cpython/Lib/multiprocessing/popen_fork.py
Allen W. Smith, Ph.D bd73e72b4a 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.
2017-08-30 00:52:18 +02:00

85 lines
2.4 KiB
Python

import os
import sys
import signal
from . import util
__all__ = ['Popen']
#
# Start child process using fork
#
class Popen(object):
method = 'fork'
def __init__(self, process_obj):
sys.stdout.flush()
sys.stderr.flush()
self.returncode = None
self.finalizer = None
self._launch(process_obj)
def duplicate_for_child(self, fd):
return fd
def poll(self, flag=os.WNOHANG):
if self.returncode is None:
try:
pid, sts = os.waitpid(self.pid, flag)
except OSError as e:
# Child process not yet created. See #1731717
# e.errno == errno.ECHILD == 10
return None
if pid == self.pid:
if os.WIFSIGNALED(sts):
self.returncode = -os.WTERMSIG(sts)
else:
assert os.WIFEXITED(sts), "Status is {:n}".format(sts)
self.returncode = os.WEXITSTATUS(sts)
return self.returncode
def wait(self, timeout=None):
if self.returncode is None:
if timeout is not None:
from multiprocessing.connection import wait
if not wait([self.sentinel], timeout):
return None
# This shouldn't block if wait() returned successfully.
return self.poll(os.WNOHANG if timeout == 0.0 else 0)
return self.returncode
def _send_signal(self, sig):
if self.returncode is None:
try:
os.kill(self.pid, sig)
except ProcessLookupError:
pass
except OSError:
if self.wait(timeout=0.1) is None:
raise
def terminate(self):
self._send_signal(signal.SIGTERM)
def kill(self):
self._send_signal(signal.SIGKILL)
def _launch(self, process_obj):
code = 1
parent_r, child_w = os.pipe()
self.pid = os.fork()
if self.pid == 0:
try:
os.close(parent_r)
code = process_obj._bootstrap()
finally:
os._exit(code)
else:
os.close(child_w)
self.finalizer = util.Finalize(self, os.close, (parent_r,))
self.sentinel = parent_r
def close(self):
if self.finalizer is not None:
self.finalizer()