Move thread safety check in area_registry sooner (#116265)

It turns out we have custom components that are writing to the area registry using the async APIs from threads. We now catch it at the point async_fire is called. Instead we should check sooner and use async_fire_internal so we catch the unsafe operation before it can corrupt the registry.

homeassistant/helpers/area_registry.py

@@ -202,6 +202,7 @@ class AreaRegistry(BaseRegistry[AreasRegistryStoreData]):
         picture: str | None = None,
     ) -> AreaEntry:
         """Create a new area."""
+        self.hass.verify_event_loop_thread("async_create")
         normalized_name = normalize_name(name)
 
         if self.async_get_area_by_name(name):
@@ -221,7 +222,7 @@ class AreaRegistry(BaseRegistry[AreasRegistryStoreData]):
         assert area.id is not None
         self.areas[area.id] = area
         self.async_schedule_save()
-        self.hass.bus.async_fire(
+        self.hass.bus.async_fire_internal(
             EVENT_AREA_REGISTRY_UPDATED,
             EventAreaRegistryUpdatedData(action="create", area_id=area.id),
         )
@@ -230,6 +231,7 @@ class AreaRegistry(BaseRegistry[AreasRegistryStoreData]):
     @callback
     def async_delete(self, area_id: str) -> None:
         """Delete area."""
+        self.hass.verify_event_loop_thread("async_delete")
         device_registry = dr.async_get(self.hass)
         entity_registry = er.async_get(self.hass)
         device_registry.async_clear_area_id(area_id)
@@ -237,7 +239,7 @@ class AreaRegistry(BaseRegistry[AreasRegistryStoreData]):
 
         del self.areas[area_id]
 
-        self.hass.bus.async_fire(
+        self.hass.bus.async_fire_internal(
             EVENT_AREA_REGISTRY_UPDATED,
             EventAreaRegistryUpdatedData(action="remove", area_id=area_id),
         )
@@ -266,6 +268,10 @@ class AreaRegistry(BaseRegistry[AreasRegistryStoreData]):
             name=name,
             picture=picture,
         )
+        # Since updated may be the old or the new and we always fire
+        # an event even if nothing has changed we cannot use async_fire_internal
+        # here because we do not know if the thread safety check already
+        # happened or not in _async_update.
         self.hass.bus.async_fire(
             EVENT_AREA_REGISTRY_UPDATED,
             EventAreaRegistryUpdatedData(action="update", area_id=area_id),
@@ -306,6 +312,7 @@ class AreaRegistry(BaseRegistry[AreasRegistryStoreData]):
         if not new_values:
             return old
 
+        self.hass.verify_event_loop_thread("_async_update")
         new = self.areas[area_id] = dataclasses.replace(old, **new_values)  # type: ignore[arg-type]
 
         self.async_schedule_save()

tests/helpers/test_area_registry.py

@@ -1,5 +1,6 @@
 """Tests for the Area Registry."""
 
+from functools import partial
 from typing import Any
 
 import pytest
@@ -491,3 +492,40 @@ async def test_entries_for_label(
 
     assert not ar.async_entries_for_label(area_registry, "unknown")
     assert not ar.async_entries_for_label(area_registry, "")
+
+
+async def test_async_get_or_create_thread_checks(
+    hass: HomeAssistant, area_registry: ar.AreaRegistry
+) -> None:
+    """We raise when trying to create in the wrong thread."""
+    with pytest.raises(
+        RuntimeError,
+        match="Detected code that calls async_create from a thread. Please report this issue.",
+    ):
+        await hass.async_add_executor_job(area_registry.async_create, "Mock1")
+
+
+async def test_async_update_thread_checks(
+    hass: HomeAssistant, area_registry: ar.AreaRegistry
+) -> None:
+    """We raise when trying to update in the wrong thread."""
+    area = area_registry.async_create("Mock1")
+    with pytest.raises(
+        RuntimeError,
+        match="Detected code that calls _async_update from a thread. Please report this issue.",
+    ):
+        await hass.async_add_executor_job(
+            partial(area_registry.async_update, area.id, name="Mock2")
+        )
+
+
+async def test_async_delete_thread_checks(
+    hass: HomeAssistant, area_registry: ar.AreaRegistry
+) -> None:
+    """We raise when trying to delete in the wrong thread."""
+    area = area_registry.async_create("Mock1")
+    with pytest.raises(
+        RuntimeError,
+        match="Detected code that calls async_delete from a thread. Please report this issue.",
+    ):
+        await hass.async_add_executor_job(area_registry.async_delete, area.id)