Merge branch 'dev' into mqtt_reduce_heap_alloc

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

esphome/codegen.py

@@ -69,6 +69,7 @@ from esphome.cpp_types import (  # noqa: F401
     JsonObjectConst,
     Parented,
     PollingComponent,
+    StringRef,
     arduino_json_ns,
     bool_,
     const_char_ptr,

esphome/components/dfrobot_sen0395/commands.h

@@ -75,8 +75,8 @@ class SetLatencyCommand : public Command {
 class SensorCfgStartCommand : public Command {
  public:
   SensorCfgStartCommand(bool startup_mode) : startup_mode_(startup_mode) {
-    char tmp_cmd[20] = {0};
-    sprintf(tmp_cmd, "sensorCfgStart %d", startup_mode);
+    char tmp_cmd[20];  // "sensorCfgStart " (15) + "0/1" (1) + null = 17
+    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "sensorCfgStart %d", startup_mode);
     cmd_ = std::string(tmp_cmd);
   }
   uint8_t on_message(std::string &message) override;
@@ -142,8 +142,8 @@ class SensitivityCommand : public Command {
   SensitivityCommand(uint8_t sensitivity) : sensitivity_(sensitivity) {
     if (sensitivity > 9)
       sensitivity_ = sensitivity = 9;
-    char tmp_cmd[20] = {0};
-    sprintf(tmp_cmd, "setSensitivity %d", sensitivity);
+    char tmp_cmd[20];  // "setSensitivity " (15) + "0-9" (1) + null = 17
+    buf_append_printf(tmp_cmd, sizeof(tmp_cmd), 0, "setSensitivity %d", sensitivity);
     cmd_ = std::string(tmp_cmd);
   };
   uint8_t on_message(std::string &message) override;

esphome/components/event/__init__.py

@@ -90,9 +90,7 @@ async def setup_event_core_(var, config, *, event_types: list[str]):
 
     for conf in config.get(CONF_ON_EVENT, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(
-            trigger, [(cg.std_string, "event_type")], conf
-        )
+        await automation.build_automation(trigger, [(cg.StringRef, "event_type")], conf)
 
     cg.add(var.set_event_types(event_types))
 

esphome/components/event/automation.h

@@ -14,10 +14,10 @@ template<typename... Ts> class TriggerEventAction : public Action<Ts...>, public
   void play(const Ts &...x) override { this->parent_->trigger(this->event_type_.value(x...)); }
 };
 
-class EventTrigger : public Trigger<std::string> {
+class EventTrigger : public Trigger<StringRef> {
  public:
   EventTrigger(Event *event) {
-    event->add_on_event_callback([this](const std::string &event_type) { this->trigger(event_type); });
+    event->add_on_event_callback([this](StringRef event_type) { this->trigger(event_type); });
   }
 };
 

esphome/components/event/event.cpp

@@ -23,7 +23,7 @@ void Event::trigger(const std::string &event_type) {
   }
   this->last_event_type_ = found;
   ESP_LOGD(TAG, "'%s' >> '%s'", this->get_name().c_str(), this->last_event_type_);
-  this->event_callback_.call(event_type);
+  this->event_callback_.call(StringRef(found));
 #if defined(USE_EVENT) && defined(USE_CONTROLLER_REGISTRY)
   ControllerRegistry::notify_event(this);
 #endif
@@ -45,7 +45,7 @@ void Event::set_event_types(const std::vector<const char *> &event_types) {
   this->last_event_type_ = nullptr;  // Reset when types change
 }
 
-void Event::add_on_event_callback(std::function<void(const std::string &event_type)> &&callback) {
+void Event::add_on_event_callback(std::function<void(StringRef event_type)> &&callback) {
   this->event_callback_.add(std::move(callback));
 }
 

esphome/components/event/event.h

@@ -70,10 +70,10 @@ class Event : public EntityBase, public EntityBase_DeviceClass {
   /// Check if an event has been triggered.
   bool has_event() const { return this->last_event_type_ != nullptr; }
 
-  void add_on_event_callback(std::function<void(const std::string &event_type)> &&callback);
+  void add_on_event_callback(std::function<void(StringRef event_type)> &&callback);
 
  protected:
-  LazyCallbackManager<void(const std::string &event_type)> event_callback_;
+  LazyCallbackManager<void(StringRef event_type)> event_callback_;
   FixedVector<const char *> types_;
 
  private:

esphome/components/fan/__init__.py

@@ -77,7 +77,7 @@ FanSpeedSetTrigger = fan_ns.class_(
     "FanSpeedSetTrigger", automation.Trigger.template(cg.int_)
 )
 FanPresetSetTrigger = fan_ns.class_(
-    "FanPresetSetTrigger", automation.Trigger.template(cg.std_string)
+    "FanPresetSetTrigger", automation.Trigger.template(cg.StringRef)
 )
 
 FanIsOnCondition = fan_ns.class_("FanIsOnCondition", automation.Condition.template())
@@ -287,7 +287,7 @@ async def setup_fan_core_(var, config):
         await automation.build_automation(trigger, [(cg.int_, "x")], conf)
     for conf in config.get(CONF_ON_PRESET_SET, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
-        await automation.build_automation(trigger, [(cg.std_string, "x")], conf)
+        await automation.build_automation(trigger, [(cg.StringRef, "x")], conf)
 
 
 async def register_fan(var, config):

esphome/components/fan/automation.h

@@ -208,7 +208,7 @@ class FanSpeedSetTrigger : public Trigger<int> {
   int last_speed_;
 };
 
-class FanPresetSetTrigger : public Trigger<std::string> {
+class FanPresetSetTrigger : public Trigger<StringRef> {
  public:
   FanPresetSetTrigger(Fan *state) {
     state->add_on_state_callback([this, state]() {
@@ -216,7 +216,7 @@ class FanPresetSetTrigger : public Trigger<std::string> {
       auto should_trigger = preset_mode != this->last_preset_mode_;
       this->last_preset_mode_ = preset_mode;
       if (should_trigger) {
-        this->trigger(std::string(preset_mode));
+        this->trigger(preset_mode);
       }
     });
     this->last_preset_mode_ = state->get_preset_mode();

esphome/components/mqtt/mqtt_alarm_control_panel.cpp

@@ -43,7 +43,7 @@ void MQTTAlarmControlPanelComponent::setup() {
 
 void MQTTAlarmControlPanelComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT alarm_control_panel '%s':", this->alarm_control_panel_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, true)
+  LOG_MQTT_COMPONENT(true, true);
   ESP_LOGCONFIG(TAG,
                 "  Supported Features: %" PRIu32 "\n"
                 "  Requires Code to Disarm: %s\n"

esphome/components/mqtt/mqtt_binary_sensor.cpp

@@ -19,7 +19,7 @@ void MQTTBinarySensorComponent::setup() {
 
 void MQTTBinarySensorComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT Binary Sensor '%s':", this->binary_sensor_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, false)
+  LOG_MQTT_COMPONENT(true, false);
 }
 MQTTBinarySensorComponent::MQTTBinarySensorComponent(binary_sensor::BinarySensor *binary_sensor)
     : binary_sensor_(binary_sensor) {

esphome/components/mqtt/mqtt_component.cpp

@@ -27,20 +27,23 @@ inline char *append_char(char *p, char c) {
 // Max lengths for stack-based topic building.
 // These limits are enforced at Python config validation time in mqtt/__init__.py
 // using cv.Length() validators for topic_prefix and discovery_prefix.
-// MQTT_COMPONENT_TYPE_MAX_LEN and MQTT_SUFFIX_MAX_LEN are defined in mqtt_component.h.
+// MQTT_COMPONENT_TYPE_MAX_LEN, MQTT_SUFFIX_MAX_LEN, and MQTT_DEFAULT_TOPIC_MAX_LEN are in mqtt_component.h.
 // ESPHOME_DEVICE_NAME_MAX_LEN and OBJECT_ID_MAX_LEN are defined in entity_base.h.
 // This ensures the stack buffers below are always large enough.
-static constexpr size_t TOPIC_PREFIX_MAX_LEN = 64;      // Validated in Python: cv.Length(max=64)
 static constexpr size_t DISCOVERY_PREFIX_MAX_LEN = 64;  // Validated in Python: cv.Length(max=64)
-
-// Stack buffer sizes - safe because all inputs are length-validated at config time
-// Format: prefix + "/" + type + "/" + object_id + "/" + suffix + null
-static constexpr size_t DEFAULT_TOPIC_MAX_LEN =
-    TOPIC_PREFIX_MAX_LEN + 1 + MQTT_COMPONENT_TYPE_MAX_LEN + 1 + OBJECT_ID_MAX_LEN + 1 + MQTT_SUFFIX_MAX_LEN + 1;
 // Format: prefix + "/" + type + "/" + name + "/" + object_id + "/config" + null
 static constexpr size_t DISCOVERY_TOPIC_MAX_LEN = DISCOVERY_PREFIX_MAX_LEN + 1 + MQTT_COMPONENT_TYPE_MAX_LEN + 1 +
                                                   ESPHOME_DEVICE_NAME_MAX_LEN + 1 + OBJECT_ID_MAX_LEN + 7 + 1;
 
+// Function implementation of LOG_MQTT_COMPONENT macro to reduce code size
+void log_mqtt_component(const char *tag, MQTTComponent *obj, bool state_topic, bool command_topic) {
+  char buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
+  if (state_topic)
+    ESP_LOGCONFIG(tag, "  State Topic: '%s'", obj->get_state_topic_to_(buf).c_str());
+  if (command_topic)
+    ESP_LOGCONFIG(tag, "  Command Topic: '%s'", obj->get_command_topic_to_(buf).c_str());
+}
+
 void MQTTComponent::set_qos(uint8_t qos) { this->qos_ = qos; }
 
 void MQTTComponent::set_subscribe_qos(uint8_t qos) { this->subscribe_qos_ = qos; }
@@ -69,19 +72,18 @@ std::string MQTTComponent::get_discovery_topic_(const MQTTDiscoveryInfo &discove
   return std::string(buf, p - buf);
 }
 
-std::string MQTTComponent::get_default_topic_for_(const std::string &suffix) const {
+StringRef MQTTComponent::get_default_topic_for_to_(std::span<char, MQTT_DEFAULT_TOPIC_MAX_LEN> buf, const char *suffix,
+                                                   size_t suffix_len) const {
   const std::string &topic_prefix = global_mqtt_client->get_topic_prefix();
   if (topic_prefix.empty()) {
-    // If the topic_prefix is null, the default topic should be null
-    return "";
+    return StringRef();  // Empty topic_prefix means no default topic
   }
 
   const char *comp_type = this->component_type();
   char object_id_buf[OBJECT_ID_MAX_LEN];
   StringRef object_id = this->get_default_object_id_to_(object_id_buf);
 
-  char buf[DEFAULT_TOPIC_MAX_LEN];
-  char *p = buf;
+  char *p = buf.data();
 
   p = append_str(p, topic_prefix.data(), topic_prefix.size());
   p = append_char(p, '/');
@@ -89,21 +91,44 @@ std::string MQTTComponent::get_default_topic_for_(const std::string &suffix) con
   p = append_char(p, '/');
   p = append_str(p, object_id.c_str(), object_id.size());
   p = append_char(p, '/');
-  p = append_str(p, suffix.data(), suffix.size());
+  p = append_str(p, suffix, suffix_len);
+  *p = '\0';
 
