diff options
| -rw-r--r-- | Lib/multiprocessing/pool.py | 25 | ||||
| -rw-r--r-- | Lib/test/test_multiprocessing.py | 29 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 57 insertions, 0 deletions
diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py index c0aa7170794..82a2923fd61 100644 --- a/Lib/multiprocessing/pool.py +++ b/Lib/multiprocessing/pool.py @@ -18,6 +18,7 @@ import queue import itertools import collections import time +import traceback from multiprocessing import Process, cpu_count, TimeoutError from multiprocessing.util import Finalize, debug @@ -43,6 +44,29 @@ def starmapstar(args): return list(itertools.starmap(args[0], args[1])) # +# Hack to embed stringification of remote traceback in local traceback +# + +class RemoteTraceback(Exception): + def __init__(self, tb): + self.tb = tb + def __str__(self): + return self.tb + +class ExceptionWithTraceback: + def __init__(self, exc, tb): + tb = traceback.format_exception(type(exc), exc, tb) + tb = ''.join(tb) + self.exc = exc + self.tb = '\n"""\n%s"""' % tb + def __reduce__(self): + return rebuild_exc, (self.exc, self.tb) + +def rebuild_exc(exc, tb): + exc.__cause__ = RemoteTraceback(tb) + return exc + +# # Code run by worker processes # @@ -90,6 +114,7 @@ def worker(inqueue, outqueue, initializer=None, initargs=(), maxtasks=None): try: result = (True, func(*args, **kwds)) except Exception as e: + e = ExceptionWithTraceback(e, e.__traceback__) result = (False, e) try: put((job, i, result)) diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py index 094bbd6716b..3be72c4ad1a 100644 --- a/Lib/test/test_multiprocessing.py +++ b/Lib/test/test_multiprocessing.py @@ -1757,6 +1757,35 @@ class _TestPool(BaseTestCase): self.assertEqual(r.get(), expected) self.assertRaises(ValueError, p.map_async, sqr, L) + @classmethod + def _test_traceback(cls): + raise RuntimeError(123) # some comment + + def test_traceback(self): + # We want ensure that the traceback from the child process is + # contained in the traceback raised in the main process. + if self.TYPE == 'processes': + with self.Pool(1) as p: + try: + p.apply(self._test_traceback) + except Exception as e: + exc = e + else: + raise AssertionError('expected RuntimeError') + self.assertIs(type(exc), RuntimeError) + self.assertEqual(exc.args, (123,)) + cause = exc.__cause__ + self.assertIs(type(cause), multiprocessing.pool.RemoteTraceback) + self.assertIn('raise RuntimeError(123) # some comment', cause.tb) + + with test.support.captured_stderr() as f1: + try: + raise exc + except RuntimeError: + sys.excepthook(*sys.exc_info()) + self.assertIn('raise RuntimeError(123) # some comment', + f1.getvalue()) + def raising(): raise KeyError("key") diff --git a/Misc/NEWS b/Misc/NEWS index da695dddb34..949c20047d0 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -74,6 +74,9 @@ Core and Builtins Library ------- +- Issue #13813: Embed stringification of remote traceback in local + traceback raised when pool task raises an exception. + - Issue #15528: Add weakref.finalize to support finalization using weakref callbacks. |