[core] Eliminate global constructor overhead for component vectors

Co-authored-by: Claude Opus 4.5 <noreply@anthropic.com>

esphome/components/cs5460a/cs5460a.h

@@ -76,7 +76,6 @@ class CS5460AComponent : public Component,
   void restart() { restart_(); }
 
   void setup() override;
-  void loop() override {}
   void dump_config() override;
 
  protected:

esphome/components/lock/lock.cpp

@@ -28,16 +28,14 @@ const LogString *lock_state_to_string(LockState state) {
 Lock::Lock() : state(LOCK_STATE_NONE) {}
 LockCall Lock::make_call() { return LockCall(this); }
 
-void Lock::lock() {
+void Lock::set_state_(LockState state) {
   auto call = this->make_call();
-  call.set_state(LOCK_STATE_LOCKED);
-  this->control(call);
-}
-void Lock::unlock() {
-  auto call = this->make_call();
-  call.set_state(LOCK_STATE_UNLOCKED);
+  call.set_state(state);
   this->control(call);
 }
+
+void Lock::lock() { this->set_state_(LOCK_STATE_LOCKED); }
+void Lock::unlock() { this->set_state_(LOCK_STATE_UNLOCKED); }
 void Lock::open() {
   if (traits.get_supports_open()) {
     ESP_LOGD(TAG, "'%s' Opening.", this->get_name().c_str());

esphome/components/lock/lock.h

@@ -156,6 +156,9 @@ class Lock : public EntityBase {
  protected:
   friend LockCall;
 
+  /// Helper for lock/unlock convenience methods
+  void set_state_(LockState state);
+
   /** Perform the open latch action with hardware. This method is optional to implement
    * when creating a new lock.
    *

esphome/components/mapping/mapping.h

@@ -2,6 +2,7 @@
 
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
+#include <cinttypes>
 #include <map>
 #include <string>
 
@@ -43,8 +44,17 @@ template<typename K, typename V> class Mapping {
       esph_log_e(TAG, "Key '%p' not found in mapping", key);
     } else if constexpr (std::is_same_v<K, std::string>) {
       esph_log_e(TAG, "Key '%s' not found in mapping", key.c_str());
+    } else if constexpr (std::is_integral_v<K>) {
+      char buf[24];  // enough for 64-bit integer
+      if constexpr (std::is_unsigned_v<K>) {
+        buf_append_printf(buf, sizeof(buf), 0, "%" PRIu64, static_cast<uint64_t>(key));
+      } else {
+        buf_append_printf(buf, sizeof(buf), 0, "%" PRId64, static_cast<int64_t>(key));
+      }
+      esph_log_e(TAG, "Key '%s' not found in mapping", buf);
     } else {
-      esph_log_e(TAG, "Key '%s' not found in mapping", to_string(key).c_str());
+      // All supported key types are handled above - this should never be reached
+      static_assert(sizeof(K) == 0, "Unsupported key type for Mapping error logging");
     }
     return {};
   }

esphome/components/mqtt/custom_mqtt_device.cpp

@@ -18,7 +18,7 @@ bool CustomMQTTDevice::publish(const std::string &topic, float value, int8_t num
 }
 bool CustomMQTTDevice::publish(const std::string &topic, int value) {
   char buffer[24];
-  size_t len = buf_append_printf(buffer, sizeof(buffer), 0, "%d", value);
+  int len = snprintf(buffer, sizeof(buffer), "%d", value);
   return global_mqtt_client->publish(topic, buffer, len);
 }
 bool CustomMQTTDevice::publish_json(const std::string &topic, const json::json_build_t &f, uint8_t qos, bool retain) {

esphome/components/mqtt/mqtt_client.cpp

@@ -98,17 +98,7 @@ void MQTTClientComponent::send_device_info_() {
         uint8_t index = 0;
         for (auto &ip : network::get_ip_addresses()) {
           if (ip.is_set()) {
-            char key[8];  // "ip" + up to 3 digits + null
-            char ip_buf[network::IP_ADDRESS_BUFFER_SIZE];
-            if (index == 0) {
-              key[0] = 'i';
-              key[1] = 'p';
-              key[2] = '\0';
-            } else {
-              buf_append_printf(key, sizeof(key), 0, "ip%u", index);
-            }
-            ip.str_to(ip_buf);
-            root[key] = ip_buf;
+            root["ip" + (index == 0 ? "" : esphome::to_string(index))] = ip.str();
             index++;
           }
         }
@@ -413,6 +403,12 @@ void MQTTClientComponent::loop() {
 
