Reduce SerializationBuffer stack size from 768 to 512 bytes

768 bytes on the httpd task stack contributes to stack overflow when
combined with other stack-allocated buffers (query string parsing, etc.).
512 bytes still covers all typical JSON payloads (sensors ~200B, lights
~170B, climate ~500-700B). Only extreme edge cases with 40+ options
trigger heap fallback.

.clang-tidy.hash

@@ -1 +1 @@
-069fa9526c52f7c580a9ec17c7678d12f142221387e9b561c18f95394d4629a3
+cf3d341206b4184ec8b7fe85141aef4fe4696aa720c3f8a06d4e57930574bdab

CODEOWNERS

@@ -134,7 +134,6 @@ esphome/components/dfplayer/* @glmnet
 esphome/components/dfrobot_sen0395/* @niklasweber
 esphome/components/dht/* @OttoWinter
 esphome/components/display_menu_base/* @numo68
-esphome/components/dlms_meter/* @SimonFischer04
 esphome/components/dps310/* @kbx81
 esphome/components/ds1307/* @badbadc0ffee
 esphome/components/ds2484/* @mrk-its

esphome/components/api/user_services.h

@@ -264,9 +264,9 @@ template<typename... Ts> class APIRespondAction : public Action<Ts...> {
       // Build and send JSON response
       json::JsonBuilder builder;
       this->json_builder_(x..., builder.root());
-      std::string json_str = builder.serialize();
+      auto json_buf = builder.serialize();
       this->parent_->send_action_response(call_id, success, StringRef(error_message),
-                                          reinterpret_cast<const uint8_t *>(json_str.data()), json_str.size());
+                                          reinterpret_cast<const uint8_t *>(json_buf.data()), json_buf.size());
       return;
     }
 #endif

esphome/components/dlms_meter/__init__.py

@@ -1,57 +0,0 @@
-import esphome.codegen as cg
-from esphome.components import uart
-import esphome.config_validation as cv
-from esphome.const import CONF_ID, PLATFORM_ESP32, PLATFORM_ESP8266
-
-CODEOWNERS = ["@SimonFischer04"]
-DEPENDENCIES = ["uart"]
-
-CONF_DLMS_METER_ID = "dlms_meter_id"
-CONF_DECRYPTION_KEY = "decryption_key"
-CONF_PROVIDER = "provider"
-
-PROVIDERS = {"generic": 0, "netznoe": 1}
-
-dlms_meter_component_ns = cg.esphome_ns.namespace("dlms_meter")
-DlmsMeterComponent = dlms_meter_component_ns.class_(
-    "DlmsMeterComponent", cg.Component, uart.UARTDevice
-)
-
-
-def validate_key(value):
-    value = cv.string_strict(value)
-    if len(value) != 32:
-        raise cv.Invalid("Decryption key must be 32 hex characters (16 bytes)")
-    try:
-        return [int(value[i : i + 2], 16) for i in range(0, 32, 2)]
-    except ValueError as exc:
-        raise cv.Invalid("Decryption key must be hex values from 00 to FF") from exc
-
-
-CONFIG_SCHEMA = cv.All(
-    cv.Schema(
-        {
-            cv.GenerateID(): cv.declare_id(DlmsMeterComponent),
-            cv.Required(CONF_DECRYPTION_KEY): validate_key,
-            cv.Optional(CONF_PROVIDER, default="generic"): cv.enum(
-                PROVIDERS, lower=True
-            ),
-        }
-    )
-    .extend(uart.UART_DEVICE_SCHEMA)
-    .extend(cv.COMPONENT_SCHEMA),
-    cv.only_on([PLATFORM_ESP8266, PLATFORM_ESP32]),
-)
-
-FINAL_VALIDATE_SCHEMA = uart.final_validate_device_schema(
-    "dlms_meter", baud_rate=2400, require_rx=True
-)
-
-
-async def to_code(config):
-    var = cg.new_Pvariable(config[CONF_ID])
-    await cg.register_component(var, config)
-    await uart.register_uart_device(var, config)
-    key = ", ".join(str(b) for b in config[CONF_DECRYPTION_KEY])
-    cg.add(var.set_decryption_key(cg.RawExpression(f"{{{key}}}")))
-    cg.add(var.set_provider(PROVIDERS[config[CONF_PROVIDER]]))

esphome/components/dlms_meter/dlms.h

@@ -1,71 +0,0 @@
-#pragma once
-
-#include <cstdint>
-
-namespace esphome::dlms_meter {
-
-/*
-+-------------------------------+
-|       Ciphering Service       |
-+-------------------------------+
-|      System Title Length      |
-+-------------------------------+
-|                               |
-|                               |
-|                               |
-|            System             |
-|            Title              |
-|                               |
-|                               |
-|                               |
-+-------------------------------+
-|            Length             | (1 or 3 Bytes)
-+-------------------------------+
-|     Security Control Byte     |
-+-------------------------------+
-|                               |
-|             Frame             |
-|            Counter            |
-|                               |
-+-------------------------------+
-|                               |
-~                               ~
-        Encrypted Payload
-~                               ~
-|                               |
-+-------------------------------+
-
-Ciphering Service: 0xDB (General-Glo-Ciphering)
-System Title Length: 0x08
-System Title: Unique ID of meter
-Length: 1 Byte=Length <= 127, 3 Bytes=Length > 127 (0x82 & 2 Bytes length)
-Security Control Byte:
-- Bit 3…0: Security_Suite_Id
-- Bit 4: "A" subfield: indicates that authentication is applied
-- Bit 5: "E" subfield: indicates that encryption is applied
-- Bit 6: Key_Set subfield: 0 = Unicast, 1 = Broadcast
-- Bit 7: Indicates the use of compression.
- */
-
-static constexpr uint8_t DLMS_HEADER_LENGTH = 16;
-static constexpr uint8_t DLMS_HEADER_EXT_OFFSET = 2;  // Extra offset for extended length header
-static constexpr uint8_t DLMS_CIPHER_OFFSET = 0;
-static constexpr uint8_t DLMS_SYST_OFFSET = 1;
-static constexpr uint8_t DLMS_LENGTH_OFFSET = 10;
-static constexpr uint8_t TWO_BYTE_LENGTH = 0x82;
-static constexpr uint8_t DLMS_LENGTH_CORRECTION = 5;  // Header bytes included in length field
-static constexpr uint8_t DLMS_SECBYTE_OFFSET = 11;
-static constexpr uint8_t DLMS_FRAMECOUNTER_OFFSET = 12;
-static constexpr uint8_t DLMS_FRAMECOUNTER_LENGTH = 4;
-static constexpr uint8_t DLMS_PAYLOAD_OFFSET = 16;
-static constexpr uint8_t GLO_CIPHERING = 0xDB;
-static constexpr uint8_t DATA_NOTIFICATION = 0x0F;
-static constexpr uint8_t TIMESTAMP_DATETIME = 0x0C;
-static constexpr uint16_t MAX_MESSAGE_LENGTH = 512;  // Maximum size of message (when having 2 bytes length in header).
-
-// Provider specific quirks
-static constexpr uint8_t NETZ_NOE_MAGIC_BYTE = 0x81;  // Magic length byte used by Netz NOE
-static constexpr uint8_t NETZ_NOE_EXPECTED_MESSAGE_LENGTH = 0xF8;
-static constexpr uint8_t NETZ_NOE_EXPECTED_SECURITY_CONTROL_BYTE = 0x20;
-
-}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/dlms_meter.cpp

