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| author | Antonin Delpeuch <antonin@delpeuch.eu> | 2025-11-17 08:04:32 +0000 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2025-11-17 09:31:59 -0800 |
| commit | ffffb987fcd3b3d6b88aceed87000ef4a5b6114e (patch) | |
| tree | 62f688bdffc9d7749755cce9aa785705e2a7c838 /t/t8015-blame-diff-algorithm.sh | |
| parent | 881793c4f71c84e70af256c5721475c7c088b3f7 (diff) | |
| download | git-ffffb987fcd3b3d6b88aceed87000ef4a5b6114e.tar.gz | |
blame: make diff algorithm configurable
The diff algorithm used in 'git-blame(1)' is set to 'myers',
without the possibility to change it aside from the `--minimal` option.
There has been long-standing interest in changing the default diff
algorithm to "histogram", and Git 3.0 was floated as a possible occasion
for taking some steps towards that:
https://lore.kernel.org/git/xmqqed873vgn.fsf@gitster.g/
As a preparation for this move, it is worth making sure that the diff
algorithm is configurable where useful.
Make it configurable in the `git-blame(1)` command by introducing the
`--diff-algorithm` option and make honor the `diff.algorithm` config
variable. Keep Myers diff as the default.
Signed-off-by: Antonin Delpeuch <antonin@delpeuch.eu>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 't/t8015-blame-diff-algorithm.sh')
| -rwxr-xr-x | t/t8015-blame-diff-algorithm.sh | 203 |
1 files changed, 203 insertions, 0 deletions
diff --git a/t/t8015-blame-diff-algorithm.sh b/t/t8015-blame-diff-algorithm.sh new file mode 100755 index 0000000000..cd709536c6 --- /dev/null +++ b/t/t8015-blame-diff-algorithm.sh @@ -0,0 +1,203 @@ +#!/bin/sh + +test_description='git blame with specific diff algorithm' + +. ./test-lib.sh + +test_expect_success setup ' + cat >file.c <<-\EOF && + int f(int x, int y) + { + if (x == 0) + { + return y; + } + return x; + } + + int g(size_t u) + { + while (u < 30) + { + u++; + } + return u; + } + EOF + test_write_lines x x x x >file.txt && + git add file.c file.txt && + GIT_AUTHOR_NAME=Commit_1 git commit -m Commit_1 && + + cat >file.c <<-\EOF && + int g(size_t u) + { + while (u < 30) + { + u++; + } + return u; + } + + int h(int x, int y, int z) + { + if (z == 0) + { + return x; + } + return y; + } + EOF + test_write_lines x x x A B C D x E F G >file.txt && + git add file.c file.txt && + GIT_AUTHOR_NAME=Commit_2 git commit -m Commit_2 +' + +test_expect_success 'blame uses Myers diff algorithm by default' ' + cat >expected <<-\EOF && + Commit_2 int g(size_t u) + Commit_1 { + Commit_2 while (u < 30) + Commit_1 { + Commit_2 u++; + Commit_1 } + Commit_2 return u; + Commit_1 } + Commit_1 + Commit_2 int h(int x, int y, int z) + Commit_1 { + Commit_2 if (z == 0) + Commit_1 { + Commit_2 return x; + Commit_1 } + Commit_2 return y; + Commit_1 } + EOF + + git blame file.c >output && + sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" output >without_varying_parts && + sed -e "s/ *$//g" without_varying_parts >actual && + test_cmp expected actual +' + +test_expect_success 'blame honors --diff-algorithm option' ' + cat >expected <<-\EOF && + Commit_1 int g(size_t u) + Commit_1 { + Commit_1 while (u < 30) + Commit_1 { + Commit_1 u++; + Commit_1 } + Commit_1 return u; + Commit_1 } + Commit_2 + Commit_2 int h(int x, int y, int z) + Commit_2 { + Commit_2 if (z == 0) + Commit_2 { + Commit_2 return x; + Commit_2 } + Commit_2 return y; + Commit_2 } + EOF + + git blame file.c --diff-algorithm histogram >output && + sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" output >without_varying_parts && + sed -e "s/ *$//g" without_varying_parts >actual && + test_cmp expected actual +' + +test_expect_success 'blame honors diff.algorithm config variable' ' + cat >expected <<-\EOF && + Commit_1 int g(size_t u) + Commit_1 { + Commit_1 while (u < 30) + Commit_1 { + Commit_1 u++; + Commit_1 } + Commit_1 return u; + Commit_1 } + Commit_2 + Commit_2 int h(int x, int y, int z) + Commit_2 { + Commit_2 if (z == 0) + Commit_2 { + Commit_2 return x; + Commit_2 } + Commit_2 return y; + Commit_2 } + EOF + + git -c diff.algorithm=histogram blame file.c >output && + sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" \ + -e "s/ *$//g" output >actual && + test_cmp expected actual +' + +test_expect_success 'blame gives priority to --diff-algorithm over diff.algorithm' ' + cat >expected <<-\EOF && + Commit_1 int g(size_t u) + Commit_1 { + Commit_1 while (u < 30) + Commit_1 { + Commit_1 u++; + Commit_1 } + Commit_1 return u; + Commit_1 } + Commit_2 + Commit_2 int h(int x, int y, int z) + Commit_2 { + Commit_2 if (z == 0) + Commit_2 { + Commit_2 return x; + Commit_2 } + Commit_2 return y; + Commit_2 } + EOF + + git -c diff.algorithm=myers blame file.c --diff-algorithm histogram >output && + sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" \ + -e "s/ *$//g" output >actual && + test_cmp expected actual +' + +test_expect_success 'blame honors --minimal option' ' + cat >expected <<-\EOF && + Commit_1 x + Commit_1 x + Commit_1 x + Commit_2 A + Commit_2 B + Commit_2 C + Commit_2 D + Commit_1 x + Commit_2 E + Commit_2 F + Commit_2 G + EOF + + git blame file.txt --minimal >output && + sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" output >actual && + test_cmp expected actual +' + +test_expect_success 'blame respects the order of diff options' ' + cat >expected <<-\EOF && + Commit_1 x + Commit_1 x + Commit_1 x + Commit_2 A + Commit_2 B + Commit_2 C + Commit_2 D + Commit_2 x + Commit_2 E + Commit_2 F + Commit_2 G + EOF + + git blame file.txt --minimal --diff-algorithm myers >output && + sed -e "s/^[^ ]* (\([^ ]*\) [^)]*)/\1/g" output >actual && + test_cmp expected actual +' + +test_done |