Ignore empty output from MQTT fan's value template (#50122)

* Allow empty payload

* Add tests for ignoring empty payload

* logging on empty state and osccilation with tests

* Improve warning log when invalid value is received

homeassistant/components/mqtt/fan.py

@@ -344,6 +344,9 @@ class MqttFan(MqttEntity, FanEntity):
         def state_received(msg):
             """Handle new received MQTT message."""
             payload = self._value_templates[CONF_STATE](msg.payload)
+            if not payload:
+                _LOGGER.debug("Ignoring empty state from '%s'", msg.topic)
+                return
             if payload == self._payload["STATE_ON"]:
                 self._state = True
             elif payload == self._payload["STATE_OFF"]:
@@ -362,22 +365,27 @@ class MqttFan(MqttEntity, FanEntity):
         def percentage_received(msg):
             """Handle new received MQTT message for the percentage."""
             numeric_val_str = self._value_templates[ATTR_PERCENTAGE](msg.payload)
+            if not numeric_val_str:
+                _LOGGER.debug("Ignoring empty speed from '%s'", msg.topic)
+                return
             try:
                 percentage = ranged_value_to_percentage(
                     self._speed_range, int(numeric_val_str)
                 )
             except ValueError:
                 _LOGGER.warning(
-                    "'%s' received on topic %s is not a valid speed within the speed range",
+                    "'%s' received on topic %s. '%s' is not a valid speed within the speed range",
                     msg.payload,
                     msg.topic,
+                    numeric_val_str,
                 )
                 return
             if percentage < 0 or percentage > 100:
                 _LOGGER.warning(
-                    "'%s' received on topic %s is not a valid speed within the speed range",
+                    "'%s' received on topic %s. '%s' is not a valid speed within the speed range",
                     msg.payload,
                     msg.topic,
+                    numeric_val_str,
                 )
                 return
             self._percentage = percentage
@@ -396,11 +404,15 @@ class MqttFan(MqttEntity, FanEntity):
         def preset_mode_received(msg):
             """Handle new received MQTT message for preset mode."""
             preset_mode = self._value_templates[ATTR_PRESET_MODE](msg.payload)
+            if not preset_mode:
+                _LOGGER.debug("Ignoring empty preset_mode from '%s'", msg.topic)
+                return
             if preset_mode not in self.preset_modes:
                 _LOGGER.warning(
-                    "'%s' received on topic %s is not a valid preset mode",
+                    "'%s' received on topic %s. '%s' is not a valid preset mode",
                     msg.payload,
                     msg.topic,
+                    preset_mode,
                 )
                 return
 
@@ -436,9 +448,10 @@ class MqttFan(MqttEntity, FanEntity):
                 self._speed = speed
             else:
                 _LOGGER.warning(
-                    "'%s' received on topic %s is not a valid speed",
+                    "'%s' received on topic %s. '%s' is not a valid speed",
                     msg.payload,
                     msg.topic,
+                    speed,
                 )
                 return
 
@@ -464,6 +477,9 @@ class MqttFan(MqttEntity, FanEntity):
         def oscillation_received(msg):
             """Handle new received MQTT message for the oscillation."""
             payload = self._value_templates[ATTR_OSCILLATING](msg.payload)
+            if not payload:
+                _LOGGER.debug("Ignoring empty oscillation from '%s'", msg.topic)
+                return
             if payload == self._payload["OSCILLATE_ON_PAYLOAD"]:
                 self._oscillation = True
             elif payload == self._payload["OSCILLATE_OFF_PAYLOAD"]:

tests/components/mqtt/test_fan.py

@@ -408,6 +408,10 @@ async def test_controlling_state_via_topic_and_json_message(hass, mqtt_mock, cap
     state = hass.states.get("fan.test")
     assert state.attributes.get(fan.ATTR_PERCENTAGE) == 100
 
+    async_fire_mqtt_message(hass, "percentage-state-topic", '{"otherval": 100}')
+    assert "Ignoring empty speed from" in caplog.text
+    caplog.clear()
+
     async_fire_mqtt_message(hass, "preset-mode-state-topic", '{"val": "low"}')
     assert "not a valid preset mode" in caplog.text
     caplog.clear()
@@ -424,6 +428,99 @@ async def test_controlling_state_via_topic_and_json_message(hass, mqtt_mock, cap
     state = hass.states.get("fan.test")
     assert state.attributes.get("preset_mode") == "silent"
 
