bpo-33097: Fix submit accepting callable after executor shutdown by interpreter exit (GH-6144)
Executors in concurrent.futures accepted tasks after executor was shutdown by interpreter exit. Tasks were left in PENDING state forever. This fix changes submit to instead raise a RuntimeError.
diff --git a/Lib/concurrent/futures/process.py b/Lib/concurrent/futures/process.py
index 63f22cf..ce7d642 100644
--- a/Lib/concurrent/futures/process.py
+++ b/Lib/concurrent/futures/process.py
@@ -423,6 +423,10 @@
# - The executor that owns this worker has been shutdown.
if shutting_down():
try:
+ # Flag the executor as shutting down as early as possible if it
+ # is not gc-ed yet.
+ if executor is not None:
+ executor._shutdown_thread = True
# Since no new work items can be added, it is safe to shutdown
# this thread if there are no pending work items.
if not pending_work_items:
@@ -595,6 +599,9 @@
raise BrokenProcessPool(self._broken)
if self._shutdown_thread:
raise RuntimeError('cannot schedule new futures after shutdown')
+ if _global_shutdown:
+ raise RuntimeError('cannot schedule new futures after '
+ 'interpreter shutdown')
f = _base.Future()
w = _WorkItem(f, fn, args, kwargs)
diff --git a/Lib/concurrent/futures/thread.py b/Lib/concurrent/futures/thread.py
index 6e22950..b65dee1 100644
--- a/Lib/concurrent/futures/thread.py
+++ b/Lib/concurrent/futures/thread.py
@@ -87,6 +87,10 @@
# - The executor that owns the worker has been collected OR
# - The executor that owns the worker has been shutdown.
if _shutdown or executor is None or executor._shutdown:
+ # Flag the executor as shutting down as early as possible if it
+ # is not gc-ed yet.
+ if executor is not None:
+ executor._shutdown = True
# Notice other workers
work_queue.put(None)
return
@@ -145,6 +149,9 @@
if self._shutdown:
raise RuntimeError('cannot schedule new futures after shutdown')
+ if _shutdown:
+ raise RuntimeError('cannot schedule new futures after'
+ 'interpreter shutdown')
f = _base.Future()
w = _WorkItem(f, fn, args, kwargs)
diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py
index 18d0265..b258a0e 100644
--- a/Lib/test/test_concurrent_futures.py
+++ b/Lib/test/test_concurrent_futures.py
@@ -303,6 +303,34 @@
self.assertFalse(err)
self.assertEqual(out.strip(), b"apple")
+ def test_submit_after_interpreter_shutdown(self):
+ # Test the atexit hook for shutdown of worker threads and processes
+ rc, out, err = assert_python_ok('-c', """if 1:
+ import atexit
+ @atexit.register
+ def run_last():
+ try:
+ t.submit(id, None)
+ except RuntimeError:
+ print("runtime-error")
+ raise
+ from concurrent.futures import {executor_type}
+ if __name__ == "__main__":
+ context = '{context}'
+ if not context:
+ t = {executor_type}(5)
+ else:
+ from multiprocessing import get_context
+ context = get_context(context)
+ t = {executor_type}(5, mp_context=context)
+ t.submit(id, 42).result()
+ """.format(executor_type=self.executor_type.__name__,
+ context=getattr(self, "ctx", "")))
+ # Errors in atexit hooks don't change the process exit code, check
+ # stderr manually.
+ self.assertIn("RuntimeError: cannot schedule new futures", err.decode())
+ self.assertEqual(out.strip(), b"runtime-error")
+
def test_hang_issue12364(self):
fs = [self.executor.submit(time.sleep, 0.1) for _ in range(50)]
self.executor.shutdown()