bpo-5001: More-informative multiprocessing error messages (#3079)

* Make error message more informative

Replace assertions in error-reporting code with more-informative version that doesn't cause confusion over where and what the error is.

* Additional clarification + get travis to check

* Change from SystemError to TypeError

As suggested in PR comment by @pitrou, changing from SystemError; TypeError appears appropriate.

* NEWS file installation; ACKS addition (will do my best to justify it by additional work)

* Making current AssertionErrors in multiprocessing more informative

* Blurb added re multiprocessing managers.py, queues.py cleanup

* Further multiprocessing cleanup - went through pool.py

* Fix two asserts in multiprocessing/util.py

* Most asserts in multiprocessing more informative

* Didn't save right version

* Further work on multiprocessing error messages

* Correct typo

* Correct typo v2

* Blasted colon... serves me right for trying to work on two things at once

* Simplify NEWS entry

* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst

* Update 2017-08-18-17-16-38.bpo-5001.gwnthq.rst

OK, never mind.

* Corrected (thanks to pitrou) error messages for notify

* Remove extraneous backslash in docstring.
This commit is contained in:
Allen W. Smith, Ph.D 2017-08-29 17:52:18 -05:00 committed by Antoine Pitrou
parent 631fdee6e6
commit bd73e72b4a
15 changed files with 120 additions and 39 deletions

View File

@ -720,7 +720,9 @@ FAILURE = b'#FAILURE#'
def deliver_challenge(connection, authkey):
import hmac
assert isinstance(authkey, bytes)
if not isinstance(authkey, bytes):
raise ValueError(
"Authkey must be bytes, not {0!s}".format(type(authkey)))
message = os.urandom(MESSAGE_LENGTH)
connection.send_bytes(CHALLENGE + message)
digest = hmac.new(authkey, message, 'md5').digest()
@ -733,7 +735,9 @@ def deliver_challenge(connection, authkey):
def answer_challenge(connection, authkey):
import hmac
assert isinstance(authkey, bytes)
if not isinstance(authkey, bytes):
raise ValueError(
"Authkey must be bytes, not {0!s}".format(type(authkey)))
message = connection.recv_bytes(256) # reject large message
assert message[:len(CHALLENGE)] == CHALLENGE, 'message = %r' % message
message = message[len(CHALLENGE):]

View File

@ -41,7 +41,10 @@ class DummyProcess(threading.Thread):
self._parent = current_process()
def start(self):
assert self._parent is current_process()
if self._parent is not current_process():
raise RuntimeError(
"Parent is {0!r} but current_process is {1!r}".format(
self._parent, current_process()))
self._start_called = True
if hasattr(self._parent, '_children'):
self._parent._children[self] = None

View File

@ -189,7 +189,7 @@ def main(listener_fd, alive_r, preload, main_path=None, sys_path=None):
if alive_r in rfds:
# EOF because no more client processes left
assert os.read(alive_r, 1) == b''
assert os.read(alive_r, 1) == b'', "Not at EOF?"
raise SystemExit
if sig_r in rfds:
@ -208,7 +208,10 @@ def main(listener_fd, alive_r, preload, main_path=None, sys_path=None):
if os.WIFSIGNALED(sts):
returncode = -os.WTERMSIG(sts)
else:
assert os.WIFEXITED(sts)
if not os.WIFEXITED(sts):
raise AssertionError(
"Child {0:n} status is {1:n}".format(
pid,sts))
returncode = os.WEXITSTATUS(sts)
# Send exit code to client process
try:
@ -227,7 +230,10 @@ def main(listener_fd, alive_r, preload, main_path=None, sys_path=None):
with listener.accept()[0] as s:
# Receive fds from client
fds = reduction.recvfds(s, MAXFDS_TO_SEND + 1)
assert len(fds) <= MAXFDS_TO_SEND
if len(fds) > MAXFDS_TO_SEND:
raise RuntimeError(
"Too many ({0:n}) fds to send".format(
len(fds)))
child_r, child_w, *fds = fds
s.close()
pid = os.fork()

