fix garbage collection issue

Author: rmorshea

src/idom/core/layout.py

@@ -255,7 +255,7 @@ def _render_model_children(
                 key = child.get("key") or hex(id(child))[2:]
             elif isinstance(child, AbstractComponent):
                 child_type = COMPONENT_TYPE
-                key = getattr(child, "key", "") or hex(id(child))[2:]
+                key = getattr(child, "key", None) or hex(id(child))[2:]
             else:
                 child = str(child)
                 child_type = STRING_TYPE
@@ -288,6 +288,8 @@ def _render_model_children(
             elif child_type is COMPONENT_TYPE:
                 old_child_state = old_state.children_by_key.get(key)
                 if old_child_state is not None:
+                    old_component = old_child_state.life_cycle_hook.component
+                    del self._model_state_by_component_id[id(old_component)]
                     new_child_state = old_child_state.new(new_state, child)
                 else:
                     hook = LifeCycleHook(child, self)
@@ -329,10 +331,6 @@ def _unmount_model_states(self, old_states: List[_ModelState]) -> None:
                 hook = state.life_cycle_hook
                 hook.component_will_unmount()
                 del self._model_state_by_component_id[id(hook.component)]
-                import gc
-
-                print(state)
-                print(gc.get_referrers(hook))
             to_unmount.extend(state.children_by_key.values())
 
     def __repr__(self) -> str:

tests/test_core/test_layout.py

@@ -387,6 +387,7 @@ def Inner():
 async def test_hooks_for_keyed_components_get_garbage_collected():
     pop_item = idom.Ref(None)
     garbage_collect_items = []
+    registered_finalizers = set()
 
     @idom.component
     def Outer():
@@ -396,7 +397,10 @@ def Outer():
 
     @idom.component
     def Inner(key):
-        finalize(idom.hooks.current_hook(), lambda: garbage_collect_items.append(key))
+        if key not in registered_finalizers:
+            hook = idom.hooks.current_hook()
+            finalize(hook, lambda: garbage_collect_items.append(key))
+            registered_finalizers.add(key)
         return idom.html.div(key)
 
     async with idom.Layout(Outer()) as layout: