From 81d89d1d90af56c208bc0ce0b304f4cc5f4c3119 Mon Sep 17 00:00:00 2001
From: "Jeong, YunWon" <69878+youknowone@users.noreply.github.com>
Date: Wed, 14 Jan 2026 16:59:10 +0900
Subject: [PATCH] Fix flaky multiprocessing tests (#6725)

---
 .github/workflows/ci.yaml         | 2 --
 Lib/test/_test_multiprocessing.py | 6 ++++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index cc7f745af..778890a9f 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -108,14 +108,12 @@ env:
   ENV_POLLUTING_TESTS_COMMON: >-
   ENV_POLLUTING_TESTS_LINUX: >-
     test.test_multiprocessing_fork.test_processes
-    test.test_multiprocessing_fork.test_threads
     test.test_multiprocessing_forkserver.test_processes
     test.test_multiprocessing_forkserver.test_threads
     test.test_multiprocessing_spawn.test_processes
     test.test_multiprocessing_spawn.test_threads
   ENV_POLLUTING_TESTS_MACOS: >-
     test.test_multiprocessing_forkserver.test_processes
-    test.test_multiprocessing_forkserver.test_threads
     test.test_multiprocessing_spawn.test_processes
     test.test_multiprocessing_spawn.test_threads
   ENV_POLLUTING_TESTS_WINDOWS: >-
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 2fc206f7d..80b663d32 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -6597,7 +6597,8 @@ class BaseMixin(object):
             support.print_warning(f'Dangling processes: {processes}')
         processes = None
 
-        threads = set(threading._dangling) - set(cls.dangling[1])
+        # TODO: RUSTPYTHON: Filter out stopped threads since gc.collect() is a no-op
+        threads = {t for t in threading._dangling if t.is_alive()} - {t for t in cls.dangling[1] if t.is_alive()}
         if threads:
             test.support.environment_altered = True
             support.print_warning(f'Dangling threads: {threads}')
@@ -6794,7 +6795,8 @@ def install_tests_in_module_dict(remote_globs, start_method,
             support.print_warning(f'Dangling processes: {processes}')
         processes = None
 
-        threads = set(threading._dangling) - set(dangling[1])
+        # TODO: RUSTPYTHON: Filter out stopped threads since gc.collect() is a no-op
+        threads = {t for t in threading._dangling if t.is_alive()} - {t for t in dangling[1] if t.is_alive()}
         if threads:
             need_sleep = True
             test.support.environment_altered = True