@@ -1,468 +0,0 @@
-#include "dlms_meter.h"
-
-#include <cmath>
-
-#if defined(USE_ESP8266_FRAMEWORK_ARDUINO)
-#include <bearssl/bearssl.h>
-#elif defined(USE_ESP32)
-#include "mbedtls/esp_config.h"
-#include "mbedtls/gcm.h"
-#endif
-
-namespace esphome::dlms_meter {
-
-static constexpr const char *TAG = "dlms_meter";
-
-void DlmsMeterComponent::dump_config() {
-  const char *provider_name = this->provider_ == PROVIDER_NETZNOE ? "Netz NOE" : "Generic";
-  ESP_LOGCONFIG(TAG,
-                "DLMS Meter:\n"
-                "  Provider: %s\n"
-                "  Read Timeout: %u ms",
-                provider_name, this->read_timeout_);
-#define DLMS_METER_LOG_SENSOR(s) LOG_SENSOR("  ", #s, this->s##_sensor_);
-  DLMS_METER_SENSOR_LIST(DLMS_METER_LOG_SENSOR, )
-#define DLMS_METER_LOG_TEXT_SENSOR(s) LOG_TEXT_SENSOR("  ", #s, this->s##_text_sensor_);
-  DLMS_METER_TEXT_SENSOR_LIST(DLMS_METER_LOG_TEXT_SENSOR, )
-}
-
-void DlmsMeterComponent::loop() {
-  // Read while data is available, netznoe uses two frames so allow 2x max frame length
-  while (this->available()) {
-    if (this->receive_buffer_.size() >= MBUS_MAX_FRAME_LENGTH * 2) {
-      ESP_LOGW(TAG, "Receive buffer full, dropping remaining bytes");
-      break;
-    }
-    uint8_t c;
-    this->read_byte(&c);
-    this->receive_buffer_.push_back(c);
-    this->last_read_ = millis();
-  }
-
-  if (!this->receive_buffer_.empty() && millis() - this->last_read_ > this->read_timeout_) {
-    this->mbus_payload_.clear();
-    if (!this->parse_mbus_(this->mbus_payload_))
-      return;
-
-    uint16_t message_length;
-    uint8_t systitle_length;
-    uint16_t header_offset;
-    if (!this->parse_dlms_(this->mbus_payload_, message_length, systitle_length, header_offset))
-      return;
-
-    if (message_length < DECODER_START_OFFSET || message_length > MAX_MESSAGE_LENGTH) {
-      ESP_LOGE(TAG, "DLMS: Message length invalid: %u", message_length);
-      this->receive_buffer_.clear();
-      return;
-    }
-
-    // Decrypt in place and then decode the OBIS codes
-    if (!this->decrypt_(this->mbus_payload_, message_length, systitle_length, header_offset))
-      return;
-    this->decode_obis_(&this->mbus_payload_[header_offset + DLMS_PAYLOAD_OFFSET], message_length);
-  }
-}
-
-bool DlmsMeterComponent::parse_mbus_(std::vector<uint8_t> &mbus_payload) {
-  ESP_LOGV(TAG, "Parsing M-Bus frames");
-  uint16_t frame_offset = 0;  // Offset is used if the M-Bus message is split into multiple frames
-
-  while (frame_offset < this->receive_buffer_.size()) {
-    // Ensure enough bytes remain for the minimal intro header before accessing indices
-    if (this->receive_buffer_.size() - frame_offset < MBUS_HEADER_INTRO_LENGTH) {
-      ESP_LOGE(TAG, "MBUS: Not enough data for frame header (need %d, have %d)", MBUS_HEADER_INTRO_LENGTH,
-               (this->receive_buffer_.size() - frame_offset));
-      this->receive_buffer_.clear();
-      return false;
-    }
-
-    // Check start bytes
-    if (this->receive_buffer_[frame_offset + MBUS_START1_OFFSET] != START_BYTE_LONG_FRAME ||
-        this->receive_buffer_[frame_offset + MBUS_START2_OFFSET] != START_BYTE_LONG_FRAME) {
-      ESP_LOGE(TAG, "MBUS: Start bytes do not match");
-      this->receive_buffer_.clear();
-      return false;
-    }
-
-    // Both length bytes must be identical
-    if (this->receive_buffer_[frame_offset + MBUS_LENGTH1_OFFSET] !=
-        this->receive_buffer_[frame_offset + MBUS_LENGTH2_OFFSET]) {
-      ESP_LOGE(TAG, "MBUS: Length bytes do not match");
-      this->receive_buffer_.clear();
-      return false;
-    }
-
-    uint8_t frame_length = this->receive_buffer_[frame_offset + MBUS_LENGTH1_OFFSET];  // Get length of this frame
-
-    // Check if received data is enough for the given frame length
-    if (this->receive_buffer_.size() - frame_offset <
-        frame_length + 3) {  // length field inside packet does not account for second start- + checksum- + stop- byte
-      ESP_LOGE(TAG, "MBUS: Frame too big for received data");
-      this->receive_buffer_.clear();
-      return false;
-    }
-
-    // Ensure we have full frame (header + payload + checksum + stop byte) before accessing stop byte
-    size_t required_total =
-        frame_length + MBUS_HEADER_INTRO_LENGTH + MBUS_FOOTER_LENGTH;  // payload + header + 2 footer bytes
-    if (this->receive_buffer_.size() - frame_offset < required_total) {
-      ESP_LOGE(TAG, "MBUS: Incomplete frame (need %d, have %d)", (unsigned int) required_total,
-               this->receive_buffer_.size() - frame_offset);
-      this->receive_buffer_.clear();
-      return false;
-    }
-
-    if (this->receive_buffer_[frame_offset + frame_length + MBUS_HEADER_INTRO_LENGTH + MBUS_FOOTER_LENGTH - 1] !=
-        STOP_BYTE) {
-      ESP_LOGE(TAG, "MBUS: Invalid stop byte");
-      this->receive_buffer_.clear();
-      return false;
-    }
-
-    // Verify checksum: sum of all bytes starting at MBUS_HEADER_INTRO_LENGTH, take last byte
-    uint8_t checksum = 0;  // use uint8_t so only the 8 least significant bits are stored
-    for (uint16_t i = 0; i < frame_length; i++) {
-      checksum += this->receive_buffer_[frame_offset + MBUS_HEADER_INTRO_LENGTH + i];
-    }
-    if (checksum != this->receive_buffer_[frame_offset + frame_length + MBUS_HEADER_INTRO_LENGTH]) {
-      ESP_LOGE(TAG, "MBUS: Invalid checksum: %x != %x", checksum,
-               this->receive_buffer_[frame_offset + frame_length + MBUS_HEADER_INTRO_LENGTH]);
-      this->receive_buffer_.clear();
-      return false;
-    }
-
-    mbus_payload.insert(mbus_payload.end(), &this->receive_buffer_[frame_offset + MBUS_FULL_HEADER_LENGTH],
-                        &this->receive_buffer_[frame_offset + MBUS_HEADER_INTRO_LENGTH + frame_length]);
-
-    frame_offset += MBUS_HEADER_INTRO_LENGTH + frame_length + MBUS_FOOTER_LENGTH;
-  }
-  return true;
-}
-
-bool DlmsMeterComponent::parse_dlms_(const std::vector<uint8_t> &mbus_payload, uint16_t &message_length,
-                                     uint8_t &systitle_length, uint16_t &header_offset) {
-  ESP_LOGV(TAG, "Parsing DLMS header");
-  if (mbus_payload.size() < DLMS_HEADER_LENGTH + DLMS_HEADER_EXT_OFFSET) {
-    ESP_LOGE(TAG, "DLMS: Payload too short");
-    this->receive_buffer_.clear();
-    return false;
-  }
-
-  if (mbus_payload[DLMS_CIPHER_OFFSET] != GLO_CIPHERING) {  // Only general-glo-ciphering is supported (0xDB)
-    ESP_LOGE(TAG, "DLMS: Unsupported cipher");
-    this->receive_buffer_.clear();
-    return false;
-  }
-
-  systitle_length = mbus_payload[DLMS_SYST_OFFSET];
-
-  if (systitle_length != 0x08) {  // Only system titles with length of 8 are supported
-    ESP_LOGE(TAG, "DLMS: Unsupported system title length");
-    this->receive_buffer_.clear();
-    return false;
-  }
-
-  message_length = mbus_payload[DLMS_LENGTH_OFFSET];
-  header_offset = 0;
-
-  if (this->provider_ == PROVIDER_NETZNOE) {
-    // for some reason EVN seems to set the standard "length" field to 0x81 and then the actual length is in the next
-    // byte. Check some bytes to see if received data still matches expectation
-    if (message_length == NETZ_NOE_MAGIC_BYTE &&
-        mbus_payload[DLMS_LENGTH_OFFSET + 1] == NETZ_NOE_EXPECTED_MESSAGE_LENGTH &&
-        mbus_payload[DLMS_LENGTH_OFFSET + 2] == NETZ_NOE_EXPECTED_SECURITY_CONTROL_BYTE) {
-      message_length = mbus_payload[DLMS_LENGTH_OFFSET + 1];
-      header_offset = 1;
-    } else {
-      ESP_LOGE(TAG, "Wrong Length - Security Control Byte sequence detected for provider EVN");
-    }
-  } else {
-    if (message_length == TWO_BYTE_LENGTH) {
-      message_length = encode_uint16(mbus_payload[DLMS_LENGTH_OFFSET + 1], mbus_payload[DLMS_LENGTH_OFFSET + 2]);
-      header_offset = DLMS_HEADER_EXT_OFFSET;
-    }
-  }
-  if (message_length < DLMS_LENGTH_CORRECTION) {
-    ESP_LOGE(TAG, "DLMS: Message length too short: %u", message_length);
-    this->receive_buffer_.clear();
-    return false;
-  }
-  message_length -= DLMS_LENGTH_CORRECTION;  // Correct message length due to part of header being included in length
-
-  if (mbus_payload.size() - DLMS_HEADER_LENGTH - header_offset != message_length) {
-    ESP_LOGV(TAG, "DLMS: Length mismatch - payload=%d, header=%d, offset=%d, message=%d", mbus_payload.size(),
-             DLMS_HEADER_LENGTH, header_offset, message_length);
-    ESP_LOGE(TAG, "DLMS: Message has invalid length");
-    this->receive_buffer_.clear();
-    return false;
-  }
-
-  if (mbus_payload[header_offset + DLMS_SECBYTE_OFFSET] != 0x21 &&
-      mbus_payload[header_offset + DLMS_SECBYTE_OFFSET] !=
-          0x20) {  // Only certain security suite is supported (0x21 || 0x20)
-    ESP_LOGE(TAG, "DLMS: Unsupported security control byte");
-    this->receive_buffer_.clear();
-    return false;
-  }
-
-  return true;
-}
-
-bool DlmsMeterComponent::decrypt_(std::vector<uint8_t> &mbus_payload, uint16_t message_length, uint8_t systitle_length,
-                                  uint16_t header_offset) {
-  ESP_LOGV(TAG, "Decrypting payload");
-  uint8_t iv[12];  // Reserve space for the IV, always 12 bytes
-  // Copy system title to IV (System title is before length; no header offset needed!)
-  // Add 1 to the offset in order to skip the system title length byte
-  memcpy(&iv[0], &mbus_payload[DLMS_SYST_OFFSET + 1], systitle_length);
-  memcpy(&iv[8], &mbus_payload[header_offset + DLMS_FRAMECOUNTER_OFFSET],
-         DLMS_FRAMECOUNTER_LENGTH);  // Copy frame counter to IV
-
-  uint8_t *payload_ptr = &mbus_payload[header_offset + DLMS_PAYLOAD_OFFSET];
-
-#if defined(USE_ESP8266_FRAMEWORK_ARDUINO)
-  br_gcm_context gcm_ctx;
-  br_aes_ct_ctr_keys bc;
-  br_aes_ct_ctr_init(&bc, this->decryption_key_.data(), this->decryption_key_.size());
-  br_gcm_init(&gcm_ctx, &bc.vtable, br_ghash_ctmul32);
-  br_gcm_reset(&gcm_ctx, iv, sizeof(iv));
-  br_gcm_flip(&gcm_ctx);
-  br_gcm_run(&gcm_ctx, 0, payload_ptr, message_length);
-#elif defined(USE_ESP32)
-  size_t outlen = 0;
-  mbedtls_gcm_context gcm_ctx;
-  mbedtls_gcm_init(&gcm_ctx);
-  mbedtls_gcm_setkey(&gcm_ctx, MBEDTLS_CIPHER_ID_AES, this->decryption_key_.data(), this->decryption_key_.size() * 8);
-  mbedtls_gcm_starts(&gcm_ctx, MBEDTLS_GCM_DECRYPT, iv, sizeof(iv));
-  auto ret = mbedtls_gcm_update(&gcm_ctx, payload_ptr, message_length, payload_ptr, message_length, &outlen);
-  mbedtls_gcm_free(&gcm_ctx);
-  if (ret != 0) {
-    ESP_LOGE(TAG, "Decryption failed with error: %d", ret);
-    this->receive_buffer_.clear();
-    return false;
-  }
-#else
-#error "Invalid Platform"
-#endif
-
-  if (payload_ptr[0] != DATA_NOTIFICATION || payload_ptr[5] != TIMESTAMP_DATETIME) {
-    ESP_LOGE(TAG, "OBIS: Packet was decrypted but data is invalid");
-    this->receive_buffer_.clear();
-    return false;
-  }
-  ESP_LOGV(TAG, "Decrypted payload: %d bytes", message_length);
-  return true;
-}
-
-void DlmsMeterComponent::decode_obis_(uint8_t *plaintext, uint16_t message_length) {
-  ESP_LOGV(TAG, "Decoding payload");
-  MeterData data{};
-  uint16_t current_position = DECODER_START_OFFSET;
-  bool power_factor_found = false;
-
-  while (current_position + OBIS_CODE_OFFSET <= message_length) {
-    if (plaintext[current_position + OBIS_TYPE_OFFSET] != DataType::OCTET_STRING) {
-      ESP_LOGE(TAG, "OBIS: Unsupported OBIS header type: %x", plaintext[current_position + OBIS_TYPE_OFFSET]);
-      this->receive_buffer_.clear();
-      return;
-    }
-
-    uint8_t obis_code_length = plaintext[current_position + OBIS_LENGTH_OFFSET];
-    if (obis_code_length != OBIS_CODE_LENGTH_STANDARD && obis_code_length != OBIS_CODE_LENGTH_EXTENDED) {
-      ESP_LOGE(TAG, "OBIS: Unsupported OBIS header length: %x", obis_code_length);
-      this->receive_buffer_.clear();
-      return;
-    }
-    if (current_position + OBIS_CODE_OFFSET + obis_code_length > message_length) {
-      ESP_LOGE(TAG, "OBIS: Buffer too short for OBIS code");
-      this->receive_buffer_.clear();
-      return;
-    }
-
-    uint8_t *obis_code = &plaintext[current_position + OBIS_CODE_OFFSET];
-    uint8_t obis_medium = obis_code[OBIS_A];
-    uint16_t obis_cd = encode_uint16(obis_code[OBIS_C], obis_code[OBIS_D]);
-
-    bool timestamp_found = false;
-    bool meter_number_found = false;
-    if (this->provider_ == PROVIDER_NETZNOE) {
-      // Do not advance Position when reading the Timestamp at DECODER_START_OFFSET
-      if ((obis_code_length == OBIS_CODE_LENGTH_EXTENDED) && (current_position == DECODER_START_OFFSET)) {
-        timestamp_found = true;
-      } else if (power_factor_found) {
-        meter_number_found = true;
-        power_factor_found = false;
-      } else {
-        current_position += obis_code_length + OBIS_CODE_OFFSET;  // Advance past code and position
-      }
-    } else {
-      current_position += obis_code_length + OBIS_CODE_OFFSET;  // Advance past code, position and type
-    }
-    if (!timestamp_found && !meter_number_found && obis_medium != Medium::ELECTRICITY &&
-        obis_medium != Medium::ABSTRACT) {
-      ESP_LOGE(TAG, "OBIS: Unsupported OBIS medium: %x", obis_medium);
-      this->receive_buffer_.clear();
-      return;
-    }
-
-    if (current_position >= message_length) {
-      ESP_LOGE(TAG, "OBIS: Buffer too short for data type");
-      this->receive_buffer_.clear();
-      return;
-    }
-
-    float value = 0.0f;
-    uint8_t value_size = 0;
-    uint8_t data_type = plaintext[current_position];
-    current_position++;
-
-    switch (data_type) {
-      case DataType::DOUBLE_LONG_UNSIGNED: {
-        value_size = 4;
-        if (current_position + value_size > message_length) {
-          ESP_LOGE(TAG, "OBIS: Buffer too short for DOUBLE_LONG_UNSIGNED");
-          this->receive_buffer_.clear();
-          return;
-        }
-        value = encode_uint32(plaintext[current_position + 0], plaintext[current_position + 1],
-                              plaintext[current_position + 2], plaintext[current_position + 3]);
-        current_position += value_size;
-        break;
-      }
-      case DataType::LONG_UNSIGNED: {
-        value_size = 2;
-        if (current_position + value_size > message_length) {
-          ESP_LOGE(TAG, "OBIS: Buffer too short for LONG_UNSIGNED");
-          this->receive_buffer_.clear();
-          return;
-        }
-        value = encode_uint16(plaintext[current_position + 0], plaintext[current_position + 1]);
-        current_position += value_size;
-        break;
-      }
-      case DataType::OCTET_STRING: {
-        uint8_t data_length = plaintext[current_position];
-        current_position++;  // Advance past string length
-        if (current_position + data_length > message_length) {
-          ESP_LOGE(TAG, "OBIS: Buffer too short for OCTET_STRING");
-          this->receive_buffer_.clear();
-          return;
-        }
-        // Handle timestamp (normal OBIS code or NETZNOE special case)
-        if (obis_cd == OBIS_TIMESTAMP || timestamp_found) {
-          if (data_length < 8) {
-            ESP_LOGE(TAG, "OBIS: Timestamp data too short: %u", data_length);
-            this->receive_buffer_.clear();
-            return;
-          }
-          uint16_t year = encode_uint16(plaintext[current_position + 0], plaintext[current_position + 1]);
-          uint8_t month = plaintext[current_position + 2];
-          uint8_t day = plaintext[current_position + 3];
-          uint8_t hour = plaintext[current_position + 5];
-          uint8_t minute = plaintext[current_position + 6];
-          uint8_t second = plaintext[current_position + 7];
-          if (year > 9999 || month > 12 || day > 31 || hour > 23 || minute > 59 || second > 59) {
-            ESP_LOGE(TAG, "Invalid timestamp values: %04u-%02u-%02uT%02u:%02u:%02uZ", year, month, day, hour, minute,
-                     second);
-            this->receive_buffer_.clear();
-            return;
-          }
-          snprintf(data.timestamp, sizeof(data.timestamp), "%04u-%02u-%02uT%02u:%02u:%02uZ", year, month, day, hour,
-                   minute, second);
-        } else if (meter_number_found) {
-          snprintf(data.meternumber, sizeof(data.meternumber), "%.*s", data_length, &plaintext[current_position]);
-        }
-        current_position += data_length;
-        break;
-      }
-      default:
-        ESP_LOGE(TAG, "OBIS: Unsupported OBIS data type: %x", data_type);
-        this->receive_buffer_.clear();
-        return;
-    }
-
-    // Skip break after data
-    if (this->provider_ == PROVIDER_NETZNOE) {
-      // Don't skip the break on the first timestamp, as there's none
-      if (!timestamp_found) {
-        current_position += 2;
-      }
-    } else {
-      current_position += 2;
-    }
-
-    // Check for additional data (scaler-unit structure)
-    if (current_position < message_length && plaintext[current_position] == DataType::INTEGER) {
-      // Apply scaler: real_value = raw_value × 10^scaler
-      if (current_position + 1 < message_length) {
-        int8_t scaler = static_cast<int8_t>(plaintext[current_position + 1]);
-        if (scaler != 0) {
-          value *= powf(10.0f, scaler);
-        }
-      }
-
-      // on EVN Meters there is no additional break
-      if (this->provider_ == PROVIDER_NETZNOE) {
-        current_position += 4;
-      } else {
-        current_position += 6;
-      }
-    }
-
-    // Handle numeric values (LONG_UNSIGNED and DOUBLE_LONG_UNSIGNED)
-    if (value_size > 0) {
-      switch (obis_cd) {
-        case OBIS_VOLTAGE_L1:
-          data.voltage_l1 = value;
-          break;
-        case OBIS_VOLTAGE_L2:
-          data.voltage_l2 = value;
-          break;
-        case OBIS_VOLTAGE_L3:
-          data.voltage_l3 = value;
-          break;
-        case OBIS_CURRENT_L1:
-          data.current_l1 = value;
-          break;
-        case OBIS_CURRENT_L2:
-          data.current_l2 = value;
-          break;
-        case OBIS_CURRENT_L3:
-          data.current_l3 = value;
-          break;
-        case OBIS_ACTIVE_POWER_PLUS:
-          data.active_power_plus = value;
-          break;
-        case OBIS_ACTIVE_POWER_MINUS:
-          data.active_power_minus = value;
-          break;
-        case OBIS_ACTIVE_ENERGY_PLUS:
-          data.active_energy_plus = value;
-          break;
-        case OBIS_ACTIVE_ENERGY_MINUS:
-          data.active_energy_minus = value;
-          break;
-        case OBIS_REACTIVE_ENERGY_PLUS:
-          data.reactive_energy_plus = value;
-          break;
-        case OBIS_REACTIVE_ENERGY_MINUS:
-          data.reactive_energy_minus = value;
-          break;
-        case OBIS_POWER_FACTOR:
-          data.power_factor = value;
-          power_factor_found = true;
-          break;
-        default:
-          ESP_LOGW(TAG, "Unsupported OBIS code 0x%04X", obis_cd);
-      }
-    }
-  }
-
-  this->receive_buffer_.clear();
-
-  ESP_LOGI(TAG, "Received valid data");
-  this->publish_sensors(data);
-  this->status_clear_warning();
-}
-
-}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/dlms_meter.h

@@ -1,96 +0,0 @@
-#pragma once
-
-#include "esphome/core/component.h"
-#include "esphome/core/defines.h"
-#include "esphome/core/log.h"
-#ifdef USE_SENSOR
-#include "esphome/components/sensor/sensor.h"
-#endif
-#ifdef USE_TEXT_SENSOR
-#include "esphome/components/text_sensor/text_sensor.h"
-#endif
-#include "esphome/components/uart/uart.h"
-
-#include "mbus.h"
-#include "dlms.h"
-#include "obis.h"
-
-#include <array>
-#include <vector>
-
-namespace esphome::dlms_meter {
-
-#ifndef DLMS_METER_SENSOR_LIST
-#define DLMS_METER_SENSOR_LIST(F, SEP)
-#endif
-
-#ifndef DLMS_METER_TEXT_SENSOR_LIST
-#define DLMS_METER_TEXT_SENSOR_LIST(F, SEP)
-#endif
-
-struct MeterData {
-  float voltage_l1 = 0.0f;             // Voltage L1
-  float voltage_l2 = 0.0f;             // Voltage L2
-  float voltage_l3 = 0.0f;             // Voltage L3
-  float current_l1 = 0.0f;             // Current L1
-  float current_l2 = 0.0f;             // Current L2
-  float current_l3 = 0.0f;             // Current L3
-  float active_power_plus = 0.0f;      // Active power taken from grid
-  float active_power_minus = 0.0f;     // Active power put into grid
-  float active_energy_plus = 0.0f;     // Active energy taken from grid
-  float active_energy_minus = 0.0f;    // Active energy put into grid
-  float reactive_energy_plus = 0.0f;   // Reactive energy taken from grid
-  float reactive_energy_minus = 0.0f;  // Reactive energy put into grid
-  char timestamp[27]{};                // Text sensor for the timestamp value
-
-  // Netz NOE
-  float power_factor = 0.0f;  // Power Factor
-  char meternumber[13]{};     // Text sensor for the meterNumber value
-};
-
-// Provider constants
-enum Providers : uint32_t { PROVIDER_GENERIC = 0x00, PROVIDER_NETZNOE = 0x01 };
-
-class DlmsMeterComponent : public Component, public uart::UARTDevice {
- public:
-  DlmsMeterComponent() = default;
-
-  void dump_config() override;
-  void loop() override;
-
-  void set_decryption_key(const std::array<uint8_t, 16> &key) { this->decryption_key_ = key; }
-  void set_provider(uint32_t provider) { this->provider_ = provider; }
-
-  void publish_sensors(MeterData &data) {
-#define DLMS_METER_PUBLISH_SENSOR(s) \
-  if (this->s##_sensor_ != nullptr) \
-    s##_sensor_->publish_state(data.s);
-    DLMS_METER_SENSOR_LIST(DLMS_METER_PUBLISH_SENSOR, )
-
-#define DLMS_METER_PUBLISH_TEXT_SENSOR(s) \
-  if (this->s##_text_sensor_ != nullptr) \
-    s##_text_sensor_->publish_state(data.s);
-    DLMS_METER_TEXT_SENSOR_LIST(DLMS_METER_PUBLISH_TEXT_SENSOR, )
-  }
-
-  DLMS_METER_SENSOR_LIST(SUB_SENSOR, )
-  DLMS_METER_TEXT_SENSOR_LIST(SUB_TEXT_SENSOR, )
-
- protected:
-  bool parse_mbus_(std::vector<uint8_t> &mbus_payload);
-  bool parse_dlms_(const std::vector<uint8_t> &mbus_payload, uint16_t &message_length, uint8_t &systitle_length,
-                   uint16_t &header_offset);
-  bool decrypt_(std::vector<uint8_t> &mbus_payload, uint16_t message_length, uint8_t systitle_length,
-                uint16_t header_offset);
-  void decode_obis_(uint8_t *plaintext, uint16_t message_length);
-
-  std::vector<uint8_t> receive_buffer_;  // Stores the packet currently being received
-  std::vector<uint8_t> mbus_payload_;    // Parsed M-Bus payload, reused to avoid heap churn
-  uint32_t last_read_ = 0;               // Timestamp when data was last read
-  uint32_t read_timeout_ = 1000;         // Time to wait after last byte before considering data complete
-
-  uint32_t provider_ = PROVIDER_GENERIC;  // Provider of the meter / your grid operator
-  std::array<uint8_t, 16> decryption_key_;
-};
-
-}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/mbus.h

