From cb019fff9a1ff6548bcdd39c9b54e96b968aaa75 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 14 Jun 2025 22:28:15 -0500
Subject: [PATCH] Optimize memory usage by lazy-allocating raw callbacks in
 sensors (#9077)

---
 esphome/components/sensor/sensor.cpp           | 9 +++++++--
 esphome/components/sensor/sensor.h             | 5 +++--
 esphome/components/text_sensor/text_sensor.cpp | 9 +++++++--
 esphome/components/text_sensor/text_sensor.h   | 8 ++++++--
 4 files changed, 23 insertions(+), 8 deletions(-)

diff --git a/esphome/components/sensor/sensor.cpp b/esphome/components/sensor/sensor.cpp
index 251ef47ecc..3be0df9963 100644
--- a/esphome/components/sensor/sensor.cpp
+++ b/esphome/components/sensor/sensor.cpp
@@ -38,7 +38,9 @@ StateClass Sensor::get_state_class() {
 
 void Sensor::publish_state(float state) {
   this->raw_state = state;
-  this->raw_callback_.call(state);
+  if (this->raw_callback_) {
+    this->raw_callback_->call(state);
+  }
 
   ESP_LOGV(TAG, "'%s': Received new state %f", this->name_.c_str(), state);
 
@@ -51,7 +53,10 @@ void Sensor::publish_state(float state) {
 
 void Sensor::add_on_state_callback(std::function<void(float)> &&callback) { this->callback_.add(std::move(callback)); }
 void Sensor::add_on_raw_state_callback(std::function<void(float)> &&callback) {
-  this->raw_callback_.add(std::move(callback));
+  if (!this->raw_callback_) {
+    this->raw_callback_ = std::make_unique<CallbackManager<void(float)>>();
+  }
+  this->raw_callback_->add(std::move(callback));
 }
 
 void Sensor::add_filter(Filter *filter) {
diff --git a/esphome/components/sensor/sensor.h b/esphome/components/sensor/sensor.h
index ac61548a55..456e876497 100644
--- a/esphome/components/sensor/sensor.h
+++ b/esphome/components/sensor/sensor.h
@@ -7,6 +7,7 @@
 #include "esphome/components/sensor/filter.h"
 
 #include <vector>
+#include <memory>
 
 namespace esphome {
 namespace sensor {
@@ -149,8 +150,8 @@ class Sensor : public EntityBase, public EntityBase_DeviceClass, public EntityBa
   void internal_send_state_to_frontend(float state);
 
  protected:
-  CallbackManager<void(float)> raw_callback_;  ///< Storage for raw state callbacks.
-  CallbackManager<void(float)> callback_;      ///< Storage for filtered state callbacks.
+  std::unique_ptr<CallbackManager<void(float)>> raw_callback_;  ///< Storage for raw state callbacks (lazy allocated).
+  CallbackManager<void(float)> callback_;                       ///< Storage for filtered state callbacks.
 
   Filter *filter_list_{nullptr};  ///< Store all active filters.
 
diff --git a/esphome/components/text_sensor/text_sensor.cpp b/esphome/components/text_sensor/text_sensor.cpp
index 1138ada281..91cb320782 100644
--- a/esphome/components/text_sensor/text_sensor.cpp
+++ b/esphome/components/text_sensor/text_sensor.cpp
@@ -8,7 +8,9 @@ static const char *const TAG = "text_sensor";
 
 void TextSensor::publish_state(const std::string &state) {
   this->raw_state = state;
-  this->raw_callback_.call(state);
+  if (this->raw_callback_) {
+    this->raw_callback_->call(state);
+  }
 
   ESP_LOGV(TAG, "'%s': Received new state %s", this->name_.c_str(), state.c_str());
 
@@ -53,7 +55,10 @@ void TextSensor::add_on_state_callback(std::function<void(std::string)> callback
   this->callback_.add(std::move(callback));
 }
 void TextSensor::add_on_raw_state_callback(std::function<void(std::string)> callback) {
-  this->raw_callback_.add(std::move(callback));
+  if (!this->raw_callback_) {
+    this->raw_callback_ = std::make_unique<CallbackManager<void(std::string)>>();
+  }
+  this->raw_callback_->add(std::move(callback));
 }
 
 std::string TextSensor::get_state() const { return this->state; }
diff --git a/esphome/components/text_sensor/text_sensor.h b/esphome/components/text_sensor/text_sensor.h
index 5e45968ef4..b27145aa18 100644
--- a/esphome/components/text_sensor/text_sensor.h
+++ b/esphome/components/text_sensor/text_sensor.h
@@ -6,6 +6,7 @@
 #include "esphome/components/text_sensor/filter.h"
 
 #include <vector>
+#include <memory>
 
 namespace esphome {
 namespace text_sensor {
@@ -33,6 +34,8 @@ namespace text_sensor {
 
 class TextSensor : public EntityBase, public EntityBase_DeviceClass {
  public:
+  TextSensor() = default;
+
   /// Getter-syntax for .state.
   std::string get_state() const;
   /// Getter-syntax for .raw_state
@@ -70,8 +73,9 @@ class TextSensor : public EntityBase, public EntityBase_DeviceClass {
   void internal_send_state_to_frontend(const std::string &state);
 
  protected:
-  CallbackManager<void(std::string)> raw_callback_;  ///< Storage for raw state callbacks.
-  CallbackManager<void(std::string)> callback_;      ///< Storage for filtered state callbacks.
+  std::unique_ptr<CallbackManager<void(std::string)>>
+      raw_callback_;                             ///< Storage for raw state callbacks (lazy allocated).
+  CallbackManager<void(std::string)> callback_;  ///< Storage for filtered state callbacks.
 
   Filter *filter_list_{nullptr};  ///< Store all active filters.
 };