-  return std::string(buf, p - buf);
+  return StringRef(buf.data(), p - buf.data());
+}
+
+std::string MQTTComponent::get_default_topic_for_(const std::string &suffix) const {
+  char buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
+  StringRef ref = this->get_default_topic_for_to_(buf, suffix.data(), suffix.size());
+  return std::string(ref.c_str(), ref.size());
+}
+
+StringRef MQTTComponent::get_state_topic_to_(std::span<char, MQTT_DEFAULT_TOPIC_MAX_LEN> buf) const {
+  if (this->custom_state_topic_.has_value()) {
+    // Returns ref to existing data for static/value, uses buf only for lambda case
+    return this->custom_state_topic_.ref_or_copy_to(buf.data(), buf.size());
+  }
+  return this->get_default_topic_for_to_(buf, "state", 5);
+}
+
+StringRef MQTTComponent::get_command_topic_to_(std::span<char, MQTT_DEFAULT_TOPIC_MAX_LEN> buf) const {
+  if (this->custom_command_topic_.has_value()) {
+    // Returns ref to existing data for static/value, uses buf only for lambda case
+    return this->custom_command_topic_.ref_or_copy_to(buf.data(), buf.size());
+  }
+  return this->get_default_topic_for_to_(buf, "command", 7);
 }
 
 std::string MQTTComponent::get_state_topic_() const {
-  if (this->custom_state_topic_.has_value())
-    return this->custom_state_topic_.value();
-  return this->get_default_topic_for_("state");
+  char buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
+  StringRef ref = this->get_state_topic_to_(buf);
+  return std::string(ref.c_str(), ref.size());
 }
 
 std::string MQTTComponent::get_command_topic_() const {
-  if (this->custom_command_topic_.has_value())
-    return this->custom_command_topic_.value();
-  return this->get_default_topic_for_("command");
+  char buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
+  StringRef ref = this->get_command_topic_to_(buf);
+  return std::string(ref.c_str(), ref.size());
 }
 
 bool MQTTComponent::publish(const std::string &topic, const std::string &payload) {
@@ -168,10 +193,14 @@ bool MQTTComponent::send_discovery_() {
             break;
         }
 
-        if (config.state_topic)
-          root[MQTT_STATE_TOPIC] = this->get_state_topic_();
-        if (config.command_topic)
-          root[MQTT_COMMAND_TOPIC] = this->get_command_topic_();
+        if (config.state_topic) {
+          char state_topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
+          root[MQTT_STATE_TOPIC] = this->get_state_topic_to_(state_topic_buf);
+        }
+        if (config.command_topic) {
+          char command_topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
+          root[MQTT_COMMAND_TOPIC] = this->get_command_topic_to_(command_topic_buf);
+        }
         if (this->command_retain_)
           root[MQTT_COMMAND_RETAIN] = true;
 
@@ -288,7 +317,9 @@ void MQTTComponent::set_availability(std::string topic, std::string payload_avai
 }
 void MQTTComponent::disable_availability() { this->set_availability("", "", ""); }
 void MQTTComponent::call_setup() {
-  if (this->is_internal())
+  // Cache is_internal result once during setup - topics don't change after this
+  this->is_internal_ = this->compute_is_internal_();
+  if (this->is_internal_)
     return;
 
   this->setup();
@@ -344,26 +375,28 @@ StringRef MQTTComponent::get_default_object_id_to_(std::span<char, OBJECT_ID_MAX
 }
 StringRef MQTTComponent::get_icon_ref_() const { return this->get_entity()->get_icon_ref(); }
 bool MQTTComponent::is_disabled_by_default_() const { return this->get_entity()->is_disabled_by_default(); }
-bool MQTTComponent::is_internal() {
+bool MQTTComponent::compute_is_internal_() {
   if (this->custom_state_topic_.has_value()) {
-    // If the custom state_topic is null, return true as it is internal and should not publish
+    // If the custom state_topic is empty, return true as it is internal and should not publish
     // else, return false, as it is explicitly set to a topic, so it is not internal and should publish
-    return this->get_state_topic_().empty();
+    // Using is_empty() avoids heap allocation for non-lambda cases
+    return this->custom_state_topic_.is_empty();
   }
 
   if (this->custom_command_topic_.has_value()) {
-    // If the custom command_topic is null, return true as it is internal and should not publish
+    // If the custom command_topic is empty, return true as it is internal and should not publish
     // else, return false, as it is explicitly set to a topic, so it is not internal and should publish
-    return this->get_command_topic_().empty();
+    // Using is_empty() avoids heap allocation for non-lambda cases
+    return this->custom_command_topic_.is_empty();
   }
 
-  // No custom topics have been set
-  if (this->get_default_topic_for_("").empty()) {
-    // If the default topic prefix is null, then the component, by default, is internal and should not publish
+  // No custom topics have been set - check topic_prefix directly to avoid allocation
+  if (global_mqtt_client->get_topic_prefix().empty()) {
+    // If the default topic prefix is empty, then the component, by default, is internal and should not publish
     return true;
   }
 
-  // Use ESPHome's component internal state if topic_prefix is not null with no custom state_topic or command_topic
+  // Use ESPHome's component internal state if topic_prefix is not empty with no custom state_topic or command_topic
   return this->get_entity()->is_internal();
 }
 

esphome/components/mqtt/mqtt_component.h

@@ -20,17 +20,22 @@ struct SendDiscoveryConfig {
   bool command_topic{true};  ///< If the command topic should be included. Default to true.
 };
 
-// Max lengths for stack-based topic building (must match mqtt_component.cpp)
+// Max lengths for stack-based topic building.
+// These limits are enforced at Python config validation time in mqtt/__init__.py
+// using cv.Length() validators for topic_prefix and discovery_prefix.
+// This ensures the stack buffers are always large enough.
 static constexpr size_t MQTT_COMPONENT_TYPE_MAX_LEN = 20;
 static constexpr size_t MQTT_SUFFIX_MAX_LEN = 32;
+static constexpr size_t MQTT_TOPIC_PREFIX_MAX_LEN = 64;  // Validated in Python: cv.Length(max=64)
+// Stack buffer size - safe because all inputs are length-validated at config time
+// Format: prefix + "/" + type + "/" + object_id + "/" + suffix + null
+static constexpr size_t MQTT_DEFAULT_TOPIC_MAX_LEN =
+    MQTT_TOPIC_PREFIX_MAX_LEN + 1 + MQTT_COMPONENT_TYPE_MAX_LEN + 1 + OBJECT_ID_MAX_LEN + 1 + MQTT_SUFFIX_MAX_LEN + 1;
 
