bpo-39995: Split test_concurrent_futures.test_crash() into sub-tests (GH-19739)

Now only test_error_during_result_unpickle_in_result_handler()
captures and ignores sys.stderr in the test process.

Tools like test.bisect_cmd don't support subTest() but only
work with the granularity of one method.

Remove unused ExecutorDeadlockTest._sleep_id() method.
This commit is contained in:
Victor Stinner 2020-04-27 21:36:51 +02:00 committed by GitHub
parent 1a275013d1
commit 5d1f32d33b
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1 changed files with 85 additions and 63 deletions

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@ -1006,11 +1006,6 @@ create_executor_tests(ProcessPoolExecutorTest,
ProcessPoolForkserverMixin,
ProcessPoolSpawnMixin))
def hide_process_stderr():
import io
sys.stderr = io.StringIO()
def _crash(delay=None):
"""Induces a segfault."""
if delay:
@ -1027,13 +1022,18 @@ def _exit():
def _raise_error(Err):
"""Function that raises an Exception in process."""
hide_process_stderr()
raise Err()
def _raise_error_ignore_stderr(Err):
"""Function that raises an Exception in process and ignores stderr."""
import io
sys.stderr = io.StringIO()
raise Err()
def _return_instance(cls):
"""Function that returns a instance of cls."""
hide_process_stderr()
return cls()
@ -1072,17 +1072,12 @@ class ErrorAtUnpickle(object):
"""Bad object that triggers an error at unpickling time."""
def __reduce__(self):
from pickle import UnpicklingError
return _raise_error, (UnpicklingError, )
return _raise_error_ignore_stderr, (UnpicklingError, )
class ExecutorDeadlockTest:
TIMEOUT = support.SHORT_TIMEOUT
@classmethod
def _sleep_id(cls, x, delay):
time.sleep(delay)
return x
def _fail_on_deadlock(self, executor):
# If we did not recover before TIMEOUT seconds, consider that the
# executor is in a deadlock state and forcefully clean all its
@ -1102,57 +1097,84 @@ class ExecutorDeadlockTest:
self.fail(f"Executor deadlock:\n\n{tb}")
def test_crash(self):
# extensive testing for deadlock caused by crashes in a pool.
def _check_crash(self, error, func, *args, ignore_stderr=False):
# test for deadlock caused by crashes in a pool
self.executor.shutdown(wait=True)
crash_cases = [
# Check problem occurring while pickling a task in
# the task_handler thread
(id, (ErrorAtPickle(),), PicklingError, "error at task pickle"),
# Check problem occurring while unpickling a task on workers
(id, (ExitAtUnpickle(),), BrokenProcessPool,
"exit at task unpickle"),
(id, (ErrorAtUnpickle(),), BrokenProcessPool,
"error at task unpickle"),
(id, (CrashAtUnpickle(),), BrokenProcessPool,
"crash at task unpickle"),
# Check problem occurring during func execution on workers
(_crash, (), BrokenProcessPool,
"crash during func execution on worker"),
(_exit, (), SystemExit,
"exit during func execution on worker"),
(_raise_error, (RuntimeError, ), RuntimeError,
"error during func execution on worker"),
# Check problem occurring while pickling a task result
# on workers
(_return_instance, (CrashAtPickle,), BrokenProcessPool,
"crash during result pickle on worker"),
(_return_instance, (ExitAtPickle,), SystemExit,
"exit during result pickle on worker"),
(_return_instance, (ErrorAtPickle,), PicklingError,
"error during result pickle on worker"),
# Check problem occurring while unpickling a task in
# the result_handler thread
(_return_instance, (ErrorAtUnpickle,), BrokenProcessPool,
"error during result unpickle in result_handler"),
(_return_instance, (ExitAtUnpickle,), BrokenProcessPool,
"exit during result unpickle in result_handler")
]
for func, args, error, name in crash_cases:
with self.subTest(name):
# The captured_stderr reduces the noise in the test report
with support.captured_stderr():
executor = self.executor_type(
max_workers=2, mp_context=get_context(self.ctx))
res = executor.submit(func, *args)
with self.assertRaises(error):
try:
res.result(timeout=self.TIMEOUT)
except futures.TimeoutError:
# If we did not recover before TIMEOUT seconds,
# consider that the executor is in a deadlock state
self._fail_on_deadlock(executor)
executor.shutdown(wait=True)
executor = self.executor_type(
max_workers=2, mp_context=get_context(self.ctx))
res = executor.submit(func, *args)
if ignore_stderr:
cm = support.captured_stderr()
else:
cm = contextlib.nullcontext()
try:
with self.assertRaises(error):
with cm:
res.result(timeout=self.TIMEOUT)
except futures.TimeoutError:
# If we did not recover before TIMEOUT seconds,
# consider that the executor is in a deadlock state
self._fail_on_deadlock(executor)
executor.shutdown(wait=True)
def test_error_at_task_pickle(self):
# Check problem occurring while pickling a task in
# the task_handler thread
self._check_crash(PicklingError, id, ErrorAtPickle())
def test_exit_at_task_unpickle(self):
# Check problem occurring while unpickling a task on workers
self._check_crash(BrokenProcessPool, id, ExitAtUnpickle())
def test_error_at_task_unpickle(self):
# Check problem occurring while unpickling a task on workers
self._check_crash(BrokenProcessPool, id, ErrorAtUnpickle())
def test_crash_at_task_unpickle(self):
# Check problem occurring while unpickling a task on workers
self._check_crash(BrokenProcessPool, id, CrashAtUnpickle())
def test_crash_during_func_exec_on_worker(self):
# Check problem occurring during func execution on workers
self._check_crash(BrokenProcessPool, _crash)
def test_exit_during_func_exec_on_worker(self):
# Check problem occurring during func execution on workers
self._check_crash(SystemExit, _exit)
def test_error_during_func_exec_on_worker(self):
# Check problem occurring during func execution on workers
self._check_crash(RuntimeError, _raise_error, RuntimeError)
def test_crash_during_result_pickle_on_worker(self):
# Check problem occurring while pickling a task result
# on workers
self._check_crash(BrokenProcessPool, _return_instance, CrashAtPickle)
def test_exit_during_result_pickle_on_worker(self):
# Check problem occurring while pickling a task result
# on workers
self._check_crash(SystemExit, _return_instance, ExitAtPickle)
def test_error_during_result_pickle_on_worker(self):
# Check problem occurring while pickling a task result
# on workers
self._check_crash(PicklingError, _return_instance, ErrorAtPickle)
def test_error_during_result_unpickle_in_result_handler(self):
# Check problem occurring while unpickling a task in
# the result_handler thread
self._check_crash(BrokenProcessPool,
_return_instance, ErrorAtUnpickle,
ignore_stderr=True)
def test_exit_during_result_unpickle_in_result_handler(self):
# Check problem occurring while unpickling a task in
# the result_handler thread
self._check_crash(BrokenProcessPool, _return_instance, ExitAtUnpickle)
def test_shutdown_deadlock(self):
# Test that the pool calling shutdown do not cause deadlock