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[3.6] bpo-30121: Fix debug assert in subprocess on Windows (#1224) #3173

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Merged
merged 2 commits into from
Aug 21, 2017
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[3.6] bpo-30121: Fix debug assert in subprocess on Windows (#1224) #3173

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a043bf1
bpo-30121: Fix debug assert in subprocess on Windows (#1224)
segevfiner Aug 18, 2017
d4e183b
Add test_subprocess.test_nonexisting_with_pipes() (#3133)
vstinner Aug 21, 2017
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8 changes: 7 additions & 1 deletion Lib/subprocess.py
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Original file line number Diff line number Diff line change
Expand Up @@ -725,7 +725,10 @@ def __init__(self, args, bufsize=-1, executable=None,
to_close.append(self._devnull)
for fd in to_close:
try:
os.close(fd)
if _mswindows and isinstance(fd, Handle):
fd.Close()
else:
os.close(fd)
except OSError:
pass

Expand Down Expand Up @@ -1005,6 +1008,9 @@ def _execute_child(self, args, executable, preexec_fn, close_fds,
errwrite.Close()
if hasattr(self, '_devnull'):
os.close(self._devnull)
# Prevent a double close of these handles/fds from __init__
# on error.
self._closed_child_pipe_fds = True

# Retain the process handle, but close the thread handle
self._child_created = True
Expand Down
60 changes: 52 additions & 8 deletions Lib/test/test_subprocess.py
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Original file line number Diff line number Diff line change
Expand Up @@ -49,6 +49,8 @@
else:
SETBINARY = ''

NONEXISTING_CMD = ('nonexisting_i_hope',)


class BaseTestCase(unittest.TestCase):
def setUp(self):
Expand Down Expand Up @@ -1120,10 +1122,11 @@ def _test_bufsize_equal_one(self, line, expected, universal_newlines):
p.stdin.write(line) # expect that it flushes the line in text mode
os.close(p.stdin.fileno()) # close it without flushing the buffer
read_line = p.stdout.readline()
try:
p.stdin.close()
except OSError:
pass
with support.SuppressCrashReport():
try:
p.stdin.close()
except OSError:
pass
p.stdin = None
self.assertEqual(p.returncode, 0)
self.assertEqual(read_line, expected)
Expand All @@ -1148,13 +1151,54 @@ def test_leaking_fds_on_error(self):
# 1024 times (each call leaked two fds).
for i in range(1024):
with self.assertRaises(OSError) as c:
subprocess.Popen(['nonexisting_i_hope'],
subprocess.Popen(NONEXISTING_CMD,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
# ignore errors that indicate the command was not found
if c.exception.errno not in (errno.ENOENT, errno.EACCES):
raise c.exception

def test_nonexisting_with_pipes(self):
# bpo-30121: Popen with pipes must close properly pipes on error.
# Previously, os.close() was called with a Windows handle which is not
# a valid file descriptor.
#
# Run the test in a subprocess to control how the CRT reports errors
# and to get stderr content.
try:
import msvcrt
msvcrt.CrtSetReportMode
except (AttributeError, ImportError):
self.skipTest("need msvcrt.CrtSetReportMode")

code = textwrap.dedent(f"""
import msvcrt
import subprocess

cmd = {NONEXISTING_CMD!r}

for report_type in [msvcrt.CRT_WARN,
msvcrt.CRT_ERROR,
msvcrt.CRT_ASSERT]:
msvcrt.CrtSetReportMode(report_type, msvcrt.CRTDBG_MODE_FILE)
msvcrt.CrtSetReportFile(report_type, msvcrt.CRTDBG_FILE_STDERR)

try:
subprocess.Popen([cmd],
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
except OSError:
pass
""")
cmd = [sys.executable, "-c", code]
proc = subprocess.Popen(cmd,
stderr=subprocess.PIPE,
universal_newlines=True)
with proc:
stderr = proc.communicate()[1]
self.assertEqual(stderr, "")
self.assertEqual(proc.returncode, 0)

@unittest.skipIf(threading is None, "threading required")
def test_double_close_on_error(self):
# Issue #18851
Expand All @@ -1167,7 +1211,7 @@ def open_fds():
t.start()
try:
with self.assertRaises(EnvironmentError):
subprocess.Popen(['nonexisting_i_hope'],
subprocess.Popen(NONEXISTING_CMD,
stdin=subprocess.PIPE,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE)
Expand Down Expand Up @@ -2433,7 +2477,7 @@ def test_leak_fast_process_del_killed(self):
# should trigger the wait() of p
time.sleep(0.2)
with self.assertRaises(OSError) as c:
with subprocess.Popen(['nonexisting_i_hope'],
with subprocess.Popen(NONEXISTING_CMD,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE) as proc:
pass
Expand Down Expand Up @@ -2863,7 +2907,7 @@ def test_communicate_stdin(self):

def test_invalid_args(self):
with self.assertRaises((FileNotFoundError, PermissionError)) as c:
with subprocess.Popen(['nonexisting_i_hope'],
with subprocess.Popen(NONEXISTING_CMD,
stdout=subprocess.PIPE,
stderr=subprocess.PIPE) as proc:
pass
Expand Down