-#define LOG_MQTT_COMPONENT(state_topic, command_topic) \
-  if (state_topic) { \
-    ESP_LOGCONFIG(TAG, "  State Topic: '%s'", this->get_state_topic_().c_str()); \
-  } \
-  if (command_topic) { \
-    ESP_LOGCONFIG(TAG, "  Command Topic: '%s'", this->get_command_topic_().c_str()); \
-  }
+class MQTTComponent;  // Forward declaration
+void log_mqtt_component(const char *tag, MQTTComponent *obj, bool state_topic, bool command_topic);
+
+#define LOG_MQTT_COMPONENT(state_topic, command_topic) log_mqtt_component(TAG, this, state_topic, command_topic)
 
 // Macro to define component_type() with compile-time length verification
 // Usage: MQTT_COMPONENT_TYPE(MQTTSensorComponent, "sensor")
@@ -74,6 +79,8 @@ static constexpr size_t MQTT_SUFFIX_MAX_LEN = 32;
  * a clean separation.
  */
 class MQTTComponent : public Component {
+  friend void log_mqtt_component(const char *tag, MQTTComponent *obj, bool state_topic, bool command_topic);
+
  public:
   /// Constructs a MQTTComponent.
   explicit MQTTComponent();
@@ -90,7 +97,8 @@ class MQTTComponent : public Component {
 
   virtual bool send_initial_state() = 0;
 
-  virtual bool is_internal();
+  /// Returns cached is_internal result (computed once during setup).
+  bool is_internal() const { return this->is_internal_; }
 
   /// Set QOS for state messages.
   void set_qos(uint8_t qos);
@@ -178,7 +186,16 @@ class MQTTComponent : public Component {
   /// Helper method to get the discovery topic for this component.
   std::string get_discovery_topic_(const MQTTDiscoveryInfo &discovery_info) const;
 
-  /** Get this components state/command/... topic.
+  /** Get this components state/command/... topic into a buffer.
+   *
+   * @param buf The buffer to write to (must be exactly MQTT_DEFAULT_TOPIC_MAX_LEN).
+   * @param suffix The suffix/key such as "state" or "command".
+   * @return StringRef pointing to the buffer with the topic.
+   */
+  StringRef get_default_topic_for_to_(std::span<char, MQTT_DEFAULT_TOPIC_MAX_LEN> buf, const char *suffix,
+                                      size_t suffix_len) const;
+
+  /** Get this components state/command/... topic (allocates std::string).
    *
    * @param suffix The suffix/key such as "state" or "command".
    * @return The full topic.
@@ -199,10 +216,20 @@ class MQTTComponent : public Component {
   /// Get whether the underlying Entity is disabled by default
   bool is_disabled_by_default_() const;
 
-  /// Get the MQTT topic that new states will be shared to.
+  /// Get the MQTT state topic into a buffer (no heap allocation for non-lambda custom topics).
+  /// @param buf Buffer of exactly MQTT_DEFAULT_TOPIC_MAX_LEN bytes.
+  /// @return StringRef pointing to the topic in the buffer.
+  StringRef get_state_topic_to_(std::span<char, MQTT_DEFAULT_TOPIC_MAX_LEN> buf) const;
+
+  /// Get the MQTT command topic into a buffer (no heap allocation for non-lambda custom topics).
+  /// @param buf Buffer of exactly MQTT_DEFAULT_TOPIC_MAX_LEN bytes.
+  /// @return StringRef pointing to the topic in the buffer.
+  StringRef get_command_topic_to_(std::span<char, MQTT_DEFAULT_TOPIC_MAX_LEN> buf) const;
+
+  /// Get the MQTT topic that new states will be shared to (allocates std::string).
   std::string get_state_topic_() const;
 
-  /// Get the MQTT topic for listening to commands.
+  /// Get the MQTT topic for listening to commands (allocates std::string).
   std::string get_command_topic_() const;
 
   bool is_connected_() const;
@@ -220,12 +247,18 @@ class MQTTComponent : public Component {
 
   std::unique_ptr<Availability> availability_;
 
-  bool command_retain_{false};
-  bool retain_{true};
-  uint8_t qos_{0};
-  uint8_t subscribe_qos_{0};
-  bool discovery_enabled_{true};
-  bool resend_state_{false};
+  // Packed bitfields - QoS values are 0-2, bools are flags
+  uint8_t qos_ : 2 {0};
+  uint8_t subscribe_qos_ : 2 {0};
+  bool command_retain_ : 1 {false};
+  bool retain_ : 1 {true};
+  bool discovery_enabled_ : 1 {true};
+  bool resend_state_ : 1 {false};
+  bool is_internal_ : 1 {false};  ///< Cached result of compute_is_internal_(), set during setup
+
+  /// Compute is_internal status based on topics and entity state.
+  /// Called once during setup to cache the result.
+  bool compute_is_internal_();
 };
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_cover.cpp

@@ -51,7 +51,7 @@ void MQTTCoverComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT cover '%s':", this->cover_->get_name().c_str());
   auto traits = this->cover_->get_traits();
   bool has_command_topic = traits.get_supports_position() || !traits.get_supports_tilt();
-  LOG_MQTT_COMPONENT(true, has_command_topic)
+  LOG_MQTT_COMPONENT(true, has_command_topic);
   if (traits.get_supports_position()) {
     ESP_LOGCONFIG(TAG,
                   "  Position State Topic: '%s'\n"

esphome/components/mqtt/mqtt_date.cpp

@@ -36,7 +36,7 @@ void MQTTDateComponent::setup() {
 
 void MQTTDateComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT Date '%s':", this->date_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, true)
+  LOG_MQTT_COMPONENT(true, true);
 }
 
 MQTT_COMPONENT_TYPE(MQTTDateComponent, "date")

esphome/components/mqtt/mqtt_datetime.cpp

@@ -47,7 +47,7 @@ void MQTTDateTimeComponent::setup() {
 
 void MQTTDateTimeComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT DateTime '%s':", this->datetime_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, true)
+  LOG_MQTT_COMPONENT(true, true);
 }
 
 MQTT_COMPONENT_TYPE(MQTTDateTimeComponent, "datetime")

esphome/components/mqtt/mqtt_light.cpp

@@ -90,7 +90,7 @@ void MQTTJSONLightComponent::send_discovery(JsonObject root, mqtt::SendDiscovery
 bool MQTTJSONLightComponent::send_initial_state() { return this->publish_state_(); }
 void MQTTJSONLightComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT Light '%s':", this->state_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, true)
+  LOG_MQTT_COMPONENT(true, true);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_number.cpp

@@ -30,7 +30,7 @@ void MQTTNumberComponent::setup() {
 
 void MQTTNumberComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT Number '%s':", this->number_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, false)
+  LOG_MQTT_COMPONENT(true, false);
 }
 
 MQTT_COMPONENT_TYPE(MQTTNumberComponent, "number")

esphome/components/mqtt/mqtt_select.cpp

@@ -25,7 +25,7 @@ void MQTTSelectComponent::setup() {
 
 void MQTTSelectComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT Select '%s':", this->select_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, false)
+  LOG_MQTT_COMPONENT(true, false);
 }
 
 MQTT_COMPONENT_TYPE(MQTTSelectComponent, "select")

esphome/components/mqtt/mqtt_sensor.cpp

@@ -28,7 +28,7 @@ void MQTTSensorComponent::dump_config() {
   if (this->get_expire_after() > 0) {
     ESP_LOGCONFIG(TAG, "  Expire After: %" PRIu32 "s", this->get_expire_after() / 1000);
   }
-  LOG_MQTT_COMPONENT(true, false)
+  LOG_MQTT_COMPONENT(true, false);
 }
 
 MQTT_COMPONENT_TYPE(MQTTSensorComponent, "sensor")

esphome/components/mqtt/mqtt_text.cpp

@@ -26,7 +26,7 @@ void MQTTTextComponent::setup() {
 
 void MQTTTextComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT text '%s':", this->text_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, true)
+  LOG_MQTT_COMPONENT(true, true);
 }
 
 MQTT_COMPONENT_TYPE(MQTTTextComponent, "text")

esphome/components/mqtt/mqtt_time.cpp

@@ -36,7 +36,7 @@ void MQTTTimeComponent::setup() {
 
 void MQTTTimeComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT Time '%s':", this->time_->get_name().c_str());
-  LOG_MQTT_COMPONENT(true, true)
+  LOG_MQTT_COMPONENT(true, true);
 }
 
 MQTT_COMPONENT_TYPE(MQTTTimeComponent, "time")

esphome/components/mqtt/mqtt_valve.cpp

@@ -39,7 +39,7 @@ void MQTTValveComponent::dump_config() {
   ESP_LOGCONFIG(TAG, "MQTT valve '%s':", this->valve_->get_name().c_str());
   auto traits = this->valve_->get_traits();
   bool has_command_topic = traits.get_supports_position();
-  LOG_MQTT_COMPONENT(true, has_command_topic)
+  LOG_MQTT_COMPONENT(true, has_command_topic);
   if (traits.get_supports_position()) {
     ESP_LOGCONFIG(TAG,
                   "  Position State Topic: '%s'\n"

esphome/components/pipsolar/output/pipsolar_output.cpp

@@ -8,7 +8,7 @@ namespace pipsolar {
 static const char *const TAG = "pipsolar.output";
 
 void PipsolarOutput::write_state(float state) {
-  char tmp[10];
+  char tmp[16];
   snprintf(tmp, sizeof(tmp), this->set_command_, state);
 
   if (std::find(this->possible_values_.begin(), this->possible_values_.end(), state) != this->possible_values_.end()) {

esphome/components/select/__init__.py

@@ -33,7 +33,7 @@ SelectPtr = Select.operator("ptr")
 # Triggers
 SelectStateTrigger = select_ns.class_(
     "SelectStateTrigger",
-    automation.Trigger.template(cg.std_string, cg.size_t),
+    automation.Trigger.template(cg.StringRef, cg.size_t),
 )
 
 # Actions
@@ -100,7 +100,7 @@ async def setup_select_core_(var, config, *, options: list[str]):
     for conf in config.get(CONF_ON_VALUE, []):
         trigger = cg.new_Pvariable(conf[CONF_TRIGGER_ID], var)
         await automation.build_automation(
-            trigger, [(cg.std_string, "x"), (cg.size_t, "i")], conf
+            trigger, [(cg.StringRef, "x"), (cg.size_t, "i")], conf
         )
 
     if (mqtt_id := config.get(CONF_MQTT_ID)) is not None:

esphome/components/select/automation.h

@@ -6,11 +6,11 @@
 
 namespace esphome::select {
 
-class SelectStateTrigger : public Trigger<std::string, size_t> {
+class SelectStateTrigger : public Trigger<StringRef, size_t> {
  public:
   explicit SelectStateTrigger(Select *parent) : parent_(parent) {
     parent->add_on_state_callback(
-        [this](size_t index) { this->trigger(std::string(this->parent_->option_at(index)), index); });
+        [this](size_t index) { this->trigger(StringRef(this->parent_->option_at(index)), index); });
   }
 
  protected:

esphome/components/sim800l/sim800l.cpp

@@ -1,4 +1,5 @@
 #include "sim800l.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include <cstring>
 
@@ -50,8 +51,8 @@ void Sim800LComponent::update() {
   } else if (state_ == STATE_RECEIVED_SMS) {
     // Serial Buffer should have flushed.
     // Send cmd to delete received sms
-    char delete_cmd[20];
-    sprintf(delete_cmd, "AT+CMGD=%d", this->parse_index_);
+    char delete_cmd[20];  // "AT+CMGD=" (8) + uint8_t (max 3) + null = 12 <= 20
+    buf_append_printf(delete_cmd, sizeof(delete_cmd), 0, "AT+CMGD=%d", this->parse_index_);
     this->send_cmd_(delete_cmd);
     this->state_ = STATE_CHECK_SMS;
     this->expect_ack_ = true;

esphome/components/template/select/__init__.py

@@ -88,5 +88,5 @@ async def to_code(config):
 
     if CONF_SET_ACTION in config:
         await automation.build_automation(
-            var.get_set_trigger(), [(cg.std_string, "x")], config[CONF_SET_ACTION]
+            var.get_set_trigger(), [(cg.StringRef, "x")], config[CONF_SET_ACTION]
         )