         this->last_connected_ = now;
         this->resubscribe_subscriptions_();
+
+        // Process pending resends for all MQTT components centrally
+        // This is more efficient than each component polling in its own loop
+        for (MQTTComponent *component : this->children_) {
+          component->process_resend();
+        }
       }
       break;
   }

esphome/components/mqtt/mqtt_component.cpp

@@ -190,37 +190,27 @@ bool MQTTComponent::send_discovery_() {
         StringRef object_id = this->get_default_object_id_to_(object_id_buf);
         if (discovery_info.unique_id_generator == MQTT_MAC_ADDRESS_UNIQUE_ID_GENERATOR) {
           char friendly_name_hash[9];
-          buf_append_printf(friendly_name_hash, sizeof(friendly_name_hash), 0, "%08" PRIx32,
-                            fnv1_hash(this->friendly_name_()));
+          snprintf(friendly_name_hash, sizeof(friendly_name_hash), "%08" PRIx32, fnv1_hash(this->friendly_name_()));
           // Format: mac-component_type-hash (e.g. "aabbccddeeff-sensor-12345678")
           // MAC (12) + "-" (1) + domain (max 20) + "-" (1) + hash (8) + null (1) = 43
           char unique_id[MAC_ADDRESS_BUFFER_SIZE + ESPHOME_DOMAIN_MAX_LEN + 11];
           char mac_buf[MAC_ADDRESS_BUFFER_SIZE];
           get_mac_address_into_buffer(mac_buf);
-          buf_append_printf(unique_id, sizeof(unique_id), 0, "%s-%s-%s", mac_buf, this->component_type(),
-                            friendly_name_hash);
+          snprintf(unique_id, sizeof(unique_id), "%s-%s-%s", mac_buf, this->component_type(), friendly_name_hash);
           root[MQTT_UNIQUE_ID] = unique_id;
         } else {
           // default to almost-unique ID. It's a hack but the only way to get that
           // gorgeous device registry view.
-          // "ESP" (3) + component_type (max 20) + object_id (max 128) + null
-          char unique_id_buf[3 + MQTT_COMPONENT_TYPE_MAX_LEN + OBJECT_ID_MAX_LEN + 1];
-          buf_append_printf(unique_id_buf, sizeof(unique_id_buf), 0, "ESP%s%s", this->component_type(),
-                            object_id.c_str());
-          root[MQTT_UNIQUE_ID] = unique_id_buf;
+          root[MQTT_UNIQUE_ID] = "ESP" + std::string(this->component_type()) + object_id.c_str();
         }
 
         const std::string &node_name = App.get_name();
-        if (discovery_info.object_id_generator == MQTT_DEVICE_NAME_OBJECT_ID_GENERATOR) {
-          // node_name (max 31) + "_" (1) + object_id (max 128) + null
-          char object_id_full[ESPHOME_DEVICE_NAME_MAX_LEN + 1 + OBJECT_ID_MAX_LEN + 1];
-          buf_append_printf(object_id_full, sizeof(object_id_full), 0, "%s_%s", node_name.c_str(), object_id.c_str());
-          root[MQTT_OBJECT_ID] = object_id_full;
-        }
+        if (discovery_info.object_id_generator == MQTT_DEVICE_NAME_OBJECT_ID_GENERATOR)
+          root[MQTT_OBJECT_ID] = node_name + "_" + object_id.c_str();
 
         const std::string &friendly_name_ref = App.get_friendly_name();
         const std::string &node_friendly_name = friendly_name_ref.empty() ? node_name : friendly_name_ref;
-        const char *node_area = App.get_area();
+        std::string node_area = App.get_area();
 
         JsonObject device_info = root[MQTT_DEVICE].to<JsonObject>();
         char mac[MAC_ADDRESS_BUFFER_SIZE];
@@ -231,29 +221,18 @@ bool MQTTComponent::send_discovery_() {
         device_info[MQTT_DEVICE_SW_VERSION] = ESPHOME_PROJECT_VERSION " (ESPHome " ESPHOME_VERSION ")";
         const char *model = std::strchr(ESPHOME_PROJECT_NAME, '.');
         device_info[MQTT_DEVICE_MODEL] = model == nullptr ? ESPHOME_BOARD : model + 1;
-        if (model == nullptr) {
-          device_info[MQTT_DEVICE_MANUFACTURER] = ESPHOME_PROJECT_NAME;
-        } else {
-          // Extract manufacturer (part before '.') using stack buffer to avoid heap allocation
-          // memcpy is used instead of strncpy since we know the exact length and strncpy
-          // would still require manual null-termination
-          char manufacturer[sizeof(ESPHOME_PROJECT_NAME)];
-          size_t len = model - ESPHOME_PROJECT_NAME;
-          memcpy(manufacturer, ESPHOME_PROJECT_NAME, len);
-          manufacturer[len] = '\0';
-          device_info[MQTT_DEVICE_MANUFACTURER] = manufacturer;
-        }
+        device_info[MQTT_DEVICE_MANUFACTURER] =
+            model == nullptr ? ESPHOME_PROJECT_NAME : std::string(ESPHOME_PROJECT_NAME, model - ESPHOME_PROJECT_NAME);
 #else
         static const char ver_fmt[] PROGMEM = ESPHOME_VERSION " (config hash 0x%08" PRIx32 ")";
-        // Buffer sized for format string expansion: ~4 bytes net growth from format specifier to 8 hex digits, plus
-        // safety margin
-        char version_buf[sizeof(ver_fmt) + 8];
 #ifdef USE_ESP8266
-        snprintf_P(version_buf, sizeof(version_buf), ver_fmt, App.get_config_hash());
+        char fmt_buf[sizeof(ver_fmt)];
+        strcpy_P(fmt_buf, ver_fmt);
+        const char *fmt = fmt_buf;
 #else
-        snprintf(version_buf, sizeof(version_buf), ver_fmt, App.get_config_hash());
+        const char *fmt = ver_fmt;
 #endif
-        device_info[MQTT_DEVICE_SW_VERSION] = version_buf;
+        device_info[MQTT_DEVICE_SW_VERSION] = str_sprintf(fmt, App.get_config_hash());
         device_info[MQTT_DEVICE_MODEL] = ESPHOME_BOARD;
 #if defined(USE_ESP8266) || defined(USE_ESP32)
         device_info[MQTT_DEVICE_MANUFACTURER] = "Espressif";
@@ -267,7 +246,7 @@ bool MQTTComponent::send_discovery_() {
         device_info[MQTT_DEVICE_MANUFACTURER] = "Host";
 #endif
 #endif
-        if (node_area[0] != '\0') {
+        if (!node_area.empty()) {
           device_info[MQTT_DEVICE_SUGGESTED_AREA] = node_area;
         }
 
@@ -329,16 +308,12 @@ void MQTTComponent::call_setup() {
   }
 }
 
-void MQTTComponent::call_loop() {
-  if (this->is_internal())
+void MQTTComponent::process_resend() {
+  // Called by MQTTClientComponent when connected to process pending resends
+  // Note: is_internal() check not needed - internal components are never registered
+  if (!this->resend_state_)
     return;
 
-  this->loop();
-
-  if (!this->resend_state_ || !this->is_connected_()) {
-    return;
-  }
-
   this->resend_state_ = false;
   if (this->is_discovery_enabled()) {
     if (!this->send_discovery_()) {

esphome/components/mqtt/mqtt_component.h

@@ -81,8 +81,6 @@ class MQTTComponent : public Component {
   /// Override setup_ so that we can call send_discovery() when needed.
   void call_setup() override;
 
-  void call_loop() override;
-
   void call_dump_config() override;
 
   /// Send discovery info the Home Assistant, override this.
@@ -133,6 +131,9 @@ class MQTTComponent : public Component {
   /// Internal method for the MQTT client base to schedule a resend of the state on reconnect.
   void schedule_resend_state();
 
+  /// Process pending resend if needed (called by MQTTClientComponent)
+  void process_resend();
+
   /** Send a MQTT message.
    *
    * @param topic The topic.

