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| author | SZEDER Gábor <szeder@ira.uka.de> | 2016-03-30 10:35:07 +0200 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2016-03-30 13:46:04 -0700 |
| commit | ca4e3ca029def86b7b29451d4ba77ef76574949e (patch) | |
| tree | fd786af948557ed06142807e3f48d7a9ddc8d598 /diffcore-rename.c | |
| parent | 765428699a5381f113d19974720bc91b5bfeaf1d (diff) | |
| download | git-ca4e3ca029def86b7b29451d4ba77ef76574949e.tar.gz git-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>
Diffstat (limited to 'diffcore-rename.c')
| -rw-r--r-- | diffcore-rename.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/diffcore-rename.c b/diffcore-rename.c index af1fe0886..69fcf77be 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 */ |