gh-124538: Fix crash when using `gc.get_referents` on an untracked capsule object (#124559)

1 files changed, 18 insertions, 0 deletions

diff --git a/Lib/test/test_gc.py b/Lib/test/test_gc.py
index 906f988..bb7df1f 100644
--- a/Lib/test/test_gc.py
+++ b/Lib/test/test_gc.py
@@ -1048,6 +1048,24 @@ class GCTests(unittest.TestCase):
         callback.assert_not_called()
         gc.enable()
 
+    @cpython_only
+    def test_get_referents_on_capsule(self):
+        # gh-124538: Calling gc.get_referents() on an untracked capsule must not crash.
+        import _datetime
+        import _socket
+        untracked_capsule = _datetime.datetime_CAPI
+        tracked_capsule = _socket.CAPI
+
+        # For whoever sees this in the future: if this is failing
+        # after making datetime's capsule tracked, that's fine -- this isn't something
+        # users are relying on. Just find a different capsule that is untracked.
+        self.assertFalse(gc.is_tracked(untracked_capsule))
+        self.assertTrue(gc.is_tracked(tracked_capsule))
+
+        self.assertEqual(len(gc.get_referents(untracked_capsule)), 0)
+        gc.get_referents(tracked_capsule)
+
+
 
 class IncrementalGCTests(unittest.TestCase):