Use ESPHOME_DEBUG_API guard instead of DEBUG

CI compile tests also define DEBUG, so a dedicated guard is needed.
Enable ESPHOME_DEBUG_API in integration tests via conftest.py.

esphome/components/api/api_connection.cpp

@@ -1510,7 +1510,7 @@ bool APIConnection::send_hello_response_(const HelloRequest &msg) {
   this->client_api_version_major_ = msg.api_version_major;
   this->client_api_version_minor_ = msg.api_version_minor;
   char peername[socket::SOCKADDR_STR_LEN];
-  ESP_LOGV(TAG, "Hello from client: '%s' | %s | API Version %" PRIu32 ".%" PRIu32, this->helper_->get_client_name(),
+  ESP_LOGV(TAG, "Hello from client: '%s' | %s | API Version %" PRIu16 ".%" PRIu16, this->helper_->get_client_name(),
            this->helper_->get_peername_to(peername), this->client_api_version_major_, this->client_api_version_minor_);
 
   HelloResponse resp;

esphome/components/api/api_frame_helper_plaintext.cpp

@@ -295,9 +295,8 @@ APIError APIPlaintextFrameHelper::write_protobuf_messages(ProtoWriteBuffer buffe
     buf_start[header_offset] = 0x00;  // indicator
 
     // Encode varints directly into buffer
-    ProtoVarInt(msg.payload_size).encode_to_buffer_unchecked(buf_start + header_offset + 1, size_varint_len);
-    ProtoVarInt(msg.message_type)
-        .encode_to_buffer_unchecked(buf_start + header_offset + 1 + size_varint_len, type_varint_len);
+    encode_varint_to_buffer(msg.payload_size, buf_start + header_offset + 1);
+    encode_varint_to_buffer(msg.message_type, buf_start + header_offset + 1 + size_varint_len);
 
     // Add iovec for this message (header + payload)
     size_t msg_len = static_cast<size_t>(total_header_len + msg.payload_size);

esphome/components/api/proto.cpp

@@ -133,7 +133,7 @@ void ProtoDecodableMessage::decode(const uint8_t *buffer, size_t length) {
         break;
       }
       default:
-        ESP_LOGV(TAG, "Invalid field type %u at offset %ld", field_type, (long) (ptr - buffer));
+        ESP_LOGV(TAG, "Invalid field type %" PRIu32 " at offset %ld", field_type, (long) (ptr - buffer));
         return;
     }
   }

esphome/components/api/proto.h

@@ -57,6 +57,16 @@ inline uint16_t count_packed_varints(const uint8_t *data, size_t len) {
   return count;
 }
 
+/// Encode a varint directly into a pre-allocated buffer.
+/// Caller must ensure buffer has space (use ProtoSize::varint() to calculate).
+inline void encode_varint_to_buffer(uint32_t val, uint8_t *buffer) {
+  while (val > 0x7F) {
+    *buffer++ = static_cast<uint8_t>(val | 0x80);
+    val >>= 7;
+  }
+  *buffer = static_cast<uint8_t>(val);
+}
+
 /*
  * StringRef Ownership Model for API Protocol Messages
  * ===================================================
@@ -93,17 +103,17 @@ class ProtoVarInt {
   ProtoVarInt() : value_(0) {}
   explicit ProtoVarInt(uint64_t value) : value_(value) {}
 
+  /// Parse a varint from buffer. consumed must be a valid pointer (not null).
   static optional<ProtoVarInt> parse(const uint8_t *buffer, uint32_t len, uint32_t *consumed) {
-    if (len == 0) {
-      if (consumed != nullptr)
-        *consumed = 0;
+#ifdef ESPHOME_DEBUG_API
+    assert(consumed != nullptr);
+#endif
+    if (len == 0)
       return {};
-    }
 
     // Most common case: single-byte varint (values 0-127)
     if ((buffer[0] & 0x80) == 0) {
-      if (consumed != nullptr)
-        *consumed = 1;
+      *consumed = 1;
       return ProtoVarInt(buffer[0]);
     }
 
@@ -122,14 +132,11 @@ class ProtoVarInt {
       result |= uint64_t(val & 0x7F) << uint64_t(bitpos);
       bitpos += 7;
       if ((val & 0x80) == 0) {
-        if (consumed != nullptr)
-          *consumed = i + 1;
+        *consumed = i + 1;
         return ProtoVarInt(result);
       }
     }
 
-    if (consumed != nullptr)
-      *consumed = 0;
     return {};  // Incomplete or invalid varint
   }
 
@@ -153,50 +160,6 @@ class ProtoVarInt {
     // with ZigZag encoding
     return decode_zigzag64(this->value_);
   }
-  /**
-   * Encode the varint value to a pre-allocated buffer without bounds checking.
-   *
-   * @param buffer The pre-allocated buffer to write the encoded varint to
-   * @param len The size of the buffer in bytes
-   *
-   * @note The caller is responsible for ensuring the buffer is large enough
-   *       to hold the encoded value. Use ProtoSize::varint() to calculate
-   *       the exact size needed before calling this method.
-   * @note No bounds checking is performed for performance reasons.
-   */
-  void encode_to_buffer_unchecked(uint8_t *buffer, size_t len) {
-    uint64_t val = this->value_;
-    if (val <= 0x7F) {
-      buffer[0] = val;
-      return;
-    }
-    size_t i = 0;
-    while (val && i < len) {
-      uint8_t temp = val & 0x7F;
-      val >>= 7;
-      if (val) {
-        buffer[i++] = temp | 0x80;
-      } else {
-        buffer[i++] = temp;
-      }
-    }
-  }
-  void encode(std::vector<uint8_t> &out) {
-    uint64_t val = this->value_;
-    if (val <= 0x7F) {
-      out.push_back(val);
-      return;
-    }
-    while (val) {
-      uint8_t temp = val & 0x7F;
-      val >>= 7;
-      if (val) {
-        out.push_back(temp | 0x80);
-      } else {
-        out.push_back(temp);
-      }
-    }
-  }
 
  protected:
   uint64_t value_;
@@ -256,8 +219,24 @@ class ProtoWriteBuffer {
  public:
   ProtoWriteBuffer(std::vector<uint8_t> *buffer) : buffer_(buffer) {}
   void write(uint8_t value) { this->buffer_->push_back(value); }
-  void encode_varint_raw(ProtoVarInt value) { value.encode(*this->buffer_); }
-  void encode_varint_raw(uint32_t value) { this->encode_varint_raw(ProtoVarInt(value)); }
+  void encode_varint_raw(uint32_t value) {
+    if (value <= 0x7F) {
+      this->buffer_->push_back(static_cast<uint8_t>(value));
+      return;
+    }
+    while (value > 0x7F) {
+      this->buffer_->push_back(static_cast<uint8_t>(value | 0x80));
+      value >>= 7;
+    }
+    this->buffer_->push_back(static_cast<uint8_t>(value));
+  }
+  void encode_varint_raw_64(uint64_t value) {
+    while (value > 0x7F) {
+      this->buffer_->push_back(static_cast<uint8_t>(value | 0x80));
+      value >>= 7;
+    }
+    this->buffer_->push_back(static_cast<uint8_t>(value));
+  }
   /**
    * Encode a field key (tag/wire type combination).
    *
@@ -307,13 +286,13 @@ class ProtoWriteBuffer {
     if (value == 0 && !force)
       return;
     this->encode_field_raw(field_id, 0);  // type 0: Varint - uint64
-    this->encode_varint_raw(ProtoVarInt(value));
+    this->encode_varint_raw_64(value);
   }
   void encode_bool(uint32_t field_id, bool value, bool force = false) {
     if (!value && !force)
       return;
     this->encode_field_raw(field_id, 0);  // type 0: Varint - bool
-    this->write(0x01);
+    this->buffer_->push_back(value ? 0x01 : 0x00);
   }
   void encode_fixed32(uint32_t field_id, uint32_t value, bool force = false) {
     if (value == 0 && !force)
@@ -938,13 +917,15 @@ inline void ProtoWriteBuffer::encode_message(uint32_t field_id, const ProtoMessa
   this->buffer_->resize(this->buffer_->size() + varint_length_bytes);
 
   // Write the length varint directly
-  ProtoVarInt(msg_length_bytes).encode_to_buffer_unchecked(this->buffer_->data() + begin, varint_length_bytes);
+  encode_varint_to_buffer(msg_length_bytes, this->buffer_->data() + begin);
 
   // Now encode the message content - it will append to the buffer
   value.encode(*this);
 
+#ifdef ESPHOME_DEBUG_API
   // Verify that the encoded size matches what we calculated
   assert(this->buffer_->size() == begin + varint_length_bytes + msg_length_bytes);
+#endif
 }
 
 // Implementation of decode_to_message - must be after ProtoDecodableMessage is defined

esphome/components/bl0942/bl0942.h

@@ -59,10 +59,10 @@ namespace bl0942 {
 //
 // Which makes BL0952_EREF = BL0942_PREF * 3600000 / 419430.4
 
