bpo-40504: Allow weakrefs to lru_cache objects (GH-19938)

1 files changed, 31 insertions, 0 deletions

diff --git a/Lib/test/test_functools.py b/Lib/test/test_functools.py
index 9503f40..b3893a1 100644
--- a/Lib/test/test_functools.py
+++ b/Lib/test/test_functools.py
@@ -14,6 +14,8 @@ import typing
 import unittest
 import unittest.mock
 import os
+import weakref
+import gc
 from weakref import proxy
 import contextlib
 
@@ -1938,6 +1940,35 @@ class TestLRU:
             return 1
         self.assertEqual(f.cache_parameters(), {'maxsize': 1000, "typed": True})
 
+    def test_lru_cache_weakrefable(self):
+        @self.module.lru_cache
+        def test_function(x):
+            return x
+
+        class A:
+            @self.module.lru_cache
+            def test_method(self, x):
+                return (self, x)
+
+            @staticmethod
+            @self.module.lru_cache
+            def test_staticmethod(x):
+                return (self, x)
+
+        refs = [weakref.ref(test_function),
+                weakref.ref(A.test_method),
+                weakref.ref(A.test_staticmethod)]
+
+        for ref in refs:
+            self.assertIsNotNone(ref())
+
+        del A
+        del test_function
+        gc.collect()
+
+        for ref in refs:
+            self.assertIsNone(ref())
+
 
 @py_functools.lru_cache()
 def py_cached_func(x, y):