Guard bad entity ID in entity registry (#35271)

homeassistant/helpers/entity_registry.py

@@ -428,6 +428,12 @@ class EntityRegistry:
 
         if data is not None:
             for entity in data["entities"]:
+                # Some old installations can have some bad entities.
+                # Filter them out as they cause errors down the line.
+                # Can be removed in Jan 2021
+                if not valid_entity_id(entity["entity_id"]):
+                    continue
+
                 entities[entity["entity_id"]] = RegistryEntry(
                     entity_id=entity["entity_id"],
                     config_entry_id=entity.get("config_entry_id"),

tests/helpers/test_entity_registry.py

@@ -241,12 +241,20 @@ async def test_loading_extra_values(hass, hass_storage):
                     "unique_id": "disabled-hass",
                     "disabled_by": "hass",
                 },
+                {
+                    "entity_id": "test.invalid__entity",
+                    "platform": "super_platform",
+                    "unique_id": "invalid-hass",
+                    "disabled_by": "hass",
+                },
             ]
         },
     }
 
     registry = await entity_registry.async_get_registry(hass)
 
+    assert len(registry.entities) == 4
+
     entry_with_name = registry.async_get_or_create(
         "test", "super_platform", "with-name"
     )