Only fire device_registry_updated for suggested_area if the suggestion results in an area change

homeassistant/helpers/device_registry.py

@@ -43,6 +43,8 @@
 
 ORPHANED_DEVICE_KEEP_SECONDS = 86400 * 30
 
+RUNTIME_ONLY_ATTRS = {"suggested_area"}
+
 
 class _DeviceIndex(NamedTuple):
     identifiers: dict[tuple[str, str], str]
@@ -509,6 +511,15 @@ def async_update_device(
 
         new = attr.evolve(old, **new_values)
         self._update_device(old, new)
+
+        # If its only run time attributes (suggested_area)
+        # that do not get saved we do not want to write
+        # to disk or fire an event as we would end up
+        # firing events for data we have nothing to compare
+        # against since its never saved on disk
+        if RUNTIME_ONLY_ATTRS.issuperset(new_values):
+            return new
+
         self.async_schedule_save()
 
         data: dict[str, Any] = {

tests/helpers/test_device_registry.py

@@ -1128,6 +1128,16 @@ async def test_update_suggested_area(hass, registry, area_registry, update_event
     assert update_events[1]["device_id"] == entry.id
     assert update_events[1]["changes"] == {"area_id": None, "suggested_area": None}
 
+    # Do not save or fire the event if the suggested
+    # area does not result in a change of area
+    # but still update the actual entry
+    with patch.object(registry, "async_schedule_save") as mock_save_2:
+        updated_entry = registry.async_update_device(entry.id, suggested_area="Other")
+    assert len(update_events) == 2
+    assert mock_save_2.call_count == 0
+    assert updated_entry != entry
+    assert updated_entry.suggested_area == "Other"
+
 
 async def test_cleanup_device_registry(hass, registry):
     """Test cleanup works."""