hdr

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/datetime/date_entity.cpp

@@ -106,9 +106,9 @@ DateCall &DateCall::set_date(uint16_t year, uint8_t month, uint8_t day) {
 
 DateCall &DateCall::set_date(ESPTime time) { return this->set_date(time.year, time.month, time.day_of_month); };
 
-DateCall &DateCall::set_date(const std::string &date) {
+DateCall &DateCall::set_date(const char *date, size_t len) {
   ESPTime val{};
-  if (!ESPTime::strptime(date, val)) {
+  if (!ESPTime::strptime(date, len, val)) {
     ESP_LOGE(TAG, "Could not convert the date string to an ESPTime object");
     return *this;
   }

esphome/components/datetime/date_entity.h

@@ -67,7 +67,9 @@ class DateCall {
   void perform();
   DateCall &set_date(uint16_t year, uint8_t month, uint8_t day);
   DateCall &set_date(ESPTime time);
-  DateCall &set_date(const std::string &date);
+  DateCall &set_date(const char *date, size_t len);
+  DateCall &set_date(const char *date) { return this->set_date(date, strlen(date)); }
+  DateCall &set_date(const std::string &date) { return this->set_date(date.c_str(), date.size()); }
 
   DateCall &set_year(uint16_t year) {
     this->year_ = year;

esphome/components/datetime/datetime_entity.cpp

@@ -163,9 +163,9 @@ DateTimeCall &DateTimeCall::set_datetime(ESPTime datetime) {
                             datetime.second);
 };
 
-DateTimeCall &DateTimeCall::set_datetime(const std::string &datetime) {
+DateTimeCall &DateTimeCall::set_datetime(const char *datetime, size_t len) {
   ESPTime val{};
-  if (!ESPTime::strptime(datetime, val)) {
+  if (!ESPTime::strptime(datetime, len, val)) {
     ESP_LOGE(TAG, "Could not convert the time string to an ESPTime object");
     return *this;
   }

esphome/components/datetime/datetime_entity.h

@@ -71,7 +71,11 @@ class DateTimeCall {
   void perform();
   DateTimeCall &set_datetime(uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute, uint8_t second);
   DateTimeCall &set_datetime(ESPTime datetime);
-  DateTimeCall &set_datetime(const std::string &datetime);
+  DateTimeCall &set_datetime(const char *datetime, size_t len);
+  DateTimeCall &set_datetime(const char *datetime) { return this->set_datetime(datetime, strlen(datetime)); }
+  DateTimeCall &set_datetime(const std::string &datetime) {
+    return this->set_datetime(datetime.c_str(), datetime.size());
+  }
   DateTimeCall &set_datetime(time_t epoch_seconds);
 
   DateTimeCall &set_year(uint16_t year) {

esphome/components/datetime/time_entity.cpp

@@ -74,9 +74,9 @@ TimeCall &TimeCall::set_time(uint8_t hour, uint8_t minute, uint8_t second) {
 
 TimeCall &TimeCall::set_time(ESPTime time) { return this->set_time(time.hour, time.minute, time.second); };
 
-TimeCall &TimeCall::set_time(const std::string &time) {
+TimeCall &TimeCall::set_time(const char *time, size_t len) {
   ESPTime val{};
-  if (!ESPTime::strptime(time, val)) {
+  if (!ESPTime::strptime(time, len, val)) {
     ESP_LOGE(TAG, "Could not convert the time string to an ESPTime object");
     return *this;
   }

esphome/components/datetime/time_entity.h

@@ -69,7 +69,9 @@ class TimeCall {
   void perform();
   TimeCall &set_time(uint8_t hour, uint8_t minute, uint8_t second);
   TimeCall &set_time(ESPTime time);
-  TimeCall &set_time(const std::string &time);
+  TimeCall &set_time(const char *time, size_t len);
+  TimeCall &set_time(const char *time) { return this->set_time(time, strlen(time)); }
+  TimeCall &set_time(const std::string &time) { return this->set_time(time.c_str(), time.size()); }
 
