gh-121381 Remove subprocess._USE_VFORK escape hatch (#121383)

This flag was added as an escape hatch in gh-91401 and backported to
Python 3.10. The flag broke at some point between its addition and now.
As there is currently no publicly known environments that require this,
remove it rather than work on fixing it.

This leaves the flag in the subprocess module to not break code which
may have used / checked the flag itself.

discussion: https://discuss.python.org/t/subprocess-use-vfork-escape-hatch-broken-fix-or-remove/56915/2
This commit is contained in:
Cody Maloney 2024-07-30 18:39:54 -07:00 committed by GitHub
parent 82db572813
commit a9344cdffa
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GPG key ID: B5690EEEBB952194
8 changed files with 21 additions and 62 deletions

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@ -3278,7 +3278,7 @@ class POSIXProcessTestCase(BaseTestCase):
1, 2, 3, 4,
True, True, 0,
None, None, None, -1,
None, True)
None)
self.assertIn('fds_to_keep', str(c.exception))
finally:
if not gc_enabled:
@ -3413,25 +3413,6 @@ class POSIXProcessTestCase(BaseTestCase):
self.assertEqual(out.strip(), b"OK")
self.assertIn(b"preexec_fn not supported at interpreter shutdown", err)
@unittest.skipIf(not sysconfig.get_config_var("HAVE_VFORK"),
"vfork() not enabled by configure.")
@mock.patch("subprocess._fork_exec")
@mock.patch("subprocess._USE_POSIX_SPAWN", new=False)
def test__use_vfork(self, mock_fork_exec):
self.assertTrue(subprocess._USE_VFORK) # The default value regardless.
mock_fork_exec.side_effect = RuntimeError("just testing args")
with self.assertRaises(RuntimeError):
subprocess.run([sys.executable, "-c", "pass"])
mock_fork_exec.assert_called_once()
# NOTE: These assertions are *ugly* as they require the last arg
# to remain the have_vfork boolean. We really need to refactor away
# from the giant "wall of args" internal C extension API.
self.assertTrue(mock_fork_exec.call_args.args[-1])
with mock.patch.object(subprocess, '_USE_VFORK', False):
with self.assertRaises(RuntimeError):
subprocess.run([sys.executable, "-c", "pass"])
self.assertFalse(mock_fork_exec.call_args_list[-1].args[-1])
@unittest.skipIf(not sysconfig.get_config_var("HAVE_VFORK"),
"vfork() not enabled by configure.")
@unittest.skipIf(sys.platform != "linux", "Linux only, requires strace.")
@ -3478,7 +3459,6 @@ class POSIXProcessTestCase(BaseTestCase):
# Test that each individual thing that would disable the use of vfork
# actually disables it.
for sub_name, preamble, sp_kwarg, expect_permission_error in (
("!use_vfork", "subprocess._USE_VFORK = False", "", False),
("preexec", "", "preexec_fn=lambda: None", False),
("setgid", "", f"group={os.getgid()}", True),
("setuid", "", f"user={os.getuid()}", True),