-static const float BL0942_PREF = 596;              // taken from tasmota
-static const float BL0942_UREF = 15873.35944299;   // should be 73989/1.218
-static const float BL0942_IREF = 251213.46469622;  // 305978/1.218
-static const float BL0942_EREF = 3304.61127328;    // Measured
+static const float BL0942_PREF = 623.0270705;  // calculated using UREF and IREF
+static const float BL0942_UREF = 15883.34116;  // calculated for (390k x 5 / 510R) voltage divider
+static const float BL0942_IREF = 251065.6814;  // calculated for 1mR shunt
+static const float BL0942_EREF = 5347.484240;  // calculated using UREF and IREF
 
 struct DataPacket {
   uint8_t frame_header;
@@ -86,11 +86,11 @@ enum LineFrequency : uint8_t {
 
 class BL0942 : public PollingComponent, public uart::UARTDevice {
  public:
-  void set_voltage_sensor(sensor::Sensor *voltage_sensor) { voltage_sensor_ = voltage_sensor; }
-  void set_current_sensor(sensor::Sensor *current_sensor) { current_sensor_ = current_sensor; }
-  void set_power_sensor(sensor::Sensor *power_sensor) { power_sensor_ = power_sensor; }
-  void set_energy_sensor(sensor::Sensor *energy_sensor) { energy_sensor_ = energy_sensor; }
-  void set_frequency_sensor(sensor::Sensor *frequency_sensor) { frequency_sensor_ = frequency_sensor; }
+  void set_voltage_sensor(sensor::Sensor *voltage_sensor) { this->voltage_sensor_ = voltage_sensor; }
+  void set_current_sensor(sensor::Sensor *current_sensor) { this->current_sensor_ = current_sensor; }
+  void set_power_sensor(sensor::Sensor *power_sensor) { this->power_sensor_ = power_sensor; }
+  void set_energy_sensor(sensor::Sensor *energy_sensor) { this->energy_sensor_ = energy_sensor; }
+  void set_frequency_sensor(sensor::Sensor *frequency_sensor) { this->frequency_sensor_ = frequency_sensor; }
   void set_line_freq(LineFrequency freq) { this->line_freq_ = freq; }
   void set_address(uint8_t address) { this->address_ = address; }
   void set_reset(bool reset) { this->reset_ = reset; }

esphome/components/esp8266/preferences.cpp

@@ -33,6 +33,10 @@ static constexpr uint32_t MAX_PREFERENCE_WORDS = 255;
 
 #define ESP_RTC_USER_MEM ((uint32_t *) ESP_RTC_USER_MEM_START)
 
+// Flash storage size depends on esp8266 -> restore_from_flash YAML option (default: false).
+// When enabled (USE_ESP8266_PREFERENCES_FLASH), all preferences default to flash and need
+// 128 words (512 bytes). When disabled, only explicit flash prefs use this storage so
+// 64 words (256 bytes) suffices since most preferences go to RTC memory instead.
 #ifdef USE_ESP8266_PREFERENCES_FLASH
 static constexpr uint32_t ESP8266_FLASH_STORAGE_SIZE = 128;
 #else
@@ -127,9 +131,11 @@ static bool load_from_rtc(size_t offset, uint32_t *data, size_t len) {
   return true;
 }
 
-// Stack buffer size - 16 words total: up to 15 words of preference data + 1 word CRC (60 bytes of preference data)
-// This handles virtually all real-world preferences without heap allocation
-static constexpr size_t PREF_BUFFER_WORDS = 16;
+// Maximum buffer for any single preference - bounded by storage sizes.
+// Flash prefs: bounded by ESP8266_FLASH_STORAGE_SIZE (128 or 64 words).
+// RTC prefs: bounded by RTC_NORMAL_REGION_WORDS (96) - a single pref can't span both RTC regions.
+static constexpr size_t PREF_MAX_BUFFER_WORDS =
+    ESP8266_FLASH_STORAGE_SIZE > RTC_NORMAL_REGION_WORDS ? ESP8266_FLASH_STORAGE_SIZE : RTC_NORMAL_REGION_WORDS;
 
 class ESP8266PreferenceBackend : public ESPPreferenceBackend {
  public:
@@ -141,15 +147,13 @@ class ESP8266PreferenceBackend : public ESPPreferenceBackend {
   bool save(const uint8_t *data, size_t len) override {
     if (bytes_to_words(len) != this->length_words)
       return false;
-
     const size_t buffer_size = static_cast<size_t>(this->length_words) + 1;
-    SmallBufferWithHeapFallback<PREF_BUFFER_WORDS, uint32_t> buffer_alloc(buffer_size);
-    uint32_t *buffer = buffer_alloc.get();
+    if (buffer_size > PREF_MAX_BUFFER_WORDS)
+      return false;
+    uint32_t buffer[PREF_MAX_BUFFER_WORDS];
     memset(buffer, 0, buffer_size * sizeof(uint32_t));
-
     memcpy(buffer, data, len);
     buffer[this->length_words] = calculate_crc(buffer, buffer + this->length_words, this->type);
-
     return this->in_flash ? save_to_flash(this->offset, buffer, buffer_size)
                           : save_to_rtc(this->offset, buffer, buffer_size);
   }
@@ -157,19 +161,16 @@ class ESP8266PreferenceBackend : public ESPPreferenceBackend {
   bool load(uint8_t *data, size_t len) override {
     if (bytes_to_words(len) != this->length_words)
       return false;
-
     const size_t buffer_size = static_cast<size_t>(this->length_words) + 1;
-    SmallBufferWithHeapFallback<PREF_BUFFER_WORDS, uint32_t> buffer_alloc(buffer_size);
-    uint32_t *buffer = buffer_alloc.get();
-
+    if (buffer_size > PREF_MAX_BUFFER_WORDS)
+      return false;
+    uint32_t buffer[PREF_MAX_BUFFER_WORDS];
     bool ret = this->in_flash ? load_from_flash(this->offset, buffer, buffer_size)
                               : load_from_rtc(this->offset, buffer, buffer_size);
     if (!ret)
       return false;
-
     if (buffer[this->length_words] != calculate_crc(buffer, buffer + this->length_words, this->type))
       return false;
-
     memcpy(data, buffer, len);
     return true;
   }

esphome/components/light/light_call.cpp

@@ -270,22 +270,23 @@ LightColorValues LightCall::validate_() {
   if (this->has_state())
     v.set_state(this->state_);
 
-#define VALIDATE_AND_APPLY(field, setter, name_str, ...) \
+    // clamp_and_log_if_invalid already clamps in-place, so assign directly
+    // to avoid redundant clamp code from the setter being inlined.
+#define VALIDATE_AND_APPLY(field, name_str, ...) \
   if (this->has_##field()) { \
     clamp_and_log_if_invalid(name, this->field##_, LOG_STR(name_str), ##__VA_ARGS__); \
-    v.setter(this->field##_); \
+    v.field##_ = this->field##_; \
   }
 
-  VALIDATE_AND_APPLY(brightness, set_brightness, "Brightness")
-  VALIDATE_AND_APPLY(color_brightness, set_color_brightness, "Color brightness")
-  VALIDATE_AND_APPLY(red, set_red, "Red")
-  VALIDATE_AND_APPLY(green, set_green, "Green")
-  VALIDATE_AND_APPLY(blue, set_blue, "Blue")
-  VALIDATE_AND_APPLY(white, set_white, "White")
-  VALIDATE_AND_APPLY(cold_white, set_cold_white, "Cold white")
-  VALIDATE_AND_APPLY(warm_white, set_warm_white, "Warm white")
-  VALIDATE_AND_APPLY(color_temperature, set_color_temperature, "Color temperature", traits.get_min_mireds(),
-                     traits.get_max_mireds())
+  VALIDATE_AND_APPLY(brightness, "Brightness")
+  VALIDATE_AND_APPLY(color_brightness, "Color brightness")
+  VALIDATE_AND_APPLY(red, "Red")
+  VALIDATE_AND_APPLY(green, "Green")
+  VALIDATE_AND_APPLY(blue, "Blue")
+  VALIDATE_AND_APPLY(white, "White")
+  VALIDATE_AND_APPLY(cold_white, "Cold white")
+  VALIDATE_AND_APPLY(warm_white, "Warm white")
+  VALIDATE_AND_APPLY(color_temperature, "Color temperature", traits.get_min_mireds(), traits.get_max_mireds())
 
 #undef VALIDATE_AND_APPLY
 

esphome/components/light/light_color_values.h

@@ -95,15 +95,18 @@ class LightColorValues {
    */
   void normalize_color() {
     if (this->color_mode_ & ColorCapability::RGB) {
-      float max_value = fmaxf(this->get_red(), fmaxf(this->get_green(), this->get_blue()));
+      float max_value = fmaxf(this->red_, fmaxf(this->green_, this->blue_));
+      // Assign directly to avoid redundant clamp in set_red/green/blue.
+      // Values are guaranteed in [0,1]: inputs are already clamped to [0,1],
+      // and dividing by max_value (the largest) keeps results in [0,1].
       if (max_value == 0.0f) {
-        this->set_red(1.0f);
-        this->set_green(1.0f);
-        this->set_blue(1.0f);
+        this->red_ = 1.0f;
+        this->green_ = 1.0f;
+        this->blue_ = 1.0f;
       } else {
-        this->set_red(this->get_red() / max_value);
-        this->set_green(this->get_green() / max_value);
-        this->set_blue(this->get_blue() / max_value);
+        this->red_ /= max_value;
+        this->green_ /= max_value;
+        this->blue_ /= max_value;
       }
     }
   }
@@ -276,6 +279,8 @@ class LightColorValues {
   /// Set the warm white property of these light color values. In range 0.0 to 1.0.
   void set_warm_white(float warm_white) { this->warm_white_ = clamp(warm_white, 0.0f, 1.0f); }
 
