Improve check of new_entity_id in entity_registry.async_update_entity (#78276)

* Improve check of new_entity_id in entity_registry.async_update_entity

* Fix race in rfxtrx config flow

* Make sure Event is created on time

* Rename poorly named variable

* Fix typing

* Correct typing of _handle_state_change

tests/helpers/test_entity_registry.py

@@ -6,7 +6,7 @@ import voluptuous as vol
 
 from homeassistant import config_entries
 from homeassistant.const import EVENT_HOMEASSISTANT_START, STATE_UNAVAILABLE
-from homeassistant.core import CoreState, callback
+from homeassistant.core import CoreState, HomeAssistant, callback
 from homeassistant.exceptions import MaxLengthExceeded
 from homeassistant.helpers import device_registry as dr, entity_registry as er
 from homeassistant.helpers.entity import EntityCategory
@@ -597,6 +597,56 @@ async def test_update_entity_unique_id_conflict(registry):
     assert registry.async_get_entity_id("light", "hue", "1234") == entry2.entity_id
 
 
+async def test_update_entity_entity_id(registry):
+    """Test entity's entity_id is updated."""
+    entry = registry.async_get_or_create("light", "hue", "5678")
+    assert registry.async_get_entity_id("light", "hue", "5678") == entry.entity_id
+
+    new_entity_id = "light.blah"
+    assert new_entity_id != entry.entity_id
+    with patch.object(registry, "async_schedule_save") as mock_schedule_save:
+        updated_entry = registry.async_update_entity(
+            entry.entity_id, new_entity_id=new_entity_id
+        )
+    assert updated_entry != entry
+    assert updated_entry.entity_id == new_entity_id
+    assert mock_schedule_save.call_count == 1
+
+    assert registry.async_get(entry.entity_id) is None
+    assert registry.async_get(new_entity_id) is not None
+
+
+async def test_update_entity_entity_id_entity_id(hass: HomeAssistant, registry):
+    """Test update raises when entity_id already in use."""
+    entry = registry.async_get_or_create("light", "hue", "5678")
+    entry2 = registry.async_get_or_create("light", "hue", "1234")
+    state_entity_id = "light.blah"
+    hass.states.async_set(state_entity_id, "on")
+    assert entry.entity_id != state_entity_id
+    assert entry2.entity_id != state_entity_id
+
+    # Try updating to a registered entity_id
+    with patch.object(
+        registry, "async_schedule_save"
+    ) as mock_schedule_save, pytest.raises(ValueError):
+        registry.async_update_entity(entry.entity_id, new_entity_id=entry2.entity_id)
+    assert mock_schedule_save.call_count == 0
+    assert registry.async_get_entity_id("light", "hue", "5678") == entry.entity_id
+    assert registry.async_get(entry.entity_id) is entry
+    assert registry.async_get_entity_id("light", "hue", "1234") == entry2.entity_id
+    assert registry.async_get(entry2.entity_id) is entry2
+
+    # Try updating to an entity_id which is in the state machine
+    with patch.object(
+        registry, "async_schedule_save"
+    ) as mock_schedule_save, pytest.raises(ValueError):
+        registry.async_update_entity(entry.entity_id, new_entity_id=state_entity_id)
+    assert mock_schedule_save.call_count == 0
+    assert registry.async_get_entity_id("light", "hue", "5678") == entry.entity_id
+    assert registry.async_get(entry.entity_id) is entry
+    assert registry.async_get(state_entity_id) is None
+
+
 async def test_update_entity(registry):
     """Test updating entity."""
     mock_config = MockConfigEntry(domain="light", entry_id="mock-id-1")