Fixed #20943 -- Weakly reference senders when caching their associated receivers

Backport of e55ca60903 from master.

1 files changed, 21 insertions, 0 deletions

diff --git a/tests/dispatch/tests/test_dispatcher.py b/tests/dispatch/tests/test_dispatcher.py
index a1d4c7e176..2586aeee62 100644
--- a/tests/dispatch/tests/test_dispatcher.py
+++ b/tests/dispatch/tests/test_dispatcher.py
@@ -1,6 +1,7 @@
 import gc
 import sys
 import time
+import weakref
 
 from django.dispatch import Signal, receiver
 from django.utils import unittest
@@ -35,6 +36,8 @@ class Callable(object):
 a_signal = Signal(providing_args=["val"])
 b_signal = Signal(providing_args=["val"])
 c_signal = Signal(providing_args=["val"])
+d_signal = Signal(providing_args=["val"], use_caching=True)
+
 
 class DispatcherTests(unittest.TestCase):
     """Test suite for dispatcher (barely started)"""
@@ -72,6 +75,24 @@ class DispatcherTests(unittest.TestCase):
         self.assertEqual(result, expected)
         self._testIsClean(a_signal)
 
+    def testCachedGarbagedCollected(self):
+        """
+        Make sure signal caching sender receivers don't prevent garbage
+        collection of senders.
+        """
+        class sender:
+            pass
+        wref = weakref.ref(sender)
+        d_signal.connect(receiver_1_arg)
+        d_signal.send(sender, val='garbage')
+        del sender
+        garbage_collect()
+        try:
+            self.assertIsNone(wref())
+        finally:
+            # Disconnect after reference check since it flushes the tested cache.
+            d_signal.disconnect(receiver_1_arg)
+
     def testMultipleRegistration(self):
         a = Callable()
         a_signal.connect(a)