2 files changed, 35 insertions, 1 deletions
diff --git a/diff.c b/diff.c
index c86688794f..20b121637d 100644
--- 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 d24e55aac8..7181f176b8 100755
--- 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