fix: simplify output handling in PR message checks and update test assertions

Author: shenxianpeng

main.py

@@ -156,19 +156,12 @@ def run_pr_message_checks(pr_messages: list[str], result_file: TextIO) -> int:
     """
     has_failure = False
     emitted_failure_output = False
-    total_messages = len(pr_messages)
-    for index, msg in enumerate(pr_messages, start=1):
-        subject = msg.splitlines()[0] if msg else "<empty commit message>"
+    for msg in pr_messages:
         command_args = ["--message"]
         if emitted_failure_output:
             command_args.append("--no-banner")
 
-        output_prefix = f"--- Commit {index}/{total_messages}: {subject}\n"
-        if emitted_failure_output:
-            output_prefix = (
-                f"{COMMIT_SECTION_SEPARATOR}"
-                f"--- Commit {index}/{total_messages}: {subject}\n"
-            )
+        output_prefix = COMMIT_SECTION_SEPARATOR if emitted_failure_output else None
 
         return_code = run_check_command(
             command_args,

main_test.py

@@ -101,13 +101,12 @@ def test_single_message_pass(self):
         self.assertEqual(mock_run.call_args[1]["input"], "fix: something")
         self.assertEqual(result_file.getvalue(), "")
 
-    def test_failed_message_writes_header_and_output(self):
+    def test_failed_message_writes_output(self):
         mock_result = MagicMock(returncode=1, stdout="Commit rejected.\n")
         result_file = io.StringIO()
         with patch("main.subprocess.run", return_value=mock_result):
             rc = main.run_pr_message_checks(["fix: something"], result_file)
         self.assertEqual(rc, 1)
-        self.assertIn("--- Commit 1/1: fix: something", result_file.getvalue())
         self.assertIn("Commit rejected.", result_file.getvalue())
 
     def test_multiple_messages_partial_failure(self):
@@ -169,9 +168,9 @@ def test_later_failure_prefix_uses_short_separator_without_extra_blank_lines(sel
             )
 
         output = result_file.getvalue()
-        self.assertIn("--- Commit 2/3: bad second\nCommit rejected.\n", output)
+        self.assertIn("Commit rejected.\n", output)
         self.assertIn(
-            f"{main.COMMIT_SECTION_SEPARATOR}--- Commit 3/3: bad third\n",
+            f"{main.COMMIT_SECTION_SEPARATOR}Type subject_imperative check failed ==> bad third\n",
             output,
         )
         self.assertNotIn(