Fix duplicate devices in Airthings BLE on incomplete read (#182417)

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

homeassistant/components/airthings_ble/coordinator.py

@@ -102,4 +102,14 @@ class AirthingsBLEDataUpdateCoordinator(DataUpdateCoordinator[AirthingsDevice]):
             data = await self.airthings.update_device(self.ble_device)
         except Exception as err:
             raise UpdateFailed(f"Unable to fetch data: {err}") from err
+
+        if not data.address:
+            # The device did not report its address, which means the read did not
+            # complete. Building entities from this would create a duplicate device
+            # and entities with an empty unique id prefix.
+            raise UpdateFailed(
+                translation_domain=DOMAIN,
+                translation_key="incomplete_read",
+            )
+
         return data

homeassistant/components/airthings_ble/strings.json

@@ -67,6 +67,9 @@
   "exceptions": {
     "device_not_found": {
       "message": "Could not find Airthings device with address {address}: {reason}"
+    },
+    "incomplete_read": {
+      "message": "The Airthings device did not return complete data, retrying"
     }
   }
 }

tests/components/airthings_ble/test_init.py

@@ -98,6 +98,33 @@ async def test_setup_retries_when_device_not_found(
     )
 
 
+async def test_setup_retries_on_incomplete_read(
+    hass: HomeAssistant,
+) -> None:
+    """Test setup is retried when the device returns data without an address."""
+    entry = MockConfigEntry(
+        domain=DOMAIN,
+        unique_id=WAVE_SERVICE_INFO.address,
+        data={DEVICE_MODEL: WAVE_DEVICE_INFO.model.value},
+    )
+    entry.add_to_hass(hass)
+
+    inject_bluetooth_service_info(hass, WAVE_SERVICE_INFO)
+
+    incomplete_device_info = deepcopy(WAVE_DEVICE_INFO)
+    incomplete_device_info.address = ""
+
+    with (
+        patch_async_ble_device_from_address(WAVE_SERVICE_INFO.device),
+        patch_airthings_ble(incomplete_device_info),
+    ):
+        await hass.config_entries.async_setup(entry.entry_id)
+        await hass.async_block_till_done()
+
+    assert entry.state is ConfigEntryState.SETUP_RETRY
+    assert len(hass.states.async_all()) == 0
+
+
 async def test_no_migration_when_device_model_exists(
     hass: HomeAssistant,
 ) -> None: