merge in patch from tim golden to fix contextmanager support for mp.Lock()

Lib/test/test_multiprocessing.py

@@ -546,6 +546,10 @@ class _TestLock(BaseTestCase):
         self.assertEqual(lock.release(), None)
         self.assertRaises((AssertionError, RuntimeError), lock.release)
 
+    def test_lock_context(self):
+        with self.Lock():
+            pass
+
 
 class _TestSemaphore(BaseTestCase):
 

Misc/ACKS

@@ -256,6 +256,7 @@ Dinu Gherman
 Jonathan Giddy
 Johannes Gijsbers
 Michael Gilfix
+Tim Golden
 Chris Gonnerman
 David Goodger
 Hans de Graaff
@@ -789,4 +790,3 @@ Siebren van der Zee
 Uwe Zessin
 Tarek Ziad
 Peter strand
-Jesse Noller

Misc/NEWS

@@ -199,6 +199,9 @@ Core and Builtins
 Library
 -------
 
+- Issue #5261: Patch multiprocessing's semaphore.c to support context
+  manager use: "with multiprocessing.Lock()" works now.
+
 - Issue #5177: Multiprocessing's SocketListener class now uses 
   socket.SO_REUSEADDR on all connections so that the user no longer needs
   to wait 120 seconds for the socket to expire.

Modules/_multiprocessing/semaphore.c

@@ -546,7 +546,7 @@ static PyMethodDef semlock_methods[] = {
 	 "acquire the semaphore/lock"},
 	{"release", (PyCFunction)semlock_release, METH_NOARGS, 
 	 "release the semaphore/lock"},
-	{"__enter__", (PyCFunction)semlock_acquire, METH_VARARGS,
+    {"__enter__", (PyCFunction)semlock_acquire, METH_VARARGS | METH_KEYWORDS,
 	 "enter the semaphore/lock"},
 	{"__exit__", (PyCFunction)semlock_release, METH_VARARGS, 
 	 "exit the semaphore/lock"},