https://github.com/python/cpython/commit/67d140dba72dc2cb661d55878384464de46... commit: 67d140dba72dc2cb661d55878384464de46719e7 branch: main author: Marek Marczykowski-Górecki <marmarek@invisiblethingslab.com> committer: gvanrossum <gvanrossum@gmail.com> date: 2023-04-27T17:30:26-07:00 summary: gh-83925: Make asyncio.subprocess communicate similar to non-asyncio (#18650) subprocess's communicate(None) closes stdin of the child process, after sending no (extra) data. Make asyncio variant do the same. This fixes issues with processes that waits for EOF on stdin before continuing. files: A Misc/NEWS.d/next/Library/2020-02-25-00-43-22.bpo-39744.hgK689.rst M Doc/library/asyncio-subprocess.rst M Lib/asyncio/subprocess.py M Lib/test/test_asyncio/test_subprocess.py diff --git a/Doc/library/asyncio-subprocess.rst b/Doc/library/asyncio-subprocess.rst index 4274638c5e86..b7c83aa04c09 100644 --- a/Doc/library/asyncio-subprocess.rst +++ b/Doc/library/asyncio-subprocess.rst @@ -207,8 +207,9 @@ their completion. Interact with process: 1. send data to *stdin* (if *input* is not ``None``); - 2. read data from *stdout* and *stderr*, until EOF is reached; - 3. wait for process to terminate. + 2. closes *stdin*; + 3. read data from *stdout* and *stderr*, until EOF is reached; + 4. wait for process to terminate. The optional *input* argument is the data (:class:`bytes` object) that will be sent to the child process. @@ -229,6 +230,10 @@ their completion. Note, that the data read is buffered in memory, so do not use this method if the data size is large or unlimited. + .. versionchanged:: 3.12 + + *stdin* gets closed when `input=None` too. + .. method:: send_signal(signal) Sends the signal *signal* to the child process. diff --git a/Lib/asyncio/subprocess.py b/Lib/asyncio/subprocess.py index cd10231f710f..50727ca300e6 100644 --- a/Lib/asyncio/subprocess.py +++ b/Lib/asyncio/subprocess.py @@ -144,10 +144,11 @@ def kill(self): async def _feed_stdin(self, input): debug = self._loop.get_debug() - self.stdin.write(input) - if debug: - logger.debug( - '%r communicate: feed stdin (%s bytes)', self, len(input)) + if input is not None: + self.stdin.write(input) + if debug: + logger.debug( + '%r communicate: feed stdin (%s bytes)', self, len(input)) try: await self.stdin.drain() except (BrokenPipeError, ConnectionResetError) as exc: @@ -180,7 +181,7 @@ async def _read_stream(self, fd): return output async def communicate(self, input=None): - if input is not None: + if self.stdin is not None: stdin = self._feed_stdin(input) else: stdin = self._noop() diff --git a/Lib/test/test_asyncio/test_subprocess.py b/Lib/test/test_asyncio/test_subprocess.py index eba6e2d1f28f..eeeca40c15cd 100644 --- a/Lib/test/test_asyncio/test_subprocess.py +++ b/Lib/test/test_asyncio/test_subprocess.py @@ -151,6 +151,24 @@ async def run(data): self.assertEqual(exitcode, 0) self.assertEqual(stdout, b'some data') + def test_communicate_none_input(self): + args = PROGRAM_CAT + + async def run(): + proc = await asyncio.create_subprocess_exec( + *args, + stdin=subprocess.PIPE, + stdout=subprocess.PIPE, + ) + stdout, stderr = await proc.communicate() + return proc.returncode, stdout + + task = run() + task = asyncio.wait_for(task, support.LONG_TIMEOUT) + exitcode, stdout = self.loop.run_until_complete(task) + self.assertEqual(exitcode, 0) + self.assertEqual(stdout, b'') + def test_shell(self): proc = self.loop.run_until_complete( asyncio.create_subprocess_shell('exit 7') diff --git a/Misc/NEWS.d/next/Library/2020-02-25-00-43-22.bpo-39744.hgK689.rst b/Misc/NEWS.d/next/Library/2020-02-25-00-43-22.bpo-39744.hgK689.rst new file mode 100644 index 000000000000..6e690f996569 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2020-02-25-00-43-22.bpo-39744.hgK689.rst @@ -0,0 +1 @@ +Make :func:`asyncio.subprocess.Process.communicate` close the subprocess's stdin even when called with ``input=None``.