diff --git a/routers/web/repo/compare.go b/routers/web/repo/compare.go
index 41ad365ce1..d216403b53 100644
--- a/routers/web/repo/compare.go
+++ b/routers/web/repo/compare.go
@@ -231,13 +231,6 @@ func ParseCompareInfo(ctx *context.Context) *common.CompareInfo {
 	if infoPath == "" {
 		infos = []string{baseRepo.DefaultBranch, baseRepo.DefaultBranch}
 	} else {
-		infoPath, isDiff := strings.CutSuffix(infoPath, ".diff")
-		ctx.Data["ComparingDiff"] = isDiff
-		if !isDiff {
-			var isPatch bool
-			infoPath, isPatch = strings.CutSuffix(infoPath, ".patch")
-			ctx.Data["ComparingPatch"] = isPatch
-		}
 		infos = strings.SplitN(infoPath, "...", 2)
 		if len(infos) != 2 {
 			if infos = strings.SplitN(infoPath, "..", 2); len(infos) == 2 {
@@ -247,6 +240,14 @@ func ParseCompareInfo(ctx *context.Context) *common.CompareInfo {
 				infos = []string{baseRepo.DefaultBranch, infoPath}
 			}
 		}
+		var isDiff bool
+		infos[1], isDiff = strings.CutSuffix(infos[1], ".diff")
+		ctx.Data["ComparingDiff"] = isDiff
+		if !isDiff {
+			var isPatch bool
+			infos[1], isPatch = strings.CutSuffix(infos[1], ".patch")
+			ctx.Data["ComparingPatch"] = isPatch
+		}
 	}
 
 	ctx.Data["BaseName"] = baseRepo.OwnerName
diff --git a/tests/gitea-repositories-meta/user2/repo16.git/refs/heads/diff b/tests/gitea-repositories-meta/user2/repo16.git/refs/heads/diff
new file mode 100644
index 0000000000..4750a76432
--- /dev/null
+++ b/tests/gitea-repositories-meta/user2/repo16.git/refs/heads/diff
@@ -0,0 +1 @@
+f27c2b2b03dcab38beaf89b0ab4ff61f6de63441
diff --git a/tests/gitea-repositories-meta/user2/repo16.git/refs/heads/patch b/tests/gitea-repositories-meta/user2/repo16.git/refs/heads/patch
new file mode 100644
index 0000000000..4750a76432
--- /dev/null
+++ b/tests/gitea-repositories-meta/user2/repo16.git/refs/heads/patch
@@ -0,0 +1 @@
+f27c2b2b03dcab38beaf89b0ab4ff61f6de63441
diff --git a/tests/integration/compare_test.go b/tests/integration/compare_test.go
index 396c1c22ad..070f7e1b20 100644
--- a/tests/integration/compare_test.go
+++ b/tests/integration/compare_test.go
@@ -239,6 +239,16 @@ func TestCompareBranches(t *testing.T) {
 	diffChanges = []string{"test.txt"}
 
 	inspectCompare(t, htmlDoc, diffCount, diffChanges)
+
+	// Branches with name 'diff' or 'patch'
+	req = NewRequest(t, "GET", "/user2/repo16/compare/master..diff")
+	session.MakeRequest(t, req, http.StatusOK)
+	req = NewRequest(t, "GET", "/user2/repo16/compare/master..diff.patch")
+	session.MakeRequest(t, req, http.StatusOK)
+	req = NewRequest(t, "GET", "/user2/repo16/compare/master..patch")
+	session.MakeRequest(t, req, http.StatusOK)
+	req = NewRequest(t, "GET", "/user2/repo16/compare/master..patch.diff")
+	session.MakeRequest(t, req, http.StatusOK)
 }
 
 func TestCompareWithPRsDisabled(t *testing.T) {