 2s for diff.renameLimit, and bumping merge.renameLimit from 10s to 60s, I found the following timings using the simple script at the end of this commit message (on an AWS c5.xlarge which reports as "Intel(R) Xeon(R) Platinum 8124M CPU @ 3.00GHz"): N Timing 1300 1.995s 7100 59.973s So let's round down to nice even numbers and bump the limits from 400->1000, and from 1000->7000. Here is the measure_rename_perf script (adapted from https://lore.kernel.org/git/20080211113516.GB6344@coredump.intra.peff.net/ in particular to avoid triggering the linear handling from basename-guided rename detection): #!/bin/bash n=$1; shift rm -rf repo mkdir repo && cd repo git init -q -b main mkdata() { mkdir $1 for i in `seq 1 $2`; do (sed "s/^/$i /" <../sample echo tag: $1 ) >$1/$i done } mkdata initial $n git add . git commit -q -m initial mkdata new $n git add . cd new for i in *; do git mv $i $i.renamed; done cd .. git rm -q -rf initial git commit -q -m new time git diff-tree -M -l0 --summary HEAD^ HEAD Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-15diff: correct warning message when renameLimit exceededLibravatar Elijah Newren1-1/+1
The warning when quadratic rename detection was skipped referred to "inexact rename detection". For years, the only linear portion of rename detection was looking for exact renames, so "inexact rename detection" was an accurate way to refer to the quadratic portion of rename detection. However, that changed with commit bd24aa2f97a0 (diffcore-rename: guide inexact rename detection based on basenames, 2021-02-14). Let's instead use the term "exhaustive rename detection" to refer to the quadratic portion. Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-07-13Merge branch 'ab/pickaxe-pcre2'Libravatar Junio C Hamano1-14/+25
Rewrite the backend for "diff -G/-S" to use pcre2 engine when available. * ab/pickaxe-pcre2: (22 commits) xdiff-interface: replace discard_hunk_line() with a flag xdiff users: use designated initializers for out_line pickaxe -G: don't special-case create/delete pickaxe -G: terminate early on matching lines xdiff-interface: allow early return from xdiff_emit_line_fn xdiff-interface: prepare for allowing early return pickaxe -S: slightly optimize contains() pickaxe: rename variables in has_changes() for brevity pickaxe -S: support content with NULs under --pickaxe-regex pickaxe: assert that we must have a needle under -G or -S pickaxe: refactor function selection in diffcore-pickaxe() perf: add performance test for pickaxe pickaxe/style: consolidate declarations and assignments diff.h: move pickaxe fields together again pickaxe: die when --find-object and --pickaxe-all are combined pickaxe: die when -G and --pickaxe-regex are combined pickaxe tests: add missing test for --no-pickaxe-regex being an error pickaxe tests: test for -G, -S and --find-object incompatibility pickaxe tests: add test for "log -S" not being a regex pickaxe tests: add test for diffgrep_consume() internals ...
