diff options
| -rw-r--r-- | Lib/subprocess.py | 48 | ||||
| -rw-r--r-- | Lib/test/test_subprocess.py | 34 | ||||
| -rw-r--r-- | Misc/NEWS.d/next/Windows/2019-06-25-04-15-22.bpo-37380.tPxjuz.rst | 2 |
3 files changed, 59 insertions, 25 deletions
diff --git a/Lib/subprocess.py b/Lib/subprocess.py index c0bda96..5bbeba4 100644 --- a/Lib/subprocess.py +++ b/Lib/subprocess.py @@ -218,22 +218,38 @@ else: _PopenSelector = selectors.SelectSelector -# This lists holds Popen instances for which the underlying process had not -# exited at the time its __del__ method got called: those processes are wait()ed -# for synchronously from _cleanup() when a new Popen object is created, to avoid -# zombie processes. -_active = [] - -def _cleanup(): - for inst in _active[:]: - res = inst._internal_poll(_deadstate=sys.maxsize) - if res is not None: - try: - _active.remove(inst) - except ValueError: - # This can happen if two threads create a new Popen instance. - # It's harmless that it was already removed, so ignore. - pass +if _mswindows: + # On Windows we just need to close `Popen._handle` when we no longer need + # it, so that the kernel can free it. `Popen._handle` gets closed + # implicitly when the `Popen` instance is finalized (see `Handle.__del__`, + # which is calling `CloseHandle` as requested in [1]), so there is nothing + # for `_cleanup` to do. + # + # [1] https://docs.microsoft.com/en-us/windows/desktop/ProcThread/ + # creating-processes + _active = None + + def _cleanup(): + pass +else: + # This lists holds Popen instances for which the underlying process had not + # exited at the time its __del__ method got called: those processes are + # wait()ed for synchronously from _cleanup() when a new Popen object is + # created, to avoid zombie processes. + _active = [] + + def _cleanup(): + if _active is None: + return + for inst in _active[:]: + res = inst._internal_poll(_deadstate=sys.maxsize) + if res is not None: + try: + _active.remove(inst) + except ValueError: + # This can happen if two threads create a new Popen instance. + # It's harmless that it was already removed, so ignore. + pass PIPE = -1 STDOUT = -2 diff --git a/Lib/test/test_subprocess.py b/Lib/test/test_subprocess.py index 97d2190..6b8acb2 100644 --- a/Lib/test/test_subprocess.py +++ b/Lib/test/test_subprocess.py @@ -59,10 +59,14 @@ class BaseTestCase(unittest.TestCase): support.reap_children() def tearDown(self): - for inst in subprocess._active: - inst.wait() - subprocess._cleanup() - self.assertFalse(subprocess._active, "subprocess._active not empty") + if not mswindows: + # subprocess._active is not used on Windows and is set to None. + for inst in subprocess._active: + inst.wait() + subprocess._cleanup() + self.assertFalse( + subprocess._active, "subprocess._active not empty" + ) self.doCleanups() support.reap_children() @@ -2679,8 +2683,12 @@ class POSIXProcessTestCase(BaseTestCase): with support.check_warnings(('', ResourceWarning)): p = None - # check that p is in the active processes list - self.assertIn(ident, [id(o) for o in subprocess._active]) + if mswindows: + # subprocess._active is not used on Windows and is set to None. + self.assertIsNone(subprocess._active) + else: + # check that p is in the active processes list + self.assertIn(ident, [id(o) for o in subprocess._active]) def test_leak_fast_process_del_killed(self): # Issue #12650: on Unix, if Popen.__del__() was called before the @@ -2701,8 +2709,12 @@ class POSIXProcessTestCase(BaseTestCase): p = None os.kill(pid, signal.SIGKILL) - # check that p is in the active processes list - self.assertIn(ident, [id(o) for o in subprocess._active]) + if mswindows: + # subprocess._active is not used on Windows and is set to None. + self.assertIsNone(subprocess._active) + else: + # check that p is in the active processes list + self.assertIn(ident, [id(o) for o in subprocess._active]) # let some time for the process to exit, and create a new Popen: this # should trigger the wait() of p @@ -2714,7 +2726,11 @@ class POSIXProcessTestCase(BaseTestCase): pass # p should have been wait()ed on, and removed from the _active list self.assertRaises(OSError, os.waitpid, pid, 0) - self.assertNotIn(ident, [id(o) for o in subprocess._active]) + if mswindows: + # subprocess._active is not used on Windows and is set to None. + self.assertIsNone(subprocess._active) + else: + self.assertNotIn(ident, [id(o) for o in subprocess._active]) def test_close_fds_after_preexec(self): fd_status = support.findfile("fd_status.py", subdir="subprocessdata") diff --git a/Misc/NEWS.d/next/Windows/2019-06-25-04-15-22.bpo-37380.tPxjuz.rst b/Misc/NEWS.d/next/Windows/2019-06-25-04-15-22.bpo-37380.tPxjuz.rst new file mode 100644 index 0000000..facce27 --- /dev/null +++ b/Misc/NEWS.d/next/Windows/2019-06-25-04-15-22.bpo-37380.tPxjuz.rst @@ -0,0 +1,2 @@ +Don't collect unfinished processes with ``subprocess._active`` on Windows to +cleanup later. Patch by Ruslan Kuprieiev. |