Avoid redundant calls to async_write_ha_state in mqtt siren (#100813)

* Avoid redundant calls to async_write_ha_state

* Add comment

homeassistant/components/mqtt/siren.py

@@ -49,7 +49,12 @@ from .const import (
     PAYLOAD_NONE,
 )
 from .debug_info import log_messages
-from .mixins import MQTT_ENTITY_COMMON_SCHEMA, MqttEntity, async_setup_entry_helper
+from .mixins import (
+    MQTT_ENTITY_COMMON_SCHEMA,
+    MqttEntity,
+    async_setup_entry_helper,
+    write_state_on_attr_change,
+)
 from .models import (
     MqttCommandTemplate,
     MqttValueTemplate,
@@ -57,7 +62,6 @@ from .models import (
     ReceiveMessage,
     ReceivePayloadType,
 )
-from .util import get_mqtt_data
 
 DEFAULT_NAME = "MQTT Siren"
 DEFAULT_PAYLOAD_ON = "ON"
@@ -223,6 +227,7 @@ class MqttSiren(MqttEntity, SirenEntity):
 
         @callback
         @log_messages(self.hass, self.entity_id)
+        @write_state_on_attr_change(self, {"_attr_is_on", "_extra_attributes"})
         def state_message_received(msg: ReceiveMessage) -> None:
             """Handle new MQTT state messages."""
             payload = self._value_template(msg.payload)
@@ -265,7 +270,6 @@ class MqttSiren(MqttEntity, SirenEntity):
                 if json_payload[STATE] == PAYLOAD_NONE:
                     self._attr_is_on = None
                 del json_payload[STATE]
-                get_mqtt_data(self.hass).state_write_requests.write_state_request(self)
 
             if json_payload:
                 # process attributes
@@ -279,8 +283,10 @@ class MqttSiren(MqttEntity, SirenEntity):
                         invalid_siren_parameters,
                     )
                     return
+                # To be able to track changes to self._extra_attributes we assign
+                # a fresh copy to make the original tracked reference immutable.
+                self._extra_attributes = dict(self._extra_attributes)
                 self._update(process_turn_on_params(self, params))
-                get_mqtt_data(self.hass).state_write_requests.write_state_request(self)
 
         if self._config.get(CONF_STATE_TOPIC) is None:
             # Force into optimistic mode.

tests/components/mqtt/test_siren.py

@@ -44,6 +44,7 @@ from .test_common import (
     help_test_setting_attribute_via_mqtt_json_message,
     help_test_setting_attribute_with_template,
     help_test_setting_blocked_attribute_via_mqtt_json_message,
+    help_test_skipped_async_ha_write_state,
     help_test_unique_id,
     help_test_unload_config_entry_with_platform,
     help_test_update_with_json_attrs_bad_json,
@@ -1092,3 +1093,53 @@ async def test_unload_entry(
     await help_test_unload_config_entry_with_platform(
         hass, mqtt_mock_entry, domain, config
     )
+
+
+@pytest.mark.parametrize(
+    "hass_config",
+    [
+        help_custom_config(
+            siren.DOMAIN,
+            DEFAULT_CONFIG,
+            (
+                {
+                    "state_topic": "test-topic",
+                    "available_tones": ["siren", "bell"],
+                    "availability_topic": "availability-topic",
+                    "json_attributes_topic": "json-attributes-topic",
+                },
+            ),
+        )
+    ],
+)
+@pytest.mark.parametrize(
+    ("topic", "payload1", "payload2"),
+    [
+        ("availability-topic", "online", "offline"),
+        ("json-attributes-topic", '{"attr1": "val1"}', '{"attr1": "val2"}'),
+        ("test-topic", "ON", "OFF"),
+        ("test-topic", '{"state": "ON"}', '{"state": "OFF"}'),
+        ("test-topic", '{"state":"ON","tone":"siren"}', '{"state":"ON","tone":"bell"}'),
+        (
+            "test-topic",
+            '{"state":"ON","tone":"siren"}',
+            '{"state":"OFF","tone":"siren"}',
+        ),
+        # Attriute volume_level 2 is invalid, but the state is valid and should update
+        (
+            "test-topic",
+            '{"state":"ON","volume_level":0.5}',
+            '{"state":"OFF","volume_level":2}',
+        ),
+    ],
+)
+async def test_skipped_async_ha_write_state(
+    hass: HomeAssistant,
+    mqtt_mock_entry: MqttMockHAClientGenerator,
+    topic: str,
+    payload1: str,
+    payload2: str,
+) -> None:
+    """Test a write state command is only called when there is change."""
+    await mqtt_mock_entry()
+    await help_test_skipped_async_ha_write_state(hass, topic, payload1, payload2)