2021-05-14Merge branch 'pw/word-diff-zero-width-matches'Libravatar Junio C Hamano1-3/+7
The word-diff mode has been taught to work better with a word regexp that can match an empty string. * pw/word-diff-zero-width-matches: word diff: handle zero length matches
2021-05-11xdiff-interface: replace discard_hunk_line() with a flagLibravatar Ævar Arnfjörð Bjarmason1-3/+4
Remove the dummy discard_hunk_line() function added in 3b40a090fd4 (diff: avoid generating unused hunk header lines, 2018-11-02) in favor of having a new XDL_EMIT_NO_HUNK_HDR flag, for use along with the two existing and similar XDL_EMIT_* flags. Unlike the recently amended xdiff_emit_line_fn interface which'll be called in a loop in xdl_emit_diff(), the hunk header is only emitted once. It makes more sense to pass this as a flag than provide a dummy callback because that function may be able to skip doing certain work if it knows the caller is doing nothing with the hunk header. It would be possible to do so in the case of -U0 now, but the benefit of doing so is so small that I haven't bothered. But this leaves the door open to that, and more importantly makes the API use more intuitive. The reason we're putting a flag in the gap between 1<<0 and 1<<2 is that the old 1<<1 flag was removed in 907681e940d (xdiff: drop XDL_EMIT_COMMON, 2016-02-23) without re-ordering the remaining flags. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-11xdiff-interface: prepare for allowing early returnLibravatar Ævar Arnfjörð Bjarmason1-11/+15
Change the function prototype of xdiff_emit_line_fn to return an "int" instead of "void". Change all of those functions to "return 0", nothing checks those return values yet, and no behavior is being changed. In subsequent commits the interface will be changed to allow early return via this new return value. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-11pickaxe: die when --find-object and --pickaxe-all are combinedLibravatar Ævar Arnfjörð Bjarmason1-0/+3
Neither the --pickaxe-all documentation nor --find-object's has ever suggested that you can combine the two. See f506b8e8b5 (git log/diff: add -G<regexp> that greps in the patch text, 2010-08-23) and 15af58c1ad (diffcore: add a pickaxe option to find a specific blob, 2018-01-04). But we've silently tolerated it, which makes the logic in diffcore_pickaxe() harder to reason about. Let's assert that we won't have the two combined. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-11pickaxe: die when -G and --pickaxe-regex are combinedLibravatar Ævar Arnfjörð Bjarmason1-0/+3
When the -G and --pickaxe-regex options are combined we simply ignore the --pickaxe-regex option. Let's die instead as suggested by our documentation, since -G is always a regex. When --pickaxe-regex was added in d01d8c6782 (Support for pickaxe matching regular expressions, 2006-03-29) only the -S option existed. Then when -G was added in f506b8e8b5 (git log/diff: add -G<regexp> that greps in the patch text, 2010-08-23) neither the documentation for --pickaxe-regex was updated accordingly, nor was something like this assertion added. Since 5bc3f0b567 (diffcore-pickaxe doc: document -S and -G properly, 2013-05-31) we've claimed that --pickaxe-regex should only be used with -S, but have silently tolerated combining it with -G, let's die instead. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-05-05word diff: handle zero length matchesLibravatar Phillip Wood1-3/+7
If find_word_boundaries() encounters a zero length match (which can be caused by matching a newline or using '*' instead of '+' in the regex) we stop splitting the input into words which generates an inaccurate diff. To fix this increment the start point when there is a zero length match and try a new match. This is safe as posix regular expressions always return the longest available match so a zero length match means there are no longer matches available from the current position. Commit bf82940dbf1 (color-words: enable REG_NEWLINE to help user, 2009-01-17) prevented matching newlines in negated character classes but it is still possible for the user to have an explicit newline match in the regex which could cause a zero length match. One could argue that having explicit newline matches or using '*' rather than '+' are user errors but it seems to be better to work round them than produce inaccurate diffs. Signed-off-by: Phillip Wood <phillip.wood@dunelm.org.uk> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-27hash: provide per-algorithm null OIDsLibravatar brian m. carlson1-2/+2