   TimeCall &set_hour(uint8_t hour) {
     this->hour_ = hour;

esphome/components/debug/debug_esp8266.cpp

@@ -3,80 +3,21 @@
 #include "esphome/core/log.h"
 #include <Esp.h>
 
-extern "C" {
-#include <user_interface.h>
-
-// Global reset info struct populated by SDK at boot
-extern struct rst_info resetInfo;
-
-// Core version - either a string pointer or a version number to format as hex
-extern uint32_t core_version;
-extern const char *core_release;
-}
-
 namespace esphome {
 namespace debug {
 
 static const char *const TAG = "debug";
 
-// Get reset reason string from reason code (no heap allocation)
-// Returns LogString* pointing to flash (PROGMEM) on ESP8266
-static const LogString *get_reset_reason_str(uint32_t reason) {
-  switch (reason) {
-    case REASON_DEFAULT_RST:
-      return LOG_STR("Power On");
-    case REASON_WDT_RST:
-      return LOG_STR("Hardware Watchdog");
-    case REASON_EXCEPTION_RST:
-      return LOG_STR("Exception");
-    case REASON_SOFT_WDT_RST:
-      return LOG_STR("Software Watchdog");
-    case REASON_SOFT_RESTART:
-      return LOG_STR("Software/System restart");
-    case REASON_DEEP_SLEEP_AWAKE:
-      return LOG_STR("Deep-Sleep Wake");
-    case REASON_EXT_SYS_RST:
-      return LOG_STR("External System");
-    default:
-      return LOG_STR("Unknown");
-  }
-}
-
-// Size for core version hex buffer
-static constexpr size_t CORE_VERSION_BUFFER_SIZE = 12;
-
-// Get core version string (no heap allocation)
-// Returns either core_release directly or formats core_version as hex into provided buffer
-static const char *get_core_version_str(std::span<char, CORE_VERSION_BUFFER_SIZE> buffer) {
-  if (core_release != nullptr) {
-    return core_release;
-  }
-  snprintf_P(buffer.data(), CORE_VERSION_BUFFER_SIZE, PSTR("%08x"), core_version);
-  return buffer.data();
-}
-
-// Size for reset info buffer
-static constexpr size_t RESET_INFO_BUFFER_SIZE = 200;
-
-// Get detailed reset info string (no heap allocation)
-// For watchdog/exception resets, includes detailed exception info
-static const char *get_reset_info_str(std::span<char, RESET_INFO_BUFFER_SIZE> buffer, uint32_t reason) {
-  if (reason >= REASON_WDT_RST && reason <= REASON_SOFT_WDT_RST) {
-    snprintf_P(buffer.data(), RESET_INFO_BUFFER_SIZE,
-               PSTR("Fatal exception:%d flag:%d (%s) epc1:0x%08x epc2:0x%08x epc3:0x%08x excvaddr:0x%08x depc:0x%08x"),
-               static_cast<int>(resetInfo.exccause), static_cast<int>(reason),
-               LOG_STR_ARG(get_reset_reason_str(reason)), resetInfo.epc1, resetInfo.epc2, resetInfo.epc3,
-               resetInfo.excvaddr, resetInfo.depc);
-    return buffer.data();
-  }
-  return LOG_STR_ARG(get_reset_reason_str(reason));
-}
-
 const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
-  // Copy from flash to provided buffer
-  strncpy_P(buffer.data(), (PGM_P) get_reset_reason_str(resetInfo.reason), RESET_REASON_BUFFER_SIZE - 1);
-  buffer[RESET_REASON_BUFFER_SIZE - 1] = '\0';
-  return buffer.data();
+  char *buf = buffer.data();
+#if !defined(CLANG_TIDY)
+  String reason = ESP.getResetReason();  // NOLINT
+  snprintf_P(buf, RESET_REASON_BUFFER_SIZE, PSTR("%s"), reason.c_str());
+  return buf;
+#else
+  buf[0] = '\0';
+  return buf;
+#endif
 }
 
 const char *DebugComponent::get_wakeup_cause_(std::span<char, RESET_REASON_BUFFER_SIZE> buffer) {
@@ -92,42 +33,37 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
   constexpr size_t size = DEVICE_INFO_BUFFER_SIZE;
   char *buf = buffer.data();
 
