From 0de26965439d8c8e2b3c38ac32b3ee6128edc62b Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Sat, 14 Jun 2025 11:37:11 -0500
Subject: [PATCH] Optimize memory usage by lazy-allocating raw callbacks in
 sensors

---
 esphome/components/sensor/sensor.cpp           | 10 ++++++++--
 esphome/components/sensor/sensor.h             |  5 +++--
 esphome/components/text_sensor/text_sensor.cpp | 11 +++++++++--
 esphome/components/text_sensor/text_sensor.h   |  7 +++++--
 4 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/esphome/components/sensor/sensor.cpp b/esphome/components/sensor/sensor.cpp
index 14a8b3d490..962794b62d 100644
--- a/esphome/components/sensor/sensor.cpp
+++ b/esphome/components/sensor/sensor.cpp
@@ -21,6 +21,7 @@ std::string state_class_to_string(StateClass state_class) {
 }
 
 Sensor::Sensor() : state(NAN), raw_state(NAN) {}
+Sensor::~Sensor() { delete this->raw_callback_; }
 
 int8_t Sensor::get_accuracy_decimals() {
   if (this->accuracy_decimals_.has_value())
@@ -38,7 +39,9 @@ StateClass Sensor::get_state_class() {
 
 void Sensor::publish_state(float state) {
   this->raw_state = state;
-  this->raw_callback_.call(state);
+  if (this->raw_callback_ != nullptr) {
+    this->raw_callback_->call(state);
+  }
 
   ESP_LOGV(TAG, "'%s': Received new state %f", this->name_.c_str(), state);
 
@@ -51,7 +54,10 @@ 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_ == nullptr) {
+    this->raw_callback_ = new CallbackManager<void(float)>();  // NOLINT
+  }
+  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 ab9ff1565c..d8099116ac 100644
--- a/esphome/components/sensor/sensor.h
+++ b/esphome/components/sensor/sensor.h
@@ -61,6 +61,7 @@ std::string state_class_to_string(StateClass state_class);
 class Sensor : public EntityBase, public EntityBase_DeviceClass, public EntityBase_UnitOfMeasurement {
  public:
   explicit Sensor();
+  ~Sensor();
 
   /// Get the accuracy in decimals, using the manual override if set.
   int8_t get_accuracy_decimals();
@@ -152,8 +153,8 @@ 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.
+  CallbackManager<void(float)> *raw_callback_{nullptr};  ///< 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 f10cd50267..000e6c2dd2 100644
--- a/esphome/components/text_sensor/text_sensor.cpp
+++ b/esphome/components/text_sensor/text_sensor.cpp
@@ -6,9 +6,13 @@ namespace text_sensor {
 
 static const char *const TAG = "text_sensor";
 
+TextSensor::~TextSensor() { delete this->raw_callback_; }
+
 void TextSensor::publish_state(const std::string &state) {
   this->raw_state = state;
-  this->raw_callback_.call(state);
+  if (this->raw_callback_ != nullptr) {
+    this->raw_callback_->call(state);
+  }
 
   ESP_LOGV(TAG, "'%s': Received new state %s", this->name_.c_str(), state.c_str());
 
@@ -53,7 +57,10 @@ 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_ == nullptr) {
+    this->raw_callback_ = new CallbackManager<void(std::string)>();  // NOLINT
+  }
+  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 bd72ea70e3..de2702383e 100644
--- a/esphome/components/text_sensor/text_sensor.h
+++ b/esphome/components/text_sensor/text_sensor.h
@@ -33,6 +33,9 @@ namespace text_sensor {
 
 class TextSensor : public EntityBase, public EntityBase_DeviceClass {
  public:
+  TextSensor() = default;
+  ~TextSensor();
+
   /// Getter-syntax for .state.
   std::string get_state() const;
   /// Getter-syntax for .raw_state
@@ -72,8 +75,8 @@ 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.
+  CallbackManager<void(std::string)> *raw_callback_{nullptr};  ///< 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.