[core] Eliminate global constructor overhead for component vectors

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

esphome/components/api/homeassistant_service.h

@@ -25,9 +25,7 @@ template<typename... X> class TemplatableStringValue : public TemplatableValue<s
 
  private:
   // Helper to convert value to string - handles the case where value is already a string
-  template<typename T> static std::string value_to_string(T &&val) {
-    return to_string(std::forward<T>(val));  // NOLINT
-  }
+  template<typename T> static std::string value_to_string(T &&val) { return to_string(std::forward<T>(val)); }
 
   // Overloads for string types - needed because std::to_string doesn't support them
   static std::string value_to_string(char *val) {

esphome/components/esp32_ble/ble_uuid.h

@@ -48,7 +48,7 @@ class ESPBTUUID {
 
   // Remove before 2026.8.0
   ESPDEPRECATED("Use to_str() instead. Removed in 2026.8.0", "2026.2.0")
-  std::string to_string() const;  // NOLINT
+  std::string to_string() const;
   const char *to_str(std::span<char, UUID_STR_LEN> output) const;
 
  protected:

esphome/components/voice_assistant/voice_assistant.h

@@ -83,7 +83,7 @@ struct Timer {
   }
   // Remove before 2026.8.0
   ESPDEPRECATED("Use to_str() instead. Removed in 2026.8.0", "2026.2.0")
-  std::string to_string() const {  // NOLINT
+  std::string to_string() const {
     char buffer[TO_STR_BUFFER_SIZE];
     return this->to_str(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

script/ci-custom.py

@@ -732,47 +732,6 @@ def lint_no_heap_allocating_helpers(fname, match):
     )
 
 
-@lint_re_check(
-    # Match std::to_string() or unqualified to_string() calls
-    # The esphome namespace has "using std::to_string;" so unqualified calls resolve to std::to_string
-    # Use negative lookbehind to avoid matching:
-    #   - Function definitions: "const char *to_string(" or "std::string to_string("
-    #   - Method definitions: "Class::to_string("
-    #   - Method calls: ".to_string(" or "->to_string("
-    #   - Other identifiers: "_to_string("
-    r"(?<![*&.\w>:])to_string\s*\(" + CPP_RE_EOL,
-    include=cpp_include,
-    exclude=[
-        # Vendored library
-        "esphome/components/http_request/httplib.h",
-        # Deprecated helpers that return std::string
-        "esphome/core/helpers.cpp",
-        # The using declaration itself
-        "esphome/core/helpers.h",
-        # Test fixtures - not production embedded code
-        "tests/integration/fixtures/*",
-    ],
-)
-def lint_no_std_to_string(fname, match):
-    return (
-        f"{highlight('std::to_string()')} allocates heap memory. On long-running embedded "
-        f"devices, repeated heap allocations fragment memory over time.\n"
-        f"Please use {highlight('snprintf()')} with a stack buffer instead.\n"
-        f"\n"
-        f"Buffer sizes and format specifiers:\n"
-        f"  uint8_t/int8_t:   4 chars   - %u / %d (or PRIu8/PRId8)\n"
-        f"  uint16_t/int16_t: 6 chars   - %u / %d (or PRIu16/PRId16)\n"
-        f"  uint32_t/int32_t: 11 chars  - %" + "PRIu32 / %" + "PRId32\n"
-        "  uint64_t/int64_t: 21 chars  - %" + "PRIu64 / %" + "PRId64\n"
-        f"  float/double:     24 chars  - %.8g (15 digits + sign + decimal + e+XXX)\n"
-        f"                    317 chars - %f (for DBL_MAX: 309 int digits + decimal + 6 frac + sign)\n"
-        f"\n"
-        f"For sensor values, use value_accuracy_to_buf() from helpers.h.\n"
-        f'Example: char buf[11]; snprintf(buf, sizeof(buf), "%" PRIu32, value);\n'
-        f"(If strictly necessary, add `{highlight('// NOLINT')}` to the end of the line)"
-    )
-
-
 @lint_content_find_check(
     "ESP_LOG",
     include=["*.h", "*.tcc"],