-  const LogString *flash_mode;
+  const char *flash_mode;
   switch (ESP.getFlashChipMode()) {  // NOLINT(readability-static-accessed-through-instance)
     case FM_QIO:
-      flash_mode = LOG_STR("QIO");
+      flash_mode = "QIO";
       break;
     case FM_QOUT:
-      flash_mode = LOG_STR("QOUT");
+      flash_mode = "QOUT";
       break;
     case FM_DIO:
-      flash_mode = LOG_STR("DIO");
+      flash_mode = "DIO";
       break;
     case FM_DOUT:
-      flash_mode = LOG_STR("DOUT");
+      flash_mode = "DOUT";
       break;
     default:
-      flash_mode = LOG_STR("UNKNOWN");
+      flash_mode = "UNKNOWN";
   }
-  uint32_t flash_size = ESP.getFlashChipSize() / 1024;       // NOLINT(readability-static-accessed-through-instance)
-  uint32_t flash_speed = ESP.getFlashChipSpeed() / 1000000;  // NOLINT(readability-static-accessed-through-instance)
-  ESP_LOGD(TAG, "Flash Chip: Size=%" PRIu32 "kB Speed=%" PRIu32 "MHz Mode=%s", flash_size, flash_speed,
-           LOG_STR_ARG(flash_mode));
-  pos = buf_append_printf(buf, size, pos, "|Flash: %" PRIu32 "kB Speed:%" PRIu32 "MHz Mode:%s", flash_size, flash_speed,
-                          LOG_STR_ARG(flash_mode));
+  uint32_t flash_size = ESP.getFlashChipSize() / 1024;       // NOLINT
+  uint32_t flash_speed = ESP.getFlashChipSpeed() / 1000000;  // NOLINT
+  ESP_LOGD(TAG, "Flash Chip: Size=%" PRIu32 "kB Speed=%" PRIu32 "MHz Mode=%s", flash_size, flash_speed, flash_mode);
+  pos = buf_append(buf, size, pos, "|Flash: %" PRIu32 "kB Speed:%" PRIu32 "MHz Mode:%s", flash_size, flash_speed,
+                   flash_mode);
 
+#if !defined(CLANG_TIDY)
   char reason_buffer[RESET_REASON_BUFFER_SIZE];
-  const char *reset_reason = get_reset_reason_(reason_buffer);
-  char core_version_buffer[CORE_VERSION_BUFFER_SIZE];
-  char reset_info_buffer[RESET_INFO_BUFFER_SIZE];
-  // NOLINTBEGIN(readability-static-accessed-through-instance)
+  const char *reset_reason = get_reset_reason_(std::span<char, RESET_REASON_BUFFER_SIZE>(reason_buffer));
   uint32_t chip_id = ESP.getChipId();
   uint8_t boot_version = ESP.getBootVersion();
   uint8_t boot_mode = ESP.getBootMode();
   uint8_t cpu_freq = ESP.getCpuFreqMHz();
   uint32_t flash_chip_id = ESP.getFlashChipId();
-  const char *sdk_version = ESP.getSdkVersion();
-  // NOLINTEND(readability-static-accessed-through-instance)
 
   ESP_LOGD(TAG,
            "Chip ID: 0x%08" PRIX32 "\n"
@@ -138,18 +74,19 @@ size_t DebugComponent::get_device_info_(std::span<char, DEVICE_INFO_BUFFER_SIZE>
            "Flash Chip ID=0x%08" PRIX32 "\n"
            "Reset Reason: %s\n"
            "Reset Info: %s",
-           chip_id, sdk_version, get_core_version_str(core_version_buffer), boot_version, boot_mode, cpu_freq,
-           flash_chip_id, reset_reason, get_reset_info_str(reset_info_buffer, resetInfo.reason));
+           chip_id, ESP.getSdkVersion(), ESP.getCoreVersion().c_str(), boot_version, boot_mode, cpu_freq, flash_chip_id,
+           reset_reason, ESP.getResetInfo().c_str());
 
