Make device suggested_area only influence new devices (#149758)

Co-authored-by: Abílio Costa <abmantis@users.noreply.github.com>

tests/helpers/test_device_registry.py

@@ -3210,20 +3210,35 @@ async def test_update_remove_config_subentries(
     }
 
 
+@pytest.mark.parametrize(
+    ("initial_area", "device_area_id", "number_of_areas"),
+    [
+        (None, None, 0),
+        ("Living Room", "living_room", 1),
+    ],
+)
 async def test_update_suggested_area(
     hass: HomeAssistant,
     device_registry: dr.DeviceRegistry,
     area_registry: ar.AreaRegistry,
     mock_config_entry: MockConfigEntry,
+    initial_area: str | None,
+    device_area_id: str | None,
+    number_of_areas: int,
 ) -> None:
-    """Verify that we can update the suggested area version of a device."""
+    """Verify that we can update the suggested area of a device.
+
+    Updating the suggested area of a device should not create a new area, nor should
+    it change the area_id of the device.
+    """
     update_events = async_capture_events(hass, dr.EVENT_DEVICE_REGISTRY_UPDATED)
     entry = device_registry.async_get_or_create(
         config_entry_id=mock_config_entry.entry_id,
         connections={(dr.CONNECTION_NETWORK_MAC, "12:34:56:AB:CD:EF")},
         identifiers={("bla", "123")},
+        suggested_area=initial_area,
     )
-    assert entry.area_id is None
+    assert entry.area_id == device_area_id
 
     suggested_area = "Pool"
 
@@ -3232,26 +3247,24 @@ async def test_update_suggested_area(
             entry.id, suggested_area=suggested_area
         )
 
-    assert mock_save.call_count == 1
+    # Check the device registry was not saved
+    assert mock_save.call_count == 0
     assert updated_entry != entry
+    assert updated_entry.area_id == device_area_id
 
-    pool_area = area_registry.async_get_area_by_name("Pool")
-    assert pool_area is not None
-    assert updated_entry.area_id == pool_area.id
-    assert len(area_registry.areas) == 1
+    # Check we did not create an area
+    pool_area = area_registry.async_get_area_by_name(suggested_area)
+    assert pool_area is None
+    assert updated_entry.area_id == device_area_id
+    assert len(area_registry.areas) == number_of_areas
 
     await hass.async_block_till_done()
 
-    assert len(update_events) == 2
+    assert len(update_events) == 1
     assert update_events[0].data == {
         "action": "create",
         "device_id": entry.id,
     }
-    assert update_events[1].data == {
-        "action": "update",
-        "device_id": entry.id,
-        "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
@@ -3260,10 +3273,10 @@ async def test_update_suggested_area(
         updated_entry = device_registry.async_update_device(
             entry.id, suggested_area="Other"
         )
-    assert len(update_events) == 2
+    assert len(update_events) == 1
     assert mock_save_2.call_count == 0
     assert updated_entry != entry
-    assert updated_entry.area_id == pool_area.id
+    assert updated_entry.area_id == device_area_id
 
 
 async def test_cleanup_device_registry(
@@ -3397,11 +3410,13 @@ async def test_cleanup_entity_registry_change(
         assert len(mock_call.mock_calls) == 2
 
 
+@pytest.mark.parametrize("initial_area", [None, "12345A"])
 @pytest.mark.usefixtures("freezer")
 async def test_restore_device(
     hass: HomeAssistant,
     device_registry: dr.DeviceRegistry,
     mock_config_entry_with_subentries: MockConfigEntry,
+    initial_area: str | None,
 ) -> None:
     """Make sure device id is stable."""
     entry_id = mock_config_entry_with_subentries.entry_id
@@ -3428,7 +3443,7 @@ async def test_restore_device(
     # Apply user customizations
     entry = device_registry.async_update_device(
         entry.id,
-        area_id="12345A",
+        area_id=initial_area,
         disabled_by=dr.DeviceEntryDisabler.USER,
         labels={"label1", "label2"},
         name_by_user="Test Friendly Name",
@@ -3493,7 +3508,7 @@ async def test_restore_device(
         via_device="via_device_id_new",
     )
     assert entry3 == dr.DeviceEntry(
-        area_id="12345A",
+        area_id=initial_area,
         config_entries={entry_id},
         config_entries_subentries={entry_id: {subentry_id}},
         configuration_url="http://config_url_new.bla",
@@ -4933,3 +4948,11 @@ async def test_suggested_area_deprecation(
         "The deprecated function suggested_area was called. It will be removed in "
         "HA Core 2026.9. Use code which ignores suggested_area instead"
     ) in caplog.text
+
+    device_registry.async_update_device(entry.id, suggested_area="TV Room")
+
+    assert (
+        "Detected code that passes a suggested_area to device_registry.async_update "
+        "device. This will stop working in Home Assistant 2026.9.0, please report "
+        "this issue"
+    ) in caplog.text