[sensor] Deprecate .raw_state, guard raw_callback_ behind USE_SENSOR_FILTER (#15094)

Co-authored-by: Jonathan Swoboda <154711427+swoboda1337@users.noreply.github.com>

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/sensor.cpp

@@ -40,7 +40,10 @@ const LogString *state_class_to_string(StateClass state_class) {
   return StateClassStrings::get_log_str(static_cast<uint8_t>(state_class), 0);
 }
 
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
 Sensor::Sensor() : state(NAN), raw_state(NAN) {}
+#pragma GCC diagnostic pop
 
 int8_t Sensor::get_accuracy_decimals() {
   if (this->sensor_flags_.has_accuracy_override)
@@ -63,8 +66,13 @@ StateClass Sensor::get_state_class() {
 }
 
 void Sensor::publish_state(float state) {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
   this->raw_state = state;
+#pragma GCC diagnostic pop
+#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 +118,6 @@ 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);

esphome/components/sensor/sensor.h

@@ -95,9 +95,14 @@ 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;
+  float get_raw_state() const {
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+    return this->raw_state;
+#pragma GCC diagnostic pop
+  }
 
   /** Publish a new state to the front-end.
    *
@@ -113,8 +118,14 @@ class Sensor : public EntityBase {
   /// 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)); }
   /// Add a callback that will be called every time the sensor sends a raw value.
+  /// When USE_SENSOR_FILTER is not enabled, delegates to the regular callback
+  /// since raw state equals filtered state without filter support compiled in.
   template<typename F> void add_on_raw_state_callback(F &&callback) {
+#ifdef USE_SENSOR_FILTER
     this->raw_callback_.add(std::forward<F>(callback));
+#else
+    this->callback_.add(std::forward<F>(callback));
+#endif
   }
 
   /** This member variable stores the last state that has passed through all filters.
@@ -126,17 +137,20 @@ 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 2026.10.0.
+  ESPDEPRECATED("Use get_raw_state() instead of .raw_state. Will be removed in 2026.10.0", "2026.4.0")
   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.