@@ -1,69 +0,0 @@
-#pragma once
-
-#include <cstdint>
-
-namespace esphome::dlms_meter {
-
-/*
-+----------------------------------------------------+ -
-|               Start Character [0x68]               |  \
-+----------------------------------------------------+   |
-|                   Data Length (L)                  |   |
-+----------------------------------------------------+   |
-|               Data Length Repeat (L)               |   |
-+----------------------------------------------------+    > M-Bus Data link layer
-|            Start Character Repeat [0x68]           |   |
-+----------------------------------------------------+   |
-|             Control/Function Field (C)             |   |
-+----------------------------------------------------+   |
-|                  Address Field (A)                 |  /
-+----------------------------------------------------+ -
-|           Control Information Field (CI)           |  \
-+----------------------------------------------------+   |
-|    Source Transport Service Access Point (STSAP)   |    > DLMS/COSEM M-Bus transport layer
-+----------------------------------------------------+   |
-| Destination Transport Service Access Point (DTSAP) |  /
-+----------------------------------------------------+ -
-|                                                    |  \
-~                                                    ~   |
-                         Data                             > DLMS/COSEM Application Layer
-~                                                    ~   |
-|                                                    |  /
-+----------------------------------------------------+ -
-|                      Checksum                      |  \
-+----------------------------------------------------+    > M-Bus Data link layer
-|                Stop Character [0x16]               |  /
-+----------------------------------------------------+ -
-
-Data_Length = L - C - A - CI
-Each line (except Data) is one Byte
-
-Possible Values found in publicly available docs:
-- C: 0x53/0x73 (SND_UD)
-- A: FF (Broadcast)
-- CI: 0x00-0x1F/0x60/0x61/0x7C/0x7D
-- STSAP: 0x01 (Management Logical Device ID 1 of the meter)
-- DTSAP: 0x67 (Consumer Information Push Client ID 103)
- */
-
-// MBUS start bytes for different telegram formats:
-// - Single Character: 0xE5 (length=1)
-// - Short Frame: 0x10 (length=5)
-// - Control Frame: 0x68 (length=9)
-// - Long Frame: 0x68 (length=9+data_length)
-// This component currently only uses Long Frame.
-static constexpr uint8_t START_BYTE_SINGLE_CHARACTER = 0xE5;
-static constexpr uint8_t START_BYTE_SHORT_FRAME = 0x10;
-static constexpr uint8_t START_BYTE_CONTROL_FRAME = 0x68;
-static constexpr uint8_t START_BYTE_LONG_FRAME = 0x68;
-static constexpr uint8_t MBUS_HEADER_INTRO_LENGTH = 4;  // Header length for the intro (0x68, length, length, 0x68)
-static constexpr uint8_t MBUS_FULL_HEADER_LENGTH = 9;   // Total header length
-static constexpr uint8_t MBUS_FOOTER_LENGTH = 2;        // Footer after frame
-static constexpr uint8_t MBUS_MAX_FRAME_LENGTH = 250;   // Maximum size of frame
-static constexpr uint8_t MBUS_START1_OFFSET = 0;        // Offset of first start byte
-static constexpr uint8_t MBUS_LENGTH1_OFFSET = 1;       // Offset of first length byte
-static constexpr uint8_t MBUS_LENGTH2_OFFSET = 2;       // Offset of (duplicated) second length byte
-static constexpr uint8_t MBUS_START2_OFFSET = 3;        // Offset of (duplicated) second start byte
-static constexpr uint8_t STOP_BYTE = 0x16;
-
-}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/obis.h

@@ -1,94 +0,0 @@
-#pragma once
-
-#include <cstdint>
-
-namespace esphome::dlms_meter {
-
-// Data types as per specification
-enum DataType {
-  NULL_DATA = 0x00,
-  BOOLEAN = 0x03,
-  BIT_STRING = 0x04,
-  DOUBLE_LONG = 0x05,
-  DOUBLE_LONG_UNSIGNED = 0x06,
-  OCTET_STRING = 0x09,
-  VISIBLE_STRING = 0x0A,
-  UTF8_STRING = 0x0C,
-  BINARY_CODED_DECIMAL = 0x0D,
-  INTEGER = 0x0F,
-  LONG = 0x10,
-  UNSIGNED = 0x11,
-  LONG_UNSIGNED = 0x12,
-  LONG64 = 0x14,
-  LONG64_UNSIGNED = 0x15,
-  ENUM = 0x16,
-  FLOAT32 = 0x17,
-  FLOAT64 = 0x18,
-  DATE_TIME = 0x19,
-  DATE = 0x1A,
-  TIME = 0x1B,
-
-  ARRAY = 0x01,
-  STRUCTURE = 0x02,
-  COMPACT_ARRAY = 0x13
-};
-
-enum Medium {
-  ABSTRACT = 0x00,
-  ELECTRICITY = 0x01,
-  HEAT_COST_ALLOCATOR = 0x04,
-  COOLING = 0x05,
-  HEAT = 0x06,
-  GAS = 0x07,
-  COLD_WATER = 0x08,
-  HOT_WATER = 0x09,
-  OIL = 0x10,
-  COMPRESSED_AIR = 0x11,
-  NITROGEN = 0x12
-};
-
-// Data structure
-static constexpr uint8_t DECODER_START_OFFSET = 20;  // Skip header, timestamp and break block
-static constexpr uint8_t OBIS_TYPE_OFFSET = 0;
-static constexpr uint8_t OBIS_LENGTH_OFFSET = 1;
-static constexpr uint8_t OBIS_CODE_OFFSET = 2;
-static constexpr uint8_t OBIS_CODE_LENGTH_STANDARD = 0x06;  // 6-byte OBIS code (A.B.C.D.E.F)
-static constexpr uint8_t OBIS_CODE_LENGTH_EXTENDED = 0x0C;  // 12-byte extended OBIS code
-static constexpr uint8_t OBIS_A = 0;
-static constexpr uint8_t OBIS_B = 1;
-static constexpr uint8_t OBIS_C = 2;
-static constexpr uint8_t OBIS_D = 3;
-static constexpr uint8_t OBIS_E = 4;
-static constexpr uint8_t OBIS_F = 5;
-
-// Metadata
-static constexpr uint16_t OBIS_TIMESTAMP = 0x0100;
-static constexpr uint16_t OBIS_SERIAL_NUMBER = 0x6001;
-static constexpr uint16_t OBIS_DEVICE_NAME = 0x2A00;
-
-// Voltage
-static constexpr uint16_t OBIS_VOLTAGE_L1 = 0x2007;
-static constexpr uint16_t OBIS_VOLTAGE_L2 = 0x3407;
-static constexpr uint16_t OBIS_VOLTAGE_L3 = 0x4807;
-
-// Current
-static constexpr uint16_t OBIS_CURRENT_L1 = 0x1F07;
-static constexpr uint16_t OBIS_CURRENT_L2 = 0x3307;
-static constexpr uint16_t OBIS_CURRENT_L3 = 0x4707;
-
-// Power
-static constexpr uint16_t OBIS_ACTIVE_POWER_PLUS = 0x0107;
-static constexpr uint16_t OBIS_ACTIVE_POWER_MINUS = 0x0207;
-
-// Active energy
-static constexpr uint16_t OBIS_ACTIVE_ENERGY_PLUS = 0x0108;
-static constexpr uint16_t OBIS_ACTIVE_ENERGY_MINUS = 0x0208;
-
-// Reactive energy
-static constexpr uint16_t OBIS_REACTIVE_ENERGY_PLUS = 0x0308;
-static constexpr uint16_t OBIS_REACTIVE_ENERGY_MINUS = 0x0408;
-
-// Netz NOE specific
-static constexpr uint16_t OBIS_POWER_FACTOR = 0x0D07;
-
-}  // namespace esphome::dlms_meter

esphome/components/dlms_meter/sensor/__init__.py

@@ -1,124 +0,0 @@
-import esphome.codegen as cg
-from esphome.components import sensor
-import esphome.config_validation as cv
-from esphome.const import (
-    CONF_ID,
-    DEVICE_CLASS_CURRENT,
-    DEVICE_CLASS_ENERGY,
-    DEVICE_CLASS_POWER,
-    DEVICE_CLASS_POWER_FACTOR,
-    DEVICE_CLASS_VOLTAGE,
-    STATE_CLASS_MEASUREMENT,
-    STATE_CLASS_TOTAL_INCREASING,
-    UNIT_AMPERE,
-    UNIT_VOLT,
-    UNIT_WATT,
-    UNIT_WATT_HOURS,
-)
-
-from .. import CONF_DLMS_METER_ID, DlmsMeterComponent
-
-AUTO_LOAD = ["dlms_meter"]
-
-CONFIG_SCHEMA = cv.Schema(
-    {
-        cv.GenerateID(CONF_DLMS_METER_ID): cv.use_id(DlmsMeterComponent),
-        cv.Optional("voltage_l1"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_VOLT,
-            accuracy_decimals=1,
-            device_class=DEVICE_CLASS_VOLTAGE,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("voltage_l2"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_VOLT,
-            accuracy_decimals=1,
-            device_class=DEVICE_CLASS_VOLTAGE,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("voltage_l3"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_VOLT,
-            accuracy_decimals=1,
-            device_class=DEVICE_CLASS_VOLTAGE,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("current_l1"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_AMPERE,
-            accuracy_decimals=2,
-            device_class=DEVICE_CLASS_CURRENT,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("current_l2"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_AMPERE,
-            accuracy_decimals=2,
-            device_class=DEVICE_CLASS_CURRENT,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("current_l3"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_AMPERE,
-            accuracy_decimals=2,
-            device_class=DEVICE_CLASS_CURRENT,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("active_power_plus"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_WATT,
-            accuracy_decimals=0,
-            device_class=DEVICE_CLASS_POWER,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("active_power_minus"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_WATT,
-            accuracy_decimals=0,
-            device_class=DEVICE_CLASS_POWER,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-        cv.Optional("active_energy_plus"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_WATT_HOURS,
-            accuracy_decimals=0,
-            device_class=DEVICE_CLASS_ENERGY,
-            state_class=STATE_CLASS_TOTAL_INCREASING,
-        ),
-        cv.Optional("active_energy_minus"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_WATT_HOURS,
-            accuracy_decimals=0,
-            device_class=DEVICE_CLASS_ENERGY,
-            state_class=STATE_CLASS_TOTAL_INCREASING,
-        ),
-        cv.Optional("reactive_energy_plus"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_WATT_HOURS,
-            accuracy_decimals=0,
-            device_class=DEVICE_CLASS_ENERGY,
-            state_class=STATE_CLASS_TOTAL_INCREASING,
-        ),
-        cv.Optional("reactive_energy_minus"): sensor.sensor_schema(
-            unit_of_measurement=UNIT_WATT_HOURS,
-            accuracy_decimals=0,
-            device_class=DEVICE_CLASS_ENERGY,
-            state_class=STATE_CLASS_TOTAL_INCREASING,
-        ),
-        # Netz NOE
-        cv.Optional("power_factor"): sensor.sensor_schema(
-            accuracy_decimals=3,
-            device_class=DEVICE_CLASS_POWER_FACTOR,
-            state_class=STATE_CLASS_MEASUREMENT,
-        ),
-    }
-).extend(cv.COMPONENT_SCHEMA)
-
-
-async def to_code(config):
-    hub = await cg.get_variable(config[CONF_DLMS_METER_ID])
-
-    sensors = []
-    for key, conf in config.items():
-        if not isinstance(conf, dict):
-            continue
-        id = conf[CONF_ID]
-        if id and id.type == sensor.Sensor:
-            sens = await sensor.new_sensor(conf)
-            cg.add(getattr(hub, f"set_{key}_sensor")(sens))
-            sensors.append(f"F({key})")
-
-    if sensors:
-        cg.add_define(
-            "DLMS_METER_SENSOR_LIST(F, sep)", cg.RawExpression(" sep ".join(sensors))
-        )

esphome/components/dlms_meter/text_sensor/__init__.py

@@ -1,37 +0,0 @@
-import esphome.codegen as cg
-from esphome.components import text_sensor
-import esphome.config_validation as cv
-from esphome.const import CONF_ID
-
-from .. import CONF_DLMS_METER_ID, DlmsMeterComponent
-
-AUTO_LOAD = ["dlms_meter"]
-
-CONFIG_SCHEMA = cv.Schema(
-    {
-        cv.GenerateID(CONF_DLMS_METER_ID): cv.use_id(DlmsMeterComponent),
-        cv.Optional("timestamp"): text_sensor.text_sensor_schema(),
-        # Netz NOE
-        cv.Optional("meternumber"): text_sensor.text_sensor_schema(),
-    }
-).extend(cv.COMPONENT_SCHEMA)
-
-
-async def to_code(config):
-    hub = await cg.get_variable(config[CONF_DLMS_METER_ID])
-
-    text_sensors = []
-    for key, conf in config.items():
-        if not isinstance(conf, dict):
-            continue
-        id = conf[CONF_ID]
-        if id and id.type == text_sensor.TextSensor:
-            sens = await text_sensor.new_text_sensor(conf)
-            cg.add(getattr(hub, f"set_{key}_text_sensor")(sens))
-            text_sensors.append(f"F({key})")
-
-    if text_sensors:
-        cg.add_define(
-            "DLMS_METER_TEXT_SENSOR_LIST(F, sep)",
-            cg.RawExpression(" sep ".join(text_sensors)),
-        )

esphome/components/esp32/__init__.py

@@ -739,10 +739,9 @@ CONF_DISABLE_REGI2C_IN_IRAM = "disable_regi2c_in_iram"
 CONF_DISABLE_FATFS = "disable_fatfs"
 
 # VFS requirement tracking
-# Components that need VFS features can call require_vfs_*() functions
+# Components that need VFS features can call require_vfs_select() or require_vfs_dir()
 KEY_VFS_SELECT_REQUIRED = "vfs_select_required"
 KEY_VFS_DIR_REQUIRED = "vfs_dir_required"
-KEY_VFS_TERMIOS_REQUIRED = "vfs_termios_required"
 # Feature requirement tracking - components can call require_* functions to re-enable
 # These are stored in CORE.data[KEY_ESP32] dict
 KEY_USB_SERIAL_JTAG_SECONDARY_REQUIRED = "usb_serial_jtag_secondary_required"
@@ -769,15 +768,6 @@ def require_vfs_dir() -> None:
     CORE.data[KEY_VFS_DIR_REQUIRED] = True
 
 
-def require_vfs_termios() -> None:
-    """Mark that VFS termios support is required by a component.
-
-    Call this from components that use terminal I/O functions (usb_serial_jtag_vfs_*, etc.).
-    This prevents CONFIG_VFS_SUPPORT_TERMIOS from being disabled.
-    """
-    CORE.data[KEY_VFS_TERMIOS_REQUIRED] = True
-
-
 def require_full_certificate_bundle() -> None:
     """Request the full certificate bundle instead of the common-CAs-only bundle.
 