-  pos = buf_append_printf(buf, size, pos, "|Chip: 0x%08" PRIX32, chip_id);
-  pos = buf_append_printf(buf, size, pos, "|SDK: %s", sdk_version);
-  pos = buf_append_printf(buf, size, pos, "|Core: %s", get_core_version_str(core_version_buffer));
-  pos = buf_append_printf(buf, size, pos, "|Boot: %u", boot_version);
-  pos = buf_append_printf(buf, size, pos, "|Mode: %u", boot_mode);
-  pos = buf_append_printf(buf, size, pos, "|CPU: %u", cpu_freq);
-  pos = buf_append_printf(buf, size, pos, "|Flash: 0x%08" PRIX32, flash_chip_id);
-  pos = buf_append_printf(buf, size, pos, "|Reset: %s", reset_reason);
-  pos = buf_append_printf(buf, size, pos, "|%s", get_reset_info_str(reset_info_buffer, resetInfo.reason));
+  pos = buf_append(buf, size, pos, "|Chip: 0x%08" PRIX32, chip_id);
+  pos = buf_append(buf, size, pos, "|SDK: %s", ESP.getSdkVersion());
+  pos = buf_append(buf, size, pos, "|Core: %s", ESP.getCoreVersion().c_str());
+  pos = buf_append(buf, size, pos, "|Boot: %u", boot_version);
+  pos = buf_append(buf, size, pos, "|Mode: %u", boot_mode);
+  pos = buf_append(buf, size, pos, "|CPU: %u", cpu_freq);
+  pos = buf_append(buf, size, pos, "|Flash: 0x%08" PRIX32, flash_chip_id);
+  pos = buf_append(buf, size, pos, "|Reset: %s", reset_reason);
+  pos = buf_append(buf, size, pos, "|%s", ESP.getResetInfo().c_str());
+#endif
 
   return pos;
 }

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/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/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/core/time.cpp

@@ -67,7 +67,7 @@ std::string ESPTime::strftime(const char *format) {
 
 std::string ESPTime::strftime(const std::string &format) { return this->strftime(format.c_str()); }
 
-bool ESPTime::strptime(const std::string &time_to_parse, ESPTime &esp_time) {
+bool ESPTime::strptime(const char *time_to_parse, size_t len, ESPTime &esp_time) {
   uint16_t year;
   uint8_t month;
   uint8_t day;
@@ -75,40 +75,41 @@ bool ESPTime::strptime(const std::string &time_to_parse, ESPTime &esp_time) {
   uint8_t minute;
   uint8_t second;
   int num;
+  const int ilen = static_cast<int>(len);
 
