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gh-149879: Fix multiprocessing tests on Cygwin #150031

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Merged
vstinner merged 2 commits into from
May 18, 2026
Merged

gh-149879: Fix multiprocessing tests on Cygwin #150031

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a1b3694
gh-149879: Fix multiprocessing tests on Cygwin
vstinner May 18, 2026
9a53e4e
Fix test_logging
vstinner May 18, 2026
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2 changes: 1 addition & 1 deletion Lib/multiprocessing/connection.py
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Original file line number Diff line number Diff line change
Expand Up @@ -50,7 +50,7 @@
default_family = 'AF_INET'
families = ['AF_INET']

if hasattr(socket, 'AF_UNIX'):
if hasattr(socket, 'AF_UNIX') and sys.platform != 'cygwin':
default_family = 'AF_UNIX'
families += ['AF_UNIX']

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4 changes: 3 additions & 1 deletion Lib/multiprocessing/context.py
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Expand Up @@ -326,8 +326,10 @@ def _check_available(self):
_concrete_contexts = {
'fork': ForkContext(),
'spawn': SpawnContext(),
'forkserver': ForkServerContext(),
}
if reduction.HAVE_SEND_HANDLE:
_concrete_contexts['forkserver'] = ForkServerContext()

# bpo-33725: running arbitrary code after fork() is no longer reliable
# on macOS since macOS 10.14 (Mojave). Use spawn by default instead.
# gh-84559: We changed everyones default to a thread safeish one in 3.14.
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7 changes: 5 additions & 2 deletions Lib/test/_test_multiprocessing.py
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Expand Up @@ -6143,7 +6143,10 @@ def test_preload_resources(self):
@only_run_in_spawn_testsuite("avoids redundant testing.")
def test_mixed_startmethod(self):
# Fork-based locks cannot be used with spawned process
for process_method in ["spawn", "forkserver"]:
test_methods = ["spawn"]
if "forkserver" in multiprocessing.get_all_start_methods():
test_methods.append("forkserver")
for process_method in test_methods:
queue = multiprocessing.get_context("fork").Queue()
process_ctx = multiprocessing.get_context(process_method)
p = process_ctx.Process(target=close_queue, args=(queue,))
Expand All @@ -6152,7 +6155,7 @@ def test_mixed_startmethod(self):
p.start()

# non-fork-based locks can be used with all other start methods
for queue_method in ["spawn", "forkserver"]:
for queue_method in test_methods:
for process_method in multiprocessing.get_all_start_methods():
queue = multiprocessing.get_context(queue_method).Queue()
process_ctx = multiprocessing.get_context(process_method)
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12 changes: 3 additions & 9 deletions Lib/test/test_logging.py
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Expand Up @@ -4065,11 +4065,7 @@ def test_config_reject_simple_queue_handler_multiprocessing_context(self):
# and thus cannot be used as a queue-like object (gh-124653)

import multiprocessing

if support.MS_WINDOWS:
start_methods = ['spawn']
else:
start_methods = ['spawn', 'fork', 'forkserver']
start_methods = multiprocessing.get_all_start_methods()

for start_method in start_methods:
with self.subTest(start_method=start_method):
Expand All @@ -4085,10 +4081,8 @@ def test_config_reject_simple_queue_handler_multiprocessing_context(self):
" assertions in multiprocessing")
def test_config_queue_handler_multiprocessing_context(self):
# regression test for gh-121723
if support.MS_WINDOWS:
start_methods = ['spawn']
else:
start_methods = ['spawn', 'fork', 'forkserver']
import multiprocessing
start_methods = multiprocessing.get_all_start_methods()
for start_method in start_methods:
with self.subTest(start_method=start_method):
ctx = multiprocessing.get_context(start_method)
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2 changes: 1 addition & 1 deletion Lib/test/test_multiprocessing_forkserver/__init__.py
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Expand Up @@ -6,7 +6,7 @@
if support.PGO:
raise unittest.SkipTest("test is not helpful for PGO")

if sys.platform == "win32":
if sys.platform in ("win32", "cygwin"):
raise unittest.SkipTest("forkserver is not available on Windows")

if not support.has_fork_support:
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