@@ -1287,18 +1277,6 @@ async def to_code(config):
     # Increase freertos tick speed from 100Hz to 1kHz so that delay() resolution is 1ms
     add_idf_sdkconfig_option("CONFIG_FREERTOS_HZ", 1000)
 
-    # Reduce FreeRTOS max priorities from 25 to 16 to save RAM
-    # pxReadyTasksLists uses 20 bytes per priority level, so this saves 180 bytes
-    # All ESPHome tasks use relative priorities (configMAX_PRIORITIES - X) to scale automatically
-    # See https://github.com/espressif/esp-idf/issues/13041 for context
-    add_idf_sdkconfig_option("CONFIG_FREERTOS_MAX_PRIORITIES", 16)
-
-    # Set LWIP TCP/IP task priority to fit within reduced priority range (0-15)
-    # Default is 18, which would be invalid with MAX_PRIORITIES=16
-    # Priority 8 maintains the original hierarchy: I2S speaker (10) > LWIP (8) > mixer (6)
-    # This ensures audio I/O tasks aren't blocked by network, while network isn't starved by mixing
-    add_idf_sdkconfig_option("CONFIG_LWIP_TCPIP_TASK_PRIO", 8)
-
     # Place non-ISR FreeRTOS functions into flash instead of IRAM
     # This saves up to 8KB of IRAM. ISR-safe functions (FromISR variants) stay in IRAM.
     # In ESP-IDF 6.0 this becomes the default and CONFIG_FREERTOS_PLACE_FUNCTIONS_INTO_FLASH
@@ -1341,10 +1319,6 @@ async def to_code(config):
     # Disable dynamic log level control to save memory
     add_idf_sdkconfig_option("CONFIG_LOG_DYNAMIC_LEVEL_CONTROL", False)
 
-    # Disable per-tag log level filtering since dynamic level control is disabled above
-    # This saves ~250 bytes of RAM (tag cache) and associated code
-    add_idf_sdkconfig_option("CONFIG_LOG_TAG_LEVEL_IMPL_NONE", True)
-
     # Reduce PHY TX power in the event of a brownout
     add_idf_sdkconfig_option("CONFIG_ESP_PHY_REDUCE_TX_POWER", True)
 
@@ -1398,18 +1372,11 @@ async def to_code(config):
         add_idf_sdkconfig_option("CONFIG_LIBC_LOCKS_PLACE_IN_IRAM", False)
 
     # Disable VFS support for termios (terminal I/O functions)
-    # USB Serial JTAG VFS functions require termios support.
+    # ESPHome doesn't use termios functions on ESP32 (only used in host UART driver).
-    # Components that need it (e.g., logger when USB_SERIAL_JTAG is supported but not selected
-    # as the logger output) call require_vfs_termios().
     # Saves approximately 1.8KB of flash when disabled (default).
-    if CORE.data.get(KEY_VFS_TERMIOS_REQUIRED, False):
+    add_idf_sdkconfig_option(
-        # Component requires VFS termios - force enable regardless of user setting
+        "CONFIG_VFS_SUPPORT_TERMIOS", not advanced[CONF_DISABLE_VFS_SUPPORT_TERMIOS]
-        add_idf_sdkconfig_option("CONFIG_VFS_SUPPORT_TERMIOS", True)
+    )
-    else:
-        # No component needs it - allow user to control (default: disabled)
-        add_idf_sdkconfig_option(
-            "CONFIG_VFS_SUPPORT_TERMIOS", not advanced[CONF_DISABLE_VFS_SUPPORT_TERMIOS]
-        )
 
     # Disable VFS support for select() with file descriptors
     # ESPHome only uses select() with sockets via lwip_select(), which still works.

esphome/components/esp32/core.cpp

@@ -3,7 +3,6 @@
 #include "esphome/core/defines.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
-#include "esphome/core/task_priorities.h"
 #include "preferences.h"
 #include <esp_clk_tree.h>
 #include <esp_cpu.h>
@@ -67,14 +66,10 @@ void loop_task(void *pv_params) {
 extern "C" void app_main() {
   initArduino();
   esp32::setup_preferences();
-  // TASK_PRIORITY_APPLICATION: baseline priority for main loop - all component loops
-  // run here. Higher priority tasks (audio, network) preempt this when needed.
 #if CONFIG_FREERTOS_UNICORE
-  xTaskCreate(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, TASK_PRIORITY_APPLICATION,
+  xTaskCreate(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, 1, &loop_task_handle);
-              &loop_task_handle);
 #else
-  xTaskCreatePinnedToCore(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, TASK_PRIORITY_APPLICATION,
+  xTaskCreatePinnedToCore(loop_task, "loopTask", ESPHOME_LOOP_TASK_STACK_SIZE, nullptr, 1, &loop_task_handle, 1);
-                          &loop_task_handle, 1);
 #endif
 }
 

esphome/components/esp32_camera/esp32_camera.cpp

@@ -4,7 +4,6 @@
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include <freertos/task.h>
 
@@ -43,13 +42,11 @@ void ESP32Camera::setup() {
   /* initialize RTOS */
   this->framebuffer_get_queue_ = xQueueCreate(1, sizeof(camera_fb_t *));
   this->framebuffer_return_queue_ = xQueueCreate(1, sizeof(camera_fb_t *));
-  // TASK_PRIORITY_APPLICATION: same as main loop - camera capture is buffered,
-  // not real-time critical like audio
   xTaskCreatePinnedToCore(&ESP32Camera::framebuffer_task,
                           "framebuffer_task",           // name
                           FRAMEBUFFER_TASK_STACK_SIZE,  // stack size
                           this,                         // task pv params
-                          TASK_PRIORITY_APPLICATION,    // priority
+                          1,                            // priority
                           nullptr,                      // handle
                           1                             // core
   );

esphome/components/http_request/update/http_request_update.cpp

@@ -2,9 +2,6 @@
 
 #include "esphome/core/application.h"
 #include "esphome/core/version.h"
-#ifdef USE_ESP32
-#include "esphome/core/task_priorities.h"
-#endif
 
 #include "esphome/components/json/json_util.h"
 #include "esphome/components/network/util.h"
@@ -49,9 +46,7 @@ void HttpRequestUpdate::update() {
     return;
   }
 #ifdef USE_ESP32
-  // TASK_PRIORITY_APPLICATION: same as main loop - update check is background work
+  xTaskCreate(HttpRequestUpdate::update_task, "update_task", 8192, (void *) this, 1, &this->update_task_handle_);
-  xTaskCreate(HttpRequestUpdate::update_task, "update_task", 8192, (void *) this, TASK_PRIORITY_APPLICATION,
-              &this->update_task_handle_);
 #else
   this->update_task(this);
 #endif

esphome/components/i2c/i2c.cpp

@@ -11,6 +11,12 @@ namespace i2c {
 static const char *const TAG = "i2c";
 
 void I2CBus::i2c_scan_() {
+  // suppress logs from the IDF I2C library during the scan
+#if defined(USE_ESP32) && defined(USE_LOGGER)
+  auto previous = esp_log_level_get("*");
+  esp_log_level_set("*", ESP_LOG_NONE);
+#endif
+
   for (uint8_t address = 8; address != 120; address++) {
     auto err = write_readv(address, nullptr, 0, nullptr, 0);
     if (err == ERROR_OK) {
@@ -21,6 +27,9 @@ void I2CBus::i2c_scan_() {
     // it takes 16sec to scan on nrf52. It prevents board reset.
     arch_feed_wdt();
   }
+#if defined(USE_ESP32) && defined(USE_LOGGER)
+  esp_log_level_set("*", previous);
+#endif
 }
 
 ErrorCode I2CDevice::read_register(uint8_t a_register, uint8_t *data, size_t len) {

esphome/components/i2s_audio/microphone/i2s_audio_microphone.cpp

@@ -11,7 +11,6 @@
 
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include "esphome/components/audio/audio.h"
 
@@ -23,6 +22,7 @@ static const UBaseType_t MAX_LISTENERS = 16;
 static const uint32_t READ_DURATION_MS = 16;
 
 static const size_t TASK_STACK_SIZE = 4096;
+static const ssize_t TASK_PRIORITY = 23;
 
 static const char *const TAG = "i2s_audio.microphone";
 
@@ -520,10 +520,8 @@ void I2SAudioMicrophone::loop() {
       }
 
       if (this->task_handle_ == nullptr) {
-        // TASK_PRIORITY_AUDIO_CAPTURE: highest application priority - real-time audio
+        xTaskCreate(I2SAudioMicrophone::mic_task, "mic_task", TASK_STACK_SIZE, (void *) this, TASK_PRIORITY,
-        // input cannot tolerate delays without dropping samples
+                    &this->task_handle_);
-        xTaskCreate(I2SAudioMicrophone::mic_task, "mic_task", TASK_STACK_SIZE, (void *) this,
-                    TASK_PRIORITY_AUDIO_CAPTURE, &this->task_handle_);
 
         if (this->task_handle_ == nullptr) {
           ESP_LOGE(TAG, "Task failed to start, retrying in 1 second");

esphome/components/i2s_audio/speaker/i2s_audio_speaker.cpp

@@ -14,7 +14,6 @@
 #include "esphome/core/application.h"
 #include "esphome/core/hal.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include "esp_timer.h"
 
@@ -25,6 +24,7 @@ static const uint32_t DMA_BUFFER_DURATION_MS = 15;
 static const size_t DMA_BUFFERS_COUNT = 4;
 
 static const size_t TASK_STACK_SIZE = 4096;
+static const ssize_t TASK_PRIORITY = 19;
 
 static const size_t I2S_EVENT_QUEUE_COUNT = DMA_BUFFERS_COUNT + 1;
 
@@ -151,10 +151,8 @@ void I2SAudioSpeaker::loop() {
       }
 
       if (this->speaker_task_handle_ == nullptr) {
-        // TASK_PRIORITY_AUDIO_OUTPUT: high priority for real-time audio output,
+        xTaskCreate(I2SAudioSpeaker::speaker_task, "speaker_task", TASK_STACK_SIZE, (void *) this, TASK_PRIORITY,
-        // below capture (TASK_PRIORITY_AUDIO_CAPTURE) but above network tasks
+                    &this->speaker_task_handle_);
-        xTaskCreate(I2SAudioSpeaker::speaker_task, "speaker_task", TASK_STACK_SIZE, (void *) this,
-                    TASK_PRIORITY_AUDIO_OUTPUT, &this->speaker_task_handle_);
 
         if (this->speaker_task_handle_ == nullptr) {
           ESP_LOGE(TAG, "Task failed to start, retrying in 1 second");

esphome/components/json/json_util.cpp

@@ -15,7 +15,7 @@ static const char *const TAG = "json";
 static SpiRamAllocator global_json_allocator;
 #endif
 
-std::string build_json(const json_build_t &f) {
+SerializationBuffer<> build_json(const json_build_t &f) {
   // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   JsonBuilder builder;
   JsonObject root = builder.root();
@@ -61,14 +61,62 @@ JsonDocument parse_json(const uint8_t *data, size_t len) {
   // NOLINTEND(clang-analyzer-cplusplus.NewDeleteLeaks)
 }
 
-std::string JsonBuilder::serialize() {
+SerializationBuffer<> JsonBuilder::serialize() {
+  // ===========================================================================================
+  // CRITICAL: NRVO (Named Return Value Optimization) - DO NOT REFACTOR WITHOUT UNDERSTANDING
+  // ===========================================================================================
+  //
+  // This function is carefully structured to enable NRVO. The compiler constructs `result`
+  // directly in the caller's stack frame, eliminating the move constructor call entirely.
+  //
+  // WITHOUT NRVO: Each return would trigger SerializationBuffer's move constructor, which
+  // must memcpy up to 512 bytes of stack buffer content. This happens on EVERY JSON
+  // serialization (sensor updates, web server responses, MQTT publishes, etc.).
+  //
+  // WITH NRVO: Zero memcpy, zero move constructor overhead. The buffer lives directly
+  // where the caller needs it.
+  //
+  // Requirements for NRVO to work:
+  //   1. Single named variable (`result`) returned from ALL paths
+  //   2. All paths must return the SAME variable (not different variables)
+  //   3. No std::move() on the return statement
+  //
+  // If you must modify this function:
+  //   - Keep a single `result` variable declared at the top
+  //   - All code paths must return `result` (not a different variable)
+  //   - Verify NRVO still works by checking the disassembly for move constructor calls
+  //   - Test: objdump -d -C firmware.elf | grep "SerializationBuffer.*SerializationBuffer"
+  //     Should show only destructor, NOT move constructor
+  //
+  // Why we avoid measureJson(): It instantiates DummyWriter templates adding ~1KB flash.
+  // Instead, try stack buffer first. 512 bytes covers 99.9% of JSON payloads (sensors ~200B,
+  // lights ~170B, climate ~700B). Only entities with 40+ options exceed this.
+  //
+  // ===========================================================================================
+  constexpr size_t buf_size = SerializationBuffer<>::BUFFER_SIZE;
+  SerializationBuffer<> result(buf_size - 1);  // Max content size (reserve 1 for null)
+
   if (doc_.overflowed()) {
     ESP_LOGE(TAG, "JSON document overflow");
-    return "{}";
+    auto *buf = result.data_writable_();
+    buf[0] = '{';
+    buf[1] = '}';
+    buf[2] = '\0';
+    result.set_size_(2);
+    return result;
   }
-  std::string output;
+
-  serializeJson(doc_, output);
+  size_t size = serializeJson(doc_, result.data_writable_(), buf_size);
-  return output;
+  if (size < buf_size) {
+    // Fits in stack buffer - update size to actual length
+    result.set_size_(size);
+    return result;
+  }
+
+  // Needs heap allocation - reallocate and serialize again with exact size
+  result.reallocate_heap_(size);
+  serializeJson(doc_, result.data_writable_(), size + 1);
+  return result;
 }
 
 }  // namespace json

esphome/components/json/json_util.h

@@ -1,5 +1,7 @@
 #pragma once
 
+#include <cstring>
+#include <string>
 #include <vector>
 
 #include "esphome/core/defines.h"
@@ -14,6 +16,108 @@
 namespace esphome {
 namespace json {
 
+/// Buffer for JSON serialization that uses stack allocation for small payloads.
+/// Template parameter STACK_SIZE specifies the stack buffer size (default 512 bytes).
+/// Supports move semantics for efficient return-by-value.
+template<size_t STACK_SIZE = 512> class SerializationBuffer {
+ public:
+  static constexpr size_t BUFFER_SIZE = STACK_SIZE;  ///< Stack buffer size for this instantiation
+
+  /// Construct with known size (typically from measureJson)
+  explicit SerializationBuffer(size_t size) : size_(size) {
+    if (size + 1 <= STACK_SIZE) {
+      buffer_ = stack_buffer_;
+    } else {
+      heap_buffer_ = new char[size + 1];
+      buffer_ = heap_buffer_;
+    }
+    buffer_[0] = '\0';
+  }
+
+  ~SerializationBuffer() { delete[] heap_buffer_; }
+
+  // Move constructor - works with same template instantiation
+  SerializationBuffer(SerializationBuffer &&other) noexcept : heap_buffer_(other.heap_buffer_), size_(other.size_) {
+    if (other.buffer_ == other.stack_buffer_) {
+      // Stack buffer - must copy content
+      std::memcpy(stack_buffer_, other.stack_buffer_, size_ + 1);
+      buffer_ = stack_buffer_;
+    } else {
+      // Heap buffer - steal ownership
+      buffer_ = heap_buffer_;
+      other.heap_buffer_ = nullptr;
+    }
+    // Leave moved-from object in valid empty state
+    other.stack_buffer_[0] = '\0';
+    other.buffer_ = other.stack_buffer_;
+    other.size_ = 0;
+  }
+
+  // Move assignment
+  SerializationBuffer &operator=(SerializationBuffer &&other) noexcept {
+    if (this != &other) {
+      delete[] heap_buffer_;
+      heap_buffer_ = other.heap_buffer_;
+      size_ = other.size_;
+      if (other.buffer_ == other.stack_buffer_) {
+        std::memcpy(stack_buffer_, other.stack_buffer_, size_ + 1);
+        buffer_ = stack_buffer_;
+      } else {
+        buffer_ = heap_buffer_;
+        other.heap_buffer_ = nullptr;
+      }
+      // Leave moved-from object in valid empty state
+      other.stack_buffer_[0] = '\0';
+      other.buffer_ = other.stack_buffer_;
+      other.size_ = 0;
+    }
+    return *this;
+  }
+
+  // Delete copy operations
+  SerializationBuffer(const SerializationBuffer &) = delete;
+  SerializationBuffer &operator=(const SerializationBuffer &) = delete;
+
+  /// Get null-terminated C string
+  const char *c_str() const { return buffer_; }
+  /// Get data pointer
+  const char *data() const { return buffer_; }
+  /// Get string length (excluding null terminator)
+  size_t size() const { return size_; }
+
+  /// Implicit conversion to std::string for backward compatibility
+  /// WARNING: This allocates a new std::string on the heap. Prefer using
+  /// c_str() or data()/size() directly when possible to avoid allocation.
+  operator std::string() const { return std::string(buffer_, size_); }  // NOLINT(google-explicit-constructor)
+
+ private:
+  friend class JsonBuilder;  ///< Allows JsonBuilder::serialize() to call private methods
+
+  /// Get writable buffer (for serialization)
+  char *data_writable_() { return buffer_; }
+  /// Set actual size after serialization (must not exceed allocated size)
+  /// Also ensures null termination for c_str() safety
+  void set_size_(size_t size) {
+    size_ = size;
+    buffer_[size] = '\0';
+  }
+
+  /// Reallocate to heap buffer with new size (for when stack buffer is too small)
+  /// This invalidates any previous buffer content. Used by JsonBuilder::serialize().
+  void reallocate_heap_(size_t size) {
+    delete[] heap_buffer_;
+    heap_buffer_ = new char[size + 1];
+    buffer_ = heap_buffer_;
+    size_ = size;
+    buffer_[0] = '\0';
+  }
+
+  char stack_buffer_[STACK_SIZE];
+  char *heap_buffer_{nullptr};
+  char *buffer_;
+  size_t size_;
+};
+
 #ifdef USE_PSRAM
 // Build an allocator for the JSON Library using the RAMAllocator class
 // This is only compiled when PSRAM is enabled
@@ -46,7 +150,8 @@ using json_parse_t = std::function<bool(JsonObject)>;
 using json_build_t = std::function<void(JsonObject)>;
 
