tidy

Author: 0x0L

Lib/concurrent/futures/thread.py

@@ -36,7 +36,7 @@ def _python_exit():
 # See bpo-39812 for context.
 threading._register_atexit(_python_exit)
 
-# Make sure `_global_shutdown_lock` is reinit in forked children
+# At fork, reinitialize the `_global_shutdown_lock` lock in the child process
 if hasattr(os, 'register_at_fork'):
     os.register_at_fork(before=_global_shutdown_lock.acquire,
                         after_in_child=_global_shutdown_lock._at_fork_reinit,

Lib/test/test_concurrent_futures.py

@@ -568,19 +568,6 @@ def test_shutdown_no_wait(self):
         # shutdown.
         assert all([r == abs(v) for r, v in zip(res, range(-5, 5))])
 
-    def test_hang_issue45021(self):
-        """https://bugs.python.org/issue45021"""
-        def submit(pool):
-            pool.submit(submit, pool)
-
-        if hasattr(os, 'register_at_fork'):
-            with futures.ThreadPoolExecutor(1) as pool:
-                pool.submit(submit, pool)
-
-                for _ in range(50):
-                    with futures.ProcessPoolExecutor(1, mp_context=get_context('fork')) as workers:
-                        workers.submit(tuple)
-
 
 create_executor_tests(ProcessPoolShutdownTest,
                       executor_mixins=(ProcessPoolForkMixin,
@@ -918,6 +905,20 @@ def test_idle_thread_reuse(self):
         self.assertEqual(len(executor._threads), 1)
         executor.shutdown(wait=True)
 
+    @unittest.skipUnless(hasattr(os, 'register_at_fork'), 'need os.register_at_fork')
+    def test_hang_global_shutdown_lock(self):
+        # bpo-45021: _global_shutdown_lock should be reinitialized in the child
+        # process, otherwise it will never exit
+        def submit(pool):
+            pool.submit(submit, pool)
+
+        with futures.ThreadPoolExecutor(1) as pool:
+            pool.submit(submit, pool)
+
+            for _ in range(50):
+                with futures.ProcessPoolExecutor(1, mp_context=get_context('fork')) as workers:
+                    workers.submit(tuple)
+
 
 class ProcessPoolExecutorTest(ExecutorTest):