From 701eb032115f2f468d71c1c331ae18a2f1b3f4a8 Mon Sep 17 00:00:00 2001
From: Erik Montnemery <erik@montnemery.com>
Date: Mon, 27 Jul 2026 17:39:49 +0200
Subject: [PATCH] Update MQTT device registry event handling (#176965)

---
 homeassistant/components/mqtt/entity.py | 23 ++++-----------
 tests/components/mqtt/test_discovery.py | 38 +++++++++++++++++++++++++
 2 files changed, 44 insertions(+), 17 deletions(-)

diff --git a/homeassistant/components/mqtt/entity.py b/homeassistant/components/mqtt/entity.py
index 65edaf103317..70c8283744f5 100644
--- a/homeassistant/components/mqtt/entity.py
+++ b/homeassistant/components/mqtt/entity.py
@@ -959,9 +959,7 @@ class MqttDiscoveryDeviceUpdateMixin(ABC):
         self, event: Event[EventDeviceRegistryUpdatedData]
     ) -> None:
         """Handle the manual removal of a device."""
-        if self._skip_device_removal or not async_removed_from_device(
-            self.hass, event, cast(str, self._device_id), self._config_entry_id
-        ):
+        if self._skip_device_removal or not async_removed_from_device(event):
             return
         # Prevent a second cleanup round after the device is removed
         self._remove_device_updated()
@@ -1747,20 +1745,11 @@ def update_device(
 
 @callback
 def async_removed_from_device(
-    hass: HomeAssistant,
     event: Event[EventDeviceRegistryUpdatedData],
-    mqtt_device_id: str,
-    config_entry_id: str,
 ) -> bool:
-    """Check if the passed event indicates MQTT was removed from a device."""
-    if event.data["action"] == "update":
-        if "config_entries" not in event.data["changes"]:
-            return False
-        device_registry = dr.async_get(hass)
-        if (
-            device_entry := device_registry.async_get(mqtt_device_id)
-        ) and config_entry_id in device_entry.config_entries:
-            # Not removed from device
-            return False
+    """Check if the passed event indicates MQTT was removed from a device.
 
-    return True
+    A device is associated with a single config entry, so MQTT is removed from a
+    device only when the device itself is removed.
+    """
+    return event.data["action"] == "remove"
diff --git a/tests/components/mqtt/test_discovery.py b/tests/components/mqtt/test_discovery.py
index 26abd4018071..b8241c860b79 100644
--- a/tests/components/mqtt/test_discovery.py
+++ b/tests/components/mqtt/test_discovery.py
@@ -26,6 +26,7 @@ from homeassistant.components.mqtt.discovery import (
     MQTTDiscoveryPayload,
     async_start,
 )
+from homeassistant.components.mqtt.entity import async_removed_from_device
 from homeassistant.components.mqtt.models import ReceiveMessage
 from homeassistant.components.mqtt.schemas import (
     DEVICE_DISCOVERY_SCHEMA,
@@ -3495,3 +3496,40 @@ async def test_shared_qos_with_device_discovery(
     mqtt_mock.async_subscribe.assert_has_calls(
         [call("foobar/sensors/bla2/state", ANY, qos, "utf-8", ANY)]
     )
+
+
+@pytest.mark.parametrize(
+    ("event_data", "expected"),
+    [
+        pytest.param(
+            {"action": "remove", "device_id": "abc", "device": {}},
+            True,
+            id="remove",
+        ),
+        pytest.param(
+            {
+                "action": "update",
+                "device_id": "abc",
+                "changes": {"config_entry_id": "mqtt_entry_id"},
+            },
+            False,
+            id="update-config-entry",
+        ),
+        pytest.param(
+            {"action": "update", "device_id": "abc", "changes": {"name": "New name"}},
+            False,
+            id="update-other",
+        ),
+    ],
+)
+async def test_async_removed_from_device(
+    event_data: dr.EventDeviceRegistryUpdatedData,
+    expected: bool,
+) -> None:
+    """MQTT leaves a device only when the device is removed.
+
+    A device belongs to a single config entry, so a config-entry change on an update
+    event is not a removal; only a 'remove' action is.
+    """
+    event = Event(dr.EVENT_DEVICE_REGISTRY_UPDATED, event_data)
+    assert async_removed_from_device(event) is expected