View File

@ -211,7 +211,10 @@ class Heap(object):
# synchronously sometimes later from malloc() or free(), by calling
# _free_pending_blocks() (appending and retrieving from a list is not
# strictly thread-safe but under cPython it's atomic thanks to the GIL).
assert os.getpid() == self._lastpid
if os.getpid() != self._lastpid:
raise ValueError(
"My pid ({0:n}) is not last pid {1:n}".format(
os.getpid(),self._lastpid))
if not self._lock.acquire(False):
# can't acquire the lock right now, add the block to the list of
# pending blocks to free
@ -227,7 +230,10 @@ class Heap(object):
def malloc(self, size):
# return a block of right size (possibly rounded up)
assert 0 <= size < sys.maxsize
if size < 0:
raise ValueError("Size {0:n} out of range".format(size))
if sys.maxsize <= size:
raise OverflowError("Size {0:n} too large".format(size))
if os.getpid() != self._lastpid:
self.__init__() # reinitialize after fork
with self._lock:
@ -250,7 +256,10 @@ class BufferWrapper(object):
_heap = Heap()
def __init__(self, size):
assert 0 <= size < sys.maxsize
if size < 0:
raise ValueError("Size {0:n} out of range".format(size))
if sys.maxsize <= size:
raise OverflowError("Size {0:n} too large".format(size))
block = BufferWrapper._heap.malloc(size)
self._state = (block, size)
util.Finalize(self, BufferWrapper._heap.free, args=(block,))

View File

@ -23,7 +23,7 @@ from time import time as _time
from traceback import format_exc
from . import connection
from .context import reduction, get_spawning_popen
from .context import reduction, get_spawning_popen, ProcessError
from . import pool
from . import process
from . import util
@ -133,7 +133,10 @@ class Server(object):
'debug_info', 'number_of_objects', 'dummy', 'incref', 'decref']
def __init__(self, registry, address, authkey, serializer):
assert isinstance(authkey, bytes)
if not isinstance(authkey, bytes):
raise TypeError(
"Authkey {0!r} is type {1!s}, not bytes".format(
authkey, type(authkey)))
self.registry = registry
self.authkey = process.AuthenticationString(authkey)
Listener, Client = listener_client[serializer]
@ -163,7 +166,7 @@ class Server(object):
except (KeyboardInterrupt, SystemExit):
pass
finally:
if sys.stdout != sys.__stdout__:
if sys.stdout != sys.__stdout__: # what about stderr?
util.debug('resetting stdout, stderr')
sys.stdout = sys.__stdout__
sys.stderr = sys.__stderr__
@ -316,6 +319,7 @@ class Server(object):
'''
Return some info --- useful to spot problems with refcounting
'''
# Perhaps include debug info about 'c'?
with self.mutex:
result = []
keys = list(self.id_to_refcount.keys())
@ -356,7 +360,9 @@ class Server(object):
self.registry[typeid]
if callable is None:
assert len(args) == 1 and not kwds
if kwds or (len(args) != 1):
raise ValueError(
"Without callable, must have one non-keyword argument")
obj = args[0]
else:
obj = callable(*args, **kwds)
@ -364,7 +370,10 @@ class Server(object):
if exposed is None:
exposed = public_methods(obj)
if method_to_typeid is not None:
assert type(method_to_typeid) is dict
if not isinstance(method_to_typeid, dict):
raise TypeError(
"Method_to_typeid {0!r}: type {1!s}, not dict".format(
method_to_typeid, type(method_to_typeid)))
exposed = list(exposed) + list(method_to_typeid)
ident = '%x' % id(obj) # convert to string because xmlrpclib
@ -417,7 +426,11 @@ class Server(object):
return
with self.mutex:
assert self.id_to_refcount[ident] >= 1
if self.id_to_refcount[ident] <= 0:
raise AssertionError(
"Id {0!s} ({1!r}) has refcount {2:n}, not 1+".format(
ident, self.id_to_obj[ident],
self.id_to_refcount[ident]))
self.id_to_refcount[ident] -= 1
if self.id_to_refcount[ident] == 0:
del self.id_to_refcount[ident]
@ -480,7 +493,14 @@ class BaseManager(object):
'''
Return server object with serve_forever() method and address attribute
'''
assert self._state.value == State.INITIAL
if self._state.value != State.INITIAL:
if self._state.value == State.STARTED:
raise ProcessError("Already started server")
elif self._state.value == State.SHUTDOWN:
raise ProcessError("Manager has shut down")
else:
raise ProcessError(
"Unknown state {!r}".format(self._state.value))
return Server(self._registry, self._address,
self._authkey, self._serializer)
@ -497,7 +517,14 @@ class BaseManager(object):
'''
Spawn a server process for this manager object
'''
assert self._state.value == State.INITIAL
if self._state.value != State.INITIAL:
if self._state.value == State.STARTED:
raise ProcessError("Already started server")
elif self._state.value == State.SHUTDOWN:
raise ProcessError("Manager has shut down")
else:
raise ProcessError(
"Unknown state {!r}".format(self._state.value))
if initializer is not None and not callable(initializer):
raise TypeError('initializer must be a callable')
@ -593,7 +620,14 @@ class BaseManager(object):
def __enter__(self):
if self._state.value == State.INITIAL:
self.start()
assert self._state.value == State.STARTED
if self._state.value != State.STARTED:
if self._state.value == State.INITIAL:
raise ProcessError("Unable to start server")
elif self._state.value == State.SHUTDOWN:
raise ProcessError("Manager has shut down")
else:
raise ProcessError(
"Unknown state {!r}".format(self._state.value))
return self
def __exit__(self, exc_type, exc_val, exc_tb):
@ -653,7 +687,7 @@ class BaseManager(object):
getattr(proxytype, '_method_to_typeid_', None)
if method_to_typeid:
for key, value in list(method_to_typeid.items()):
for key, value in list(method_to_typeid.items()): # isinstance?
assert type(key) is str, '%r is not a string' % key
assert type(value) is str, '%r is not a string' % value

