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| author |  Johannes Schindelin <johannes.schindelin@gmx.de> | 2019-09-30 10:21:55 -0700 |
|---|---|---|
| committer |  Junio C Hamano <gitster@pobox.com> | 2019-10-02 14:44:54 +0900 |
| commit | 2049b8dc65e7371c56452cfda5234182d58b704e (patch) | |
| tree | 50ad08a526b3ef7bd06beceb6255984b78f5af64 | |
| parent | Move git_sort(), a stable sort, into into libgit.a (diff) | |
| download | tgif-2049b8dc65e7371c56452cfda5234182d58b704e.tar.xz | |
diffcore_rename(): use a stable sort
During Git's rename detection, the file names are sorted. At the moment,
this job is performed by `qsort()`. As that function is not guaranteed
to implement a stable sort algorithm, this can lead to inconsistent
and/or surprising behavior: a rename might be detected differently
depending on the platform where Git was run.
The `qsort()` in MS Visual C's runtime does _not_ implement a stable
sort algorithm, and it even leads to an inconsistency leading to a test
failure in t3030.35 "merge-recursive remembers the names of all base
trees": a different code path than on Linux is taken in the rename
detection of an ambiguous rename between either `e` to `a` or
`a~Temporary merge branch 2_0` to `a` during a recursive merge,
unexpectedly resulting in a clean merge.
Let's use the stable sort provided by `git_stable_qsort()` to avoid this
inconsistency.
Signed-off-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
| -rw-r--r-- | diffcore-rename.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/diffcore-rename.c b/diffcore-rename.c index 9624864858..9042936aba 100644 --- a/diffcore-rename.c +++ b/diffcore-rename.c @@ -585,7 +585,7 @@ void diffcore_rename(struct diff_options *options) stop_progress(&progress); /* cost matrix sorted by most to least similar pair */ - QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare); + STABLE_QSORT(mx, dst_cnt * NUM_CANDIDATE_PER_DST, score_compare); rename_count += find_renames(mx, dst_cnt, minimum_score, 0); if (detect_rename == DIFF_DETECT_COPY) |