[Python-checkins] cpython: #12098: Make multiprocessing's child processes inherit sys.flags on Windows
richard.oudkerk
python-checkins at python.org
Fri May 18 17:41:12 CEST 2012
http://hg.python.org/cpython/rev/347735ec92eb
changeset: 77035:347735ec92eb
user: Richard Oudkerk <shibturn at gmail.com>
date: Fri May 18 14:28:02 2012 +0100
summary:
#12098: Make multiprocessing's child processes inherit sys.flags on Windows
Initial patch by Sergey Mezentsev.
files:
Lib/multiprocessing/forking.py | 3 +-
Lib/multiprocessing/util.py | 31 +++++++++++++++++
Lib/test/support.py | 20 +----------
Lib/test/test_multiprocessing.py | 35 +++++++++++++++++++-
Misc/NEWS | 4 ++
5 files changed, 73 insertions(+), 20 deletions(-)
diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py
--- a/Lib/multiprocessing/forking.py
+++ b/Lib/multiprocessing/forking.py
@@ -324,7 +324,8 @@
return [sys.executable, '--multiprocessing-fork']
else:
prog = 'from multiprocessing.forking import main; main()'
- return [_python_exe, '-c', prog, '--multiprocessing-fork']
+ opts = util._args_from_interpreter_flags()
+ return [_python_exe] + opts + ['-c', prog, '--multiprocessing-fork']
def main():
diff --git a/Lib/multiprocessing/util.py b/Lib/multiprocessing/util.py
--- a/Lib/multiprocessing/util.py
+++ b/Lib/multiprocessing/util.py
@@ -7,6 +7,7 @@
# Licensed to PSF under a Contributor Agreement.
#
+import sys
import functools
import itertools
import weakref
@@ -295,3 +296,33 @@
register_after_fork(self, lambda obj : obj.__dict__.clear())
def __reduce__(self):
return type(self), ()
+
+#
+# Get options for python to produce the same sys.flags
+#
+
+def _args_from_interpreter_flags():
+ """Return a list of command-line arguments reproducing the current
+ settings in sys.flags and sys.warnoptions."""
+ flag_opt_map = {
+ 'debug': 'd',
+ # 'inspect': 'i',
+ # 'interactive': 'i',
+ 'optimize': 'O',
+ 'dont_write_bytecode': 'B',
+ 'no_user_site': 's',
+ 'no_site': 'S',
+ 'ignore_environment': 'E',
+ 'verbose': 'v',
+ 'bytes_warning': 'b',
+ 'quiet': 'q',
+ 'hash_randomization': 'R',
+ }
+ args = []
+ for flag, opt in flag_opt_map.items():
+ v = getattr(sys.flags, flag)
+ if v > 0:
+ args.append('-' + opt * v)
+ for opt in sys.warnoptions:
+ args.append('-W' + opt)
+ return args
diff --git a/Lib/test/support.py b/Lib/test/support.py
--- a/Lib/test/support.py
+++ b/Lib/test/support.py
@@ -1596,24 +1596,8 @@
def args_from_interpreter_flags():
"""Return a list of command-line arguments reproducing the current
settings in sys.flags and sys.warnoptions."""
- flag_opt_map = {
- 'bytes_warning': 'b',
- 'dont_write_bytecode': 'B',
- 'hash_randomization': 'R',
- 'ignore_environment': 'E',
- 'no_user_site': 's',
- 'no_site': 'S',
- 'optimize': 'O',
- 'verbose': 'v',
- }
- args = []
- for flag, opt in flag_opt_map.items():
- v = getattr(sys.flags, flag)
- if v > 0:
- args.append('-' + opt * v)
- for opt in sys.warnoptions:
- args.append('-W' + opt)
- return args
+ from multiprocessing.util import _args_from_interpreter_flags
+ return _args_from_interpreter_flags()
#============================================================
# Support for assertions about logging.
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
@@ -2814,8 +2814,41 @@
with self.assertRaises(ValueError):
multiprocessing.connection.Listener('/var/test.pipe')
+#
+# Issue 12098: check sys.flags of child matches that for parent
+#
+
+class TestFlags(unittest.TestCase):
+ @classmethod
+ def run_in_grandchild(cls, conn):
+ conn.send(tuple(sys.flags))
+
+ @classmethod
+ def run_in_child(cls):
+ import json
+ r, w = multiprocessing.Pipe(duplex=False)
+ p = multiprocessing.Process(target=cls.run_in_grandchild, args=(w,))
+ p.start()
+ grandchild_flags = r.recv()
+ p.join()
+ r.close()
+ w.close()
+ flags = (tuple(sys.flags), grandchild_flags)
+ print(json.dumps(flags))
+
+ def test_flags(self):
+ import json, subprocess
+ # start child process using unusual flags
+ prog = ('from test.test_multiprocessing import TestFlags; ' +
+ 'TestFlags.run_in_child()')
+ data = subprocess.check_output(
+ [sys.executable, '-E', '-S', '-O', '-c', prog])
+ child_flags, grandchild_flags = json.loads(data.decode('ascii'))
+ self.assertEqual(child_flags, grandchild_flags)
+
testcases_other = [OtherTest, TestInvalidHandle, TestInitializers,
- TestStdinBadfiledescriptor, TestWait, TestInvalidFamily]
+ TestStdinBadfiledescriptor, TestWait, TestInvalidFamily,
+ TestFlags]
#
#
diff --git a/Misc/NEWS b/Misc/NEWS
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -38,6 +38,10 @@
Library
-------
+- Issue #12098: multiprocessing on Windows now starts child processes
+ using the same sys.flags as the current process. Initial patch by
+ Sergey Mezentsev.
+
- Issue #13031: Small speed-up for tarfile when unzipping tarfiles.
Patch by Justin Peel.
--
Repository URL: http://hg.python.org/cpython
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