From 2df0adfbc74ce3e9d9bc16f39a3974c4a56b9275 Mon Sep 17 00:00:00 2001
From: Allen Porter <allen@thebends.org>
Date: Wed, 29 Dec 2021 03:20:55 -0800
Subject: [PATCH] Reload nest integration when new devices are added (#62976)

---
 homeassistant/components/nest/__init__.py | 17 +++++-
 tests/components/nest/test_events.py      | 63 +++++++++++++++++++++++
 2 files changed, 78 insertions(+), 2 deletions(-)

diff --git a/homeassistant/components/nest/__init__.py b/homeassistant/components/nest/__init__.py
index 3cad979165a..bb5edefc2ca 100644
--- a/homeassistant/components/nest/__init__.py
+++ b/homeassistant/components/nest/__init__.py
@@ -1,6 +1,7 @@
 """Support for Nest devices."""
 from __future__ import annotations
 
+from collections.abc import Awaitable, Callable
 from http import HTTPStatus
 import logging
 
@@ -178,12 +179,21 @@ async def async_setup(hass: HomeAssistant, config: ConfigType) -> bool:
 class SignalUpdateCallback:
     """An EventCallback invoked when new events arrive from subscriber."""
 
-    def __init__(self, hass: HomeAssistant) -> None:
+    def __init__(
+        self, hass: HomeAssistant, config_reload_cb: Callable[[], Awaitable[None]]
+    ) -> None:
         """Initialize EventCallback."""
         self._hass = hass
+        self._config_reload_cb = config_reload_cb
 
     async def async_handle_event(self, event_message: EventMessage) -> None:
         """Process an incoming EventMessage."""
+        if event_message.relation_update:
+            # A device was added/removed or a home was added/removed. Reload the integration
+            # in order to detect any changes.
+            _LOGGER.info("Devices or homes have changed; Reloading")
+            self._hass.async_create_task(self._config_reload_cb())
+            return
         if not event_message.resource_update_name:
             return
         device_id = event_message.resource_update_name
@@ -221,7 +231,10 @@ async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
     # Use disk backed event media store
     subscriber.cache_policy.store = await async_get_media_event_store(hass, subscriber)
 
-    callback = SignalUpdateCallback(hass)
+    async def async_config_reload() -> None:
+        await hass.config_entries.async_reload(entry.entry_id)
+
+    callback = SignalUpdateCallback(hass, async_config_reload)
     subscriber.set_update_callback(callback.async_handle_event)
     try:
         await subscriber.start_async()
diff --git a/tests/components/nest/test_events.py b/tests/components/nest/test_events.py
index 4a625999155..0c4496603bd 100644
--- a/tests/components/nest/test_events.py
+++ b/tests/components/nest/test_events.py
@@ -5,6 +5,7 @@ pubsub subscriber.
 """
 
 import datetime
+from unittest.mock import patch
 
 from google_nest_sdm.device import Device
 from google_nest_sdm.event import EventMessage
@@ -446,3 +447,65 @@ async def test_doorbell_event_session_update(hass):
         "timestamp": timestamp2.replace(microsecond=0),
         "nest_event_id": EVENT_SESSION_ID,
     }
+
+
+async def test_structure_update_event(hass):
+    """Test a pubsub message for a new device being added."""
+    events = async_capture_events(hass, NEST_EVENT)
+    subscriber = await async_setup_devices(
+        hass,
+        "sdm.devices.types.DOORBELL",
+        create_device_traits(["sdm.devices.traits.DoorbellChime"]),
+    )
+
+    # Entity for first device is registered
+    registry = er.async_get(hass)
+    assert registry.async_get("camera.front")
+
+    new_device = Device.MakeDevice(
+        {
+            "name": "device-id-2",
+            "type": "sdm.devices.types.CAMERA",
+            "traits": {
+                "sdm.devices.traits.Info": {
+                    "customName": "Back",
+                },
+                "sdm.devices.traits.CameraLiveStream": {},
+            },
+        },
+        auth=None,
+    )
+    device_manager = await subscriber.async_get_device_manager()
+    device_manager.add_device(new_device)
+
+    # Entity for new devie has not yet been loaded
+    assert not registry.async_get("camera.back")
+
+    # Send a message that triggers the device to be loaded
+    message = EventMessage(
+        {
+            "eventId": "some-event-id",
+            "timestamp": utcnow().isoformat(timespec="seconds"),
+            "relationUpdate": {
+                "type": "CREATED",
+                "subject": "enterprise/example/foo",
+                "object": "enterprise/example/devices/some-device-id2",
+            },
+        },
+        auth=None,
+    )
+    with patch(
+        "homeassistant.helpers.config_entry_oauth2_flow.async_get_config_entry_implementation"
+    ), patch("homeassistant.components.nest.PLATFORMS", [PLATFORM]), patch(
+        "homeassistant.components.nest.api.GoogleNestSubscriber",
+        return_value=subscriber,
+    ):
+        await subscriber.async_receive_event(message)
+        await hass.async_block_till_done()
+
+    # No home assistant events published
+    assert not events
+
+    # Both enties now exist
+    assert registry.async_get("camera.front")
+    assert registry.async_get("camera.back")