+  friend class LightCall;
+
  protected:
   float state_;  ///< ON / OFF, float for transition
   float brightness_;

esphome/components/logger/__init__.py

@@ -231,9 +231,16 @@ CONFIG_SCHEMA = cv.All(
                 bk72xx=768,
                 ln882x=768,
                 rtl87xx=768,
+                nrf52=768,
             ): cv.All(
                 cv.only_on(
-                    [PLATFORM_ESP32, PLATFORM_BK72XX, PLATFORM_LN882X, PLATFORM_RTL87XX]
+                    [
+                        PLATFORM_ESP32,
+                        PLATFORM_BK72XX,
+                        PLATFORM_LN882X,
+                        PLATFORM_RTL87XX,
+                        PLATFORM_NRF52,
+                    ]
                 ),
                 cv.validate_bytes,
                 cv.Any(
@@ -313,11 +320,13 @@ async def to_code(config):
     )
     if CORE.is_esp32:
         cg.add(log.create_pthread_key())
-    if CORE.is_esp32 or CORE.is_libretiny:
+    if CORE.is_esp32 or CORE.is_libretiny or CORE.is_nrf52:
         task_log_buffer_size = config[CONF_TASK_LOG_BUFFER_SIZE]
         if task_log_buffer_size > 0:
             cg.add_define("USE_ESPHOME_TASK_LOG_BUFFER")
             cg.add(log.init_log_buffer(task_log_buffer_size))
+            if CORE.using_zephyr:
+                zephyr_add_prj_conf("MPSC_PBUF", True)
     elif CORE.is_host:
         cg.add(log.create_pthread_key())
         cg.add_define("USE_ESPHOME_TASK_LOG_BUFFER")
@@ -417,6 +426,7 @@ async def to_code(config):
         pass
 
     if CORE.is_nrf52:
+        zephyr_add_prj_conf("THREAD_LOCAL_STORAGE", True)
         if config[CONF_HARDWARE_UART] == UART0:
             zephyr_add_overlay("""&uart0 { status = "okay";};""")
         if config[CONF_HARDWARE_UART] == UART1:

esphome/components/logger/log_buffer.h

@@ -0,0 +1,190 @@
+#pragma once
+
+#include "esphome/core/helpers.h"
+#include "esphome/core/log.h"
+
+namespace esphome::logger {
+
+// Maximum header size: 35 bytes fixed + 32 bytes tag + 16 bytes thread name = 83 bytes (45 byte safety margin)
+static constexpr uint16_t MAX_HEADER_SIZE = 128;
+
+// ANSI color code last digit (30-38 range, store only last digit to save RAM)
+static constexpr char LOG_LEVEL_COLOR_DIGIT[] = {
+    '\0',  // NONE
+    '1',   // ERROR (31 = red)
+    '3',   // WARNING (33 = yellow)
+    '2',   // INFO (32 = green)
+    '5',   // CONFIG (35 = magenta)
+    '6',   // DEBUG (36 = cyan)
+    '7',   // VERBOSE (37 = gray)
+    '8',   // VERY_VERBOSE (38 = white)
+};
+
+static constexpr char LOG_LEVEL_LETTER_CHARS[] = {
+    '\0',  // NONE
+    'E',   // ERROR
+    'W',   // WARNING
+    'I',   // INFO
+    'C',   // CONFIG
+    'D',   // DEBUG
+    'V',   // VERBOSE (VERY_VERBOSE uses two 'V's)
+};
+
+// Buffer wrapper for log formatting functions
+struct LogBuffer {
+  char *data;
+  uint16_t size;
+  uint16_t pos{0};
+  // Replaces the null terminator with a newline for console output.
+  // Must be called after notify_listeners_() since listeners need null-terminated strings.
+  // Console output uses length-based writes (buf.pos), so null terminator is not needed.
+  void terminate_with_newline() {
+    if (this->pos < this->size) {
+      this->data[this->pos++] = '\n';
+    } else if (this->size > 0) {
+      // Buffer was full - replace last char with newline to ensure it's visible
+      this->data[this->size - 1] = '\n';
+      this->pos = this->size;
+    }
+  }
+  void HOT write_header(uint8_t level, const char *tag, int line, const char *thread_name) {
+    // Early return if insufficient space - intentionally don't update pos to prevent partial writes
+    if (this->pos + MAX_HEADER_SIZE > this->size)
+      return;
+
+    char *p = this->current_();
+
+    // Write ANSI color
+    this->write_ansi_color_(p, level);
+
+    // Construct: [LEVEL][tag:line]
+    *p++ = '[';
+    if (level != 0) {
+      if (level >= 7) {
+        *p++ = 'V';  // VERY_VERBOSE = "VV"
+        *p++ = 'V';
+      } else {
+        *p++ = LOG_LEVEL_LETTER_CHARS[level];
+      }
+    }
+    *p++ = ']';
+    *p++ = '[';
+
+    // Copy tag
+    this->copy_string_(p, tag);
+
+    *p++ = ':';
+
+    // Format line number without modulo operations
+    if (line > 999) [[unlikely]] {
+      int thousands = line / 1000;
+      *p++ = '0' + thousands;
+      line -= thousands * 1000;
+    }
+    int hundreds = line / 100;
+    int remainder = line - hundreds * 100;
+    int tens = remainder / 10;
+    *p++ = '0' + hundreds;
+    *p++ = '0' + tens;
+    *p++ = '0' + (remainder - tens * 10);
+    *p++ = ']';
+
+#if defined(USE_ESP32) || defined(USE_LIBRETINY) || defined(USE_ZEPHYR) || defined(USE_HOST)
+    // Write thread name with bold red color
+    if (thread_name != nullptr) {
+      this->write_ansi_color_(p, 1);  // Bold red for thread name
+      *p++ = '[';
+      this->copy_string_(p, thread_name);
+      *p++ = ']';
+      this->write_ansi_color_(p, level);  // Restore original color
+    }
+#endif
+
+    *p++ = ':';
+    *p++ = ' ';
+
+    this->pos = p - this->data;
+  }
+  void HOT format_body(const char *format, va_list args) {
+    this->format_vsnprintf_(format, args);
+    this->finalize_();
+  }
+#ifdef USE_STORE_LOG_STR_IN_FLASH
+  void HOT format_body_P(PGM_P format, va_list args) {
+    this->format_vsnprintf_P_(format, args);
+    this->finalize_();
+  }
+#endif
+  void write_body(const char *text, uint16_t text_length) {
+    this->write_(text, text_length);
+    this->finalize_();
+  }
+
+ private:
+  bool full_() const { return this->pos >= this->size; }
+  uint16_t remaining_() const { return this->size - this->pos; }
+  char *current_() { return this->data + this->pos; }
+  void write_(const char *value, uint16_t length) {
+    const uint16_t available = this->remaining_();
+    const uint16_t copy_len = (length < available) ? length : available;
+    if (copy_len > 0) {
+      memcpy(this->current_(), value, copy_len);
+      this->pos += copy_len;
+    }
+  }
+  void finalize_() {
+    // Write color reset sequence
+    static constexpr uint16_t RESET_COLOR_LEN = sizeof(ESPHOME_LOG_RESET_COLOR) - 1;
+    this->write_(ESPHOME_LOG_RESET_COLOR, RESET_COLOR_LEN);
+    // Null terminate
+    this->data[this->full_() ? this->size - 1 : this->pos] = '\0';
+  }
+  void strip_trailing_newlines_() {
+    while (this->pos > 0 && this->data[this->pos - 1] == '\n')
+      this->pos--;
+  }
+  void process_vsnprintf_result_(int ret) {
+    if (ret < 0)
+      return;
+    const uint16_t rem = this->remaining_();
+    this->pos += (ret >= rem) ? (rem - 1) : static_cast<uint16_t>(ret);
+    this->strip_trailing_newlines_();
+  }
+  void format_vsnprintf_(const char *format, va_list args) {
+    if (this->full_())
+      return;
+    this->process_vsnprintf_result_(vsnprintf(this->current_(), this->remaining_(), format, args));
+  }
+#ifdef USE_STORE_LOG_STR_IN_FLASH
+  void format_vsnprintf_P_(PGM_P format, va_list args) {
+    if (this->full_())
+      return;
+    this->process_vsnprintf_result_(vsnprintf_P(this->current_(), this->remaining_(), format, args));
+  }
+#endif
+  // Write ANSI color escape sequence to buffer, updates pointer in place
+  // Caller is responsible for ensuring buffer has sufficient space
+  void write_ansi_color_(char *&p, uint8_t level) {
+    if (level == 0)
+      return;
+    // Direct buffer fill: "\033[{bold};3{color}m" (7 bytes)
+    *p++ = '\033';
+    *p++ = '[';
+    *p++ = (level == 1) ? '1' : '0';  // Only ERROR is bold
+    *p++ = ';';
+    *p++ = '3';
+    *p++ = LOG_LEVEL_COLOR_DIGIT[level];
+    *p++ = 'm';
+  }
+  // Copy string without null terminator, updates pointer in place
+  // Caller is responsible for ensuring buffer has sufficient space
+  void copy_string_(char *&p, const char *str) {
+    const size_t len = strlen(str);
+    // NOLINTNEXTLINE(bugprone-not-null-terminated-result) - intentionally no null terminator, building string piece by
+    // piece
+    memcpy(p, str, len);
+    p += len;
+  }
+};
+
+}  // namespace esphome::logger

esphome/components/logger/logger.cpp

@@ -10,9 +10,9 @@ namespace esphome::logger {
 
 static const char *const TAG = "logger";
 