Up until recently, object IDs did not have an algorithm member, only a hash. Consequently, it was possible to share one null (all-zeros) object ID among all hash algorithms. Now that we're going to be handling objects from multiple hash algorithms, it's important to make sure that all object IDs have a correct algorithm field. Introduce a per-algorithm null OID, and add it to struct hash_algo. Introduce a wrapper function as well, and use it everywhere we used to use the null_oid constant. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-04-27Use the final_oid_fn to finalize hashing of object IDsLibravatar brian m. carlson1-1/+1
When we're hashing a value which is going to be an object ID, we want to zero-pad that value if necessary. To do so, use the final_oid_fn instead of the final_fn anytime we're going to create an object ID to ensure we perform this operation. Signed-off-by: brian m. carlson <sandals@crustytoothpaste.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-03-13use CALLOC_ARRAYLibravatar René Scharfe1-6/+4
Add and apply a semantic patch for converting code that open-codes CALLOC_ARRAY to use it instead. It shortens the code and infers the element size automatically. Signed-off-by: René Scharfe <l.s.r@web.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-25Merge branch 'jc/diffcore-rotate'Libravatar Junio C Hamano1-0/+21
"git {diff,log} --{skip,rotate}-to=<path>" allows the user to discard diff output for early paths or move them to the end of the output. * jc/diffcore-rotate: diff: --{rotate,skip}-to=<path>
2021-02-16diff: --{rotate,skip}-to=<path>Libravatar Junio C Hamano1-0/+21
In the implementation of "git difftool", there is a case where the user wants to start viewing the diffs at a specific path and continue on to the rest, optionally wrapping around to the beginning. Since it is somewhat cumbersome to implement such a feature as a post-processing step of "git diff" output, let's support it internally with two new options. - "git diff --rotate-to=C", when the resulting patch would show paths A B C D E without the option, would "rotate" the paths to shows patch to C D E A B instead. It is an error when there is no patch for C is shown. - "git diff --skip-to=C" would instead "skip" the paths before C, and shows patch to C D E. Again, it is an error when there is no patch for C is shown. - "git log [-p]" also accepts these two options, but it is not an error if there is no change to the specified path. Instead, the set of output paths are rotated or skipped to the specified path or the first path that sorts after the specified path. Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-11diff: plug memory leak from regcomp() on {log,diff} -ILibravatar Ævar Arnfjörð Bjarmason1-0/+12
Fix a memory leak in 296d4a94e7 (diff: add -I<regex> that ignores matching changes, 2020-10-20) by freeing the memory it allocates in the newly introduced diff_free(). See the previous commit for details on that. This memory leak was intentionally introduced in 296d4a94e7, see the discussion on a previous iteration of it in https://lore.kernel.org/git/xmqqeelycajx.fsf@gitster.c.googlers.com/ At that time freeing the memory was somewhat tedious, but since it isn't anymore with the newly introduced diff_free() let's use it. Let's retain the pattern for diff_free_file() and add a diff_free_ignore_regex(), even though (unlike "diff_free_file") we don't need to call it elsewhere. I think this'll make for more readable code than gradually accumulating a giant diff_free() function, sharing "int i" across unrelated code etc. Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-02-11diff: add an API for deferred freeingLibravatar Ævar Arnfjörð Bjarmason1-4/+16
Add a diff_free() function to free anything we may have allocated in the "diff_options" struct, and the ability to make calling it a noop by setting "no_free" in "diff_options". This is required because when e.g. "git diff" is run we'll allocate things in that struct, use the diff machinery once, and then exit. But if we run e.g. "git log -p" we're going to re-use what we allocated across multiple diff_flush() calls, and only want to free things at the end. We've thus ended up with features like the recently added "diff -I"[1] where we'll leak memory. As it turns out it could have simply used the pattern established in 6ea57703f6 (log: prepare log/log-tree to reuse the diffopt.close_file attribute, 2016-06-22). Manually adding more such flags to things log_tree_commit() every time we need to allocate something would be tedious. Let's instead move that fclose() code it to a new diff_free(), in anticipation of freeing more things in that function in follow-up commits. Some functions such as log_tree_commit() need an idiom of optionally retaining a previous "no_free", as they may either free the memory themselves, or their caller may do so. I'm keeping that idiom in log_show_early() for good measure, even though I don't think it's currently called in this manner. It also gets passed an existing "struct rev_info", so future callers may want to set the "no_free" flag. This change is a bit hard to read because while the freeing pattern we're introducing isn't unusual, the "file" member is a special snowflake. We usually don't want to fclose() it. This is because "file" is usually stdout, in which case we don't want to fclose() it. We only want to opt-in to closing it when we e.g. open a file on the filesystem. Thus the opt-in "close_file" flag. So the API in general just needs a "no_free" flag to defer freeing, but the "file" member still needs its "close_file" flag. This is made more confusing because while refactoring this code we could replace some "close_file=0" with "no_free=1", whereas others need to set both flags. This is because there were some cases where an existing "close_file=0" meant "let's defer deallocation", and others where it meant "we don't want to close this file handle at all". 1. 296d4a94e7 (diff: add -I<regex> that ignores matching changes, 2020-10-20) Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2021-01-25Merge branch 'sj/untracked-files-in-submodule-directory-is-not-dirty'Libravatar Junio C Hamano1-0/+3
"git diff" showed a submodule working tree with untracked cruft as "Submodule commit <objectname>-dirty", but a natural expectation is that the "-dirty" indicator would align with "git describe --dirty", which does not consider having untracked files in the working tree as source of dirtiness. The inconsistency has been fixed. * sj/untracked-files-in-submodule-directory-is-not-dirty: diff: do not show submodule with untracked files as "-dirty"
2020-12-18Merge branch 'jc/diff-I-status-fix'Libravatar Junio C Hamano1-1/+2
"git diff -I<pattern> -exit-code" should exit with 0 status when all the changes match the ignored pattern, but it didn't. * jc/diff-I-status-fix: diff: correct interaction between --exit-code and -I<pattern>
2020-12-16diff: correct interaction between --exit-code and -I<pattern>Libravatar Junio C Hamano1-1/+2
Just like "git diff -w --exit-code" should exit with 0 when ignoring whitespace differences results in no changes shown, if ignoring certain changes with "git diff -I<pattern> --exit-code" result in an empty patch, we should exit with 0. The test suite did not cover the interaction between "--exit-code" and "-w"; add one while adding a new test for "--exit-code" + "-I". Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-12-08diff: do not show submodule with untracked files as "-dirty"Libravatar Sangeeta Jain1-0/+3
Git diff reports a submodule directory as -dirty even when there are only untracked files in the submodule directory. This is inconsistent with what `git describe --dirty` says when run in the submodule directory in that state. Make `--ignore-submodules=untracked` the default for `git diff` when there is no configuration variable or command line option, so that the command would not give '-dirty' suffix to a submodule whose working tree has untracked files, to make it consistent with `git describe --dirty` that is run in the submodule working tree. And also make `--ignore-submodules=none` the default for `git status` so that the user doesn't end up deleting a submodule that has uncommitted (untracked) files. Signed-off-by: Sangeeta Jain <sangunb09@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-21Merge branch 'en/strmap'Libravatar Junio C Hamano1-2/+2
A specialization of hashmap that uses a string as key has been introduced. Hopefully it will see wider use over time. * en/strmap: shortlog: use strset from strmap.h Use new HASHMAP_INIT macro to simplify hashmap initialization strmap: take advantage of FLEXPTR_ALLOC_STR when relevant strmap: enable allocations to come from a mem_pool strmap: add a strset sub-type strmap: split create_entry() out of strmap_put() strmap: add functions facilitating use as a string->int map strmap: enable faster clearing and reusing of strmaps strmap: add more utility functions strmap: new utility functions hashmap: provide deallocation function names hashmap: introduce a new hashmap_partial_clear() hashmap: allow re-use after hashmap_free() hashmap: adjust spacing to fix argument alignment hashmap: add usage documentation explaining hashmap_free[_entries]()
2020-11-21Merge branch 'jk/diff-release-filespec-fix'Libravatar Junio C Hamano1-0/+3