esphome/components/mqtt/mqtt_fan.cpp

@@ -175,7 +175,7 @@ bool MQTTFanComponent::publish_state() {
   auto traits = this->state_->get_traits();
   if (traits.supports_speed()) {
     char buf[12];
-    size_t len = buf_append_printf(buf, sizeof(buf), 0, "%d", this->state_->speed);
+    int len = snprintf(buf, sizeof(buf), "%d", this->state_->speed);
     bool success = this->publish(this->get_speed_level_state_topic(), buf, len);
     failed = failed || !success;
   }

esphome/components/mqtt/mqtt_number.cpp

@@ -75,7 +75,7 @@ bool MQTTNumberComponent::send_initial_state() {
 }
 bool MQTTNumberComponent::publish_state(float value) {
   char buffer[64];
-  buf_append_printf(buffer, sizeof(buffer), 0, "%f", value);
+  snprintf(buffer, sizeof(buffer), "%f", value);
   return this->publish(this->get_state_topic_(), buffer);
 }
 

esphome/components/x9c/x9c.cpp

@@ -6,7 +6,7 @@ namespace x9c {
 
 static const char *const TAG = "x9c.output";
 
-void X9cOutput::trim_value(int change_amount) {
+void X9cOutput::trim_value(int32_t change_amount) {
   if (change_amount == 0) {
     return;
   }
@@ -47,17 +47,17 @@ void X9cOutput::setup() {
 
   if (this->initial_value_ <= 0.50) {
     this->trim_value(-101);  // Set min value (beyond 0)
-    this->trim_value(static_cast<uint32_t>(roundf(this->initial_value_ * 100)));
+    this->trim_value(lroundf(this->initial_value_ * 100));
   } else {
     this->trim_value(101);  // Set max value (beyond 100)
-    this->trim_value(static_cast<uint32_t>(roundf(this->initial_value_ * 100) - 100));
+    this->trim_value(lroundf(this->initial_value_ * 100) - 100);
   }
   this->pot_value_ = this->initial_value_;
   this->write_state(this->initial_value_);
 }
 
 void X9cOutput::write_state(float state) {
-  this->trim_value(static_cast<uint32_t>(roundf((state - this->pot_value_) * 100)));
+  this->trim_value(lroundf((state - this->pot_value_) * 100));
   this->pot_value_ = state;
 }
 

esphome/components/x9c/x9c.h

@@ -18,7 +18,7 @@ class X9cOutput : public output::FloatOutput, public Component {
   void setup() override;
   void dump_config() override;
 
-  void trim_value(int change_amount);
+  void trim_value(int32_t change_amount);
 
  protected:
   void write_state(float state) override;

esphome/core/component.cpp

@@ -47,18 +47,21 @@ struct ComponentPriorityOverride {
 };
 
 // Error messages for failed components
+// Using raw pointer instead of unique_ptr to avoid global constructor/destructor overhead
+// This is never freed as error messages persist for the lifetime of the device
 // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
-std::unique_ptr<std::vector<ComponentErrorMessage>> component_error_messages;
+std::vector<ComponentErrorMessage> *component_error_messages = nullptr;
 // Setup priority overrides - freed after setup completes
+// Using raw pointer instead of unique_ptr to avoid global constructor/destructor overhead
 // NOLINTNEXTLINE(cppcoreguidelines-avoid-non-const-global-variables)
-std::unique_ptr<std::vector<ComponentPriorityOverride>> setup_priority_overrides;
+std::vector<ComponentPriorityOverride> *setup_priority_overrides = nullptr;
 
 // Helper to store error messages - reduces duplication between deprecated and new API
 // Remove before 2026.6.0 when deprecated const char* API is removed
 void store_component_error_message(const Component *component, const char *message, bool is_flash_ptr) {
   // Lazy allocate the error messages vector if needed
   if (!component_error_messages) {
-    component_error_messages = std::make_unique<std::vector<ComponentErrorMessage>>();
+    component_error_messages = new std::vector<ComponentErrorMessage>();
   }
   // Check if this component already has an error message
   for (auto &entry : *component_error_messages) {
@@ -467,7 +470,7 @@ float Component::get_actual_setup_priority() const {
 void Component::set_setup_priority(float priority) {
   // Lazy allocate the vector if needed
   if (!setup_priority_overrides) {
-    setup_priority_overrides = std::make_unique<std::vector<ComponentPriorityOverride>>();
+    setup_priority_overrides = new std::vector<ComponentPriorityOverride>();
     // Reserve some space to avoid reallocations (most configs have < 10 overrides)
     setup_priority_overrides->reserve(10);
   }
@@ -553,7 +556,8 @@ WarnIfComponentBlockingGuard::~WarnIfComponentBlockingGuard() {}
 
 void clear_setup_priority_overrides() {
   // Free the setup priority map completely
-  setup_priority_overrides.reset();
+  delete setup_priority_overrides;
+  setup_priority_overrides = nullptr;
 }
 
 }  // namespace esphome