Add support Mqtt switch for unkown state (#65294)

* Mqtt switch allow unkown state

* correct type

* Update discovery tests

* Optimistic mode if not state_topic is configured.

* Default state UNKNOWN in optimistic mode

* fix discovery test

homeassistant/components/mqtt/switch.py

@@ -51,6 +51,8 @@ DEFAULT_OPTIMISTIC = False
 CONF_STATE_ON = "state_on"
 CONF_STATE_OFF = "state_off"
 
+PAYLOAD_NONE = "None"
+
 PLATFORM_SCHEMA = mqtt.MQTT_RW_PLATFORM_SCHEMA.extend(
     {
         vol.Optional(CONF_NAME, default=DEFAULT_NAME): cv.string,
@@ -105,7 +107,7 @@ class MqttSwitch(MqttEntity, SwitchEntity, RestoreEntity):
 
     def __init__(self, hass, config, config_entry, discovery_data):
         """Initialize the MQTT switch."""
-        self._state = False
+        self._state = None
 
         self._state_on = None
         self._state_off = None
@@ -126,7 +128,9 @@ class MqttSwitch(MqttEntity, SwitchEntity, RestoreEntity):
         state_off = config.get(CONF_STATE_OFF)
         self._state_off = state_off if state_off else config[CONF_PAYLOAD_OFF]
 
-        self._optimistic = config[CONF_OPTIMISTIC]
+        self._optimistic = (
+            config[CONF_OPTIMISTIC] or config.get(CONF_STATE_TOPIC) is None
+        )
 
         self._value_template = MqttValueTemplate(
             self._config.get(CONF_VALUE_TEMPLATE), entity=self
@@ -144,6 +148,8 @@ class MqttSwitch(MqttEntity, SwitchEntity, RestoreEntity):
                 self._state = True
             elif payload == self._state_off:
                 self._state = False
+            elif payload == PAYLOAD_NONE:
+                self._state = None
 
             self.async_write_ha_state()
 
@@ -172,7 +178,7 @@ class MqttSwitch(MqttEntity, SwitchEntity, RestoreEntity):
             self._state = last_state.state == STATE_ON
 
     @property
-    def is_on(self):
+    def is_on(self) -> bool | None:
         """Return true if device is on."""
         return self._state
 

tests/components/mqtt/test_discovery.py

@@ -14,9 +14,9 @@ from homeassistant.components.mqtt.abbreviations import (
 from homeassistant.components.mqtt.discovery import ALREADY_DISCOVERED, async_start
 from homeassistant.const import (
     EVENT_STATE_CHANGED,
-    STATE_OFF,
     STATE_ON,
     STATE_UNAVAILABLE,
+    STATE_UNKNOWN,
 )
 import homeassistant.core as ha
 
@@ -649,7 +649,7 @@ async def test_discovery_expansion(hass, mqtt_mock, caplog):
     assert state is not None
     assert state.name == "DiscoveryExpansionTest1"
     assert ("switch", "bla") in hass.data[ALREADY_DISCOVERED]
-    assert state.state == STATE_OFF
+    assert state.state == STATE_UNKNOWN
 
     async_fire_mqtt_message(hass, "test_topic/some/base/topic", "ON")
 
@@ -699,7 +699,7 @@ async def test_discovery_expansion_2(hass, mqtt_mock, caplog):
     assert state is not None
     assert state.name == "DiscoveryExpansionTest1"
     assert ("switch", "bla") in hass.data[ALREADY_DISCOVERED]
-    assert state.state == STATE_OFF
+    assert state.state == STATE_UNKNOWN
 
 
 @pytest.mark.no_fail_on_log_exception
@@ -773,7 +773,7 @@ async def test_discovery_expansion_without_encoding_and_value_template_1(
     assert state is not None
     assert state.name == "DiscoveryExpansionTest1"
     assert ("switch", "bla") in hass.data[ALREADY_DISCOVERED]
-    assert state.state == STATE_OFF
+    assert state.state == STATE_UNKNOWN
 
     async_fire_mqtt_message(hass, "some/base/topic/avail_item1", b"\x00")
 
@@ -819,7 +819,7 @@ async def test_discovery_expansion_without_encoding_and_value_template_2(
     assert state is not None
     assert state.name == "DiscoveryExpansionTest1"
     assert ("switch", "bla") in hass.data[ALREADY_DISCOVERED]
-    assert state.state == STATE_OFF
+    assert state.state == STATE_UNKNOWN
 
     async_fire_mqtt_message(hass, "some/base/topic/avail_item1", b"\x00")
 