-#if defined(USE_ESP32) || defined(USE_HOST) || defined(USE_LIBRETINY)
-// Implementation for multi-threaded platforms (ESP32 with FreeRTOS, Host with pthreads, LibreTiny with FreeRTOS)
-// Main thread/task always uses direct buffer access for console output and callbacks
+#if defined(USE_ESP32) || defined(USE_HOST) || defined(USE_LIBRETINY) || defined(USE_ZEPHYR)
+// Implementation for multi-threaded platforms (ESP32 with FreeRTOS, Host with pthreads, LibreTiny with FreeRTOS,
+// Zephyr) Main thread/task always uses direct buffer access for console output and callbacks
 //
 // For non-main threads/tasks:
 //  - WITH task log buffer: Prefer sending to ring buffer for async processing
@@ -31,6 +31,9 @@ void HOT Logger::log_vprintf_(uint8_t level, const char *tag, int line, const ch
   // Get task handle once - used for both main task check and passing to non-main thread handler
   TaskHandle_t current_task = xTaskGetCurrentTaskHandle();
   const bool is_main_task = (current_task == this->main_task_);
+#elif (USE_ZEPHYR)
+  k_tid_t current_task = k_current_get();
+  const bool is_main_task = (current_task == this->main_task_);
 #else  // USE_HOST
   const bool is_main_task = pthread_equal(pthread_self(), this->main_thread_);
 #endif
@@ -54,6 +57,9 @@ void HOT Logger::log_vprintf_(uint8_t level, const char *tag, int line, const ch
   // Host: pass a stack buffer for pthread_getname_np to write into.
 #if defined(USE_ESP32) || defined(USE_LIBRETINY)
   const char *thread_name = get_thread_name_(current_task);
+#elif defined(USE_ZEPHYR)
+  char thread_name_buf[MAX_POINTER_REPRESENTATION];
+  const char *thread_name = get_thread_name_(thread_name_buf, current_task);
 #else  // USE_HOST
   char thread_name_buf[THREAD_NAME_BUF_SIZE];
   const char *thread_name = this->get_thread_name_(thread_name_buf);
@@ -83,18 +89,21 @@ void Logger::log_vprintf_non_main_thread_(uint8_t level, const char *tag, int li
     // This is safe to call from any context including ISRs
     this->enable_loop_soon_any_context();
   }
-#endif  // USE_ESPHOME_TASK_LOG_BUFFER
-
+#endif
   // Emergency console logging for non-main threads when ring buffer is full or disabled
   // This is a fallback mechanism to ensure critical log messages are visible
   // Note: This may cause interleaved/corrupted console output if multiple threads
   // log simultaneously, but it's better than losing important messages entirely
 #ifdef USE_HOST
-  if (!message_sent) {
+  if (!message_sent)
+#else
+  if (!message_sent && this->baud_rate_ > 0)  // If logging is enabled, write to console
+#endif
+  {
+#ifdef USE_HOST
     // Host always has console output - no baud_rate check needed
     static const size_t MAX_CONSOLE_LOG_MSG_SIZE = 512;
 #else
-  if (!message_sent && this->baud_rate_ > 0) {  // If logging is enabled, write to console
     // Maximum size for console log messages (includes null terminator)
     static const size_t MAX_CONSOLE_LOG_MSG_SIZE = 144;
 #endif
@@ -107,22 +116,16 @@ void Logger::log_vprintf_non_main_thread_(uint8_t level, const char *tag, int li
   // RAII guard automatically resets on return
 }
 #else
-// Implementation for single-task platforms (ESP8266, RP2040, Zephyr)
-// TODO: Zephyr may have multiple threads (work queues, etc.) but uses this single-task path.
+// Implementation for single-task platforms (ESP8266, RP2040)
 // Logging calls are NOT thread-safe: global_recursion_guard_ is a plain bool and tx_buffer_ has no locking.
 // Not a problem in practice yet since Zephyr has no API support (logs are console-only).
 void HOT Logger::log_vprintf_(uint8_t level, const char *tag, int line, const char *format, va_list args) {  // NOLINT
   if (level > this->level_for(tag) || global_recursion_guard_)
     return;
-#ifdef USE_ZEPHYR
-  char tmp[MAX_POINTER_REPRESENTATION];
-  this->log_message_to_buffer_and_send_(global_recursion_guard_, level, tag, line, format, args,
-                                        this->get_thread_name_(tmp));
-#else  // Other single-task platforms don't have thread names, so pass nullptr
+  // Other single-task platforms don't have thread names, so pass nullptr
   this->log_message_to_buffer_and_send_(global_recursion_guard_, level, tag, line, format, args, nullptr);
-#endif
 }
-#endif  // USE_ESP32 / USE_HOST / USE_LIBRETINY
+#endif  // USE_ESP32 || USE_HOST || USE_LIBRETINY || USE_ZEPHYR
 
 #ifdef USE_STORE_LOG_STR_IN_FLASH
 // Implementation for ESP8266 with flash string support.
@@ -163,19 +166,12 @@ Logger::Logger(uint32_t baud_rate, size_t tx_buffer_size) : baud_rate_(baud_rate
 }
 #ifdef USE_ESPHOME_TASK_LOG_BUFFER
 void Logger::init_log_buffer(size_t total_buffer_size) {
-#ifdef USE_HOST
   // Host uses slot count instead of byte size
-  // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
-  this->log_buffer_ = new logger::TaskLogBufferHost(total_buffer_size);
-#elif defined(USE_ESP32)
   // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
   this->log_buffer_ = new logger::TaskLogBuffer(total_buffer_size);
-#elif defined(USE_LIBRETINY)
-  // NOLINTNEXTLINE(cppcoreguidelines-owning-memory) - allocated once, never freed
-  this->log_buffer_ = new logger::TaskLogBufferLibreTiny(total_buffer_size);
-#endif
 
-#if defined(USE_ESP32) || defined(USE_LIBRETINY)
+// Zephyr needs loop working to check when CDC port is open
+#if !(defined(USE_ZEPHYR) || defined(USE_LOGGER_USB_CDC))
   // Start with loop disabled when using task buffer (unless using USB CDC on ESP32)
   // The loop will be enabled automatically when messages arrive
   this->disable_loop_when_buffer_empty_();
@@ -183,52 +179,33 @@ void Logger::init_log_buffer(size_t total_buffer_size) {
 }
 #endif
 
-#ifdef USE_ESPHOME_TASK_LOG_BUFFER
-void Logger::loop() { this->process_messages_(); }
+#if defined(USE_ESPHOME_TASK_LOG_BUFFER) || (defined(USE_ZEPHYR) && defined(USE_LOGGER_USB_CDC))
+void Logger::loop() {
+  this->process_messages_();
+#if defined(USE_ZEPHYR) && defined(USE_LOGGER_USB_CDC)
+  this->cdc_loop_();
+#endif
+}
 #endif
 
 void Logger::process_messages_() {
 #ifdef USE_ESPHOME_TASK_LOG_BUFFER
   // Process any buffered messages when available
   if (this->log_buffer_->has_messages()) {
-#ifdef USE_HOST
-    logger::TaskLogBufferHost::LogMessage *message;
-    while (this->log_buffer_->get_message_main_loop(&message)) {
-      const char *thread_name = message->thread_name[0] != '\0' ? message->thread_name : nullptr;
-      LogBuffer buf{this->tx_buffer_, this->tx_buffer_size_};
-      this->format_buffered_message_and_notify_(message->level, message->tag, message->line, thread_name, message->text,
-                                                message->text_length, buf);
-      this->log_buffer_->release_message_main_loop();
-      this->write_log_buffer_to_console_(buf);
-    }
-#elif defined(USE_ESP32)
     logger::TaskLogBuffer::LogMessage *message;
-    const char *text;
-    void *received_token;
-    while (this->log_buffer_->borrow_message_main_loop(&message, &text, &received_token)) {
+    uint16_t text_length;
+    while (this->log_buffer_->borrow_message_main_loop(message, text_length)) {
       const char *thread_name = message->thread_name[0] != '\0' ? message->thread_name : nullptr;
       LogBuffer buf{this->tx_buffer_, this->tx_buffer_size_};
-      this->format_buffered_message_and_notify_(message->level, message->tag, message->line, thread_name, text,
-                                                message->text_length, buf);
-      // Release the message to allow other tasks to use it as soon as possible
-      this->log_buffer_->release_message_main_loop(received_token);
-      this->write_log_buffer_to_console_(buf);
-    }
-#elif defined(USE_LIBRETINY)
-    logger::TaskLogBufferLibreTiny::LogMessage *message;
-    const char *text;
-    while (this->log_buffer_->borrow_message_main_loop(&message, &text)) {
-      const char *thread_name = message->thread_name[0] != '\0' ? message->thread_name : nullptr;
-      LogBuffer buf{this->tx_buffer_, this->tx_buffer_size_};
-      this->format_buffered_message_and_notify_(message->level, message->tag, message->line, thread_name, text,
-                                                message->text_length, buf);
+      this->format_buffered_message_and_notify_(message->level, message->tag, message->line, thread_name,
+                                                message->text_data(), text_length, buf);
       // Release the message to allow other tasks to use it as soon as possible
       this->log_buffer_->release_message_main_loop();
       this->write_log_buffer_to_console_(buf);
     }
-#endif
   }
-#if defined(USE_ESP32) || defined(USE_LIBRETINY)
+// Zephyr needs loop working to check when CDC port is open
+#if !(defined(USE_ZEPHYR) || defined(USE_LOGGER_USB_CDC))
   else {
     // No messages to process, disable loop if appropriate
     // This reduces overhead when there's no async logging activity

esphome/components/logger/logger.h

@@ -13,15 +13,11 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-#ifdef USE_ESPHOME_TASK_LOG_BUFFER
-#ifdef USE_HOST
+#include "log_buffer.h"
 #include "task_log_buffer_host.h"
-#elif defined(USE_ESP32)
 #include "task_log_buffer_esp32.h"
-#elif defined(USE_LIBRETINY)
 #include "task_log_buffer_libretiny.h"
-#endif
-#endif
+#include "task_log_buffer_zephyr.h"
 
 #ifdef USE_ARDUINO
 #if defined(USE_ESP8266)
@@ -97,195 +93,10 @@ struct CStrCompare {
 };
 #endif
 
