[Python-checkins] bpo-38377: Add support.skip_if_broken_multiprocessing_synchronize() (GH-20944)
Victor Stinner
webhook-mailer at python.org
Thu Jun 18 08:53:27 EDT 2020
https://github.com/python/cpython/commit/ddbeb2f3e02a510c5784ffd74c5e09e8c70b5881
commit: ddbeb2f3e02a510c5784ffd74c5e09e8c70b5881
branch: master
author: Victor Stinner <vstinner at python.org>
committer: GitHub <noreply at github.com>
date: 2020-06-18T14:53:19+02:00
summary:
bpo-38377: Add support.skip_if_broken_multiprocessing_synchronize() (GH-20944)
On Linux, skip tests using multiprocessing if the current user cannot
create a file in /dev/shm/ directory. Add the
skip_if_broken_multiprocessing_synchronize() function to the
test.support module.
files:
A Misc/NEWS.d/next/Tests/2020-06-17-18-00-21.bpo-38377.jfg4TH.rst
M Doc/library/test.rst
M Lib/test/_test_multiprocessing.py
M Lib/test/support/__init__.py
M Lib/test/test_asyncio/test_events.py
M Lib/test/test_concurrent_futures.py
M Lib/test/test_logging.py
M Lib/test/test_multiprocessing_main_handling.py
M Lib/test/test_venv.py
diff --git a/Doc/library/test.rst b/Doc/library/test.rst
index b39b601fb64f6..cd05ef07b4a21 100644
--- a/Doc/library/test.rst
+++ b/Doc/library/test.rst
@@ -919,6 +919,14 @@ The :mod:`test.support` module defines the following functions:
.. versionadded:: 3.6
+.. function:: skip_if_broken_multiprocessing_synchronize()
+
+ Skip tests if the :mod:`multiprocessing.synchronize` module is missing, if
+ there is no available semaphore implementation, or if creating a lock raises
+ an :exc:`OSError`.
+
+ .. versionadded:: 3.10
+
The :mod:`test.support` module defines the following classes:
diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index d01a6680e409c..444e234509c27 100644
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -34,7 +34,7 @@
# Skip tests if _multiprocessing wasn't built.
_multiprocessing = test.support.import_module('_multiprocessing')
# Skip tests if sem_open implementation is broken.
-test.support.import_module('multiprocessing.synchronize')
+support.skip_if_broken_multiprocessing_synchronize()
import threading
import multiprocessing.connection
diff --git a/Lib/test/support/__init__.py b/Lib/test/support/__init__.py
index da63d9281b107..d9dbdc13008dc 100644
--- a/Lib/test/support/__init__.py
+++ b/Lib/test/support/__init__.py
@@ -1957,3 +1957,25 @@ def wait_process(pid, *, exitcode, timeout=None):
# sanity check: it should not fail in practice
if pid2 != pid:
raise AssertionError(f"pid {pid2} != pid {pid}")
+
+def skip_if_broken_multiprocessing_synchronize():
+ """
+ Skip tests if the multiprocessing.synchronize module is missing, if there
+ is no available semaphore implementation, or if creating a lock raises an
+ OSError.
+ """
+
+ # Skip tests if the _multiprocessing extension is missing.
+ import_module('_multiprocessing')
+
+ # Skip tests if there is no available semaphore implementation:
+ # multiprocessing.synchronize requires _multiprocessing.SemLock.
+ synchronize = import_module('multiprocessing.synchronize')
+
+ try:
+ # bpo-38377: On Linux, creating a semaphore is the current user
+ # does not have the permission to create a file in /dev/shm.
+ # Create a semaphore to check permissions.
+ synchronize.Lock(ctx=None)
+ except OSError as exc:
+ raise unittest.SkipTest(f"broken multiprocessing SemLock: {exc!r}")
diff --git a/Lib/test/test_asyncio/test_events.py b/Lib/test/test_asyncio/test_events.py
index e7324d2e4811b..ef9d6fc48e9f8 100644
--- a/Lib/test/test_asyncio/test_events.py
+++ b/Lib/test/test_asyncio/test_events.py
@@ -2673,10 +2673,10 @@ def tearDown(self):
if sys.platform != 'win32':
def test_get_event_loop_new_process(self):