Running "git diff" while allowing external diff in a state with unmerged paths used to segfault, which has been corrected. * jk/diff-release-filespec-fix: t7800: simplify difftool test diff: allow passing NULL to diff_free_filespec_data()
2020-11-06diff: allow passing NULL to diff_free_filespec_data()Libravatar Jinoh Kang1-0/+3
Commit 3aef54e8b8 ("diff: munmap() file contents before running external diff") introduced calls to diff_free_filespec_data in run_external_diff, which may pass NULL pointers. Fix this and prevent any such bugs in the future by making `diff_free_filespec_data(NULL)` a no-op. Fixes: 3aef54e8b8 ("diff: munmap() file contents before running external diff") Signed-off-by: Jinoh Kang <luke1337@theori.io> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-11-02Merge branch 'mk/diff-ignore-regex'Libravatar Junio C Hamano1-0/+23
"git diff" family of commands learned the "-I<regex>" option to ignore hunks whose changed lines all match the given pattern. * mk/diff-ignore-regex: diff: add -I<regex> that ignores matching changes merge-base, xdiff: zero out xpparam_t structures
2020-11-02hashmap: provide deallocation function namesLibravatar Elijah Newren1-2/+2
hashmap_free(), hashmap_free_entries(), and hashmap_free_() have existed for a while, but aren't necessarily the clearest names, especially with hashmap_partial_clear() being added to the mix and lazy-initialization now being supported. Peff suggested we adopt the following names[1]: - hashmap_clear() - remove all entries and de-allocate any hashmap-specific data, but be ready for reuse - hashmap_clear_and_free() - ditto, but free the entries themselves - hashmap_partial_clear() - remove all entries but don't deallocate table - hashmap_partial_clear_and_free() - ditto, but free the entries This patch provides the new names and converts all existing callers over to the new naming scheme. [1] https://lore.kernel.org/git/20201030125059.GA3277724@coredump.intra.peff.net/ Signed-off-by: Elijah Newren <newren@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-20diff: add -I<regex> that ignores matching changesLibravatar Michał Kępień1-0/+23
Add a new diff option that enables ignoring changes whose all lines (changed, removed, and added) match a given regular expression. This is similar to the -I/--ignore-matching-lines option in standalone diff utilities and can be used e.g. to ignore changes which only affect code comments or to look for unrelated changes in commits containing a large number of automatically applied modifications (e.g. a tree-wide string replacement). The difference between -G/-S and the new -I option is that the latter filters output on a per-change basis. Use the 'ignore' field of xdchange_t for marking a change as ignored or not. Since the same field is used by --ignore-blank-lines, identical hunk emitting rules apply for --ignore-blank-lines and -I. These two options can also be used together in the same git invocation (they are complementary to each other). Rename xdl_mark_ignorable() to xdl_mark_ignorable_lines(), to indicate that it is logically a "sibling" of xdl_mark_ignorable_regex() rather than its "parent". Signed-off-by: Michał Kępień <michal@isc.org> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-24diff: fix modified lines stats with --stat and --numstatLibravatar Thomas Guyot-Sionnest1-5/+7
Only skip diffstats when both oids are valid and identical. This check was causing both false-positives (files included in diffstats with no actual changes (0 lines modified) and false-negatives (showing 0 lines modified in stats when files had actually changed). Also replaced same_contents with may_differ to avoid confusion. Signed-off-by: Thomas Guyot-Sionnest <tguyot@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-09-18Merge branch 'jc/quote-path-cleanup'Libravatar Junio C Hamano1-4/+4
"git status --short" quoted a path with SP in it when tracked, but not those that are untracked, ignored or unmerged. They are all shown quoted consistently. * jc/quote-path-cleanup: quote: turn 'nodq' parameter into a set of flags quote: rename misnamed sq_lookup[] to cq_lookup[] wt-status: consistently quote paths in "status --short" output quote_path: code clarification quote_path: optionally allow quoting a path with SP in it quote_path: give flags parameter to quote_path() quote_path: rename quote_path_relative() to quote_path()
2020-09-10quote: turn 'nodq' parameter into a set of flagsLibravatar Junio C Hamano1-4/+4
quote_c_style() and its friend quote_two_c_style() both take an optional "please omit the double quotes around the quoted body" parameter. Turn it into a flag word, assign one bit out of it, and call it CQUOTE_NODQ bit. No behaviour change intended. Signed-off-by: Junio C Hamano <gitster@pobox.com>