-// ANSI color code last digit (30-38 range, store only last digit to save RAM)
-static constexpr char LOG_LEVEL_COLOR_DIGIT[] = {
-    '\0',  // NONE
-    '1',   // ERROR (31 = red)
-    '3',   // WARNING (33 = yellow)
-    '2',   // INFO (32 = green)
-    '5',   // CONFIG (35 = magenta)
-    '6',   // DEBUG (36 = cyan)
-    '7',   // VERBOSE (37 = gray)
-    '8',   // VERY_VERBOSE (38 = white)
-};
-
-static constexpr char LOG_LEVEL_LETTER_CHARS[] = {
-    '\0',  // NONE
-    'E',   // ERROR
-    'W',   // WARNING
-    'I',   // INFO
-    'C',   // CONFIG
-    'D',   // DEBUG
-    'V',   // VERBOSE (VERY_VERBOSE uses two 'V's)
-};
-
-// Maximum header size: 35 bytes fixed + 32 bytes tag + 16 bytes thread name = 83 bytes (45 byte safety margin)
-static constexpr uint16_t MAX_HEADER_SIZE = 128;
-
-// "0x" + 2 hex digits per byte + '\0'
-static constexpr size_t MAX_POINTER_REPRESENTATION = 2 + sizeof(void *) * 2 + 1;
-
 // Stack buffer size for retrieving thread/task names from the OS
 // macOS allows up to 64 bytes, Linux up to 16
 static constexpr size_t THREAD_NAME_BUF_SIZE = 64;
 
-// Buffer wrapper for log formatting functions
-struct LogBuffer {
-  char *data;
-  uint16_t size;
-  uint16_t pos{0};
-  // Replaces the null terminator with a newline for console output.
-  // Must be called after notify_listeners_() since listeners need null-terminated strings.
-  // Console output uses length-based writes (buf.pos), so null terminator is not needed.
-  void terminate_with_newline() {
-    if (this->pos < this->size) {
-      this->data[this->pos++] = '\n';
-    } else if (this->size > 0) {
-      // Buffer was full - replace last char with newline to ensure it's visible
-      this->data[this->size - 1] = '\n';
-      this->pos = this->size;
-    }
-  }
-  void HOT write_header(uint8_t level, const char *tag, int line, const char *thread_name) {
-    // Early return if insufficient space - intentionally don't update pos to prevent partial writes
-    if (this->pos + MAX_HEADER_SIZE > this->size)
-      return;
-
-    char *p = this->current_();
-
-    // Write ANSI color
-    this->write_ansi_color_(p, level);
-
-    // Construct: [LEVEL][tag:line]
-    *p++ = '[';
-    if (level != 0) {
-      if (level >= 7) {
-        *p++ = 'V';  // VERY_VERBOSE = "VV"
-        *p++ = 'V';
-      } else {
-        *p++ = LOG_LEVEL_LETTER_CHARS[level];
-      }
-    }
-    *p++ = ']';
-    *p++ = '[';
-
-    // Copy tag
-    this->copy_string_(p, tag);
-
-    *p++ = ':';
-
-    // Format line number without modulo operations
-    if (line > 999) [[unlikely]] {
-      int thousands = line / 1000;
-      *p++ = '0' + thousands;
-      line -= thousands * 1000;
-    }
-    int hundreds = line / 100;
-    int remainder = line - hundreds * 100;
-    int tens = remainder / 10;
-    *p++ = '0' + hundreds;
-    *p++ = '0' + tens;
-    *p++ = '0' + (remainder - tens * 10);
-    *p++ = ']';
-
-#if defined(USE_ESP32) || defined(USE_LIBRETINY) || defined(USE_ZEPHYR) || defined(USE_HOST)
-    // Write thread name with bold red color
-    if (thread_name != nullptr) {
-      this->write_ansi_color_(p, 1);  // Bold red for thread name
-      *p++ = '[';
-      this->copy_string_(p, thread_name);
-      *p++ = ']';
-      this->write_ansi_color_(p, level);  // Restore original color
-    }
-#endif
-
-    *p++ = ':';
-    *p++ = ' ';
-
-    this->pos = p - this->data;
-  }
-  void HOT format_body(const char *format, va_list args) {
-    this->format_vsnprintf_(format, args);
-    this->finalize_();
-  }
-#ifdef USE_STORE_LOG_STR_IN_FLASH
-  void HOT format_body_P(PGM_P format, va_list args) {
-    this->format_vsnprintf_P_(format, args);
-    this->finalize_();
-  }
-#endif
-  void write_body(const char *text, uint16_t text_length) {
-    this->write_(text, text_length);
-    this->finalize_();
-  }
-
- private:
-  bool full_() const { return this->pos >= this->size; }
-  uint16_t remaining_() const { return this->size - this->pos; }
-  char *current_() { return this->data + this->pos; }
-  void write_(const char *value, uint16_t length) {
-    const uint16_t available = this->remaining_();
-    const uint16_t copy_len = (length < available) ? length : available;
-    if (copy_len > 0) {
-      memcpy(this->current_(), value, copy_len);
-      this->pos += copy_len;
-    }
-  }
-  void finalize_() {
-    // Write color reset sequence
-    static constexpr uint16_t RESET_COLOR_LEN = sizeof(ESPHOME_LOG_RESET_COLOR) - 1;
-    this->write_(ESPHOME_LOG_RESET_COLOR, RESET_COLOR_LEN);
-    // Null terminate
-    this->data[this->full_() ? this->size - 1 : this->pos] = '\0';
-  }
-  void strip_trailing_newlines_() {
-    while (this->pos > 0 && this->data[this->pos - 1] == '\n')
-      this->pos--;
-  }
-  void process_vsnprintf_result_(int ret) {
-    if (ret < 0)
-      return;
-    const uint16_t rem = this->remaining_();
-    this->pos += (ret >= rem) ? (rem - 1) : static_cast<uint16_t>(ret);
-    this->strip_trailing_newlines_();
-  }
-  void format_vsnprintf_(const char *format, va_list args) {
-    if (this->full_())
-      return;
-    this->process_vsnprintf_result_(vsnprintf(this->current_(), this->remaining_(), format, args));
-  }
-#ifdef USE_STORE_LOG_STR_IN_FLASH
-  void format_vsnprintf_P_(PGM_P format, va_list args) {
-    if (this->full_())
-      return;
-    this->process_vsnprintf_result_(vsnprintf_P(this->current_(), this->remaining_(), format, args));
-  }
-#endif
-  // Write ANSI color escape sequence to buffer, updates pointer in place
-  // Caller is responsible for ensuring buffer has sufficient space
-  void write_ansi_color_(char *&p, uint8_t level) {
-    if (level == 0)
-      return;
-    // Direct buffer fill: "\033[{bold};3{color}m" (7 bytes)
-    *p++ = '\033';
-    *p++ = '[';
-    *p++ = (level == 1) ? '1' : '0';  // Only ERROR is bold
-    *p++ = ';';
-    *p++ = '3';
-    *p++ = LOG_LEVEL_COLOR_DIGIT[level];
-    *p++ = 'm';
-  }
-  // Copy string without null terminator, updates pointer in place
-  // Caller is responsible for ensuring buffer has sufficient space
-  void copy_string_(char *&p, const char *str) {
-    const size_t len = strlen(str);
-    // NOLINTNEXTLINE(bugprone-not-null-terminated-result) - intentionally no null terminator, building string piece by
-    // piece
-    memcpy(p, str, len);
-    p += len;
-  }
-};
-
 #if defined(USE_ESP32) || defined(USE_ESP8266) || defined(USE_RP2040) || defined(USE_LIBRETINY) || defined(USE_ZEPHYR)
 /** Enum for logging UART selection
  *
@@ -411,11 +222,14 @@ class Logger : public Component {
     bool &flag_;
   };
 
-#if defined(USE_ESP32) || defined(USE_HOST) || defined(USE_LIBRETINY)
+#if defined(USE_ESP32) || defined(USE_HOST) || defined(USE_LIBRETINY) || defined(USE_ZEPHYR)
   // Handles non-main thread logging only (~0.1% of calls)
   // thread_name is resolved by the caller from the task handle, avoiding redundant lookups
   void log_vprintf_non_main_thread_(uint8_t level, const char *tag, int line, const char *format, va_list args,
                                     const char *thread_name);
+#endif
+#if defined(USE_ZEPHYR) && defined(USE_LOGGER_USB_CDC)
+  void cdc_loop_();
 #endif
   void process_messages_();
   void write_msg_(const char *msg, uint16_t len);
@@ -534,13 +348,7 @@ class Logger : public Component {
   std::vector<LoggerLevelListener *> level_listeners_;  // Log level change listeners
 #endif
 #ifdef USE_ESPHOME_TASK_LOG_BUFFER
-#ifdef USE_HOST
-  logger::TaskLogBufferHost *log_buffer_{nullptr};  // Allocated once, never freed
-#elif defined(USE_ESP32)
   logger::TaskLogBuffer *log_buffer_{nullptr};  // Allocated once, never freed
-#elif defined(USE_LIBRETINY)
-  logger::TaskLogBufferLibreTiny *log_buffer_{nullptr};  // Allocated once, never freed
-#endif
 #endif
 
   // Group smaller types together at the end
@@ -552,7 +360,7 @@ class Logger : public Component {
 #ifdef USE_LIBRETINY
   UARTSelection uart_{UART_SELECTION_DEFAULT};
 #endif
-#if defined(USE_ESP32) || defined(USE_HOST) || defined(USE_LIBRETINY)
+#if defined(USE_ESP32) || defined(USE_HOST) || defined(USE_LIBRETINY) || defined(USE_ZEPHYR)
   bool main_task_recursion_guard_{false};
 #ifdef USE_LIBRETINY
   bool non_main_task_recursion_guard_{false};  // Shared guard for all non-main tasks on LibreTiny
@@ -595,8 +403,10 @@ class Logger : public Component {
   }
 
