bpo-35797: Fix default executable used by the multiprocessing module (GH-11676)
diff --git a/Lib/multiprocessing/spawn.py b/Lib/multiprocessing/spawn.py
index 73aa694..860fa4c 100644
--- a/Lib/multiprocessing/spawn.py
+++ b/Lib/multiprocessing/spawn.py
@@ -29,12 +29,19 @@
if sys.platform != 'win32':
WINEXE = False
WINSERVICE = False
+ _WINENV = False
else:
- WINEXE = (sys.platform == 'win32' and getattr(sys, 'frozen', False))
+ WINEXE = getattr(sys, 'frozen', False)
WINSERVICE = sys.executable.lower().endswith("pythonservice.exe")
+ _WINENV = '__PYVENV_LAUNCHER__' in os.environ
if WINSERVICE:
_python_exe = os.path.join(sys.exec_prefix, 'python.exe')
+elif _WINENV:
+ # bpo-35797: When running in a venv, we need to bypass the redirect
+ # executor and launch our base Python.
+ import _winapi
+ _python_exe = _winapi.GetModuleFileName(0)
else:
_python_exe = sys.executable
diff --git a/Lib/test/test_venv.py b/Lib/test/test_venv.py
index 22a3b78..34c2234 100644
--- a/Lib/test/test_venv.py
+++ b/Lib/test/test_venv.py
@@ -306,6 +306,19 @@
)
self.assertEqual(out.strip(), '0')
+ def test_multiprocessing(self):
+ """
+ Test that the multiprocessing is able to spawn.
+ """
+ rmtree(self.env_dir)
+ self.run_with_capture(venv.create, self.env_dir)
+ envpy = os.path.join(os.path.realpath(self.env_dir),
+ self.bindir, self.exe)
+ out, err = check_output([envpy, '-c',
+ 'from multiprocessing import Pool; ' +
+ 'print(Pool(1).apply_async("Python".lower).get(3))'])
+ self.assertEqual(out.strip(), "python".encode())
+
@skipInVenv
class EnsurePipTest(BaseTest):
"""Test venv module installation of pip."""
diff --git a/Misc/NEWS.d/next/Windows/2019-01-25-12-29-14.bpo-35797.MzyOK9.rst b/Misc/NEWS.d/next/Windows/2019-01-25-12-29-14.bpo-35797.MzyOK9.rst
new file mode 100644
index 0000000..a0745f5
--- /dev/null
+++ b/Misc/NEWS.d/next/Windows/2019-01-25-12-29-14.bpo-35797.MzyOK9.rst
@@ -0,0 +1 @@
+Fix default executable used by the multiprocessing module