patch-id: fix patch-id for mode changes

Currently patch-id as used in rebase and cherry-pick does not account
for file modes if the file is modified. One consequence of this is
that if you have a local patch that changes modes, but upstream
has applied an outdated version of the patch that doesn't include
that mode change, "git rebase" will drop your local version of the
patch along with your mode changes. It also means that internal
patch-id doesn't produce the same output as the builtin, which does
account for mode changes due to them being part of diff output.

Fix by adding mode to the patch-id if it has changed, in the same
format that would be produced by diff, so that it is compatible
with builtin patch-id.

Signed-off-by: Jerry Zhang <Jerry@skydio.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/diff.c b/diff.c
index c86688794f70ee4b7b6a2bd1d1c260919037119b..20b121637d80fa1516253eb475d6785535729221 100644 (file)
--- a/diff.c
+++ b/diff.c
@@ -6224,6 +6224,11 @@ static int diff_get_patch_id(struct diff_options *options, struct object_id *oid
                } else if (p->two->mode == 0) {
                        patch_id_add_string(&ctx, "deletedfilemode");
                        patch_id_add_mode(&ctx, p->one->mode);
+               } else if (p->one->mode != p->two->mode) {
+                       patch_id_add_string(&ctx, "oldmode");
+                       patch_id_add_mode(&ctx, p->one->mode);
+                       patch_id_add_string(&ctx, "newmode");
+                       patch_id_add_mode(&ctx, p->two->mode);
                }
 
                if (diff_header_only) {

diff --git a/t/t3419-rebase-patch-id.sh b/t/t3419-rebase-patch-id.sh
index d24e55aac8dbb72cd1d3567763a3c61a503887e9..7181f176b8136504b4a9bc5e962cf358b00ffbba 100755 (executable)
--- a/t/t3419-rebase-patch-id.sh
+++ b/t/t3419-rebase-patch-id.sh
@@ -48,7 +48,17 @@ test_expect_success 'setup: 500 lines' '
        git branch -f squashed main &&
        git checkout -q -f squashed &&
        git reset -q --soft HEAD~2 &&
-       git commit -q -m squashed
+       git commit -q -m squashed &&
+
+       git branch -f mode main &&
+       git checkout -q -f mode &&
+       test_chmod +x file &&
+       git commit -q -a --amend &&
+
+       git branch -f modeother other &&
+       git checkout -q -f modeother &&
+       test_chmod +x file &&
+       git commit -q -a --amend
 '
 
 test_expect_success 'detect upstream patch' '
@@ -71,6 +81,13 @@ test_expect_success 'detect upstream patch binary' '
        test_when_finished "rm .gitattributes"
 '
 
+test_expect_success 'detect upstream patch modechange' '
+       git checkout -q modeother^{} &&
+       git rebase mode &&
+       git rev-list mode...HEAD~ >revs &&
+       test_must_be_empty revs
+'
+
 test_expect_success 'do not drop patch' '
        git checkout -q other^{} &&
        test_must_fail git rebase squashed &&
@@ -85,4 +102,16 @@ test_expect_success 'do not drop patch binary' '
        test_when_finished "rm .gitattributes"
 '
 
+test_expect_success 'do not drop patch modechange' '
+       git checkout -q modeother^{} &&
+       git rebase other &&
+       cat >expected <<-\EOF &&
+       diff --git a/file b/file
+       old mode 100644
+       new mode 100755
+       EOF
+       git diff HEAD~ >modediff &&
+       test_cmp expected modediff
+'
+
 test_done