 /// Build a JSON string with the provided json build function.
-std::string build_json(const json_build_t &f);
+/// Returns SerializationBuffer for stack-first allocation; implicitly converts to std::string.
+SerializationBuffer<> build_json(const json_build_t &f);
 
 /// Parse a JSON string and run the provided json parse function if it's valid.
 bool parse_json(const std::string &data, const json_parse_t &f);
@@ -69,7 +174,9 @@ class JsonBuilder {
     return root_;
   }
 
-  std::string serialize();
+  /// Serialize the JSON document to a SerializationBuffer (stack-first allocation)
+  /// Uses 512-byte stack buffer by default, falls back to heap for larger JSON
+  SerializationBuffer<> serialize();
 
  private:
 #ifdef USE_PSRAM

esphome/components/logger/__init__.py

@@ -16,8 +16,6 @@ from esphome.components.esp32 import (
     VARIANT_ESP32S3,
     add_idf_sdkconfig_option,
     get_esp32_variant,
-    require_usb_serial_jtag_secondary,
-    require_vfs_termios,
 )
 from esphome.components.libretiny import get_libretiny_component, get_libretiny_family
 from esphome.components.libretiny.const import (
@@ -399,15 +397,9 @@ async def to_code(config):
         elif config[CONF_HARDWARE_UART] == USB_SERIAL_JTAG:
             add_idf_sdkconfig_option("CONFIG_ESP_CONSOLE_USB_SERIAL_JTAG", True)
             cg.add_define("USE_LOGGER_UART_SELECTION_USB_SERIAL_JTAG")
-    # Define platform support flags for components that need auto-detection
     try:
         uart_selection(USB_SERIAL_JTAG)
         cg.add_define("USE_LOGGER_USB_SERIAL_JTAG")
-        # USB Serial JTAG code is compiled when platform supports it.
-        # Enable secondary USB serial JTAG console so the VFS functions are available.
-        if CORE.is_esp32 and config[CONF_HARDWARE_UART] != USB_SERIAL_JTAG:
-            require_usb_serial_jtag_secondary()
-            require_vfs_termios()
     except cv.Invalid:
         pass
     try:

esphome/components/logger/logger_esp32.cpp

@@ -114,6 +114,9 @@ void Logger::pre_setup() {
 
   global_logger = this;
   esp_log_set_vprintf(esp_idf_log_vprintf_);
+  if (ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERBOSE) {
+    esp_log_level_set("*", ESP_LOG_VERBOSE);
+  }
 
   ESP_LOGI(TAG, "Log initialized");
 }

esphome/components/max7219/display.py

@@ -28,10 +28,11 @@ CONFIG_SCHEMA = (
 
 
 async def to_code(config):
-    var = cg.new_Pvariable(config[CONF_ID], config[CONF_NUM_CHIPS])
+    var = cg.new_Pvariable(config[CONF_ID])
     await spi.register_spi_device(var, config, write_only=True)
     await display.register_display(var, config)
 
+    cg.add(var.set_num_chips(config[CONF_NUM_CHIPS]))
     cg.add(var.set_intensity(config[CONF_INTENSITY]))
     cg.add(var.set_reverse(config[CONF_REVERSE_ENABLE]))
 

esphome/components/max7219/max7219.cpp

@@ -3,7 +3,8 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 
-namespace esphome::max7219 {
+namespace esphome {
+namespace max7219 {
 
 static const char *const TAG = "max7219";
 
@@ -114,14 +115,12 @@ const uint8_t MAX7219_ASCII_TO_RAW[95] PROGMEM = {
 };
 
 float MAX7219Component::get_setup_priority() const { return setup_priority::PROCESSOR; }
-
-MAX7219Component::MAX7219Component(uint8_t num_chips) : num_chips_(num_chips) {
-  this->buffer_ = new uint8_t[this->num_chips_ * 8];  // NOLINT
-  memset(this->buffer_, 0, this->num_chips_ * 8);
-}
-
 void MAX7219Component::setup() {
   this->spi_setup();
+  this->buffer_ = new uint8_t[this->num_chips_ * 8];  // NOLINT
+  for (uint8_t i = 0; i < this->num_chips_ * 8; i++)
+    this->buffer_[i] = 0;
+
   // let's assume the user has all 8 digits connected, only important in daisy chained setups anyway
   this->send_to_all_(MAX7219_REGISTER_SCAN_LIMIT, 7);
   // let's use our own ASCII -> led pattern encoding
@@ -230,6 +229,7 @@ void MAX7219Component::set_intensity(uint8_t intensity) {
     this->intensity_ = intensity;
   }
 }
+void MAX7219Component::set_num_chips(uint8_t num_chips) { this->num_chips_ = num_chips; }
 
 uint8_t MAX7219Component::strftime(uint8_t pos, const char *format, ESPTime time) {
   char buffer[64];
@@ -240,4 +240,5 @@ uint8_t MAX7219Component::strftime(uint8_t pos, const char *format, ESPTime time
 }
 uint8_t MAX7219Component::strftime(const char *format, ESPTime time) { return this->strftime(0, format, time); }
 
-}  // namespace esphome::max7219
+}  // namespace max7219
+}  // namespace esphome

esphome/components/max7219/max7219.h

@@ -6,7 +6,8 @@
 #include "esphome/components/spi/spi.h"
 #include "esphome/components/display/display.h"
 
-namespace esphome::max7219 {
+namespace esphome {
+namespace max7219 {
 
 class MAX7219Component;
 
@@ -16,8 +17,6 @@ class MAX7219Component : public PollingComponent,
                          public spi::SPIDevice<spi::BIT_ORDER_MSB_FIRST, spi::CLOCK_POLARITY_LOW,
                                                spi::CLOCK_PHASE_LEADING, spi::DATA_RATE_1MHZ> {
  public:
-  explicit MAX7219Component(uint8_t num_chips);
-
   void set_writer(max7219_writer_t &&writer);
 
   void setup() override;
@@ -31,6 +30,7 @@ class MAX7219Component : public PollingComponent,
   void display();
 
   void set_intensity(uint8_t intensity);
+  void set_num_chips(uint8_t num_chips);
   void set_reverse(bool reverse) { this->reverse_ = reverse; };
 
   /// Evaluate the printf-format and print the result at the given position.
@@ -56,9 +56,10 @@ class MAX7219Component : public PollingComponent,
   uint8_t intensity_{15};     // Intensity of the display from 0 to 15 (most)
   bool intensity_changed_{};  // True if we need to re-send the intensity
   uint8_t num_chips_{1};
-  uint8_t *buffer_{nullptr};
+  uint8_t *buffer_;
   bool reverse_{false};
   max7219_writer_t writer_{};
 };
 
-}  // namespace esphome::max7219
+}  // namespace max7219
+}  // namespace esphome

esphome/components/micro_wake_word/micro_wake_word.cpp

@@ -6,7 +6,6 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include "esphome/components/audio/audio_transfer_buffer.h"
 
@@ -26,6 +25,7 @@ static const size_t DATA_TIMEOUT_MS = 50;
 static const uint32_t RING_BUFFER_DURATION_MS = 120;
 
 static const uint32_t INFERENCE_TASK_STACK_SIZE = 3072;
+static const UBaseType_t INFERENCE_TASK_PRIORITY = 3;
 
 enum EventGroupBits : uint32_t {
   COMMAND_STOP = (1 << 0),  // Signals the inference task should stop
@@ -305,10 +305,8 @@ void MicroWakeWord::loop() {
           return;
         }
 
-        // TASK_PRIORITY_INFERENCE: above main loop (TASK_PRIORITY_APPLICATION) but below
-        // protocol tasks (TASK_PRIORITY_PROTOCOL) - ML inference is background work
         xTaskCreate(MicroWakeWord::inference_task, "mww", INFERENCE_TASK_STACK_SIZE, (void *) this,
-                    TASK_PRIORITY_INFERENCE, &this->inference_task_handle_);
+                    INFERENCE_TASK_PRIORITY, &this->inference_task_handle_);
 
         if (this->inference_task_handle_ == nullptr) {
           FrontendFreeStateContents(&this->frontend_state_);  // Deallocate frontend state

esphome/components/mipi_spi/mipi_spi.cpp

@@ -1,39 +1,6 @@
 #include "mipi_spi.h"
 #include "esphome/core/log.h"
 
-namespace esphome::mipi_spi {
+namespace esphome {
-
+namespace mipi_spi {}  // namespace mipi_spi
-void internal_dump_config(const char *model, int width, int height, int offset_width, int offset_height, uint8_t madctl,
+}  // namespace esphome
-                          bool invert_colors, int display_bits, bool is_big_endian, const optional<uint8_t> &brightness,
-                          GPIOPin *cs, GPIOPin *reset, GPIOPin *dc, int spi_mode, uint32_t data_rate, int bus_width) {
-  ESP_LOGCONFIG(TAG,
-                "MIPI_SPI Display\n"
-                "  Model: %s\n"
-                "  Width: %d\n"
-                "  Height: %d\n"
-                "  Swap X/Y: %s\n"
-                "  Mirror X: %s\n"
-                "  Mirror Y: %s\n"
-                "  Invert colors: %s\n"
-                "  Color order: %s\n"
-                "  Display pixels: %d bits\n"
-                "  Endianness: %s\n"
-                "  SPI Mode: %d\n"
-                "  SPI Data rate: %uMHz\n"
-                "  SPI Bus width: %d",
-                model, width, height, YESNO(madctl & MADCTL_MV), YESNO(madctl & (MADCTL_MX | MADCTL_XFLIP)),
-                YESNO(madctl & (MADCTL_MY | MADCTL_YFLIP)), YESNO(invert_colors), (madctl & MADCTL_BGR) ? "BGR" : "RGB",
-                display_bits, is_big_endian ? "Big" : "Little", spi_mode, static_cast<unsigned>(data_rate / 1000000),
-                bus_width);
-  LOG_PIN("  CS Pin: ", cs);
-  LOG_PIN("  Reset Pin: ", reset);
-  LOG_PIN("  DC Pin: ", dc);
-  if (offset_width != 0)
-    ESP_LOGCONFIG(TAG, "  Offset width: %d", offset_width);
-  if (offset_height != 0)
-    ESP_LOGCONFIG(TAG, "  Offset height: %d", offset_height);
-  if (brightness.has_value())
-    ESP_LOGCONFIG(TAG, "  Brightness: %u", brightness.value());
-}
-
-}  // namespace esphome::mipi_spi

esphome/components/mipi_spi/mipi_spi.h

@@ -63,11 +63,6 @@ enum BusType {
   BUS_TYPE_SINGLE_16 = 16,  // Single bit bus, but 16 bits per transfer
 };
 
-// Helper function for dump_config - defined in mipi_spi.cpp to allow use of LOG_PIN macro
-void internal_dump_config(const char *model, int width, int height, int offset_width, int offset_height, uint8_t madctl,
-                          bool invert_colors, int display_bits, bool is_big_endian, const optional<uint8_t> &brightness,
-                          GPIOPin *cs, GPIOPin *reset, GPIOPin *dc, int spi_mode, uint32_t data_rate, int bus_width);
-
 /**
  * Base class for MIPI SPI displays.
  * All the methods are defined here in the header file, as it is not possible to define templated methods in a cpp file.
@@ -206,9 +201,37 @@ class MipiSpi : public display::Display,
   }
 
   void dump_config() override {
-    internal_dump_config(this->model_, WIDTH, HEIGHT, OFFSET_WIDTH, OFFSET_HEIGHT, this->madctl_, this->invert_colors_,
+    esph_log_config(TAG,
-                         DISPLAYPIXEL * 8, IS_BIG_ENDIAN, this->brightness_, this->cs_, this->reset_pin_, this->dc_pin_,
+                    "MIPI_SPI Display\n"
-                         this->mode_, this->data_rate_, BUS_TYPE);
+                    "  Model: %s\n"
+                    "  Width: %u\n"
+                    "  Height: %u",
+                    this->model_, WIDTH, HEIGHT);
+    if constexpr (OFFSET_WIDTH != 0)
+      esph_log_config(TAG, "  Offset width: %u", OFFSET_WIDTH);
+    if constexpr (OFFSET_HEIGHT != 0)
+      esph_log_config(TAG, "  Offset height: %u", OFFSET_HEIGHT);
+    esph_log_config(TAG,
+                    "  Swap X/Y: %s\n"
+                    "  Mirror X: %s\n"
+                    "  Mirror Y: %s\n"
+                    "  Invert colors: %s\n"
+                    "  Color order: %s\n"
+                    "  Display pixels: %d bits\n"
+                    "  Endianness: %s\n",
+                    YESNO(this->madctl_ & MADCTL_MV), YESNO(this->madctl_ & (MADCTL_MX | MADCTL_XFLIP)),
+                    YESNO(this->madctl_ & (MADCTL_MY | MADCTL_YFLIP)), YESNO(this->invert_colors_),
+                    this->madctl_ & MADCTL_BGR ? "BGR" : "RGB", DISPLAYPIXEL * 8, IS_BIG_ENDIAN ? "Big" : "Little");
+    if (this->brightness_.has_value())
+      esph_log_config(TAG, "  Brightness: %u", this->brightness_.value());
+    log_pin(TAG, "  CS Pin: ", this->cs_);
+    log_pin(TAG, "  Reset Pin: ", this->reset_pin_);
+    log_pin(TAG, "  DC Pin: ", this->dc_pin_);
+    esph_log_config(TAG,
+                    "  SPI Mode: %d\n"
+                    "  SPI Data rate: %dMHz\n"
+                    "  SPI Bus width: %d",
+                    this->mode_, static_cast<unsigned>(this->data_rate_ / 1000000), BUS_TYPE);
   }
 
  protected:

esphome/components/mixer/speaker/mixer_speaker.cpp

@@ -5,7 +5,6 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include <algorithm>
 #include <cstring>
@@ -13,6 +12,8 @@
 namespace esphome {
 namespace mixer_speaker {
 
+static const UBaseType_t MIXER_TASK_PRIORITY = 10;
+
 static const uint32_t TRANSFER_BUFFER_DURATION_MS = 50;
 static const uint32_t TASK_DELAY_MS = 25;
 