esphome/components/template/select/template_select.cpp

@@ -41,7 +41,7 @@ void TemplateSelect::update() {
 }
 
 void TemplateSelect::control(size_t index) {
-  this->set_trigger_->trigger(std::string(this->option_at(index)));
+  this->set_trigger_->trigger(StringRef(this->option_at(index)));
 
   if (this->optimistic_)
     this->publish_state(index);

esphome/components/template/select/template_select.h

@@ -4,6 +4,7 @@
 #include "esphome/core/automation.h"
 #include "esphome/core/component.h"
 #include "esphome/core/preferences.h"
+#include "esphome/core/string_ref.h"
 #include "esphome/core/template_lambda.h"
 
 namespace esphome::template_ {
@@ -17,7 +18,7 @@ class TemplateSelect final : public select::Select, public PollingComponent {
   void dump_config() override;
   float get_setup_priority() const override { return setup_priority::HARDWARE; }
 
-  Trigger<std::string> *get_set_trigger() const { return this->set_trigger_; }
+  Trigger<StringRef> *get_set_trigger() const { return this->set_trigger_; }
   void set_optimistic(bool optimistic) { this->optimistic_ = optimistic; }
   void set_initial_option_index(size_t initial_option_index) { this->initial_option_index_ = initial_option_index; }
   void set_restore_value(bool restore_value) { this->restore_value_ = restore_value; }
@@ -27,7 +28,7 @@ class TemplateSelect final : public select::Select, public PollingComponent {
   bool optimistic_ = false;
   size_t initial_option_index_{0};
   bool restore_value_ = false;
-  Trigger<std::string> *set_trigger_ = new Trigger<std::string>();
+  Trigger<StringRef> *set_trigger_ = new Trigger<StringRef>();
   TemplateLambda<std::string> f_;
 
   ESPPreferenceObject pref_;

esphome/components/wl_134/wl_134.cpp

@@ -1,4 +1,5 @@
 #include "wl_134.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
 #include <cinttypes>
@@ -78,8 +79,8 @@ Wl134Component::Rfid134Error Wl134Component::read_packet_() {
            reading.id, reading.country, reading.isData ? "true" : "false", reading.isAnimal ? "true" : "false",
            reading.reserved0, reading.reserved1);
 
-  char buf[20];
-  sprintf(buf, "%03d%012lld", reading.country, reading.id);
+  char buf[20];  // "%03d" (3) + "%012" PRId64 (12) + null = 16 max
+  buf_append_printf(buf, sizeof(buf), 0, "%03d%012" PRId64, reading.country, reading.id);
   this->publish_state(buf);
   if (this->do_reset_) {
     this->set_timeout(1000, [this]() { this->publish_state(""); });

esphome/core/automation.h

@@ -4,6 +4,7 @@
 #include "esphome/core/defines.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/preferences.h"
+#include "esphome/core/string_ref.h"
 #include <concepts>
 #include <functional>
 #include <utility>
@@ -190,15 +191,55 @@ template<typename T, typename... X> class TemplatableValue {
   /// Get the static string pointer (only valid if is_static_string() returns true)
   const char *get_static_string() const { return this->static_str_; }
 
- protected:
-  enum : uint8_t {
-    NONE,
-    VALUE,
-    LAMBDA,
-    STATELESS_LAMBDA,
-    STATIC_STRING,  // For const char* when T is std::string - avoids heap allocation
-  } type_;
+  /// Check if the string value is empty without allocating (for std::string specialization).
+  /// For NONE, returns true. For STATIC_STRING/VALUE, checks without allocation.
+  /// For LAMBDA/STATELESS_LAMBDA, must call value() which may allocate.
+  bool is_empty() const requires std::same_as<T, std::string> {
+    switch (this->type_) {
+      case NONE:
+        return true;
+      case STATIC_STRING:
+        return this->static_str_ == nullptr || this->static_str_[0] == '\0';
+      case VALUE:
+        return this->value_->empty();
+      default:  // LAMBDA/STATELESS_LAMBDA - must call value()
+        return this->value().empty();
+    }
+  }
 
+  /// Get a StringRef to the string value without heap allocation when possible.
+  /// For STATIC_STRING/VALUE, returns reference to existing data (no allocation).
+  /// For LAMBDA/STATELESS_LAMBDA, calls value(), copies to provided buffer, returns ref to buffer.
+  /// @param lambda_buf Buffer used only for lambda case (must remain valid while StringRef is used).
+  /// @param lambda_buf_size Size of the buffer.
+  /// @return StringRef pointing to the string data.
+  StringRef ref_or_copy_to(char *lambda_buf, size_t lambda_buf_size) const requires std::same_as<T, std::string> {
+    switch (this->type_) {
+      case NONE:
+        return StringRef();
+      case STATIC_STRING:
+        if (this->static_str_ == nullptr)
+          return StringRef();
+        return StringRef(this->static_str_, strlen(this->static_str_));
+      case VALUE:
+        return StringRef(this->value_->data(), this->value_->size());
+      default: {  // LAMBDA/STATELESS_LAMBDA - must call value() and copy
+        std::string result = this->value();
+        size_t copy_len = std::min(result.size(), lambda_buf_size - 1);
+        memcpy(lambda_buf, result.data(), copy_len);
+        lambda_buf[copy_len] = '\0';
+        return StringRef(lambda_buf, copy_len);
+      }
+    }
+  }
+
+ protected : enum : uint8_t {
+   NONE,
+   VALUE,
+   LAMBDA,
+   STATELESS_LAMBDA,
+   STATIC_STRING,  // For const char* when T is std::string - avoids heap allocation
+ } type_;
   // For std::string, use heap pointer to minimize union size (4 bytes vs 12+).
   // For other types, store value inline as before.
   using ValueStorage = std::conditional_t<USE_HEAP_STORAGE, T *, T>;

esphome/core/string_ref.h

@@ -72,6 +72,7 @@ class StringRef {
 
   constexpr const char *c_str() const { return base_; }
   constexpr size_type size() const { return len_; }
+  constexpr size_type length() const { return len_; }
   constexpr bool empty() const { return len_ == 0; }
   constexpr const_reference operator[](size_type pos) const { return *(base_ + pos); }
 