-  if (sscanf(time_to_parse.c_str(), "%04hu-%02hhu-%02hhu %02hhu:%02hhu:%02hhu %n", &year, &month, &day,  // NOLINT
-             &hour,                                                                                      // NOLINT
-             &minute,                                                                                    // NOLINT
-             &second, &num) == 6 &&                                                                      // NOLINT
-      num == static_cast<int>(time_to_parse.size())) {
+  if (sscanf(time_to_parse, "%04hu-%02hhu-%02hhu %02hhu:%02hhu:%02hhu %n", &year, &month, &day,  // NOLINT
+             &hour,                                                                              // NOLINT
+             &minute,                                                                            // NOLINT
+             &second, &num) == 6 &&                                                              // NOLINT
+      num == ilen) {
     esp_time.year = year;
     esp_time.month = month;
     esp_time.day_of_month = day;
     esp_time.hour = hour;
     esp_time.minute = minute;
     esp_time.second = second;
-  } else if (sscanf(time_to_parse.c_str(), "%04hu-%02hhu-%02hhu %02hhu:%02hhu %n", &year, &month, &day,  // NOLINT
-                    &hour,                                                                               // NOLINT
-                    &minute, &num) == 5 &&                                                               // NOLINT
-             num == static_cast<int>(time_to_parse.size())) {
+  } else if (sscanf(time_to_parse, "%04hu-%02hhu-%02hhu %02hhu:%02hhu %n", &year, &month, &day,  // NOLINT
+                    &hour,                                                                       // NOLINT
+                    &minute, &num) == 5 &&                                                       // NOLINT
+             num == ilen) {
     esp_time.year = year;
     esp_time.month = month;
     esp_time.day_of_month = day;
     esp_time.hour = hour;
     esp_time.minute = minute;
     esp_time.second = 0;
-  } else if (sscanf(time_to_parse.c_str(), "%02hhu:%02hhu:%02hhu %n", &hour, &minute, &second, &num) == 3 &&  // NOLINT
-             num == static_cast<int>(time_to_parse.size())) {
+  } else if (sscanf(time_to_parse, "%02hhu:%02hhu:%02hhu %n", &hour, &minute, &second, &num) == 3 &&  // NOLINT
+             num == ilen) {
     esp_time.hour = hour;
     esp_time.minute = minute;
     esp_time.second = second;
-  } else if (sscanf(time_to_parse.c_str(), "%02hhu:%02hhu %n", &hour, &minute, &num) == 2 &&  // NOLINT
-             num == static_cast<int>(time_to_parse.size())) {
+  } else if (sscanf(time_to_parse, "%02hhu:%02hhu %n", &hour, &minute, &num) == 2 &&  // NOLINT
+             num == ilen) {
     esp_time.hour = hour;
     esp_time.minute = minute;
     esp_time.second = 0;
-  } else if (sscanf(time_to_parse.c_str(), "%04hu-%02hhu-%02hhu %n", &year, &month, &day, &num) == 3 &&  // NOLINT
-             num == static_cast<int>(time_to_parse.size())) {
+  } else if (sscanf(time_to_parse, "%04hu-%02hhu-%02hhu %n", &year, &month, &day, &num) == 3 &&  // NOLINT
+             num == ilen) {
     esp_time.year = year;
     esp_time.month = month;
     esp_time.day_of_month = day;

esphome/core/time.h

@@ -2,6 +2,7 @@
 
 #include <cstdint>
 #include <cstdlib>
+#include <cstring>
 #include <ctime>
 #include <span>
 #include <string>
@@ -80,11 +81,20 @@ struct ESPTime {
   }
 
   /** Convert a string to ESPTime struct as specified by the format argument.
-   * @param time_to_parse null-terminated c string formatet like this: 2020-08-25 05:30:00.
+   * @param time_to_parse c string formatted like this: 2020-08-25 05:30:00.
+   * @param len length of the string (not including null terminator if present)
    * @param esp_time an instance of a ESPTime struct
-   * @return the success sate of the parsing
+   * @return the success state of the parsing
    */
-  static bool strptime(const std::string &time_to_parse, ESPTime &esp_time);
+  static bool strptime(const char *time_to_parse, size_t len, ESPTime &esp_time);
+  /// @copydoc strptime(const char *, size_t, ESPTime &)
+  static bool strptime(const char *time_to_parse, ESPTime &esp_time) {
+    return strptime(time_to_parse, strlen(time_to_parse), esp_time);
+  }
+  /// @copydoc strptime(const char *, size_t, ESPTime &)
+  static bool strptime(const std::string &time_to_parse, ESPTime &esp_time) {
+    return strptime(time_to_parse.c_str(), time_to_parse.size(), esp_time);
+  }
 
   /// Convert a C tm struct instance with a C unix epoch timestamp to an ESPTime instance.
   static ESPTime from_c_tm(struct tm *c_tm, time_t c_time);

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}")