bpo-37380: subprocess: don't use _active on win (GH-14360)
As noted by @eryksun in [1] and [2], using _cleanup and _active(in
__del__) is not necessary on Windows, since:
> Unlike Unix, a process in Windows doesn't have to be waited on by
> its parent to avoid a zombie. Keeping the handle open will actually
> create a zombie until the next _cleanup() call, which may be never
> if Popen() isn't called again.
This patch simply defines `subprocess._active` as `None`, for which we already
have the proper logic in place in `subprocess.Popen.__del__`, that prevents it
from trying to append the process to the `_active`. This patch also defines
`subprocess._cleanup` as a noop for Windows.
[1] https://bugs.python.org/issue37380#msg346333
[2] https://bugs.python.org/issue36067#msg336262
Signed-off-by: Ruslan Kuprieiev <ruslan@iterative.ai>
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 @@
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 @@
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 @@
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 @@
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")