During signal emission don't get return type after callback

The callback can disconnect the slot, causing the C++ object for
the connection to be deleted. Accessing the return type would then
read already freed memory.

Change-Id: Ib33fa806978793bcac42167dd45f1e59829a3104
Reviewed-by: Marcelo Lira <marcelo.lira@openbossa.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/tests/signals/disconnect_test.py b/tests/signals/disconnect_test.py
index cceaf873e..d2e7217ae 100644
--- a/tests/signals/disconnect_test.py
+++ b/tests/signals/disconnect_test.py
@@ -1,5 +1,7 @@
 import unittest
 from PySide.QtCore import *
+from testbinding import TestObject
+
 
 class Foo(QObject):
     bar = Signal()
@@ -28,5 +30,28 @@ class TestDisconnect(unittest.TestCase):
         self.assertFalse(self.called1)
         self.assertFalse(self.called2)
 
+    def testDuringCallback(self):
+        """ Test to see if the C++ object for a connection is accessed after the
+        method returns.  This causes a segfault if the memory that was used by the
+        C++ object has been reused. """
+
+        self.called = False
+        obj = TestObject(0)
+        def callback():
+            obj.signalWithDefaultValue.disconnect(callback)
+
+            # Connect more callbacks to try to overwrite memory
+            for i in range(1000):
+                obj.signalWithDefaultValue.connect(lambda: None)
+
+            self.called = True
+
+            # A non-None return value is needed
+            return True
+        obj.signalWithDefaultValue.connect(callback)
+        obj.signalWithDefaultValue.emit()
+        self.assert_(self.called)
+
+
 if __name__ == '__main__':
     unittest.main()