@@ -80,6 +81,32 @@ class StringRef {
 
   operator std::string() const { return str(); }
 
+  /// Find first occurrence of substring, returns std::string::npos if not found.
+  /// Note: Requires the underlying string to be null-terminated.
+  size_type find(const char *s, size_type pos = 0) const {
+    if (pos >= len_)
+      return std::string::npos;
+    const char *result = std::strstr(base_ + pos, s);
+    // Verify entire match is within bounds (strstr searches to null terminator)
+    if (result && result + std::strlen(s) <= base_ + len_)
+      return static_cast<size_type>(result - base_);
+    return std::string::npos;
+  }
+  size_type find(char c, size_type pos = 0) const {
+    if (pos >= len_)
+      return std::string::npos;
+    const void *result = std::memchr(base_ + pos, static_cast<unsigned char>(c), len_ - pos);
+    return result ? static_cast<size_type>(static_cast<const char *>(result) - base_) : std::string::npos;
+  }
+
+  /// Return substring as std::string
+  std::string substr(size_type pos = 0, size_type count = std::string::npos) const {
+    if (pos >= len_)
+      return std::string();
+    size_type actual_count = (count == std::string::npos || pos + count > len_) ? len_ - pos : count;
+    return std::string(base_ + pos, actual_count);
+  }
+
  private:
   const char *base_;
   size_type len_;
@@ -160,6 +187,43 @@ inline std::string operator+(const std::string &lhs, const StringRef &rhs) {
   str.append(rhs.c_str(), rhs.size());
   return str;
 }
+// String conversion functions for ADL compatibility (allows stoi(x) where x is StringRef)
+// Must be in esphome namespace for ADL to find them. Uses strtol/strtod directly to avoid heap allocation.
+namespace internal {
+// NOLINTBEGIN(google-runtime-int)
+template<typename R, typename F> inline R parse_number(const StringRef &str, size_t *pos, F conv) {
+  char *end;
+  R result = conv(str.c_str(), &end);
+  // Set pos to 0 on conversion failure (when no characters consumed), otherwise index after number
+  if (pos)
+    *pos = (end == str.c_str()) ? 0 : static_cast<size_t>(end - str.c_str());
+  return result;
+}
+template<typename R, typename F> inline R parse_number(const StringRef &str, size_t *pos, int base, F conv) {
+  char *end;
+  R result = conv(str.c_str(), &end, base);
+  // Set pos to 0 on conversion failure (when no characters consumed), otherwise index after number
+  if (pos)
+    *pos = (end == str.c_str()) ? 0 : static_cast<size_t>(end - str.c_str());
+  return result;
+}
+// NOLINTEND(google-runtime-int)
+}  // namespace internal
+// NOLINTBEGIN(readability-identifier-naming,google-runtime-int)
+inline int stoi(const StringRef &str, size_t *pos = nullptr, int base = 10) {
+  return static_cast<int>(internal::parse_number<long>(str, pos, base, std::strtol));
+}
+inline long stol(const StringRef &str, size_t *pos = nullptr, int base = 10) {
+  return internal::parse_number<long>(str, pos, base, std::strtol);
+}
+inline float stof(const StringRef &str, size_t *pos = nullptr) {
+  return internal::parse_number<float>(str, pos, std::strtof);
+}
+inline double stod(const StringRef &str, size_t *pos = nullptr) {
+  return internal::parse_number<double>(str, pos, std::strtod);
+}
+// NOLINTEND(readability-identifier-naming,google-runtime-int)
+
 #ifdef USE_JSON
 // NOLINTNEXTLINE(readability-identifier-naming)
 inline void convertToJson(const StringRef &src, JsonVariant dst) { dst.set(src.c_str()); }

esphome/cpp_types.py

@@ -44,3 +44,4 @@ gpio_Flags = gpio_ns.enum("Flags", is_class=True)
 EntityCategory = esphome_ns.enum("EntityCategory")
 Parented = esphome_ns.class_("Parented")
 ESPTime = esphome_ns.struct("ESPTime")
+StringRef = esphome_ns.class_("StringRef")

tests/integration/fixtures/select_stringref_trigger.yaml

@@ -0,0 +1,85 @@
+esphome:
+  name: select-stringref-test
+  friendly_name: Select StringRef Test
+
+host:
+
+logger:
+  level: DEBUG
+
+api:
+
+select:
+  - platform: template
+    name: "Test Select"
+    id: test_select
+    optimistic: true
+    options:
+      - "Option A"
+      - "Option B"
+      - "Option C"
+    initial_option: "Option A"
+    on_value:
+      then:
+        # Test 1: Log the value directly (StringRef -> const char* via c_str())
+        - logger.log:
+            format: "Select value: %s"
+            args: ['x.c_str()']
+        # Test 2: String concatenation (StringRef + const char* -> std::string)
+        - lambda: |-
+            std::string with_suffix = x + " selected";
+            ESP_LOGI("test", "Concatenated: %s", with_suffix.c_str());
+        # Test 3: Comparison (StringRef == const char*)
+        - lambda: |-
+            if (x == "Option B") {
+              ESP_LOGI("test", "Option B was selected");
+            }
+        # Test 4: Use index parameter (variable name is 'i')
+        - lambda: |-
+            ESP_LOGI("test", "Select index: %d", (int)i);
+        # Test 5: StringRef.length() method
+        - lambda: |-
+            ESP_LOGI("test", "Length: %d", (int)x.length());
+        # Test 6: StringRef.find() method with substring
+        - lambda: |-
+            if (x.find("Option") != std::string::npos) {
+              ESP_LOGI("test", "Found 'Option' in value");
+            }
+        # Test 7: StringRef.find() method with character
+        - lambda: |-
+            size_t space_pos = x.find(' ');
+            if (space_pos != std::string::npos) {
+              ESP_LOGI("test", "Space at position: %d", (int)space_pos);
+            }
+        # Test 8: StringRef.substr() method
+        - lambda: |-
+            std::string prefix = x.substr(0, 6);
+            ESP_LOGI("test", "Substr prefix: %s", prefix.c_str());
+
+  # Second select with numeric options to test ADL functions
+  - platform: template
+    name: "Baud Rate"
+    id: baud_select
+    optimistic: true
+    options:
+      - "9600"
+      - "115200"
+    initial_option: "9600"
+    on_value:
+      then:
+        # Test 9: stoi via ADL
+        - lambda: |-
+            int baud = stoi(x);
+            ESP_LOGI("test", "stoi result: %d", baud);
+        # Test 10: stol via ADL
+        - lambda: |-
+            long baud_long = stol(x);
+            ESP_LOGI("test", "stol result: %ld", baud_long);
+        # Test 11: stof via ADL
+        - lambda: |-
+            float baud_float = stof(x);
+            ESP_LOGI("test", "stof result: %.0f", baud_float);
+        # Test 12: stod via ADL
+        - lambda: |-
+            double baud_double = stod(x);
+            ESP_LOGI("test", "stod result: %.0f", baud_double);