 #elif defined(USE_ZEPHYR)
-  const char *HOT get_thread_name_(std::span<char> buff) {
-    k_tid_t current_task = k_current_get();
+  const char *HOT get_thread_name_(std::span<char> buff, k_tid_t current_task = nullptr) {
+    if (current_task == nullptr) {
+      current_task = k_current_get();
+    }
     if (current_task == main_task_) {
       return nullptr;  // Main task
     }
@@ -635,7 +445,7 @@ class Logger : public Component {
   // Create RAII guard for non-main task recursion
   inline NonMainTaskRecursionGuard make_non_main_task_guard_() { return NonMainTaskRecursionGuard(log_recursion_key_); }
 
-#elif defined(USE_LIBRETINY)
+#elif defined(USE_LIBRETINY) || defined(USE_ZEPHYR)
   // LibreTiny doesn't have FreeRTOS TLS, so use a simple approach:
   // - Main task uses dedicated boolean (same as ESP32)
   // - Non-main tasks share a single recursion guard
@@ -643,6 +453,8 @@ class Logger : public Component {
   // - Recursion from logging within logging is the main concern
   // - Cross-task "recursion" is prevented by the buffer mutex anyway
   // - Missing a recursive call from another task is acceptable (falls back to direct output)
+  //
+  // Zephyr use __thread as TLS
 
   // Check if non-main task is already in recursion
   inline bool HOT is_non_main_task_recursive_() const { return non_main_task_recursion_guard_; }
@@ -651,7 +463,8 @@ class Logger : public Component {
   inline RecursionGuard make_non_main_task_guard_() { return RecursionGuard(non_main_task_recursion_guard_); }
 #endif
 
-#if defined(USE_ESP32) || defined(USE_LIBRETINY)
+// Zephyr needs loop working to check when CDC port is open
+#if defined(USE_ESPHOME_TASK_LOG_BUFFER) && !(defined(USE_ZEPHYR) || defined(USE_LOGGER_USB_CDC))
   // Disable loop when task buffer is empty (with USB CDC check on ESP32)
   inline void disable_loop_when_buffer_empty_() {
     // Thread safety note: This is safe even if another task calls enable_loop_soon_any_context()

esphome/components/logger/logger_zephyr.cpp

@@ -14,7 +14,7 @@ namespace esphome::logger {
 static const char *const TAG = "logger";
 
 #ifdef USE_LOGGER_USB_CDC
-void Logger::loop() {
+void Logger::cdc_loop_() {
   if (this->uart_ != UART_SELECTION_USB_CDC || this->uart_dev_ == nullptr) {
     return;
   }

esphome/components/logger/task_log_buffer_esp32.cpp

@@ -31,8 +31,8 @@ TaskLogBuffer::~TaskLogBuffer() {
   }
 }
 
-bool TaskLogBuffer::borrow_message_main_loop(LogMessage **message, const char **text, void **received_token) {
-  if (message == nullptr || text == nullptr || received_token == nullptr) {
+bool TaskLogBuffer::borrow_message_main_loop(LogMessage *&message, uint16_t &text_length) {
+  if (this->current_token_) {
     return false;
   }
 
@@ -43,18 +43,19 @@ bool TaskLogBuffer::borrow_message_main_loop(LogMessage **message, const char **
   }
 
   LogMessage *msg = static_cast<LogMessage *>(received_item);
-  *message = msg;
-  *text = msg->text_data();
-  *received_token = received_item;
+  message = msg;
+  text_length = msg->text_length;
+  this->current_token_ = received_item;
 
   return true;
 }
 
-void TaskLogBuffer::release_message_main_loop(void *token) {
-  if (token == nullptr) {
+void TaskLogBuffer::release_message_main_loop() {
+  if (this->current_token_ == nullptr) {
     return;
   }
-  vRingbufferReturnItem(ring_buffer_, token);
+  vRingbufferReturnItem(ring_buffer_, this->current_token_);
+  this->current_token_ = nullptr;
   // Update counter to mark all messages as processed
   last_processed_counter_ = message_counter_.load(std::memory_order_relaxed);
 }

esphome/components/logger/task_log_buffer_esp32.h

@@ -52,10 +52,10 @@ class TaskLogBuffer {
   ~TaskLogBuffer();
 
   // NOT thread-safe - borrow a message from the ring buffer, only call from main loop
-  bool borrow_message_main_loop(LogMessage **message, const char **text, void **received_token);
+  bool borrow_message_main_loop(LogMessage *&message, uint16_t &text_length);
 
   // NOT thread-safe - release a message buffer and update the counter, only call from main loop
-  void release_message_main_loop(void *token);
+  void release_message_main_loop();
 
   // Thread-safe - send a message to the ring buffer from any thread
   bool send_message_thread_safe(uint8_t level, const char *tag, uint16_t line, const char *thread_name,
@@ -78,6 +78,7 @@ class TaskLogBuffer {
   // Atomic counter for message tracking (only differences matter)
   std::atomic<uint16_t> message_counter_{0};    // Incremented when messages are committed
   mutable uint16_t last_processed_counter_{0};  // Tracks last processed message
+  void *current_token_{nullptr};
 };
 
 }  // namespace esphome::logger

esphome/components/logger/task_log_buffer_host.cpp

@@ -10,16 +10,16 @@
 
 namespace esphome::logger {
 
-TaskLogBufferHost::TaskLogBufferHost(size_t slot_count) : slot_count_(slot_count) {
+TaskLogBuffer::TaskLogBuffer(size_t slot_count) : slot_count_(slot_count) {
   // Allocate message slots
   this->slots_ = std::make_unique<LogMessage[]>(slot_count);
 }
 
-TaskLogBufferHost::~TaskLogBufferHost() {
+TaskLogBuffer::~TaskLogBuffer() {
   // unique_ptr handles cleanup automatically
 }
 
-int TaskLogBufferHost::acquire_write_slot_() {
+int TaskLogBuffer::acquire_write_slot_() {
   // Try to reserve a slot using compare-and-swap
   size_t current_reserve = this->reserve_index_.load(std::memory_order_relaxed);
 
@@ -43,7 +43,7 @@ int TaskLogBufferHost::acquire_write_slot_() {
   }
 }
 
-void TaskLogBufferHost::commit_write_slot_(int slot_index) {
+void TaskLogBuffer::commit_write_slot_(int slot_index) {
   // Mark the slot as ready for reading
   this->slots_[slot_index].ready.store(true, std::memory_order_release);
 
@@ -70,8 +70,8 @@ void TaskLogBufferHost::commit_write_slot_(int slot_index) {
   }
 }
 
-bool TaskLogBufferHost::send_message_thread_safe(uint8_t level, const char *tag, uint16_t line, const char *thread_name,
-                                                 const char *format, va_list args) {
+bool TaskLogBuffer::send_message_thread_safe(uint8_t level, const char *tag, uint16_t line, const char *thread_name,
+                                             const char *format, va_list args) {
   // Acquire a slot
   int slot_index = this->acquire_write_slot_();
   if (slot_index < 0) {
@@ -115,11 +115,7 @@ bool TaskLogBufferHost::send_message_thread_safe(uint8_t level, const char *tag,
   return true;
 }
 
-bool TaskLogBufferHost::get_message_main_loop(LogMessage **message) {
-  if (message == nullptr) {
-    return false;
-  }
-
+bool TaskLogBuffer::borrow_message_main_loop(LogMessage *&message, uint16_t &text_length) {
   size_t current_read = this->read_index_.load(std::memory_order_relaxed);
   size_t current_write = this->write_index_.load(std::memory_order_acquire);
 
@@ -134,11 +130,12 @@ bool TaskLogBufferHost::get_message_main_loop(LogMessage **message) {
     return false;
   }
 
-  *message = &msg;
+  message = &msg;
+  text_length = msg.text_length;
   return true;
 }
 
-void TaskLogBufferHost::release_message_main_loop() {
+void TaskLogBuffer::release_message_main_loop() {
   size_t current_read = this->read_index_.load(std::memory_order_relaxed);
 
   // Clear the ready flag

esphome/components/logger/task_log_buffer_host.h

@@ -21,12 +21,12 @@ namespace esphome::logger {
  *
  * Threading Model: Multi-Producer Single-Consumer (MPSC)
  * - Multiple threads can safely call send_message_thread_safe() concurrently
- * - Only the main loop thread calls get_message_main_loop() and release_message_main_loop()
+ * - Only the main loop thread calls borrow_message_main_loop() and release_message_main_loop()
  *
  *   Producers (multiple threads)              Consumer (main loop only)
  *            │                                        │
  *            ▼                                        ▼
- *     acquire_write_slot_()                  get_message_main_loop()
+ *     acquire_write_slot_()                  bool borrow_message_main_loop()
  *       CAS on reserve_index_                  read write_index_
  *            │                                   check ready flag
  *            ▼                                        │
@@ -48,7 +48,7 @@ namespace esphome::logger {
  * - Atomic CAS for slot reservation allows multiple producers without locks
  * - Single consumer (main loop) processes messages in order
  */
-class TaskLogBufferHost {
+class TaskLogBuffer {
  public:
   // Default number of message slots - host has plenty of memory
   static constexpr size_t DEFAULT_SLOT_COUNT = 64;
@@ -71,15 +71,16 @@ class TaskLogBufferHost {
       thread_name[0] = '\0';
       text[0] = '\0';
     }
+    inline char *text_data() { return this->text; }
   };
 
   /// Constructor that takes the number of message slots
-  explicit TaskLogBufferHost(size_t slot_count);
-  ~TaskLogBufferHost();
+  explicit TaskLogBuffer(size_t slot_count);
+  ~TaskLogBuffer();
 
   // NOT thread-safe - get next message from buffer, only call from main loop
   // Returns true if a message was retrieved, false if buffer is empty
-  bool get_message_main_loop(LogMessage **message);
+  bool borrow_message_main_loop(LogMessage *&message, uint16_t &text_length);
 
