From 9ed1adc5c8bff83516a0beac55a448b9d4372cf7 Mon Sep 17 00:00:00 2001
From: Mohammed Alkindi <alkndymhmd692@gmail.com>
Date: Fri, 28 Aug 2026 03:36:52 +0400
Subject: [PATCH] fix: propagate the serial test runner's exit code on Windows

run_serial_tests.py ends in os.execv. Windows has no process
replacement, so the CRT spawns a child and terminates the caller with 0.
make tests-serial returns in about 100 ms reporting success while pytest
keeps running orphaned, and its output arrives afterwards, interleaved
into whatever the shell runs next.

run_integration_tests.py already handles this at lines 103-106, added in
21a1f9b4. Apply the same win32-guarded shape here: subprocess.run with
check=False, then raise SystemExit on the child's return code.

POSIX is unchanged. os.execv still runs there, so pytest keeps owning the
terminal and its own signal handling.

Adds two tests mirroring the precedent's
test_windows_bootstrap_uses_subprocess_and_propagates_exit_code: the
win32 case asserts the code propagates, that check is False, and that
os.execv is never called; the POSIX case asserts execv is still used and
subprocess.run is not.
---
 .github/scripts/run_serial_tests.py | 10 +++++-
 tests/test_run_serial_tests.py      | 55 ++++++++++++++++++++++++++++-
 2 files changed, 63 insertions(+), 2 deletions(-)

diff --git a/.github/scripts/run_serial_tests.py b/.github/scripts/run_serial_tests.py
index 9cbcaea2fe..f09f9c3302 100644
--- a/.github/scripts/run_serial_tests.py
+++ b/.github/scripts/run_serial_tests.py
@@ -3,6 +3,7 @@
 import argparse
 import fnmatch
 import os
+import subprocess
 import sys
 from pathlib import Path
 
@@ -46,7 +47,14 @@ def main() -> None:
     marker_expression = (
         "serial and not review_optional" if args.exclude_review_optional else "serial"
     )
-    os.execv(sys.executable, _serial_args(marker_expression=marker_expression))
+    command = _serial_args(marker_expression=marker_expression)
+    if sys.platform == "win32":
+        # Windows has no process replacement: os.execv spawns a child and
+        # terminates this process with 0, so the caller sees success no matter
+        # how pytest exits. Mirror run_integration_tests.py and wait instead.
+        completed = subprocess.run(command, check=False)
+        raise SystemExit(completed.returncode)
+    os.execv(sys.executable, command)
 
 
 if __name__ == "__main__":
diff --git a/tests/test_run_serial_tests.py b/tests/test_run_serial_tests.py
index 81b1c1241c..36b3c51ff6 100644
--- a/tests/test_run_serial_tests.py
+++ b/tests/test_run_serial_tests.py
@@ -1,9 +1,10 @@
 from __future__ import annotations
 
 import importlib.util
+import subprocess
 import sys
 from pathlib import Path
-from types import ModuleType
+from types import ModuleType, SimpleNamespace
 
 import pytest
 
@@ -96,3 +97,55 @@ def test_serial_command_targets_only_discovered_files(
         "-m",
         "serial",
     ]
+
+
+def test_windows_runner_uses_subprocess_and_propagates_exit_code(
+    serial_test_runner: ModuleType,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    captured: list[tuple[list[str], bool]] = []
+
+    def capture_run(command: list[str], *, check: bool) -> SimpleNamespace:
+        captured.append((command, check))
+        return SimpleNamespace(returncode=23)
+
+    monkeypatch.setattr(serial_test_runner.sys, "platform", "win32")
+    monkeypatch.setattr(subprocess, "run", capture_run)
+    monkeypatch.setattr(serial_test_runner.os, "chdir", lambda _path: None)
+    monkeypatch.setattr(
+        serial_test_runner.os,
+        "execv",
+        lambda *_args: pytest.fail("Windows serial runner must not call os.execv"),
+    )
+    monkeypatch.setattr(sys, "argv", ["run_serial_tests.py"])
+
+    with pytest.raises(SystemExit) as exc_info:
+        serial_test_runner.main()
+
+    assert exc_info.value.code == 23
+    assert len(captured) == 1
+    assert captured[0][1] is False
+
+
+def test_non_windows_runner_still_execs(
+    serial_test_runner: ModuleType,
+    monkeypatch: pytest.MonkeyPatch,
+) -> None:
+    captured: list[list[str]] = []
+
+    monkeypatch.setattr(serial_test_runner.sys, "platform", "linux")
+    monkeypatch.setattr(serial_test_runner.os, "chdir", lambda _path: None)
+    monkeypatch.setattr(
+        subprocess,
+        "run",
+        lambda *_args, **_kwargs: pytest.fail("POSIX serial runner must not call subprocess.run"),
+    )
+    monkeypatch.setattr(
+        serial_test_runner.os, "execv", lambda _executable, command: captured.append(command)
+    )
+    monkeypatch.setattr(sys, "argv", ["run_serial_tests.py"])
+
+    serial_test_runner.main()
+
+    assert len(captured) == 1
+    assert "serial" in captured[0]