@@ -384,10 +385,8 @@ esp_err_t MixerSpeaker::start_task_() {
   }
 
   if (this->task_handle_ == nullptr) {
-    // TASK_PRIORITY_AUDIO_MIXER: below I2S tasks (TASK_PRIORITY_AUDIO_OUTPUT) but
-    // above protocol tasks - mixing is buffered but feeds real-time output
     this->task_handle_ = xTaskCreateStatic(audio_mixer_task, "mixer", TASK_STACK_SIZE, (void *) this,
-                                           TASK_PRIORITY_AUDIO_MIXER, this->task_stack_buffer_, &this->task_stack_);
+                                           MIXER_TASK_PRIORITY, this->task_stack_buffer_, &this->task_stack_);
   }
 
   if (this->task_handle_ == nullptr) {

esphome/components/mqtt/mqtt_backend_esp32.cpp

@@ -61,10 +61,7 @@ bool MQTTBackendESP32::initialize_() {
     // Create the task only after MQTT client is initialized successfully
     // Use larger stack size when TLS is enabled
     size_t stack_size = this->ca_certificate_.has_value() ? TASK_STACK_SIZE_TLS : TASK_STACK_SIZE;
-    // TASK_PRIORITY_PROTOCOL: above main loop (TASK_PRIORITY_APPLICATION) but below
+    xTaskCreate(esphome_mqtt_task, "esphome_mqtt", stack_size, (void *) this, TASK_PRIORITY, &this->task_handle_);
-    // audio tasks - MQTT needs responsive scheduling for message handling
-    xTaskCreate(esphome_mqtt_task, "esphome_mqtt", stack_size, (void *) this, TASK_PRIORITY_PROTOCOL,
-                &this->task_handle_);
     if (this->task_handle_ == nullptr) {
       ESP_LOGE(TAG, "Failed to create MQTT task");
       // Clean up MQTT client since we can't start the async task

esphome/components/mqtt/mqtt_backend_esp32.h

@@ -14,7 +14,6 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/lock_free_queue.h"
 #include "esphome/core/event_pool.h"
-#include "esphome/core/task_priorities.h"
 
 namespace esphome::mqtt {
 
@@ -118,7 +117,8 @@ class MQTTBackendESP32 final : public MQTTBackend {
   static const size_t MQTT_BUFFER_SIZE = 4096;
   static const size_t TASK_STACK_SIZE = 3072;
   static const size_t TASK_STACK_SIZE_TLS = 4096;  // Larger stack for TLS operations
-  static const uint8_t MQTT_QUEUE_LENGTH = 30;     // 30*12 bytes = 360
+  static const ssize_t TASK_PRIORITY = 5;
+  static const uint8_t MQTT_QUEUE_LENGTH = 30;  // 30*12 bytes = 360
 
   void set_keep_alive(uint16_t keep_alive) final { this->keep_alive_ = keep_alive; }
   void set_client_id(const char *client_id) final { this->client_id_ = client_id; }

esphome/components/mqtt/mqtt_client.cpp

@@ -564,8 +564,8 @@ bool MQTTClientComponent::publish(const char *topic, const char *payload, size_t
 }
 
 bool MQTTClientComponent::publish_json(const char *topic, const json::json_build_t &f, uint8_t qos, bool retain) {
-  std::string message = json::build_json(f);
+  auto message = json::build_json(f);
-  return this->publish(topic, message.c_str(), message.length(), qos, retain);
+  return this->publish(topic, message.c_str(), message.size(), qos, retain);
 }
 
 void MQTTClientComponent::enable() {
@@ -643,34 +643,10 @@ static bool topic_match(const char *message, const char *subscription) {
 }
 
 void MQTTClientComponent::on_message(const std::string &topic, const std::string &payload) {
-#ifdef USE_ESP8266
+  for (auto &subscription : this->subscriptions_) {
-  // IMPORTANT: This defer is REQUIRED to prevent stack overflow crashes on ESP8266.
+    if (topic_match(topic.c_str(), subscription.topic.c_str()))
-  //
+      subscription.callback(topic, payload);
-  // On ESP8266, this callback is invoked directly from the lwIP/AsyncTCP network stack
+  }
-  // which runs in the "sys" context with a very limited stack (~4KB). By the time we
-  // reach this function, the stack is already partially consumed by the network
-  // processing chain: tcp_input -> AsyncClient::_recv -> AsyncMqttClient::_onMessage -> here.
-  //
-  // MQTT subscription callbacks can trigger arbitrary user actions (automations, HTTP
-  // requests, sensor updates, etc.) which may have deep call stacks of their own.
-  // For example, an HTTP request action requires: DNS lookup -> TCP connect -> TLS
-  // handshake (if HTTPS) -> request formatting. This easily overflows the remaining
-  // system stack space, causing a LoadStoreAlignmentCause exception or silent corruption.
-  //
-  // By deferring to the main loop, we ensure callbacks execute with a fresh, full-size
-  // stack in the normal application context rather than the constrained network task.
-  //
-  // DO NOT REMOVE THIS DEFER without understanding the above. It may appear to work
-  // in simple tests but will cause crashes with complex automations.
-  this->defer([this, topic, payload]() {
-#endif
-    for (auto &subscription : this->subscriptions_) {
-      if (topic_match(topic.c_str(), subscription.topic.c_str()))
-        subscription.callback(topic, payload);
-    }
-#ifdef USE_ESP8266
-  });
-#endif
 }
 
 // Setters

esphome/components/openthread/openthread_esp.cpp

@@ -10,7 +10,6 @@
 #include "esp_task_wdt.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include "esp_err.h"
 #include "esp_event.h"
@@ -40,14 +39,12 @@ void OpenThreadComponent::setup() {
   ESP_ERROR_CHECK(esp_netif_init());
   ESP_ERROR_CHECK(esp_vfs_eventfd_register(&eventfd_config));
 
-  // TASK_PRIORITY_PROTOCOL: same as USB host/MQTT - network protocol tasks need
-  // responsive scheduling but below audio tasks
   xTaskCreate(
       [](void *arg) {
         static_cast<OpenThreadComponent *>(arg)->ot_main();
         vTaskDelete(nullptr);
       },
-      "ot_main", 10240, this, TASK_PRIORITY_PROTOCOL, nullptr);
+      "ot_main", 10240, this, 5, nullptr);
 }
 
 static esp_netif_t *init_openthread_netif(const esp_openthread_platform_config_t *config) {

esphome/components/pmsx003/pmsx003.cpp

@@ -2,20 +2,21 @@
 #include "esphome/core/log.h"
 #include "esphome/core/application.h"
 
-namespace esphome::pmsx003 {
+namespace esphome {
+namespace pmsx003 {
 
 static const char *const TAG = "pmsx003";
 
 static const uint8_t START_CHARACTER_1 = 0x42;
 static const uint8_t START_CHARACTER_2 = 0x4D;
 
-static const uint16_t STABILISING_MS = 30000;  // time taken for the sensor to become stable after power on in ms
+static const uint16_t PMS_STABILISING_MS = 30000;  // time taken for the sensor to become stable after power on in ms
 
-static const uint16_t CMD_MEASUREMENT_MODE_PASSIVE =
+static const uint16_t PMS_CMD_MEASUREMENT_MODE_PASSIVE =
-    0x0000;  // use `Command::MANUAL_MEASUREMENT` to trigger a measurement
+    0x0000;  // use `PMS_CMD_MANUAL_MEASUREMENT` to trigger a measurement
-static const uint16_t CMD_MEASUREMENT_MODE_ACTIVE = 0x0001;  // automatically perform measurements
+static const uint16_t PMS_CMD_MEASUREMENT_MODE_ACTIVE = 0x0001;  // automatically perform measurements
-static const uint16_t CMD_SLEEP_MODE_SLEEP = 0x0000;         // go to sleep mode
+static const uint16_t PMS_CMD_SLEEP_MODE_SLEEP = 0x0000;         // go to sleep mode
-static const uint16_t CMD_SLEEP_MODE_WAKEUP = 0x0001;        // wake up from sleep mode
+static const uint16_t PMS_CMD_SLEEP_MODE_WAKEUP = 0x0001;        // wake up from sleep mode
 
 void PMSX003Component::setup() {}
 
@@ -41,7 +42,7 @@ void PMSX003Component::dump_config() {
   LOG_SENSOR("  ", "Temperature", this->temperature_sensor_);
   LOG_SENSOR("  ", "Humidity", this->humidity_sensor_);
 
-  if (this->update_interval_ <= STABILISING_MS) {
+  if (this->update_interval_ <= PMS_STABILISING_MS) {
     ESP_LOGCONFIG(TAG, "  Mode: active continuous (sensor default)");
   } else {
     ESP_LOGCONFIG(TAG, "  Mode: passive with sleep/wake cycles");
@@ -54,44 +55,44 @@ void PMSX003Component::loop() {
   const uint32_t now = App.get_loop_component_start_time();
 
   // Initialize sensor mode on first loop
-  if (!this->initialised_) {
+  if (this->initialised_ == 0) {
-    if (this->update_interval_ > STABILISING_MS) {
+    if (this->update_interval_ > PMS_STABILISING_MS) {
       // Long update interval: use passive mode with sleep/wake cycles
-      this->send_command_(Command::MEASUREMENT_MODE, CMD_MEASUREMENT_MODE_PASSIVE);
+      this->send_command_(PMS_CMD_MEASUREMENT_MODE, PMS_CMD_MEASUREMENT_MODE_PASSIVE);
-      this->send_command_(Command::SLEEP_MODE, CMD_SLEEP_MODE_WAKEUP);
+      this->send_command_(PMS_CMD_SLEEP_MODE, PMS_CMD_SLEEP_MODE_WAKEUP);
     } else {
       // Short/zero update interval: use active continuous mode
-      this->send_command_(Command::MEASUREMENT_MODE, CMD_MEASUREMENT_MODE_ACTIVE);
+      this->send_command_(PMS_CMD_MEASUREMENT_MODE, PMS_CMD_MEASUREMENT_MODE_ACTIVE);
     }
-    this->initialised_ = true;
+    this->initialised_ = 1;
   }
 
   // If we update less often than it takes the device to stabilise, spin the fan down
   // rather than running it constantly. It does take some time to stabilise, so we
   // need to keep track of what state we're in.
-  if (this->update_interval_ > STABILISING_MS) {
+  if (this->update_interval_ > PMS_STABILISING_MS) {
     switch (this->state_) {
-      case State::IDLE:
+      case PMSX003_STATE_IDLE:
         // Power on the sensor now so it'll be ready when we hit the update time
-        if (now - this->last_update_ < (this->update_interval_ - STABILISING_MS))
+        if (now - this->last_update_ < (this->update_interval_ - PMS_STABILISING_MS))
           return;
 
-        this->state_ = State::STABILISING;
+        this->state_ = PMSX003_STATE_STABILISING;
-        this->send_command_(Command::SLEEP_MODE, CMD_SLEEP_MODE_WAKEUP);
+        this->send_command_(PMS_CMD_SLEEP_MODE, PMS_CMD_SLEEP_MODE_WAKEUP);
         this->fan_on_time_ = now;
         return;
-      case State::STABILISING:
+      case PMSX003_STATE_STABILISING:
         // wait for the sensor to be stable
-        if (now - this->fan_on_time_ < STABILISING_MS)
+        if (now - this->fan_on_time_ < PMS_STABILISING_MS)
           return;
         // consume any command responses that are in the serial buffer
         while (this->available())
           this->read_byte(&this->data_[0]);
         // Trigger a new read
-        this->send_command_(Command::MANUAL_MEASUREMENT, 0);
+        this->send_command_(PMS_CMD_MANUAL_MEASUREMENT, 0);
-        this->state_ = State::WAITING;
+        this->state_ = PMSX003_STATE_WAITING;
         break;
-      case State::WAITING:
+      case PMSX003_STATE_WAITING:
         // Just go ahead and read stuff
         break;
     }
@@ -179,31 +180,27 @@ optional<bool> PMSX003Component::check_byte_() {
 }
 
 bool PMSX003Component::check_payload_length_(uint16_t payload_length) {
-  // https://avaldebe.github.io/PyPMS/sensors/Plantower/
   switch (this->type_) {
-    case Type::PMS1003:
+    case PMSX003_TYPE_X003:
-      return payload_length == 28;  // 2*13+2
+      // The expected payload length is typically 28 bytes.
-    case Type::PMS3003:             // Data 7/8/9 not set/reserved
+      // However, a 20-byte payload check was already present in the code.
-      return payload_length == 20;  // 2*9+2
+      // No official documentation was found confirming this.
-    case Type::PMSX003:             // Data 13 not set/reserved
+      // Retaining this check to avoid breaking existing behavior.
-      // Deprecated: Length 20 is for PMS3003 backwards compatibility
       return payload_length == 28 || payload_length == 20;  // 2*13+2
-    case Type::PMS5003S:
+    case PMSX003_TYPE_5003T:
-    case Type::PMS5003T:            // Data 13 not set/reserved
+    case PMSX003_TYPE_5003S:
-      return payload_length == 28;  // 2*13+2
+      return payload_length == 28;  // 2*13+2 (Data 13 not set/reserved)
-    case Type::PMS5003ST:           // Data 16 not set/reserved
+    case PMSX003_TYPE_5003ST:
-      return payload_length == 36;  // 2*17+2
+      return payload_length == 36;  // 2*17+2 (Data 16 not set/reserved)
-    case Type::PMS9003M:
-      return payload_length == 28;  // 2*13+2
   }
   return false;
 }
 
-void PMSX003Component::send_command_(Command cmd, uint16_t data) {
+void PMSX003Component::send_command_(PMSX0003Command cmd, uint16_t data) {
   uint8_t send_data[7] = {
       START_CHARACTER_1,            // Start Byte 1
       START_CHARACTER_2,            // Start Byte 2
-      static_cast<uint8_t>(cmd),    // Command
+      cmd,                          // Command
       uint8_t((data >> 8) & 0xFF),  // Data 1
       uint8_t((data >> 0) & 0xFF),  // Data 2
       0,                            // Verify Byte 1
@@ -268,7 +265,7 @@ void PMSX003Component::parse_data_() {
   if (this->pm_particles_25um_sensor_ != nullptr)
     this->pm_particles_25um_sensor_->publish_state(pm_particles_25um);
 
-  if (this->type_ == Type::PMS5003T) {
+  if (this->type_ == PMSX003_TYPE_5003T) {
     ESP_LOGD(TAG,
              "Got PM0.3 Particles: %u Count/0.1L, PM0.5 Particles: %u Count/0.1L, PM1.0 Particles: %u Count/0.1L, "
              "PM2.5 Particles %u Count/0.1L",
@@ -292,7 +289,7 @@ void PMSX003Component::parse_data_() {
   }
 
   // Formaldehyde
-  if (this->type_ == Type::PMS5003S || this->type_ == Type::PMS5003ST) {
+  if (this->type_ == PMSX003_TYPE_5003ST || this->type_ == PMSX003_TYPE_5003S) {
     const uint16_t formaldehyde = this->get_16_bit_uint_(28);
 
     ESP_LOGD(TAG, "Got Formaldehyde: %u µg/m^3", formaldehyde);
@@ -302,8 +299,8 @@ void PMSX003Component::parse_data_() {
   }
 
   // Temperature and Humidity
-  if (this->type_ == Type::PMS5003T || this->type_ == Type::PMS5003ST) {
+  if (this->type_ == PMSX003_TYPE_5003ST || this->type_ == PMSX003_TYPE_5003T) {
-    const uint8_t temperature_offset = (this->type_ == Type::PMS5003T) ? 24 : 30;
+    const uint8_t temperature_offset = (this->type_ == PMSX003_TYPE_5003T) ? 24 : 30;
 
     const float temperature = static_cast<int16_t>(this->get_16_bit_uint_(temperature_offset)) / 10.0f;
     const float humidity = this->get_16_bit_uint_(temperature_offset + 2) / 10.0f;
@@ -317,22 +314,22 @@ void PMSX003Component::parse_data_() {
   }
 
   // Firmware Version and Error Code
-  if (this->type_ == Type::PMS1003 || this->type_ == Type::PMS5003ST || this->type_ == Type::PMS9003M) {
+  if (this->type_ == PMSX003_TYPE_5003ST) {
-    const uint8_t firmware_error_code_offset = (this->type_ == Type::PMS5003ST) ? 36 : 28;
+    const uint8_t firmware_version = this->data_[36];
-    const uint8_t firmware_version = this->data_[firmware_error_code_offset];
+    const uint8_t error_code = this->data_[37];
-    const uint8_t error_code = this->data_[firmware_error_code_offset + 1];
 
     ESP_LOGD(TAG, "Got Firmware Version: 0x%02X, Error Code: 0x%02X", firmware_version, error_code);
   }
 
   // Spin down the sensor again if we aren't going to need it until more time has
   // passed than it takes to stabilise
-  if (this->update_interval_ > STABILISING_MS) {
+  if (this->update_interval_ > PMS_STABILISING_MS) {
-    this->send_command_(Command::SLEEP_MODE, CMD_SLEEP_MODE_SLEEP);
+    this->send_command_(PMS_CMD_SLEEP_MODE, PMS_CMD_SLEEP_MODE_SLEEP);
-    this->state_ = State::IDLE;
+    this->state_ = PMSX003_STATE_IDLE;
   }
 
   this->status_clear_warning();
 }
 
-}  // namespace esphome::pmsx003
+}  // namespace pmsx003
+}  // namespace esphome

esphome/components/pmsx003/pmsx003.h

@@ -5,28 +5,27 @@
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/uart/uart.h"
 
