Allow Local instances to be cleared without deleting

asgiref/local.py

@@ -84,7 +84,7 @@ def _get_storage(self):
             self._context_refs.add(context_obj)
         return getattr(context_obj, self._attr_name)
 
-    def __del__(self):
+    def clear(self):
         try:
             for context_obj in self._context_refs:
                 try:
@@ -96,6 +96,9 @@ def __del__(self):
             # to _IterationGuard being None.
             pass
 
+    def __del__(self):
+        self.clear()
+
     def __getattr__(self, key):
         with self._thread_lock:
             storage = self._get_storage()

tests/test_local.py

@@ -307,7 +307,7 @@ def run(self):
     assert test_local.counter == 6
 
 
-def test_local_del_swallows_type_error(monkeypatch):
+def test_local_clear_swallows_type_error(monkeypatch):
     test_local = Local()
 
     blow_up_calls = 0
@@ -319,6 +319,22 @@ def blow_up(self):
 
     monkeypatch.setattr("weakref.WeakSet.__iter__", blow_up)
 
-    test_local.__del__()
+    test_local.clear()
 
     assert blow_up_calls == 1
+
+
+def test_local_clears_on_deletion(monkeypatch):
+    test_local = Local()
+
+    clear_patched_call_count = 0
+
+    def clear_patched(self):
+        nonlocal clear_patched_call_count
+        clear_patched_call_count += 1
+
+    monkeypatch.setattr(test_local, "clear", clear_patched)
+
+    del test_local
+
+    assert clear_patched_call_count == 1