http://hg.python.org/cpython/rev/96c1de5acbd3 changeset: 74653:96c1de5acbd3 parent: 74651:849e113ddf83 parent: 74652:2863d9273abd user: Antoine Pitrou <solipsis@pitrou.net> date: Fri Jan 27 10:53:35 2012 +0100 summary: Issue #13812: When a multiprocessing Process child raises an exception, flush stderr after printing the exception traceback. files: Lib/multiprocessing/forking.py | 2 - Lib/multiprocessing/process.py | 7 +++-- Lib/test/test_multiprocessing.py | 23 ++++++++++++++++++++ Misc/NEWS | 3 ++ 4 files changed, 30 insertions(+), 5 deletions(-) diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py --- a/Lib/multiprocessing/forking.py +++ b/Lib/multiprocessing/forking.py @@ -129,8 +129,6 @@ import random random.seed() code = process_obj._bootstrap() - sys.stdout.flush() - sys.stderr.flush() os._exit(code) # `w` will be closed when the child exits, at which point `r` diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py --- a/Lib/multiprocessing/process.py +++ b/Lib/multiprocessing/process.py @@ -291,16 +291,17 @@ exitcode = e.args[0] else: sys.stderr.write(e.args[0] + '\n') - sys.stderr.flush() exitcode = 1 except: exitcode = 1 import traceback sys.stderr.write('Process %s:\n' % self.name) + traceback.print_exc() + finally: + util.info('process exiting with exitcode %d' % exitcode) + sys.stdout.flush() sys.stderr.flush() - traceback.print_exc() - util.info('process exiting with exitcode %d' % exitcode) return exitcode # diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py --- a/Lib/test/test_multiprocessing.py +++ b/Lib/test/test_multiprocessing.py @@ -417,6 +417,29 @@ uppercaser.stop() uppercaser.join() + def test_stderr_flush(self): + # sys.stderr is flushed at process shutdown (issue #13812) + if self.TYPE == "threads": + return + + testfn = test.support.TESTFN + self.addCleanup(test.support.unlink, testfn) + proc = self.Process(target=self._test_stderr_flush, args=(testfn,)) + proc.start() + proc.join() + with open(testfn, 'r') as f: + err = f.read() + # The whole traceback was printed + self.assertIn("ZeroDivisionError", err) + self.assertIn("test_multiprocessing.py", err) + self.assertIn("1/0 # MARKER", err) + + @classmethod + def _test_stderr_flush(cls, testfn): + sys.stderr = open(testfn, 'w') + 1/0 # MARKER + + # # # diff --git a/Misc/NEWS b/Misc/NEWS --- a/Misc/NEWS +++ b/Misc/NEWS @@ -461,6 +461,9 @@ Library ------- +- Issue #13812: When a multiprocessing Process child raises an exception, + flush stderr after printing the exception traceback. + - Issue #13885: CVE-2011-3389: the _ssl module would always disable the CBC IV attack countermeasure. -- Repository URL: http://hg.python.org/cpython