View File

@ -92,7 +92,9 @@ class MaybeEncodingError(Exception):
def worker(inqueue, outqueue, initializer=None, initargs=(), maxtasks=None,
wrap_exception=False):
assert maxtasks is None or (type(maxtasks) == int and maxtasks > 0)
if (maxtasks is not None) and not (isinstance(maxtasks, int)
and maxtasks >= 1):
raise AssertionError("Maxtasks {!r} is not valid".format(maxtasks))
put = outqueue.put
get = inqueue.get
if hasattr(inqueue, '_writer'):
@ -254,8 +256,8 @@ class Pool(object):
def apply(self, func, args=(), kwds={}):
'''
Equivalent of `func(*args, **kwds)`.
Pool must be running.
'''
assert self._state == RUN
return self.apply_async(func, args, kwds).get()
def map(self, func, iterable, chunksize=None):
@ -307,6 +309,10 @@ class Pool(object):
))
return result
else:
if chunksize < 1:
raise ValueError(
"Chunksize must be 1+, not {0:n}".format(
chunksize))
assert chunksize > 1
task_batches = Pool._get_tasks(func, iterable, chunksize)
result = IMapIterator(self._cache)
@ -334,7 +340,9 @@ class Pool(object):
))
return result
else:
assert chunksize > 1
if chunksize < 1:
raise ValueError(
"Chunksize must be 1+, not {0!r}".format(chunksize))
task_batches = Pool._get_tasks(func, iterable, chunksize)
result = IMapUnorderedIterator(self._cache)
self._taskqueue.put(
@ -466,7 +474,7 @@ class Pool(object):
return
if thread._state:
assert thread._state == TERMINATE
assert thread._state == TERMINATE, "Thread not in TERMINATE"
util.debug('result handler found thread._state=TERMINATE')
break
@ -542,7 +550,10 @@ class Pool(object):
def join(self):
util.debug('joining pool')
assert self._state in (CLOSE, TERMINATE)
if self._state == RUN:
raise ValueError("Pool is still running")
elif self._state not in (CLOSE, TERMINATE):
raise ValueError("In unknown state")
self._worker_handler.join()
self._task_handler.join()
self._result_handler.join()
@ -570,7 +581,9 @@ class Pool(object):
util.debug('helping task handler/workers to finish')
cls._help_stuff_finish(inqueue, task_handler, len(pool))
assert result_handler.is_alive() or len(cache) == 0
if (not result_handler.is_alive()) and (len(cache) != 0):
raise AssertionError(
"Cannot have cache with result_hander not alive")
result_handler._state = TERMINATE
outqueue.put(None) # sentinel
@ -628,7 +641,8 @@ class ApplyResult(object):
return self._event.is_set()
def successful(self):
assert self.ready()
if not self.ready():
raise ValueError("{0!r} not ready".format(self))
return self._success
def wait(self, timeout=None):

