fix: prevent GTK widget-tree corruption when navigating back to a page with HA buttons

actions/cores/customization_core/customization_core.py

@@ -19,6 +19,9 @@ class CustomizationCore(BaseCore):
     def __init__(self, window_implementation, customization_implementation, row_implementation, *args, **kwargs):
         # Must be set before create_ui_elements in BaseCore is called
         self.customization_expander = None
+        # Flag set during on_remove() to prevent _load_customizations() from
+        # adding child widgets to the expander while it is detached from the UI.
+        self._clearing = False
         super().__init__(*args, **kwargs)
         self.window_implementation = window_implementation
         self.customization_implementation = customization_implementation
@@ -132,7 +135,25 @@ def _get_attributes(self) -> list[str]:
         attributes.extend(list(ha_entity.get(customization_const.ATTRIBUTES, {}).keys()))
         return attributes
 
+    @requires_initialization
+    def on_remove(self) -> None:
+        """Clean up after action was removed.
+
+        Prevents _load_customizations() from modifying the customization
+        expander while it is being detached from the UI, which would corrupt
+        GTK's internal widget-tree state and cause a crash on the next
+        navigation back to this page.
+        """
+        self._clearing = True
+        try:
+            super().on_remove()
+        finally:
+            self.customization_expander.clear_rows()
+            self._clearing = False
+
     def _load_customizations(self) -> None:
+        if self._clearing:
+            return
         self.customization_expander.clear_rows()
         attributes = self._get_attributes()
         state = self.plugin_base.backend.get_entity(self.settings.get_entity())

test/actions/cores/customization_core/test_customization_core.py

@@ -320,6 +320,7 @@ def test_get_attributes(self):
     def test_load_customizations(self):
         instance = CustomizationCore.__new__(CustomizationCore)
         instance.customization_expander = Mock()
+        instance._clearing = False
         instance._get_attributes = Mock()
         instance._get_attributes.return_value = ["attr1", "attr2"]
         instance.plugin_base = Mock()
@@ -348,3 +349,72 @@ def test_load_customizations(self):
         delete_connect_mock.assert_has_calls([call(base_const.CONNECT_CLICKED, instance._on_delete_customization, 0), call(base_const.CONNECT_CLICKED, instance._on_delete_customization, 1)])
         up_connect_mock.assert_has_calls([call(base_const.CONNECT_CLICKED, instance._on_move_up, 0), call(base_const.CONNECT_CLICKED, instance._on_move_up, 1)])
         down_connect_mock.assert_has_calls([call(base_const.CONNECT_CLICKED, instance._on_move_down, 0), call(base_const.CONNECT_CLICKED, instance._on_move_down, 1)])
+
+    def test_load_customizations_skipped_while_clearing(self):
+        instance = CustomizationCore.__new__(CustomizationCore)
+        instance.customization_expander = Mock()
+        instance._clearing = True
+
+        instance._load_customizations()
+
+        instance.customization_expander.clear_rows.assert_not_called()
+
+    @patch('HomeAssistantPlugin.actions.cores.customization_core.customization_core.BaseCore.on_remove')
+    def test_on_remove_clears_expander_and_resets_flag(self, super_on_remove_mock):
+        instance = CustomizationCore.__new__(CustomizationCore)
+        instance.initialized = True
+        instance._clearing = False
+        instance.customization_expander = Mock()
+
+        instance.on_remove()
+
+        super_on_remove_mock.assert_called_once()
+        instance.customization_expander.clear_rows.assert_called_once()
+        self.assertFalse(instance._clearing)
+
+    @patch('HomeAssistantPlugin.actions.cores.customization_core.customization_core.BaseCore.on_remove')
+    def test_on_remove_sets_clearing_flag_during_super_call(self, super_on_remove_mock):
+        """_clearing must be True when super().on_remove() runs so that any
+        refresh() call triggered by the base class skips _load_customizations()."""
+        instance = CustomizationCore.__new__(CustomizationCore)
+        instance.initialized = True
+        instance._clearing = False
+        instance.customization_expander = Mock()
+
+        flag_during_super = []
+
+        def capture_flag():
+            flag_during_super.append(instance._clearing)
+
+        super_on_remove_mock.side_effect = capture_flag
+
+        instance.on_remove()
+
+        self.assertTrue(flag_during_super[0])
+        self.assertFalse(instance._clearing)
+
+    @patch('HomeAssistantPlugin.actions.cores.customization_core.customization_core.BaseCore.on_remove')
+    def test_on_remove_clears_expander_even_when_super_raises(self, super_on_remove_mock):
+        instance = CustomizationCore.__new__(CustomizationCore)
+        instance.initialized = True
+        instance._clearing = False
+        instance.customization_expander = Mock()
+        super_on_remove_mock.side_effect = RuntimeError("boom")
+
+        with self.assertRaises(RuntimeError):
+            instance.on_remove()
+
+        instance.customization_expander.clear_rows.assert_called_once()
+        self.assertFalse(instance._clearing)
+
+    def test_on_remove_not_initialized(self):
+        instance = CustomizationCore.__new__(CustomizationCore)
+        instance.initialized = False
+        instance._clearing = False
+        instance.customization_expander = Mock()
+
+        result = instance.on_remove()
+
+        self.assertIsNone(result)
+        instance.customization_expander.clear_rows.assert_not_called()
+        self.assertFalse(instance._clearing)