pythonGH-100133: fix asyncio subprocess losing stderr and `stdout…

…` output (python#100154)

Lib/asyncio/base_subprocess.py

@@ -215,9 +215,6 @@ def _process_exited(self, returncode):
  # object. On Python 3.6, it is required to avoid a ResourceWarning.
  self._proc.returncode = returncode
  self._call(self._protocol.process_exited)
- for p in self._pipes.values():
- if p is not None:
- p.pipe.close()
 
  self._try_finish()
 

Lib/test/test_asyncio/test_subprocess.py

@@ -686,6 +686,23 @@ async def execute():
 
  self.assertIsNone(self.loop.run_until_complete(execute()))
 
+ def test_subprocess_communicate_stdout(self):
+ # See https://github.com/python/cpython/issues/100133
+ async def get_command_stdout(cmd, *args):
+ proc = await asyncio.create_subprocess_exec(
+ cmd, *args, stdout=asyncio.subprocess.PIPE,
+ )
+ stdout, _ = await proc.communicate()
+ return stdout.decode().strip()
+
+ async def main():
+ outputs = [f'foo{i}' for i in range(10)]
+ res = await asyncio.gather(*[get_command_stdout(sys.executable, '-c',
+ f'print({out!r})') for out in outputs])
+ self.assertEqual(res, outputs)
+
+ self.loop.run_until_complete(main())
+
 
 if sys.platform != 'win32':
  # Unix

Misc/NEWS.d/next/Library/2022-12-10-08-36-07.gh-issue-100133.g-zQlp.rst

@@ -0,0 +1 @@
+Fix regression in :mod:`asyncio` where a subprocess would sometimes lose data received from pipe.