+    async_fire_mqtt_message(hass, "preset-mode-state-topic", '{"otherval": 100}')
+    assert "Ignoring empty preset_mode from" in caplog.text
+    caplog.clear()
+
+
+async def test_controlling_state_via_topic_and_json_message_shared_topic(
+    hass, mqtt_mock, caplog
+):
+    """Test the controlling state via topic and JSON message using a shared topic."""
+    assert await async_setup_component(
+        hass,
+        fan.DOMAIN,
+        {
+            fan.DOMAIN: {
+                "platform": "mqtt",
+                "name": "test",
+                "state_topic": "shared-state-topic",
+                "command_topic": "command-topic",
+                "oscillation_state_topic": "shared-state-topic",
+                "oscillation_command_topic": "oscillation-command-topic",
+                "percentage_state_topic": "shared-state-topic",
+                "percentage_command_topic": "percentage-command-topic",
+                "preset_mode_state_topic": "shared-state-topic",
+                "preset_mode_command_topic": "preset-mode-command-topic",
+                "preset_modes": [
+                    "auto",
+                    "smart",
+                    "whoosh",
+                    "eco",
+                    "breeze",
+                    "silent",
+                ],
+                "state_value_template": "{{ value_json.state }}",
+                "oscillation_value_template": "{{ value_json.oscillation }}",
+                "percentage_value_template": "{{ value_json.percentage }}",
+                "preset_mode_value_template": "{{ value_json.preset_mode }}",
+                "speed_range_min": 1,
+                "speed_range_max": 100,
+            }
+        },
+    )
+    await hass.async_block_till_done()
+
+    state = hass.states.get("fan.test")
+    assert state.state == STATE_OFF
+    assert not state.attributes.get(ATTR_ASSUMED_STATE)
+
+    async_fire_mqtt_message(
+        hass,
+        "shared-state-topic",
+        '{"state":"ON","preset_mode":"eco","oscillation":"oscillate_on","percentage": 50}',
+    )
+    state = hass.states.get("fan.test")
+    assert state.state == STATE_ON
+    assert state.attributes.get("oscillating") is True
+    assert state.attributes.get(fan.ATTR_PERCENTAGE) == 50
+    assert state.attributes.get("preset_mode") == "eco"
+
+    async_fire_mqtt_message(
+        hass,
+        "shared-state-topic",
+        '{"state":"ON","preset_mode":"auto","oscillation":"oscillate_off","percentage": 10}',
+    )
+    state = hass.states.get("fan.test")
+    assert state.state == STATE_ON
+    assert state.attributes.get("oscillating") is False
+    assert state.attributes.get(fan.ATTR_PERCENTAGE) == 10
+    assert state.attributes.get("preset_mode") == "auto"
+
+    async_fire_mqtt_message(
+        hass,
+        "shared-state-topic",
+        '{"state":"OFF","preset_mode":"auto","oscillation":"oscillate_off","percentage": 0}',
+    )
+    state = hass.states.get("fan.test")
+    assert state.state == STATE_OFF
+    assert state.attributes.get("oscillating") is False
+    assert state.attributes.get(fan.ATTR_PERCENTAGE) == 0
+    assert state.attributes.get("preset_mode") == "auto"
+
+    async_fire_mqtt_message(
+        hass,
+        "shared-state-topic",
+        '{"percentage": 100}',
+    )
+    state = hass.states.get("fan.test")
+    assert state.attributes.get(fan.ATTR_PERCENTAGE) == 100
+    assert state.attributes.get("preset_mode") == "auto"
+    assert "Ignoring empty preset_mode from" in caplog.text
+    assert "Ignoring empty state from" in caplog.text
+    assert "Ignoring empty oscillation from" in caplog.text
+    caplog.clear()
+
 
 async def test_sending_mqtt_commands_and_optimistic(hass, mqtt_mock, caplog):
     """Test optimistic mode without state topic."""