-namespace esphome::pmsx003 {
+namespace esphome {
+namespace pmsx003 {
 
-enum class Type : uint8_t {
+enum PMSX0003Command : uint8_t {
-  PMS1003 = 0,
+  PMS_CMD_MEASUREMENT_MODE =
-  PMS3003,
+      0xE1,  // Data Options: `PMS_CMD_MEASUREMENT_MODE_PASSIVE`, `PMS_CMD_MEASUREMENT_MODE_ACTIVE`
-  PMSX003,  // PMS5003, PMS6003, PMS7003, PMSA003 (NOT PMSA003I - see `pmsa003i` component)
+  PMS_CMD_MANUAL_MEASUREMENT = 0xE2,
-  PMS5003S,
+  PMS_CMD_SLEEP_MODE = 0xE4,  // Data Options: `PMS_CMD_SLEEP_MODE_SLEEP`, `PMS_CMD_SLEEP_MODE_WAKEUP`
-  PMS5003T,
-  PMS5003ST,
-  PMS9003M,
 };
 
-enum class Command : uint8_t {
+enum PMSX003Type {
-  MEASUREMENT_MODE = 0xE1,  // Data Options: `CMD_MEASUREMENT_MODE_PASSIVE`, `CMD_MEASUREMENT_MODE_ACTIVE`
+  PMSX003_TYPE_X003 = 0,
-  MANUAL_MEASUREMENT = 0xE2,
+  PMSX003_TYPE_5003T,
-  SLEEP_MODE = 0xE4,  // Data Options: `CMD_SLEEP_MODE_SLEEP`, `CMD_SLEEP_MODE_WAKEUP`
+  PMSX003_TYPE_5003ST,
+  PMSX003_TYPE_5003S,
 };
 
-enum class State : uint8_t {
+enum PMSX003State {
-  IDLE = 0,
+  PMSX003_STATE_IDLE = 0,
-  STABILISING,
+  PMSX003_STATE_STABILISING,
-  WAITING,
+  PMSX003_STATE_WAITING,
 };
 
 class PMSX003Component : public uart::UARTDevice, public Component {
@@ -38,7 +37,7 @@ class PMSX003Component : public uart::UARTDevice, public Component {
 
   void set_update_interval(uint32_t update_interval) { this->update_interval_ = update_interval; }
 
-  void set_type(Type type) { this->type_ = type; }
+  void set_type(PMSX003Type type) { this->type_ = type; }
 
   void set_pm_1_0_std_sensor(sensor::Sensor *pm_1_0_std_sensor) { this->pm_1_0_std_sensor_ = pm_1_0_std_sensor; }
   void set_pm_2_5_std_sensor(sensor::Sensor *pm_2_5_std_sensor) { this->pm_2_5_std_sensor_ = pm_2_5_std_sensor; }
@@ -78,20 +77,20 @@ class PMSX003Component : public uart::UARTDevice, public Component {
   optional<bool> check_byte_();
   void parse_data_();
   bool check_payload_length_(uint16_t payload_length);
-  void send_command_(Command cmd, uint16_t data);
+  void send_command_(PMSX0003Command cmd, uint16_t data);
   uint16_t get_16_bit_uint_(uint8_t start_index) const {
     return encode_uint16(this->data_[start_index], this->data_[start_index + 1]);
   }
 
-  Type type_;
-  State state_{State::IDLE};
-  bool initialised_{false};
   uint8_t data_[64];
   uint8_t data_index_{0};
+  uint8_t initialised_{0};
   uint32_t fan_on_time_{0};
   uint32_t last_update_{0};
   uint32_t last_transmission_{0};
   uint32_t update_interval_{0};
+  PMSX003State state_{PMSX003_STATE_IDLE};
+  PMSX003Type type_;
 
   // "Standard Particle"
   sensor::Sensor *pm_1_0_std_sensor_{nullptr};
@@ -119,4 +118,5 @@ class PMSX003Component : public uart::UARTDevice, public Component {
   sensor::Sensor *humidity_sensor_{nullptr};
 };
 
-}  // namespace esphome::pmsx003
+}  // namespace pmsx003
+}  // namespace esphome

esphome/components/pmsx003/sensor.py

@@ -40,128 +40,34 @@ pmsx003_ns = cg.esphome_ns.namespace("pmsx003")
 PMSX003Component = pmsx003_ns.class_("PMSX003Component", uart.UARTDevice, cg.Component)
 PMSX003Sensor = pmsx003_ns.class_("PMSX003Sensor", sensor.Sensor)
 
-TYPE_PMS1003 = "PMS1003"
+TYPE_PMSX003 = "PMSX003"
-TYPE_PMS3003 = "PMS3003"
-TYPE_PMSX003 = "PMSX003"  # PMS5003, PMS6003, PMS7003, PMSA003 (NOT PMSA003I - see `pmsa003i` component)
-TYPE_PMS5003S = "PMS5003S"
 TYPE_PMS5003T = "PMS5003T"
 TYPE_PMS5003ST = "PMS5003ST"
-TYPE_PMS9003M = "PMS9003M"
+TYPE_PMS5003S = "PMS5003S"
 
-Type = pmsx003_ns.enum("Type", is_class=True)
+PMSX003Type = pmsx003_ns.enum("PMSX003Type")
 
 PMSX003_TYPES = {
-    TYPE_PMS1003: Type.PMS1003,
+    TYPE_PMSX003: PMSX003Type.PMSX003_TYPE_X003,
-    TYPE_PMS3003: Type.PMS3003,
+    TYPE_PMS5003T: PMSX003Type.PMSX003_TYPE_5003T,
-    TYPE_PMSX003: Type.PMSX003,
+    TYPE_PMS5003ST: PMSX003Type.PMSX003_TYPE_5003ST,
-    TYPE_PMS5003S: Type.PMS5003S,
+    TYPE_PMS5003S: PMSX003Type.PMSX003_TYPE_5003S,
-    TYPE_PMS5003T: Type.PMS5003T,
-    TYPE_PMS5003ST: Type.PMS5003ST,
-    TYPE_PMS9003M: Type.PMS9003M,
 }
 
 SENSORS_TO_TYPE = {
-    CONF_PM_1_0_STD: [
+    CONF_PM_1_0: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS1003,
+    CONF_PM_2_5: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS3003,
+    CONF_PM_10_0: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMSX003,
+    CONF_PM_1_0_STD: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS5003S,
+    CONF_PM_2_5_STD: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS5003T,
+    CONF_PM_10_0_STD: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS5003ST,
+    CONF_PM_0_3UM: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS9003M,
+    CONF_PM_0_5UM: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-    ],
+    CONF_PM_1_0UM: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-    CONF_PM_2_5_STD: [
+    CONF_PM_2_5UM: [TYPE_PMSX003, TYPE_PMS5003T, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS1003,
+    CONF_PM_5_0UM: [TYPE_PMSX003, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS3003,
+    CONF_PM_10_0UM: [TYPE_PMSX003, TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMSX003,
+    CONF_FORMALDEHYDE: [TYPE_PMS5003ST, TYPE_PMS5003S],
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_10_0_STD: [
-        TYPE_PMS1003,
-        TYPE_PMS3003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_1_0: [
-        TYPE_PMS1003,
-        TYPE_PMS3003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_2_5: [
-        TYPE_PMS1003,
-        TYPE_PMS3003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_10_0: [
-        TYPE_PMS1003,
-        TYPE_PMS3003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_0_3UM: [
-        TYPE_PMS1003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_0_5UM: [
-        TYPE_PMS1003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_1_0UM: [
-        TYPE_PMS1003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_2_5UM: [
-        TYPE_PMS1003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003T,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_5_0UM: [
-        TYPE_PMS1003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_PM_10_0UM: [
-        TYPE_PMS1003,
-        TYPE_PMSX003,
-        TYPE_PMS5003S,
-        TYPE_PMS5003ST,
-        TYPE_PMS9003M,
-    ],
-    CONF_FORMALDEHYDE: [TYPE_PMS5003S, TYPE_PMS5003ST],
     CONF_TEMPERATURE: [TYPE_PMS5003T, TYPE_PMS5003ST],
     CONF_HUMIDITY: [TYPE_PMS5003T, TYPE_PMS5003ST],
 }

esphome/components/resampler/speaker/resampler_speaker.cpp

@@ -6,7 +6,6 @@
 
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include <algorithm>
 #include <cstring>
@@ -14,6 +13,8 @@
 namespace esphome {
 namespace resampler {
 
+static const UBaseType_t RESAMPLER_TASK_PRIORITY = 1;
+
 static const uint32_t TRANSFER_BUFFER_DURATION_MS = 50;
 
 static const uint32_t TASK_DELAY_MS = 20;
@@ -184,10 +185,8 @@ esp_err_t ResamplerSpeaker::start_task_() {
   }
 
   if (this->task_handle_ == nullptr) {
-    // TASK_PRIORITY_APPLICATION: same as main loop - resampling is buffered audio
-    // processing, not real-time I/O
     this->task_handle_ = xTaskCreateStatic(resample_task, "sample", TASK_STACK_SIZE, (void *) this,
-                                           TASK_PRIORITY_APPLICATION, this->task_stack_buffer_, &this->task_stack_);
+                                           RESAMPLER_TASK_PRIORITY, this->task_stack_buffer_, &this->task_stack_);
   }
 
   if (this->task_handle_ == nullptr) {

esphome/components/speaker/media_player/speaker_media_player.cpp

@@ -3,7 +3,6 @@
 #ifdef USE_ESP32
 
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include "esphome/components/audio/audio.h"
 #ifdef USE_OTA
@@ -46,6 +45,9 @@ namespace speaker {
 
 static const uint32_t MEDIA_CONTROLS_QUEUE_LENGTH = 20;
 
+static const UBaseType_t MEDIA_PIPELINE_TASK_PRIORITY = 1;
+static const UBaseType_t ANNOUNCEMENT_PIPELINE_TASK_PRIORITY = 1;
+
 static const char *const TAG = "speaker_media_player";
 
 void SpeakerMediaPlayer::setup() {
@@ -68,10 +70,9 @@ void SpeakerMediaPlayer::setup() {
   ota::get_global_ota_callback()->add_global_state_listener(this);
 #endif
 
-  // TASK_PRIORITY_APPLICATION: same as main loop - media pipelines handle buffered
+  this->announcement_pipeline_ =
-  // audio streaming, not real-time I/O, so they don't need elevated priority
+      make_unique<AudioPipeline>(this->announcement_speaker_, this->buffer_size_, this->task_stack_in_psram_, "ann",
-  this->announcement_pipeline_ = make_unique<AudioPipeline>(
+                                 ANNOUNCEMENT_PIPELINE_TASK_PRIORITY);
-      this->announcement_speaker_, this->buffer_size_, this->task_stack_in_psram_, "ann", TASK_PRIORITY_APPLICATION);
 
   if (this->announcement_pipeline_ == nullptr) {
     ESP_LOGE(TAG, "Failed to create announcement pipeline");
@@ -80,7 +81,7 @@ void SpeakerMediaPlayer::setup() {
 
   if (!this->single_pipeline_()) {
     this->media_pipeline_ = make_unique<AudioPipeline>(this->media_speaker_, this->buffer_size_,
-                                                       this->task_stack_in_psram_, "med", TASK_PRIORITY_APPLICATION);
+                                                       this->task_stack_in_psram_, "med", MEDIA_PIPELINE_TASK_PRIORITY);
 
     if (this->media_pipeline_ == nullptr) {
       ESP_LOGE(TAG, "Failed to create media pipeline");

esphome/components/uart/uart_component_esp_idf.cpp

@@ -7,7 +7,6 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "esphome/core/gpio.h"
-#include "esphome/core/task_priorities.h"
 #include "driver/gpio.h"
 #include "soc/gpio_num.h"
 #include "soc/uart_pins.h"
@@ -368,13 +367,12 @@ void IDFUARTComponent::check_logger_conflict() {}
 
 #ifdef USE_UART_WAKE_LOOP_ON_RX
 void IDFUARTComponent::start_rx_event_task_() {
-  // TASK_PRIORITY_APPLICATION: same as main loop - UART RX monitoring is lightweight,
+  // Create FreeRTOS task to monitor UART events
-  // just wakes main loop when data arrives
+  BaseType_t result = xTaskCreate(rx_event_task_func,    // Task function
-  BaseType_t result = xTaskCreate(rx_event_task_func,  // Task function
+                                  "uart_rx_evt",         // Task name (max 16 chars)
-                                  "uart_rx_evt",       // Task name (max 16 chars)
+                                  2240,                  // Stack size in bytes (~2.2KB); increase if needed for logging
-                                  2240,                // Stack size in bytes (~2.2KB)
+                                  this,                  // Task parameter (this pointer)
-                                  this,                // Task parameter (this pointer)
+                                  tskIDLE_PRIORITY + 1,  // Priority (low, just above idle)
-                                  TASK_PRIORITY_APPLICATION,
                                   &this->rx_event_task_handle_  // Task handle
   );
 

esphome/components/udp/__init__.py

@@ -12,8 +12,8 @@ from esphome.components.packet_transport import (
 )
 import esphome.config_validation as cv
 from esphome.const import CONF_DATA, CONF_ID, CONF_PORT, CONF_TRIGGER_ID
-from esphome.core import ID
+from esphome.core import ID, Lambda
-from esphome.cpp_generator import literal
+from esphome.cpp_generator import ExpressionStatement, MockObj
 
 CODEOWNERS = ["@clydebarrow"]
 DEPENDENCIES = ["network"]
@@ -24,8 +24,6 @@ udp_ns = cg.esphome_ns.namespace("udp")
 UDPComponent = udp_ns.class_("UDPComponent", cg.Component)
 UDPWriteAction = udp_ns.class_("UDPWriteAction", automation.Action)
 trigger_args = cg.std_vector.template(cg.uint8)
-trigger_argname = "data"
-trigger_argtype = [(trigger_args, trigger_argname)]
 
 CONF_ADDRESSES = "addresses"
 CONF_LISTEN_ADDRESS = "listen_address"
@@ -113,14 +111,13 @@ async def to_code(config):
     cg.add(var.set_addresses([str(addr) for addr in config[CONF_ADDRESSES]]))
     if on_receive := config.get(CONF_ON_RECEIVE):
         on_receive = on_receive[0]
-        trigger_id = cg.new_Pvariable(on_receive[CONF_TRIGGER_ID])
+        trigger = cg.new_Pvariable(on_receive[CONF_TRIGGER_ID])
         trigger = await automation.build_automation(
-            trigger_id, trigger_argtype, on_receive
+            trigger, [(trigger_args, "data")], on_receive
         )
-        trigger_lambda = await cg.process_lambda(
+        trigger = Lambda(str(ExpressionStatement(trigger.trigger(MockObj("data")))))
-            trigger.trigger(literal(trigger_argname)), trigger_argtype
+        trigger = await cg.process_lambda(trigger, [(trigger_args, "data")])
-        )
+        cg.add(var.add_listener(trigger))
-        cg.add(var.add_listener(trigger_lambda))
         cg.add(var.set_should_listen())
 
 

esphome/components/usb_cdc_acm/usb_cdc_acm_esp32.cpp

@@ -2,7 +2,6 @@
 #include "usb_cdc_acm.h"
 #include "esphome/core/application.h"
 #include "esphome/core/log.h"
-#include "esphome/core/task_priorities.h"
 
 #include <cstring>
 #include <sys/param.h>
@@ -156,16 +155,13 @@ void USBCDCACMInstance::setup() {
     return;
   }
 
-  // Use a larger stack size for very verbose logging
+  // Use a larger stack size for (very) verbose logging
-  constexpr size_t stack_size =
+  const size_t stack_size = esp_log_level_get(TAG) > ESP_LOG_DEBUG ? USB_TX_TASK_STACK_SIZE_VV : USB_TX_TASK_STACK_SIZE;
-      ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERY_VERBOSE ? USB_TX_TASK_STACK_SIZE_VV : USB_TX_TASK_STACK_SIZE;
 