- # Issue bpo-32126: The multiprocessing module used by
+ # bpo-32126: The multiprocessing module used by
# ProcessPoolExecutor is not functional when the
# multiprocessing.synchronize module cannot be imported.
- support.import_module('multiprocessing.synchronize')
+ support.skip_if_broken_multiprocessing_synchronize()
async def main():
pool = concurrent.futures.ProcessPoolExecutor()
diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py
index 0ed75e6098a80..7da967ea6ced5 100644
--- a/Lib/test/test_concurrent_futures.py
+++ b/Lib/test/test_concurrent_futures.py
@@ -4,7 +4,7 @@
# Skip tests if _multiprocessing wasn't built.
support.import_module('_multiprocessing')
# Skip tests if sem_open implementation is broken.
-support.import_module('multiprocessing.synchronize')
+support.skip_if_broken_multiprocessing_synchronize()
from test.support import hashlib_helper
from test.support.script_helper import assert_python_ok
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index 275ce2e45f169..e719d264a9191 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -3630,9 +3630,9 @@ def test_handle_called_with_queue_queue(self, mock_handle):
@patch.object(logging.handlers.QueueListener, 'handle')
def test_handle_called_with_mp_queue(self, mock_handle):
- # Issue 28668: The multiprocessing (mp) module is not functional
+ # bpo-28668: The multiprocessing (mp) module is not functional
# when the mp.synchronize module cannot be imported.
- support.import_module('multiprocessing.synchronize')
+ support.skip_if_broken_multiprocessing_synchronize()
for i in range(self.repeat):
log_queue = multiprocessing.Queue()
self.setup_and_log(log_queue, '%s_%s' % (self.id(), i))
@@ -3656,9 +3656,9 @@ def test_no_messages_in_queue_after_stop(self):
indicates that messages were not registered on the queue until
_after_ the QueueListener stopped.
"""
- # Issue 28668: The multiprocessing (mp) module is not functional
+ # bpo-28668: The multiprocessing (mp) module is not functional
# when the mp.synchronize module cannot be imported.
- support.import_module('multiprocessing.synchronize')
+ support.skip_if_broken_multiprocessing_synchronize()
for i in range(self.repeat):
queue = multiprocessing.Queue()
self.setup_and_log(queue, '%s_%s' %(self.id(), i))
diff --git a/Lib/test/test_multiprocessing_main_handling.py b/Lib/test/test_multiprocessing_main_handling.py
index b6abfcc7e283d..be1ff10e03a55 100644
--- a/Lib/test/test_multiprocessing_main_handling.py
+++ b/Lib/test/test_multiprocessing_main_handling.py
@@ -23,7 +23,7 @@
AVAILABLE_START_METHODS = set(multiprocessing.get_all_start_methods())
# Issue #22332: Skip tests if sem_open implementation is broken.
-support.import_module('multiprocessing.synchronize')
+support.skip_if_broken_multiprocessing_synchronize()
verbose = support.verbose
diff --git a/Lib/test/test_venv.py b/Lib/test/test_venv.py
index ef6d7bd5ad7da..d3191ed7b9955 100644
--- a/Lib/test/test_venv.py
+++ b/Lib/test/test_venv.py
@@ -16,7 +16,8 @@
import tempfile
from test.support import (captured_stdout, captured_stderr, requires_zlib,
can_symlink, EnvironmentVarGuard, rmtree,
- import_module)
+ import_module,
+ skip_if_broken_multiprocessing_synchronize)
import unittest
import venv
from unittest.mock import patch
@@ -357,10 +358,11 @@ def test_multiprocessing(self):
"""
Test that the multiprocessing is able to spawn.
"""
- # Issue bpo-36342: Instantiation of a Pool object imports the
+ # bpo-36342: Instantiation of a Pool object imports the
# multiprocessing.synchronize module. Skip the test if this module
# cannot be imported.
- import_module('multiprocessing.synchronize')
+ skip_if_broken_multiprocessing_synchronize()
+
rmtree(self.env_dir)
self.run_with_capture(venv.create, self.env_dir)
envpy = os.path.join(os.path.realpath(self.env_dir),
diff --git a/Misc/NEWS.d/next/Tests/2020-06-17-18-00-21.bpo-38377.jfg4TH.rst b/Misc/NEWS.d/next/Tests/2020-06-17-18-00-21.bpo-38377.jfg4TH.rst
new file mode 100644
index 0000000000000..11a30761d36c9
--- /dev/null
+++ b/Misc/NEWS.d/next/Tests/2020-06-17-18-00-21.bpo-38377.jfg4TH.rst
@@ -0,0 +1,4 @@
+On Linux, skip tests using multiprocessing if the current user cannot create
+a file in ``/dev/shm/`` directory. Add the
+:func:`~test.support.skip_if_broken_multiprocessing_synchronize` function to
+the :mod:`test.support` module.
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