[sensor] Deprecate .raw_state, guard raw_callback_ behind USE_SENSOR_FILTER

Deprecate direct access to sensor .raw_state member in favor of
get_raw_state(). This prepares for eventually compiling out raw_state
on builds without sensor filters, saving 4 bytes per sensor instance.

Guard raw_callback_ and add_on_raw_state_callback behind
USE_SENSOR_FILTER, saving 4 bytes per sensor on builds without
filters immediately.

Guard SensorRawStateTrigger behind USE_SENSOR_FILTER and ensure
on_raw_value automation sets USE_SENSOR_FILTER define.

Fix nextion sensor to stop directly writing .raw_state/.state
members - the publish=false path was redundantly setting already-current
values.

Migrate haier hon_climate from .raw_state to get_raw_state().

esphome/components/haier/hon_climate.cpp

@@ -748,7 +748,7 @@ void HonClimate::update_sub_sensor_(SubSensorType type, float value) {
   if (type < SubSensorType::SUB_SENSOR_TYPE_COUNT) {
     size_t index = (size_t) type;
     if ((this->sub_sensors_[index] != nullptr) &&
-        ((!this->sub_sensors_[index]->has_state()) || (this->sub_sensors_[index]->raw_state != value)))
+        ((!this->sub_sensors_[index]->has_state()) || (this->sub_sensors_[index]->get_raw_state() != value)))
       this->sub_sensors_[index]->publish_state(value);
   }
 }

esphome/components/nextion/sensor/nextion_sensor.cpp

@@ -85,10 +85,6 @@ void NextionSensor::set_state(float state, bool publish, bool send_to_nextion) {
       }
 
       this->publish_state(published_state);
-    } else {
-      this->raw_state = state;
-      this->state = state;
-      this->set_has_state(true);
     }
   }
   this->update_component_settings();

esphome/components/sensor/__init__.py

@@ -901,6 +901,7 @@ async def _build_sensor_automations(var, config):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(trigger, [(float, "x")], conf)
     for conf in config.get(CONF_ON_RAW_VALUE, []):
+        cg.add_define("USE_SENSOR_FILTER")
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(trigger, [(float, "x")], conf)
     for conf in config.get(CONF_ON_VALUE_RANGE, []):

esphome/components/sensor/automation.h

@@ -13,12 +13,14 @@ class SensorStateTrigger : public Trigger<float> {
   }
 };
 
+#ifdef USE_SENSOR_FILTER
 class SensorRawStateTrigger : public Trigger<float> {
  public:
   explicit SensorRawStateTrigger(Sensor *parent) {
     parent->add_on_raw_state_callback([this](float value) { this->trigger(value); });
   }
 };
+#endif
 
 template<typename... Ts> class SensorPublishAction : public Action<Ts...> {
  public:

esphome/components/sensor/sensor.cpp

@@ -4,6 +4,10 @@
 #include "esphome/core/log.h"
 #include "esphome/core/progmem.h"
 
+// Suppress deprecation warnings for internal access to .state and .raw_state
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+
 namespace esphome::sensor {
 
 static const char *const TAG = "sensor";
@@ -64,7 +68,9 @@ StateClass Sensor::get_state_class() {
 
 void Sensor::publish_state(float state) {
   this->raw_state = state;
+#ifdef USE_SENSOR_FILTER
   this->raw_callback_.call(state);
+#endif
 
   ESP_LOGV(TAG, "'%s': Received new state %f", this->name_.c_str(), state);
 
@@ -110,8 +116,6 @@ void Sensor::clear_filters() {
   this->filter_list_ = nullptr;
 }
 #endif  // USE_SENSOR_FILTER
-float Sensor::get_state() const { return this->state; }
-float Sensor::get_raw_state() const { return this->raw_state; }
 
 void Sensor::internal_send_state_to_frontend(float state) {
   this->set_has_state(true);
@@ -124,4 +128,6 @@ void Sensor::internal_send_state_to_frontend(float state) {
 #endif
 }
 
+#pragma GCC diagnostic pop
+
 }  // namespace esphome::sensor

esphome/components/sensor/sensor.h

@@ -95,9 +95,12 @@ class Sensor : public EntityBase {
 #endif
 
   /// Getter-syntax for .state.
-  float get_state() const;
+  float get_state() const { return this->state; }
   /// Getter-syntax for .raw_state
-  float get_raw_state() const;
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  float get_raw_state() const { return this->raw_state; }
+#pragma GCC diagnostic pop
 
   /** Publish a new state to the front-end.
    *
@@ -112,10 +115,12 @@ class Sensor : public EntityBase {
   // (In most use cases you won't need these)
   /// Add a callback that will be called every time a filtered value arrives.
   template<typename F> void add_on_state_callback(F &&callback) { this->callback_.add(std::forward<F>(callback)); }
+#ifdef USE_SENSOR_FILTER
   /// Add a callback that will be called every time the sensor sends a raw value.
   template<typename F> void add_on_raw_state_callback(F &&callback) {
     this->raw_callback_.add(std::forward<F>(callback));
   }
+#endif
 
   /** This member variable stores the last state that has passed through all filters.
    *
@@ -126,17 +131,20 @@ class Sensor : public EntityBase {
    */
   float state;
 
-  /** This member variable stores the current raw state of the sensor, without any filters applied.
-   *
-   * Unlike .state,this will be updated immediately when publish_state is called.
-   */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+  /// @deprecated Use get_raw_state() instead. This member will be removed in ESPHome 2027.1.0.
+  ESPDEPRECATED("Use get_raw_state() instead of .raw_state. Will be removed in 2027.1.0", "2026.7.0")
   float raw_state;
+#pragma GCC diagnostic pop
 
   void internal_send_state_to_frontend(float state);
 
  protected:
+#ifdef USE_SENSOR_FILTER
   LazyCallbackManager<void(float)> raw_callback_;  ///< Storage for raw state callbacks.
-  LazyCallbackManager<void(float)> callback_;      ///< Storage for filtered state callbacks.
+#endif
+  LazyCallbackManager<void(float)> callback_;  ///< Storage for filtered state callbacks.
 
 #ifdef USE_SENSOR_FILTER
   Filter *filter_list_{nullptr};  ///< Store all active filters.