   // NOT thread-safe - release the message after processing, only call from main loop
   void release_message_main_loop();

esphome/components/logger/task_log_buffer_libretiny.cpp

@@ -8,7 +8,7 @@
 
 namespace esphome::logger {
 
-TaskLogBufferLibreTiny::TaskLogBufferLibreTiny(size_t total_buffer_size) {
+TaskLogBuffer::TaskLogBuffer(size_t total_buffer_size) {
   this->size_ = total_buffer_size;
   // Allocate memory for the circular buffer using ESPHome's RAM allocator
   RAMAllocator<uint8_t> allocator;
@@ -17,7 +17,7 @@ TaskLogBufferLibreTiny::TaskLogBufferLibreTiny(size_t total_buffer_size) {
   this->mutex_ = xSemaphoreCreateMutex();
 }
 
-TaskLogBufferLibreTiny::~TaskLogBufferLibreTiny() {
+TaskLogBuffer::~TaskLogBuffer() {
   if (this->mutex_ != nullptr) {
     vSemaphoreDelete(this->mutex_);
     this->mutex_ = nullptr;
@@ -29,7 +29,7 @@ TaskLogBufferLibreTiny::~TaskLogBufferLibreTiny() {
   }
 }
 
-size_t TaskLogBufferLibreTiny::available_contiguous_space() const {
+size_t TaskLogBuffer::available_contiguous_space() const {
   if (this->head_ >= this->tail_) {
     // head is ahead of or equal to tail
     // Available space is from head to end, plus from start to tail
@@ -47,11 +47,7 @@ size_t TaskLogBufferLibreTiny::available_contiguous_space() const {
   }
 }
 
-bool TaskLogBufferLibreTiny::borrow_message_main_loop(LogMessage **message, const char **text) {
-  if (message == nullptr || text == nullptr) {
-    return false;
-  }
-
+bool TaskLogBuffer::borrow_message_main_loop(LogMessage *&message, uint16_t &text_length) {
   // Check if buffer was initialized successfully
   if (this->mutex_ == nullptr || this->storage_ == nullptr) {
     return false;
@@ -77,15 +73,15 @@ bool TaskLogBufferLibreTiny::borrow_message_main_loop(LogMessage **message, cons
     this->tail_ = 0;
     msg = reinterpret_cast<LogMessage *>(this->storage_);
   }
-  *message = msg;
-  *text = msg->text_data();
+  message = msg;
+  text_length = msg->text_length;
   this->current_message_size_ = message_total_size(msg->text_length);
 
   // Keep mutex held until release_message_main_loop()
   return true;
 }
 
-void TaskLogBufferLibreTiny::release_message_main_loop() {
+void TaskLogBuffer::release_message_main_loop() {
   // Advance tail past the current message
   this->tail_ += this->current_message_size_;
 
@@ -100,8 +96,8 @@ void TaskLogBufferLibreTiny::release_message_main_loop() {
   xSemaphoreGive(this->mutex_);
 }
 
-bool TaskLogBufferLibreTiny::send_message_thread_safe(uint8_t level, const char *tag, uint16_t line,
-                                                      const char *thread_name, const char *format, va_list args) {
+bool TaskLogBuffer::send_message_thread_safe(uint8_t level, const char *tag, uint16_t line, const char *thread_name,
+                                             const char *format, va_list args) {
   // First, calculate the exact length needed using a null buffer (no actual writing)
   va_list args_copy;
   va_copy(args_copy, args);

esphome/components/logger/task_log_buffer_libretiny.h

@@ -40,7 +40,7 @@ namespace esphome::logger {
  * - Volatile counter enables fast has_messages() without lock overhead
  * - If message doesn't fit at end, padding is added and message wraps to start
  */
-class TaskLogBufferLibreTiny {
+class TaskLogBuffer {
  public:
   // Structure for a log message header (text data follows immediately after)
   struct LogMessage {
@@ -60,11 +60,11 @@ class TaskLogBufferLibreTiny {
   static constexpr uint8_t PADDING_MARKER_LEVEL = 0xFF;
 
   // Constructor that takes a total buffer size
-  explicit TaskLogBufferLibreTiny(size_t total_buffer_size);
-  ~TaskLogBufferLibreTiny();
+  explicit TaskLogBuffer(size_t total_buffer_size);
+  ~TaskLogBuffer();
 
   // NOT thread-safe - borrow a message from the buffer, only call from main loop
-  bool borrow_message_main_loop(LogMessage **message, const char **text);
+  bool borrow_message_main_loop(LogMessage *&message, uint16_t &text_length);
 
   // NOT thread-safe - release a message buffer, only call from main loop
   void release_message_main_loop();

esphome/components/logger/task_log_buffer_zephyr.cpp

@@ -0,0 +1,116 @@
+#ifdef USE_ZEPHYR
+
+#include "task_log_buffer_zephyr.h"
+
+namespace esphome::logger {
+
+__thread bool non_main_task_recursion_guard_;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
+#ifdef USE_ESPHOME_TASK_LOG_BUFFER
+
+static inline uint32_t total_size_in_32bit_words(uint16_t text_length) {
+  // Calculate total size in 32-bit words needed (header + text length + null terminator + 3(4 bytes alignment)
+  return (sizeof(TaskLogBuffer::LogMessage) + text_length + 1 + 3) / sizeof(uint32_t);
+}
+
+static inline uint32_t get_wlen(const mpsc_pbuf_generic *item) {
+  return total_size_in_32bit_words(reinterpret_cast<const TaskLogBuffer::LogMessage *>(item)->text_length);
+}
+
+TaskLogBuffer::TaskLogBuffer(size_t total_buffer_size) {
+  // alignment to 4 bytes
+  total_buffer_size = (total_buffer_size + 3) / sizeof(uint32_t);
+  this->mpsc_config_.buf = new uint32_t[total_buffer_size];
+  this->mpsc_config_.size = total_buffer_size;
+  this->mpsc_config_.flags = MPSC_PBUF_MODE_OVERWRITE;
+  this->mpsc_config_.get_wlen = get_wlen,
+
+  mpsc_pbuf_init(&this->log_buffer_, &this->mpsc_config_);
+}
+
+TaskLogBuffer::~TaskLogBuffer() { delete[] this->mpsc_config_.buf; }
+
+bool TaskLogBuffer::send_message_thread_safe(uint8_t level, const char *tag, uint16_t line, const char *thread_name,
+                                             const char *format, va_list args) {
+  // First, calculate the exact length needed using a null buffer (no actual writing)
+  va_list args_copy;
+  va_copy(args_copy, args);
+  int ret = vsnprintf(nullptr, 0, format, args_copy);
+  va_end(args_copy);
+
+  if (ret <= 0) {
+    return false;  // Formatting error or empty message
+  }
+
+  // Calculate actual text length (capped to maximum size)
+  static constexpr size_t MAX_TEXT_SIZE = 255;
+  size_t text_length = (static_cast<size_t>(ret) > MAX_TEXT_SIZE) ? MAX_TEXT_SIZE : ret;
+  size_t total_size = total_size_in_32bit_words(text_length);
+  auto *msg = reinterpret_cast<LogMessage *>(mpsc_pbuf_alloc(&this->log_buffer_, total_size, K_NO_WAIT));
+  if (msg == nullptr) {
+    return false;
+  }
+  msg->level = level;
+  msg->tag = tag;
+  msg->line = line;
+  strncpy(msg->thread_name, thread_name, sizeof(msg->thread_name) - 1);
+  msg->thread_name[sizeof(msg->thread_name) - 1] = '\0';  // Ensure null termination
+
+  // Format the message text directly into the acquired memory
+  // We add 1 to text_length to ensure space for null terminator during formatting
+  char *text_area = msg->text_data();
+  ret = vsnprintf(text_area, text_length + 1, format, args);
+
+  // Handle unexpected formatting error (ret < 0 is encoding error; ret == 0 is valid empty output)
+  if (ret < 0) {
+    // this should not happen, vsnprintf was called already once
+    // fill with '\n' to not call mpsc_pbuf_free from producer
+    // it will be trimmed anyway
+    for (size_t i = 0; i < text_length; ++i) {
+      text_area[i] = '\n';
+    }
+    text_area[text_length] = 0;
+    // do not return false to free the buffer from main thread
+  }
+
+  msg->text_length = text_length;
+
+  mpsc_pbuf_commit(&this->log_buffer_, reinterpret_cast<mpsc_pbuf_generic *>(msg));
+  return true;
+}
+
+bool TaskLogBuffer::borrow_message_main_loop(LogMessage *&message, uint16_t &text_length) {
+  if (this->current_token_) {
+    return false;
+  }
+
+  this->current_token_ = mpsc_pbuf_claim(&this->log_buffer_);
+
+  if (this->current_token_ == nullptr) {
+    return false;
+  }
+
+  // we claimed buffer already, const_cast is safe here
+  message = const_cast<LogMessage *>(reinterpret_cast<const LogMessage *>(this->current_token_));
+
+  text_length = message->text_length;
+  // Remove trailing newlines
+  while (text_length > 0 && message->text_data()[text_length - 1] == '\n') {
+    text_length--;
+  }
+
+  return true;
+}
+
+void TaskLogBuffer::release_message_main_loop() {
+  if (this->current_token_ == nullptr) {
+    return;
+  }
+  mpsc_pbuf_free(&this->log_buffer_, this->current_token_);
+  this->current_token_ = nullptr;
+}
+#endif  // USE_ESPHOME_TASK_LOG_BUFFER
+
+}  // namespace esphome::logger
+
+#endif  // USE_ZEPHYR

