diff options
| -rw-r--r-- | Lib/multiprocessing/popen_fork.py | 9 | ||||
| -rw-r--r-- | Lib/multiprocessing/process.py | 3 | ||||
| -rw-r--r-- | Lib/multiprocessing/util.py | 14 | ||||
| -rw-r--r-- | Lib/test/_test_multiprocessing.py | 31 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Library/2018-03-11-19-03-52.bpo-31804.i8KUMp.rst | 2 |
5 files changed, 47 insertions, 12 deletions
diff --git a/Lib/multiprocessing/popen_fork.py b/Lib/multiprocessing/popen_fork.py index b0fc01396eb..008b97b3662 100644 --- a/Lib/multiprocessing/popen_fork.py +++ b/Lib/multiprocessing/popen_fork.py @@ -14,14 +14,7 @@ class Popen(object): method = 'fork' def __init__(self, process_obj): - try: - sys.stdout.flush() - except (AttributeError, ValueError): - pass - try: - sys.stderr.flush() - except (AttributeError, ValueError): - pass + util._flush_std_streams() self.returncode = None self.finalizer = None self._launch(process_obj) diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py index 8fff3e105ea..cd592d0bdf0 100644 --- a/Lib/multiprocessing/process.py +++ b/Lib/multiprocessing/process.py @@ -314,8 +314,7 @@ class BaseProcess(object): finally: threading._shutdown() util.info('process exiting with exitcode %d' % exitcode) - sys.stdout.flush() - sys.stderr.flush() + util._flush_std_streams() return exitcode diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py index f0827f0a969..0c4eb247327 100644 --- a/Lib/multiprocessing/util.py +++ b/Lib/multiprocessing/util.py @@ -392,6 +392,20 @@ def _close_stdin(): pass # +# Flush standard streams, if any +# + +def _flush_std_streams(): + try: + sys.stdout.flush() + except (AttributeError, ValueError): + pass + try: + sys.stderr.flush() + except (AttributeError, ValueError): + pass + +# # Start a program with only specified fds kept open # diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py index 1e497a572a7..940fe584e75 100644 --- a/Lib/test/_test_multiprocessing.py +++ b/Lib/test/_test_multiprocessing.py @@ -584,10 +584,19 @@ class _TestProcess(BaseTestCase): self.assertTrue(evt.is_set()) @classmethod - def _test_error_on_stdio_flush(self, evt): + def _test_error_on_stdio_flush(self, evt, break_std_streams={}): + for stream_name, action in break_std_streams.items(): + if action == 'close': + stream = io.StringIO() + stream.close() + else: + assert action == 'remove' + stream = None + setattr(sys, stream_name, None) evt.set() - def test_error_on_stdio_flush(self): + def test_error_on_stdio_flush_1(self): + # Check that Process works with broken standard streams streams = [io.StringIO(), None] streams[0].close() for stream_name in ('stdout', 'stderr'): @@ -601,6 +610,24 @@ class _TestProcess(BaseTestCase): proc.start() proc.join() self.assertTrue(evt.is_set()) + self.assertEqual(proc.exitcode, 0) + finally: + setattr(sys, stream_name, old_stream) + + def test_error_on_stdio_flush_2(self): + # Same as test_error_on_stdio_flush_1(), but standard streams are + # broken by the child process + for stream_name in ('stdout', 'stderr'): + for action in ('close', 'remove'): + old_stream = getattr(sys, stream_name) + try: + evt = self.Event() + proc = self.Process(target=self._test_error_on_stdio_flush, + args=(evt, {stream_name: action})) + proc.start() + proc.join() + self.assertTrue(evt.is_set()) + self.assertEqual(proc.exitcode, 0) finally: setattr(sys, stream_name, old_stream) diff --git a/Misc/NEWS.d/next/Library/2018-03-11-19-03-52.bpo-31804.i8KUMp.rst b/Misc/NEWS.d/next/Library/2018-03-11-19-03-52.bpo-31804.i8KUMp.rst new file mode 100644 index 00000000000..7fcede297ac --- /dev/null +++ b/Misc/NEWS.d/next/Library/2018-03-11-19-03-52.bpo-31804.i8KUMp.rst @@ -0,0 +1,2 @@ +Avoid failing in multiprocessing.Process if the standard streams are closed +or None at exit. |