Let channels use the new delayed decref mechanism. This fixes a crash case where a tasklet would block on a temporary channel.

kristjan.jonsson · kristjan.jonsson · commit 446a5ddc3e20 · 2010-03-26T10:14:41.000Z
git-svn-id: http://svn.python.org/projects/stackless/trunk@79438 6015fed2-1504-0410-9fe1-9d1591cc4771
diff --git a/Stackless/module/channelobject.c b/Stackless/module/channelobject.c
@@ -471,8 +471,18 @@ generic_channel_action(PyChannelObject *self, PyObject *arg, int dir, int stackl
 		slp_channel_insert(self, source, dir);
 		target = ts->st.current;
 	}
+	
+	/* Make sure that the channel will exist past the actual switch, if
+	 * we are softswitching.  A temporary channel might disappear.
+	 */
+	if (self->ob_refcnt==1) {
+		assert(ts->st.del_post_switch == NULL);
+		ts->st.del_post_switch = (PyObject*)self;
+		Py_INCREF(self);
+	}
 	ts->st.runflags |= runflags; /* extra info for slp_schedule_task */
 	retval = slp_schedule_task(source, target, stackless);
+
 	if (interthread) {
 		if (cando) {
 			Py_DECREF(target);
diff --git a/Stackless/unittests/test_defects.py b/Stackless/unittests/test_defects.py
@@ -88,6 +88,33 @@ def func(self, chan):
         chan = stackless.channel()
         stackless.tasklet(func)(self, chan)
         chan.receive()
+        
+class Channel(unittest.TestCase):
+    def testTemporaryChannel(self):
+        def f1():
+            stackless.channel().receive()
+            
+        stackless.tasklet(f1)()
+        old = stackless.enable_softswitch(True)
+        try:
+            stackless.run()
+        finally:
+            stackless.enable_softswitch(old)
+    
+    def testTemporaryChannel2(self):
+        def f1():
+            stackless.channel().receive()
+        def f2():
+            pass
+            
+        stackless.tasklet(f1)()
+        stackless.tasklet(f2)()
+        old = stackless.enable_softswitch(True)
+        try:
+            stackless.run()
+        finally:
+            stackless.enable_softswitch(old)
+
 
 if __name__ == '__main__':
     import sys