tests/integration/test_select_stringref_trigger.py

@@ -0,0 +1,143 @@
+"""Integration test for select on_value trigger with StringRef parameter."""
+
+from __future__ import annotations
+
+import asyncio
+import re
+
+import pytest
+
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_select_stringref_trigger(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Test select on_value trigger passes StringRef that works with string operations."""
+    loop = asyncio.get_running_loop()
+
+    # Track log messages to verify StringRef operations work
+    value_logged_future = loop.create_future()
+    concatenated_future = loop.create_future()
+    comparison_future = loop.create_future()
+    index_logged_future = loop.create_future()
+    length_future = loop.create_future()
+    find_substr_future = loop.create_future()
+    find_char_future = loop.create_future()
+    substr_future = loop.create_future()
+    # ADL functions
+    stoi_future = loop.create_future()
+    stol_future = loop.create_future()
+    stof_future = loop.create_future()
+    stod_future = loop.create_future()
+
+    # Patterns to match in logs
+    value_pattern = re.compile(r"Select value: Option B")
+    concatenated_pattern = re.compile(r"Concatenated: Option B selected")
+    comparison_pattern = re.compile(r"Option B was selected")
+    index_pattern = re.compile(r"Select index: 1")
+    length_pattern = re.compile(r"Length: 8")  # "Option B" is 8 chars
+    find_substr_pattern = re.compile(r"Found 'Option' in value")
+    find_char_pattern = re.compile(r"Space at position: 6")  # space at index 6
+    substr_pattern = re.compile(r"Substr prefix: Option")
+    # ADL function patterns (115200 from baud rate select)
+    stoi_pattern = re.compile(r"stoi result: 115200")
+    stol_pattern = re.compile(r"stol result: 115200")
+    stof_pattern = re.compile(r"stof result: 115200")
+    stod_pattern = re.compile(r"stod result: 115200")
+
+    def check_output(line: str) -> None:
+        """Check log output for expected messages."""
+        if not value_logged_future.done() and value_pattern.search(line):
+            value_logged_future.set_result(True)
+        if not concatenated_future.done() and concatenated_pattern.search(line):
+            concatenated_future.set_result(True)
+        if not comparison_future.done() and comparison_pattern.search(line):
+            comparison_future.set_result(True)
+        if not index_logged_future.done() and index_pattern.search(line):
+            index_logged_future.set_result(True)
+        if not length_future.done() and length_pattern.search(line):
+            length_future.set_result(True)
+        if not find_substr_future.done() and find_substr_pattern.search(line):
+            find_substr_future.set_result(True)
+        if not find_char_future.done() and find_char_pattern.search(line):
+            find_char_future.set_result(True)
+        if not substr_future.done() and substr_pattern.search(line):
+            substr_future.set_result(True)
+        # ADL functions
+        if not stoi_future.done() and stoi_pattern.search(line):
+            stoi_future.set_result(True)
+        if not stol_future.done() and stol_pattern.search(line):
+            stol_future.set_result(True)
+        if not stof_future.done() and stof_pattern.search(line):
+            stof_future.set_result(True)
+        if not stod_future.done() and stod_pattern.search(line):
+            stod_future.set_result(True)
+
+    async with (
+        run_compiled(yaml_config, line_callback=check_output),
+        api_client_connected() as client,
+    ):
+        # Verify device info
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == "select-stringref-test"
+
+        # List entities to find our select
+        entities, _ = await client.list_entities_services()
+
+        select_entity = next(
+            (e for e in entities if hasattr(e, "options") and e.name == "Test Select"),
+            None,
+        )
+        assert select_entity is not None, "Test Select entity not found"
+
+        baud_entity = next(
+            (e for e in entities if hasattr(e, "options") and e.name == "Baud Rate"),
+            None,
+        )
+        assert baud_entity is not None, "Baud Rate entity not found"
+
+        # Change select to Option B - this should trigger on_value with StringRef
+        client.select_command(select_entity.key, "Option B")
+        # Change baud to 115200 - this tests ADL functions (stoi, stol, stof, stod)
+        client.select_command(baud_entity.key, "115200")
+
+        # Wait for all log messages confirming StringRef operations work
+        try:
+            await asyncio.wait_for(
+                asyncio.gather(
+                    value_logged_future,
+                    concatenated_future,
+                    comparison_future,
+                    index_logged_future,
+                    length_future,
+                    find_substr_future,
+                    find_char_future,
+                    substr_future,
+                    stoi_future,
+                    stol_future,
+                    stof_future,
+                    stod_future,
+                ),
+                timeout=5.0,
+            )
+        except TimeoutError:
+            results = {
+                "value_logged": value_logged_future.done(),
+                "concatenated": concatenated_future.done(),
+                "comparison": comparison_future.done(),
+                "index_logged": index_logged_future.done(),
+                "length": length_future.done(),
+                "find_substr": find_substr_future.done(),
+                "find_char": find_char_future.done(),
+                "substr": substr_future.done(),
+                "stoi": stoi_future.done(),
+                "stol": stol_future.done(),
+                "stof": stof_future.done(),
+                "stod": stod_future.done(),
+            }
+            pytest.fail(f"StringRef operations failed - received: {results}")