From 8d10cdce4e1551aef3a3ff21aba56ff67358dc5d Mon Sep 17 00:00:00 2001
From: Jan Bouwhuis <jbouwh@users.noreply.github.com>
Date: Mon, 25 Sep 2023 18:06:19 +0200
Subject: [PATCH] Avoid redundant calls to async_ha_write_state in mqtt switch
 (#100815)

Avoid redundant calls to async_ha_write_state
---
 homeassistant/components/mqtt/switch.py | 11 ++++---
 tests/components/mqtt/test_switch.py    | 38 +++++++++++++++++++++++++
 2 files changed, 45 insertions(+), 4 deletions(-)

diff --git a/homeassistant/components/mqtt/switch.py b/homeassistant/components/mqtt/switch.py
index e8872d3f0d1..125998e5955 100644
--- a/homeassistant/components/mqtt/switch.py
+++ b/homeassistant/components/mqtt/switch.py
@@ -37,9 +37,13 @@ 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 MqttValueTemplate, ReceiveMessage
-from .util import get_mqtt_data
 
 DEFAULT_NAME = "MQTT Switch"
 DEFAULT_PAYLOAD_ON = "ON"
@@ -136,6 +140,7 @@ class MqttSwitch(MqttEntity, SwitchEntity, RestoreEntity):
 
         @callback
         @log_messages(self.hass, self.entity_id)
+        @write_state_on_attr_change(self, {"_attr_is_on"})
         def state_message_received(msg: ReceiveMessage) -> None:
             """Handle new MQTT state messages."""
             payload = self._value_template(msg.payload)
@@ -146,8 +151,6 @@ class MqttSwitch(MqttEntity, SwitchEntity, RestoreEntity):
             elif payload == PAYLOAD_NONE:
                 self._attr_is_on = None
 
-            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.
             self._optimistic = True
diff --git a/tests/components/mqtt/test_switch.py b/tests/components/mqtt/test_switch.py
index 4471cc7dc11..32195289aab 100644
--- a/tests/components/mqtt/test_switch.py
+++ b/tests/components/mqtt/test_switch.py
@@ -17,6 +17,7 @@ from homeassistant.const import (
 from homeassistant.core import HomeAssistant, State
 
 from .test_common import (
+    help_custom_config,
     help_test_availability_when_connection_lost,
     help_test_availability_without_topic,
     help_test_custom_availability_payload,
@@ -39,6 +40,7 @@ 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,
@@ -762,3 +764,39 @@ 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(
+            switch.DOMAIN,
+            DEFAULT_CONFIG,
+            (
+                {
+                    "state_topic": "test-topic",
+                    "availability_topic": "availability-topic",
+                    "json_attributes_topic": "json-attributes-topic",
+                },
+            ),
+        )
+    ],
+)
+@pytest.mark.parametrize(
+    ("topic", "payload1", "payload2"),
+    [
+        ("test-topic", "ON", "OFF"),
+        ("availability-topic", "online", "offline"),
+        ("json-attributes-topic", '{"attr1": "val1"}', '{"attr1": "val2"}'),
+    ],
+)
+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)