@@ -895,13 +895,13 @@ async def test_no_implicit_state_topic_switch(hass, mqtt_mock, caplog):
     assert state is not None
     assert state.name == "Test1"
     assert ("switch", "bla") in hass.data[ALREADY_DISCOVERED]
-    assert state.state == "off"
+    assert state.state == STATE_UNKNOWN
     assert state.attributes["assumed_state"] is True
 
     async_fire_mqtt_message(hass, "homeassistant/switch/bla/state", "ON")
 
     state = hass.states.get("switch.Test1")
-    assert state.state == "off"
+    assert state.state == STATE_UNKNOWN
 
 
 @pytest.mark.parametrize(

tests/components/mqtt/test_switch.py

@@ -11,6 +11,7 @@ from homeassistant.const import (
     ATTR_DEVICE_CLASS,
     STATE_OFF,
     STATE_ON,
+    STATE_UNKNOWN,
 )
 import homeassistant.core as ha
 from homeassistant.setup import async_setup_component
@@ -71,7 +72,7 @@ async def test_controlling_state_via_topic(hass, mqtt_mock):
     await hass.async_block_till_done()
 
     state = hass.states.get("switch.test")
-    assert state.state == STATE_OFF
+    assert state.state == STATE_UNKNOWN
     assert state.attributes.get(ATTR_DEVICE_CLASS) == "switch"
     assert not state.attributes.get(ATTR_ASSUMED_STATE)
 
@@ -85,6 +86,11 @@ async def test_controlling_state_via_topic(hass, mqtt_mock):
     state = hass.states.get("switch.test")
     assert state.state == STATE_OFF
 
+    async_fire_mqtt_message(hass, "state-topic", "None")
+
+    state = hass.states.get("switch.test")
+    assert state.state == STATE_UNKNOWN
+
 
 async def test_sending_mqtt_commands_and_optimistic(hass, mqtt_mock):
     """Test the sending MQTT commands in optimistic mode."""
@@ -132,6 +138,26 @@ async def test_sending_mqtt_commands_and_optimistic(hass, mqtt_mock):
     assert state.state == STATE_OFF
 
 
+async def test_sending_inital_state_and_optimistic(hass, mqtt_mock):
+    """Test the initial state in optimistic mode."""
+    assert await async_setup_component(
+        hass,
+        switch.DOMAIN,
+        {
+            switch.DOMAIN: {
+                "platform": "mqtt",
+                "name": "test",
+                "command_topic": "command-topic",
+            }
+        },
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get("switch.test")
+    assert state.state == STATE_UNKNOWN
+    assert state.attributes.get(ATTR_ASSUMED_STATE)
+
+
 async def test_controlling_state_via_topic_and_json_message(hass, mqtt_mock):
     """Test the controlling state via topic and JSON message."""
     assert await async_setup_component(
@@ -152,7 +178,7 @@ async def test_controlling_state_via_topic_and_json_message(hass, mqtt_mock):
     await hass.async_block_till_done()
 
     state = hass.states.get("switch.test")
-    assert state.state == STATE_OFF
+    assert state.state == STATE_UNKNOWN
 
     async_fire_mqtt_message(hass, "state-topic", '{"val":"beer on"}')
 
@@ -164,6 +190,11 @@ async def test_controlling_state_via_topic_and_json_message(hass, mqtt_mock):
     state = hass.states.get("switch.test")
     assert state.state == STATE_OFF
 
+    async_fire_mqtt_message(hass, "state-topic", '{"val": null}')
+
+    state = hass.states.get("switch.test")
+    assert state.state == STATE_UNKNOWN
+
 
 async def test_availability_when_connection_lost(hass, mqtt_mock):
     """Test availability after MQTT disconnection."""
@@ -236,7 +267,7 @@ async def test_custom_state_payload(hass, mqtt_mock):
     await hass.async_block_till_done()
 
     state = hass.states.get("switch.test")
-    assert state.state == STATE_OFF
+    assert state.state == STATE_UNKNOWN
     assert not state.attributes.get(ATTR_ASSUMED_STATE)
 
     async_fire_mqtt_message(hass, "state-topic", "HIGH")