esphome/components/logger/task_log_buffer_zephyr.h

@@ -0,0 +1,66 @@
+#pragma once
+
+#ifdef USE_ZEPHYR
+
+#include "esphome/core/defines.h"
+#include "esphome/core/helpers.h"
+#include <zephyr/sys/mpsc_pbuf.h>
+
+namespace esphome::logger {
+
+// "0x" + 2 hex digits per byte + '\0'
+static constexpr size_t MAX_POINTER_REPRESENTATION = 2 + sizeof(void *) * 2 + 1;
+
+extern __thread bool non_main_task_recursion_guard_;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
+
+#ifdef USE_ESPHOME_TASK_LOG_BUFFER
+
+class TaskLogBuffer {
+ public:
+  // Structure for a log message header (text data follows immediately after)
+  struct LogMessage {
+    MPSC_PBUF_HDR;  // this is only 2 bits but no more than 30 bits directly after
+    uint16_t line;  // Source code line number
+    uint8_t level;  // Log level (0-7)
+#if defined(CONFIG_THREAD_NAME)
+    char thread_name[CONFIG_THREAD_MAX_NAME_LEN];  // Store thread name directly (only used for non-main threads)
+#else
+    char thread_name[MAX_POINTER_REPRESENTATION];  // Store thread name directly (only used for non-main threads)
+#endif
+    const char *tag;       // We store the pointer, assuming tags are static
+    uint16_t text_length;  // Length of the message text (up to ~64KB)
+
+    // Methods for accessing message contents
+    inline char *text_data() { return reinterpret_cast<char *>(this) + sizeof(LogMessage); }
+  };
+  // Constructor that takes a total buffer size
+  explicit TaskLogBuffer(size_t total_buffer_size);
+  ~TaskLogBuffer();
+
+  // Check if there are messages ready to be processed using an atomic counter for performance
+  inline bool HOT has_messages() { return mpsc_pbuf_is_pending(&this->log_buffer_); }
+
+  // Get the total buffer size in bytes
+  inline size_t size() const { return this->mpsc_config_.size * sizeof(uint32_t); }
+
+  // NOT thread-safe - borrow a message from the ring buffer, only call from main loop
+  bool borrow_message_main_loop(LogMessage *&message, uint16_t &text_length);
+
+  // NOT thread-safe - release a message buffer and update the counter, only call from main loop
+  void release_message_main_loop();
+
+  // Thread-safe - send a message to the ring buffer from any thread
+  bool send_message_thread_safe(uint8_t level, const char *tag, uint16_t line, const char *thread_name,
+                                const char *format, va_list args);
+
+ protected:
+  mpsc_pbuf_buffer_config mpsc_config_{};
+  mpsc_pbuf_buffer log_buffer_{};
+  const mpsc_pbuf_generic *current_token_{};
+};
+
+#endif  // USE_ESPHOME_TASK_LOG_BUFFER
+
+}  // namespace esphome::logger
+
+#endif  // USE_ZEPHYR

esphome/components/rp2040/preferences.cpp

@@ -25,8 +25,8 @@ static uint8_t
     s_flash_storage[RP2040_FLASH_STORAGE_SIZE];  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 static bool s_flash_dirty = false;               // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
 
-// Stack buffer size for preferences - covers virtually all real-world preferences without heap allocation
-static constexpr size_t PREF_BUFFER_SIZE = 64;
+// No preference can exceed the total flash storage, so stack buffer covers all cases.
+static constexpr size_t PREF_MAX_BUFFER_SIZE = RP2040_FLASH_STORAGE_SIZE;
 
 extern "C" uint8_t _EEPROM_start;
 
@@ -46,14 +46,14 @@ class RP2040PreferenceBackend : public ESPPreferenceBackend {
 
   bool save(const uint8_t *data, size_t len) override {
     const size_t buffer_size = len + 1;
-    SmallBufferWithHeapFallback<PREF_BUFFER_SIZE> buffer_alloc(buffer_size);
-    uint8_t *buffer = buffer_alloc.get();
-
+    if (buffer_size > PREF_MAX_BUFFER_SIZE)
+      return false;
+    uint8_t buffer[PREF_MAX_BUFFER_SIZE];
     memcpy(buffer, data, len);
-    buffer[len] = calculate_crc(buffer, buffer + len, type);
+    buffer[len] = calculate_crc(buffer, buffer + len, this->type);
 
     for (size_t i = 0; i < buffer_size; i++) {
-      uint32_t j = offset + i;
+      uint32_t j = this->offset + i;
       if (j >= RP2040_FLASH_STORAGE_SIZE)
         return false;
       uint8_t v = buffer[i];
@@ -66,17 +66,18 @@ class RP2040PreferenceBackend : public ESPPreferenceBackend {
   }
   bool load(uint8_t *data, size_t len) override {
     const size_t buffer_size = len + 1;
-    SmallBufferWithHeapFallback<PREF_BUFFER_SIZE> buffer_alloc(buffer_size);
-    uint8_t *buffer = buffer_alloc.get();
+    if (buffer_size > PREF_MAX_BUFFER_SIZE)
+      return false;
+    uint8_t buffer[PREF_MAX_BUFFER_SIZE];
 
     for (size_t i = 0; i < buffer_size; i++) {
-      uint32_t j = offset + i;
+      uint32_t j = this->offset + i;
       if (j >= RP2040_FLASH_STORAGE_SIZE)
         return false;
       buffer[i] = s_flash_storage[j];
     }
 
-    uint8_t crc = calculate_crc(buffer, buffer + len, type);
+    uint8_t crc = calculate_crc(buffer, buffer + len, this->type);
     if (buffer[len] != crc) {
       return false;
     }

esphome/components/web_server/web_server.h

@@ -112,10 +112,10 @@ class DeferredUpdateEventSource : public AsyncEventSource {
   /*
     This class holds a pointer to the source component that wants to publish a state event, and a pointer to a function
     that will lazily generate that event.  The two pointers allow dedup in the deferred queue if multiple publishes for
-    the same component are backed up, and take up only 8 bytes of memory.  The entry in the deferred queue (a
-    std::vector) is the DeferredEvent instance itself (not a pointer to one elsewhere in heap) so still only 8 bytes per
-    entry (and no heap fragmentation).  Even 100 backed up events (you'd have to have at least 100 sensors publishing
-    because of dedup) would take up only 0.8 kB.
+    the same component are backed up, and take up only two pointers of memory.  The entry in the deferred queue (a
+    std::vector) is the DeferredEvent instance itself (not a pointer to one elsewhere in heap) so still only two
+    pointers per entry (and no heap fragmentation).  Even 100 backed up events (you'd have to have at least 100 sensors
+    publishing because of dedup) would take up only 0.8 kB.
   */
   struct DeferredEvent {
     friend class DeferredUpdateEventSource;
@@ -130,7 +130,9 @@ class DeferredUpdateEventSource : public AsyncEventSource {
     bool operator==(const DeferredEvent &test) const {
       return (source_ == test.source_ && message_generator_ == test.message_generator_);
     }
-  } __attribute__((packed));
+  };
+  static_assert(sizeof(DeferredEvent) == sizeof(void *) + sizeof(message_generator_t *),
+                "DeferredEvent should have no padding");
 
  protected:
   // surface a couple methods from the base class

esphome/components/web_server_idf/web_server_idf.h

@@ -259,9 +259,9 @@ using message_generator_t = std::string(esphome::web_server::WebServer *, void *
 /*
   This class holds a pointer to the source component that wants to publish a state event, and a pointer to a function
   that will lazily generate that event.  The two pointers allow dedup in the deferred queue if multiple publishes for
-  the same component are backed up, and take up only 8 bytes of memory.  The entry in the deferred queue (a
-  std::vector) is the DeferredEvent instance itself (not a pointer to one elsewhere in heap) so still only 8 bytes per
-  entry (and no heap fragmentation).  Even 100 backed up events (you'd have to have at least 100 sensors publishing
+  the same component are backed up, and take up only two pointers of memory.  The entry in the deferred queue (a
+  std::vector) is the DeferredEvent instance itself (not a pointer to one elsewhere in heap) so still only two pointers
+  per entry (and no heap fragmentation).  Even 100 backed up events (you'd have to have at least 100 sensors publishing
   because of dedup) would take up only 0.8 kB.
 */
 struct DeferredEvent {
@@ -277,7 +277,9 @@ struct DeferredEvent {
   bool operator==(const DeferredEvent &test) const {
     return (source_ == test.source_ && message_generator_ == test.message_generator_);
   }
-} __attribute__((packed));
+};
+static_assert(sizeof(DeferredEvent) == sizeof(void *) + sizeof(message_generator_t *),
+              "DeferredEvent should have no padding");
 
 class AsyncEventSourceResponse {
   friend class AsyncEventSource;

esphome/core/defines.h

@@ -14,6 +14,7 @@
 #define ESPHOME_PROJECT_VERSION_30 "v2"
 #define ESPHOME_VARIANT "ESP32"
 #define ESPHOME_DEBUG_SCHEDULER
+#define ESPHOME_DEBUG_API
 
 // Default threading model for static analysis (ESP32 is multi-threaded with atomics)
 #define ESPHOME_THREAD_MULTI_ATOMICS
@@ -320,6 +321,7 @@
 #endif
 
 #ifdef USE_NRF52
+#define USE_ESPHOME_TASK_LOG_BUFFER
 #define USE_NRF52_DFU
 #define USE_NRF52_REG0_VOUT 5
 #define USE_NRF52_UICR_ERASE

tests/components/logger/test.nrf52-adafruit.yaml

@@ -5,3 +5,4 @@ esphome:
 
 logger:
   level: DEBUG
+  task_log_buffer_size: 0

tests/integration/conftest.py

@@ -197,6 +197,7 @@ async def yaml_config(request: pytest.FixtureRequest, unused_tcp_port: int) -> s
             "  platformio_options:\n"
             "    build_flags:\n"
             '      - "-DDEBUG"  # Enable assert() statements\n'
+            '      - "-DESPHOME_DEBUG_API"  # Enable API protocol asserts\n'
             '      - "-g"       # Add debug symbols',
         )