https://github.com/python/cpython/commit/3d1b8e2a9671c9a9b152204856c8f086506c3c05 commit: 3d1b8e2a9671c9a9b152204856c8f086506c3c05 branch: 3.13 author: Miss Islington (bot) <[email protected]> committer: gpshead <[email protected]> date: 2025-05-05T01:38:30Z summary:
[3.13] gh-133089: Use original timeout value for `TimeoutExpired` when the func `subprocess.run` is called with a timeout (GH-133103) (#133418) gh-133089: Use original timeout value for `TimeoutExpired` when the func `subprocess.run` is called with a timeout (GH-133103) (cherry picked from commit 2bbcaedb75942389dacb51866948f40de5951c9c) Signed-off-by: Manjusaka <[email protected]> Co-authored-by: Nadeshiko Manju <[email protected]> Co-authored-by: Gregory P. Smith <[email protected]> files: A Misc/NEWS.d/next/Library/2025-04-29-02-23-04.gh-issue-133089.8Jy1ZS.rst M Doc/library/subprocess.rst M Lib/subprocess.py M Lib/test/test_subprocess.py diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst index 59c98e867ff42d..4728b0df6eeebc 100644 --- a/Doc/library/subprocess.rst +++ b/Doc/library/subprocess.rst @@ -1591,6 +1591,24 @@ handling consistency are valid for these functions. Notes ----- +.. _subprocess-timeout-behavior: + +Timeout Behavior +^^^^^^^^^^^^^^^^ + +When using the ``timeout`` parameter in functions like :func:`run`, +:meth:`Popen.wait`, or :meth:`Popen.communicate`, +users should be aware of the following behaviors: + +1. **Process Creation Delay**: The initial process creation itself cannot be interrupted + on many platform APIs. This means that even when specifying a timeout, you are not + guaranteed to see a timeout exception until at least after however long process + creation takes. + +2. **Extremely Small Timeout Values**: Setting very small timeout values (such as a few + milliseconds) may result in almost immediate :exc:`TimeoutExpired` exceptions because + process creation and system scheduling inherently require time. + .. _converting-argument-sequence: Converting an argument sequence to a string on Windows diff --git a/Lib/subprocess.py b/Lib/subprocess.py index 4a9a64e5577989..ffc3fdf6afb5c7 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -1237,8 +1237,11 @@ def communicate(self, input=None, timeout=None): finally: self._communication_started = True - - sts = self.wait(timeout=self._remaining_time(endtime)) + try: + sts = self.wait(timeout=self._remaining_time(endtime)) + except TimeoutExpired as exc: + exc.timeout = timeout + raise return (stdout, stderr) @@ -2147,8 +2150,11 @@ def _communicate(self, input, endtime, orig_timeout): selector.unregister(key.fileobj) key.fileobj.close() self._fileobj2output[key.fileobj].append(data) - - self.wait(timeout=self._remaining_time(endtime)) + try: + self.wait(timeout=self._remaining_time(endtime)) + except TimeoutExpired as exc: + exc.timeout = orig_timeout + raise # All data exchanged. Translate lists into strings. if stdout is not None: diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py index 7d72737e9cb066..ba02b1a1c011a1 100644 --- a/Lib/test/test_subprocess.py +++ b/Lib/test/test_subprocess.py @@ -161,6 +161,20 @@ def test_call_timeout(self): [sys.executable, "-c", "while True: pass"], timeout=0.1) + def test_timeout_exception(self): + try: + subprocess.run(['echo', 'hi'], timeout = -1) + except subprocess.TimeoutExpired as e: + self.assertIn("-1 seconds", str(e)) + else: + self.fail("Expected TimeoutExpired exception not raised") + try: + subprocess.run(['echo', 'hi'], timeout = 0) + except subprocess.TimeoutExpired as e: + self.assertIn("0 seconds", str(e)) + else: + self.fail("Expected TimeoutExpired exception not raised") + def test_check_call_zero(self): # check_call() function with zero return code rc = subprocess.check_call(ZERO_RETURN_CMD) diff --git a/Misc/NEWS.d/next/Library/2025-04-29-02-23-04.gh-issue-133089.8Jy1ZS.rst b/Misc/NEWS.d/next/Library/2025-04-29-02-23-04.gh-issue-133089.8Jy1ZS.rst new file mode 100644 index 00000000000000..8c4257a12a90e5 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2025-04-29-02-23-04.gh-issue-133089.8Jy1ZS.rst @@ -0,0 +1,4 @@ +Use original timeout value for :exc:`subprocess.TimeoutExpired` +when the func :meth:`subprocess.run` is called with a timeout +instead of sometimes a confusing partial remaining time out value +used internally on the final ``wait()``. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-checkins.python.org/ Member address: [email protected]