View File

@ -35,7 +35,7 @@ class Popen(object):
if os.WIFSIGNALED(sts):
self.returncode = -os.WTERMSIG(sts)
else:
assert os.WIFEXITED(sts)
assert os.WIFEXITED(sts), "Status is {:n}".format(sts)
self.returncode = os.WEXITSTATUS(sts)
return self.returncode

View File

@ -78,7 +78,7 @@ class Queue(object):
self._poll = self._reader.poll
def put(self, obj, block=True, timeout=None):
assert not self._closed
assert not self._closed, "Queue {0!r} has been closed".format(self)
if not self._sem.acquire(block, timeout):
raise Full
@ -140,7 +140,7 @@ class Queue(object):
def join_thread(self):
debug('Queue.join_thread()')
assert self._closed
assert self._closed, "Queue {0!r} not closed".format(self)
if self._jointhread:
self._jointhread()
@ -281,7 +281,7 @@ class JoinableQueue(Queue):
self._cond, self._unfinished_tasks = state[-2:]
def put(self, obj, block=True, timeout=None):
assert not self._closed
assert not self._closed, "Queue {0!r} is closed".format(self)
if not self._sem.acquire(block, timeout):
raise Full

View File

@ -165,7 +165,10 @@ else:
if len(cmsg_data) % a.itemsize != 0:
raise ValueError
a.frombytes(cmsg_data)
assert len(a) % 256 == msg[0]
if len(a) % 256 != msg[0]:
raise AssertionError(
"Len is {0:n} but msg[0] is {1!r}".format(
len(a), msg[0]))
return list(a)
except (ValueError, IndexError):
pass

View File

@ -125,7 +125,7 @@ class _ResourceSharer(object):
def _start(self):
from .connection import Listener
assert self._listener is None
assert self._listener is None, "Already have Listener"
util.debug('starting listener and thread for sending handles')
self._listener = Listener(authkey=process.current_process().authkey)
self._address = self._listener.address

View File

@ -80,7 +80,8 @@ class SemaphoreTracker(object):
# bytes are atomic, and that PIPE_BUF >= 512
raise ValueError('name too long')
nbytes = os.write(self._fd, msg)
assert nbytes == len(msg)
assert nbytes == len(msg), "nbytes {0:n} but len(msg) {1:n}".format(
nbytes, len(msg))
_semaphore_tracker = SemaphoreTracker()

View File

@ -93,7 +93,7 @@ def spawn_main(pipe_handle, parent_pid=None, tracker_fd=None):
'''
Run code specified by data received over pipe
'''
assert is_forking(sys.argv)
assert is_forking(sys.argv), "Not forking"
if sys.platform == 'win32':
import msvcrt
new_handle = reduction.steal_handle(parent_pid, pipe_handle)

View File

@ -270,13 +270,16 @@ class Condition(object):
def notify(self, n=1):
assert self._lock._semlock._is_mine(), 'lock is not owned'
assert not self._wait_semaphore.acquire(False)
assert not self._wait_semaphore.acquire(
False), ('notify: Should not have been able to acquire'
+ '_wait_semaphore')
# to take account of timeouts since last notify*() we subtract
# woken_count from sleeping_count and rezero woken_count
while self._woken_count.acquire(False):
res = self._sleeping_count.acquire(False)
assert res
assert res, ('notify: Bug in sleeping_count.acquire'
+ '- res should not be False')
sleepers = 0
while sleepers < n and self._sleeping_count.acquire(False):

View File

@ -149,12 +149,15 @@ class Finalize(object):
Class which supports object finalization using weakrefs
'''
def __init__(self, obj, callback, args=(), kwargs=None, exitpriority=None):
assert exitpriority is None or type(exitpriority) is int
if (exitpriority is not None) and not isinstance(exitpriority,int):
raise TypeError(
"Exitpriority ({0!r}) must be None or int, not {1!s}".format(
exitpriority, type(exitpriority)))
if obj is not None:
self._weakref = weakref.ref(obj, self)
else:
assert exitpriority is not None
elif exitpriority is None:
raise ValueError("Without object, exitpriority cannot be None")
self._callback = callback
self._args = args

View File

@ -0,0 +1 @@
Many asserts in `multiprocessing` are now more informative, and some error types have been changed to more specific ones.