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authorLibravatar SZEDER Gábor <szeder@ira.uka.de>2016-03-30 10:35:07 +0200
committerLibravatar Junio C Hamano <gitster@pobox.com>2016-03-30 13:46:04 -0700
commitca4e3ca029def86b7b29451d4ba77ef76574949e (patch)
treefd786af948557ed06142807e3f48d7a9ddc8d598
parentGit 2.4.11 (diff)
downloadtgif-ca4e3ca029def86b7b29451d4ba77ef76574949e.tar.xz
diffcore: fix iteration order of identical files during rename detection
If the two paths 'dir/A/file' and 'dir/B/file' have identical content and the parent directory is renamed, e.g. 'git mv dir other-dir', then diffcore reports the following exact renames: renamed: dir/B/file -> other-dir/A/file renamed: dir/A/file -> other-dir/B/file While technically not wrong, this is confusing not only for the user, but also for git commands that make decisions based on rename information, e.g. 'git log --follow other-dir/A/file' follows 'dir/B/file' past the rename. This behavior is a side effect of commit v2.0.0-rc4~8^2~14 (diffcore-rename.c: simplify finding exact renames, 2013-11-14): the hashmap storing sources returns entries from the same bucket, i.e. sources matching the current destination, in LIFO order. Thus the iteration first examines 'other-dir/A/file' and 'dir/B/file' and, upon finding identical content and basename, reports an exact rename. Other hashmap users are apparently happy with the current iteration order over the entries of a bucket. Changing the iteration order would risk upsetting other hashmap users and would increase the memory footprint of each bucket by a pointer to the tail element. Fill the hashmap with source entries in reverse order to restore the original exact rename detection behavior. Reported-by: Bill Okara <billokara@gmail.com> Signed-off-by: SZEDER Gábor <szeder@ira.uka.de> Signed-off-by: Junio C Hamano <gitster@pobox.com>
-rw-r--r--diffcore-rename.c6
-rwxr-xr-xt/t4001-diff-rename.sh11
2 files changed, 15 insertions, 2 deletions
diff --git a/diffcore-rename.c b/diffcore-rename.c
index af1fe08861..69fcf77be0 100644
--- a/diffcore-rename.c
+++ b/diffcore-rename.c
@@ -340,9 +340,11 @@ static int find_exact_renames(struct diff_options *options)
int i, renames = 0;
struct hashmap file_table;
- /* Add all sources to the hash table */
+ /* Add all sources to the hash table in reverse order, because
+ * later on they will be retrieved in LIFO order.
+ */
hashmap_init(&file_table, NULL, rename_src_nr);
- for (i = 0; i < rename_src_nr; i++)
+ for (i = rename_src_nr-1; i >= 0; i--)
insert_file_table(&file_table, i, rename_src[i].p->one);
/* Walk the destinations and find best source match */
diff --git a/t/t4001-diff-rename.sh b/t/t4001-diff-rename.sh
index 2f327b7495..ed90c6c6f9 100755
--- a/t/t4001-diff-rename.sh
+++ b/t/t4001-diff-rename.sh
@@ -77,6 +77,17 @@ test_expect_success 'favour same basenames even with minor differences' '
git show HEAD:path1 | sed "s/15/16/" > subdir/path1 &&
git status | test_i18ngrep "renamed: .*path1 -> subdir/path1"'
+test_expect_success 'two files with same basename and same content' '
+ git reset --hard &&
+ mkdir -p dir/A dir/B &&
+ cp path1 dir/A/file &&
+ cp path1 dir/B/file &&
+ git add dir &&
+ git commit -m 2 &&
+ git mv dir other-dir &&
+ git status | test_i18ngrep "renamed: .*dir/A/file -> other-dir/A/file"
+'
+
test_expect_success 'setup for many rename source candidates' '
git reset --hard &&
for i in 0 1 2 3 4 5 6 7 8 9;