   // Create a simple, unique task name per interface
   char task_name[] = "usb_tx_0";
   task_name[sizeof(task_name) - 1] = format_hex_char(static_cast<char>(this->itf_));
-  // TASK_PRIORITY_USB_SERIAL: above main loop (TASK_PRIORITY_APPLICATION) and
+  xTaskCreate(usb_tx_task_fn, task_name, stack_size, this, 4, &this->usb_tx_task_handle_);
-  // wake word (TASK_PRIORITY_INFERENCE), below protocol tasks (TASK_PRIORITY_PROTOCOL)
-  xTaskCreate(usb_tx_task_fn, task_name, stack_size, this, TASK_PRIORITY_USB_SERIAL, &this->usb_tx_task_handle_);
 
   if (this->usb_tx_task_handle_ == nullptr) {
     ESP_LOGE(TAG, "Failed to create USB TX task for itf %d", this->itf_);

esphome/components/usb_host/usb_host.h

@@ -4,7 +4,6 @@
 #if defined(USE_ESP32_VARIANT_ESP32P4) || defined(USE_ESP32_VARIANT_ESP32S2) || defined(USE_ESP32_VARIANT_ESP32S3)
 #include "esphome/core/defines.h"
 #include "esphome/core/component.h"
-#include "esphome/core/task_priorities.h"
 #include <vector>
 #include "usb/usb_host.h"
 #include <freertos/FreeRTOS.h>
@@ -70,6 +69,7 @@ static constexpr trq_bitmask_t ALL_REQUESTS_IN_USE = MAX_REQUESTS == 32 ? ~0 : (
 
 static constexpr size_t USB_EVENT_QUEUE_SIZE = 32;   // Size of event queue between USB task and main loop
 static constexpr size_t USB_TASK_STACK_SIZE = 4096;  // Stack size for USB task (same as ESP-IDF USB examples)
+static constexpr UBaseType_t USB_TASK_PRIORITY = 5;  // Higher priority than main loop (tskIDLE_PRIORITY + 5)
 
 // used to report a transfer status
 struct TransferStatus {

esphome/components/usb_host/usb_host_client.cpp

@@ -215,12 +215,11 @@ void USBClient::setup() {
   }
 
   // Create and start USB task
-  // TASK_PRIORITY_PROTOCOL: above main loop (TASK_PRIORITY_APPLICATION) but below
-  // audio tasks - USB host needs responsive scheduling for device communication
   xTaskCreate(usb_task_fn, "usb_task",
               USB_TASK_STACK_SIZE,  // Stack size
               this,                 // Task parameter
-              TASK_PRIORITY_PROTOCOL, &this->usb_task_handle_);
+              USB_TASK_PRIORITY,    // Priority (higher than main loop)
+              &this->usb_task_handle_);
 
   if (this->usb_task_handle_ == nullptr) {
     ESP_LOGE(TAG, "Failed to create USB task");

esphome/components/web_server/web_server.cpp

@@ -209,7 +209,7 @@ void DeferredUpdateEventSource::deq_push_back_with_dedup_(void *source, message_
 void DeferredUpdateEventSource::process_deferred_queue_() {
   while (!deferred_queue_.empty()) {
     DeferredEvent &de = deferred_queue_.front();
-    std::string message = de.message_generator_(web_server_, de.source_);
+    auto message = de.message_generator_(web_server_, de.source_);
     if (this->send(message.c_str(), "state") != DISCARDED) {
       // O(n) but memory efficiency is more important than speed here which is why std::vector was chosen
       deferred_queue_.erase(deferred_queue_.begin());
@@ -266,7 +266,7 @@ void DeferredUpdateEventSource::deferrable_send_state(void *source, const char *
     // deferred queue still not empty which means downstream event queue full, no point trying to send first
     deq_push_back_with_dedup_(source, message_generator);
   } else {
-    std::string message = message_generator(web_server_, source);
+    auto message = message_generator(web_server_, source);
     if (this->send(message.c_str(), "state") == DISCARDED) {
       deq_push_back_with_dedup_(source, message_generator);
     } else {
@@ -320,7 +320,7 @@ void DeferredUpdateEventSourceList::on_client_connect_(DeferredUpdateEventSource
   ws->defer([ws, source]() {
     // Configure reconnect timeout and send config
     // this should always go through since the AsyncEventSourceClient event queue is empty on connect
-    std::string message = ws->get_config_json();
+    auto message = ws->get_config_json();
     source->try_send_nodefer(message.c_str(), "ping", millis(), 30000);
 
 #ifdef USE_WEBSERVER_SORTING
@@ -329,10 +329,10 @@ void DeferredUpdateEventSourceList::on_client_connect_(DeferredUpdateEventSource
       JsonObject root = builder.root();
       root[ESPHOME_F("name")] = group.second.name;
       root[ESPHOME_F("sorting_weight")] = group.second.weight;
-      message = builder.serialize();
+      auto group_msg = builder.serialize();
 
       // up to 31 groups should be able to be queued initially without defer
-      source->try_send_nodefer(message.c_str(), "sorting_group");
+      source->try_send_nodefer(group_msg.c_str(), "sorting_group");
     }
 #endif
 
@@ -365,7 +365,7 @@ void WebServer::set_css_include(const char *css_include) { this->css_include_ =
 void WebServer::set_js_include(const char *js_include) { this->js_include_ = js_include; }
 #endif
 
-std::string WebServer::get_config_json() {
+json::SerializationBuffer<> WebServer::get_config_json() {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -597,20 +597,20 @@ void WebServer::handle_sensor_request(AsyncWebServerRequest *request, const UrlM
     // Note: request->method() is always HTTP_GET here (canHandle ensures this)
     if (entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->sensor_json_(obj, obj->state, detail);
+      auto data = this->sensor_json_(obj, obj->state, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
   }
   request->send(404);
 }
-std::string WebServer::sensor_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::sensor_state_json_generator(WebServer *web_server, void *source) {
   return web_server->sensor_json_((sensor::Sensor *) (source), ((sensor::Sensor *) (source))->state, DETAIL_STATE);
 }
-std::string WebServer::sensor_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::sensor_all_json_generator(WebServer *web_server, void *source) {
   return web_server->sensor_json_((sensor::Sensor *) (source), ((sensor::Sensor *) (source))->state, DETAIL_ALL);
 }
-std::string WebServer::sensor_json_(sensor::Sensor *obj, float value, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::sensor_json_(sensor::Sensor *obj, float value, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -644,23 +644,23 @@ void WebServer::handle_text_sensor_request(AsyncWebServerRequest *request, const
     // Note: request->method() is always HTTP_GET here (canHandle ensures this)
     if (entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->text_sensor_json_(obj, obj->state, detail);
+      auto data = this->text_sensor_json_(obj, obj->state, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
   }
   request->send(404);
 }
-std::string WebServer::text_sensor_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::text_sensor_state_json_generator(WebServer *web_server, void *source) {
   return web_server->text_sensor_json_((text_sensor::TextSensor *) (source),
                                        ((text_sensor::TextSensor *) (source))->state, DETAIL_STATE);
 }
-std::string WebServer::text_sensor_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::text_sensor_all_json_generator(WebServer *web_server, void *source) {
   return web_server->text_sensor_json_((text_sensor::TextSensor *) (source),
                                        ((text_sensor::TextSensor *) (source))->state, DETAIL_ALL);
 }
-std::string WebServer::text_sensor_json_(text_sensor::TextSensor *obj, const std::string &value,
+json::SerializationBuffer<> WebServer::text_sensor_json_(text_sensor::TextSensor *obj, const std::string &value,
-                                         JsonDetail start_config) {
+                                                         JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -705,7 +705,7 @@ void WebServer::handle_switch_request(AsyncWebServerRequest *request, const UrlM
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->switch_json_(obj, obj->state, detail);
+      auto data = this->switch_json_(obj, obj->state, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -734,13 +734,13 @@ void WebServer::handle_switch_request(AsyncWebServerRequest *request, const UrlM
   }
   request->send(404);
 }
-std::string WebServer::switch_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::switch_state_json_generator(WebServer *web_server, void *source) {
   return web_server->switch_json_((switch_::Switch *) (source), ((switch_::Switch *) (source))->state, DETAIL_STATE);
 }
-std::string WebServer::switch_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::switch_all_json_generator(WebServer *web_server, void *source) {
   return web_server->switch_json_((switch_::Switch *) (source), ((switch_::Switch *) (source))->state, DETAIL_ALL);
 }
-std::string WebServer::switch_json_(switch_::Switch *obj, bool value, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::switch_json_(switch_::Switch *obj, bool value, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -762,7 +762,7 @@ void WebServer::handle_button_request(AsyncWebServerRequest *request, const UrlM
       continue;
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->button_json_(obj, detail);
+      auto data = this->button_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
     } else if (match.method_equals(ESPHOME_F("press"))) {
       DEFER_ACTION(obj, obj->press());
@@ -775,10 +775,10 @@ void WebServer::handle_button_request(AsyncWebServerRequest *request, const UrlM
   }
   request->send(404);
 }
-std::string WebServer::button_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::button_all_json_generator(WebServer *web_server, void *source) {
   return web_server->button_json_((button::Button *) (source), DETAIL_ALL);
 }
-std::string WebServer::button_json_(button::Button *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::button_json_(button::Button *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -805,22 +805,23 @@ void WebServer::handle_binary_sensor_request(AsyncWebServerRequest *request, con
     // Note: request->method() is always HTTP_GET here (canHandle ensures this)
     if (entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->binary_sensor_json_(obj, obj->state, detail);
+      auto data = this->binary_sensor_json_(obj, obj->state, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
   }
   request->send(404);
 }
-std::string WebServer::binary_sensor_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::binary_sensor_state_json_generator(WebServer *web_server, void *source) {
   return web_server->binary_sensor_json_((binary_sensor::BinarySensor *) (source),
                                          ((binary_sensor::BinarySensor *) (source))->state, DETAIL_STATE);
 }
-std::string WebServer::binary_sensor_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::binary_sensor_all_json_generator(WebServer *web_server, void *source) {
   return web_server->binary_sensor_json_((binary_sensor::BinarySensor *) (source),
                                          ((binary_sensor::BinarySensor *) (source))->state, DETAIL_ALL);
 }
-std::string WebServer::binary_sensor_json_(binary_sensor::BinarySensor *obj, bool value, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::binary_sensor_json_(binary_sensor::BinarySensor *obj, bool value,
+                                                           JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -847,7 +848,7 @@ void WebServer::handle_fan_request(AsyncWebServerRequest *request, const UrlMatc
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->fan_json_(obj, detail);
+      auto data = this->fan_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
     } else if (match.method_equals(ESPHOME_F("toggle"))) {
       DEFER_ACTION(obj, obj->toggle().perform());
@@ -888,13 +889,13 @@ void WebServer::handle_fan_request(AsyncWebServerRequest *request, const UrlMatc
   }
   request->send(404);
 }
-std::string WebServer::fan_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::fan_state_json_generator(WebServer *web_server, void *source) {
   return web_server->fan_json_((fan::Fan *) (source), DETAIL_STATE);
 }
-std::string WebServer::fan_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::fan_all_json_generator(WebServer *web_server, void *source) {
   return web_server->fan_json_((fan::Fan *) (source), DETAIL_ALL);
 }
-std::string WebServer::fan_json_(fan::Fan *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::fan_json_(fan::Fan *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -928,7 +929,7 @@ void WebServer::handle_light_request(AsyncWebServerRequest *request, const UrlMa
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->light_json_(obj, detail);
+      auto data = this->light_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
     } else if (match.method_equals(ESPHOME_F("toggle"))) {
       DEFER_ACTION(obj, obj->toggle().perform());
@@ -967,13 +968,13 @@ void WebServer::handle_light_request(AsyncWebServerRequest *request, const UrlMa
   }
   request->send(404);
 }
-std::string WebServer::light_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::light_state_json_generator(WebServer *web_server, void *source) {
   return web_server->light_json_((light::LightState *) (source), DETAIL_STATE);
 }
-std::string WebServer::light_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::light_all_json_generator(WebServer *web_server, void *source) {
   return web_server->light_json_((light::LightState *) (source), DETAIL_ALL);
 }
-std::string WebServer::light_json_(light::LightState *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::light_json_(light::LightState *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1007,7 +1008,7 @@ void WebServer::handle_cover_request(AsyncWebServerRequest *request, const UrlMa
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->cover_json_(obj, detail);
+      auto data = this->cover_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1055,13 +1056,13 @@ void WebServer::handle_cover_request(AsyncWebServerRequest *request, const UrlMa
   }
   request->send(404);
 }
-std::string WebServer::cover_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::cover_state_json_generator(WebServer *web_server, void *source) {
   return web_server->cover_json_((cover::Cover *) (source), DETAIL_STATE);
 }
-std::string WebServer::cover_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::cover_all_json_generator(WebServer *web_server, void *source) {
   return web_server->cover_json_((cover::Cover *) (source), DETAIL_ALL);
 }
-std::string WebServer::cover_json_(cover::Cover *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::cover_json_(cover::Cover *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1096,7 +1097,7 @@ void WebServer::handle_number_request(AsyncWebServerRequest *request, const UrlM
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->number_json_(obj, obj->state, detail);
+      auto data = this->number_json_(obj, obj->state, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1115,13 +1116,13 @@ void WebServer::handle_number_request(AsyncWebServerRequest *request, const UrlM
   request->send(404);
 }
 
-std::string WebServer::number_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::number_state_json_generator(WebServer *web_server, void *source) {
   return web_server->number_json_((number::Number *) (source), ((number::Number *) (source))->state, DETAIL_STATE);
 }
-std::string WebServer::number_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::number_all_json_generator(WebServer *web_server, void *source) {
   return web_server->number_json_((number::Number *) (source), ((number::Number *) (source))->state, DETAIL_ALL);
 }
-std::string WebServer::number_json_(number::Number *obj, float value, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::number_json_(number::Number *obj, float value, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1163,7 +1164,7 @@ void WebServer::handle_date_request(AsyncWebServerRequest *request, const UrlMat
       continue;
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->date_json_(obj, detail);
+      auto data = this->date_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1188,13 +1189,13 @@ void WebServer::handle_date_request(AsyncWebServerRequest *request, const UrlMat
   request->send(404);
 }
 
-std::string WebServer::date_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::date_state_json_generator(WebServer *web_server, void *source) {
   return web_server->date_json_((datetime::DateEntity *) (source), DETAIL_STATE);
 }
-std::string WebServer::date_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::date_all_json_generator(WebServer *web_server, void *source) {
   return web_server->date_json_((datetime::DateEntity *) (source), DETAIL_ALL);
 }
-std::string WebServer::date_json_(datetime::DateEntity *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::date_json_(datetime::DateEntity *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1223,7 +1224,7 @@ void WebServer::handle_time_request(AsyncWebServerRequest *request, const UrlMat
       continue;
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->time_json_(obj, detail);
+      auto data = this->time_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1247,13 +1248,13 @@ void WebServer::handle_time_request(AsyncWebServerRequest *request, const UrlMat
   }
   request->send(404);
 }
-std::string WebServer::time_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::time_state_json_generator(WebServer *web_server, void *source) {
   return web_server->time_json_((datetime::TimeEntity *) (source), DETAIL_STATE);
 }
-std::string WebServer::time_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::time_all_json_generator(WebServer *web_server, void *source) {
   return web_server->time_json_((datetime::TimeEntity *) (source), DETAIL_ALL);
 }
-std::string WebServer::time_json_(datetime::TimeEntity *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::time_json_(datetime::TimeEntity *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1282,7 +1283,7 @@ void WebServer::handle_datetime_request(AsyncWebServerRequest *request, const Ur
       continue;
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->datetime_json_(obj, detail);
+      auto data = this->datetime_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1306,13 +1307,13 @@ void WebServer::handle_datetime_request(AsyncWebServerRequest *request, const Ur
   }
   request->send(404);
 }
-std::string WebServer::datetime_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::datetime_state_json_generator(WebServer *web_server, void *source) {
   return web_server->datetime_json_((datetime::DateTimeEntity *) (source), DETAIL_STATE);
 }
-std::string WebServer::datetime_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::datetime_all_json_generator(WebServer *web_server, void *source) {
   return web_server->datetime_json_((datetime::DateTimeEntity *) (source), DETAIL_ALL);
 }
-std::string WebServer::datetime_json_(datetime::DateTimeEntity *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::datetime_json_(datetime::DateTimeEntity *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1343,7 +1344,7 @@ void WebServer::handle_text_request(AsyncWebServerRequest *request, const UrlMat
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->text_json_(obj, obj->state, detail);
+      auto data = this->text_json_(obj, obj->state, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1362,13 +1363,13 @@ void WebServer::handle_text_request(AsyncWebServerRequest *request, const UrlMat
   request->send(404);
 }
 
-std::string WebServer::text_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::text_state_json_generator(WebServer *web_server, void *source) {
   return web_server->text_json_((text::Text *) (source), ((text::Text *) (source))->state, DETAIL_STATE);
 }
-std::string WebServer::text_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::text_all_json_generator(WebServer *web_server, void *source) {
   return web_server->text_json_((text::Text *) (source), ((text::Text *) (source))->state, DETAIL_ALL);
 }
-std::string WebServer::text_json_(text::Text *obj, const std::string &value, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::text_json_(text::Text *obj, const std::string &value, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1400,7 +1401,7 @@ void WebServer::handle_select_request(AsyncWebServerRequest *request, const UrlM
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->select_json_(obj, obj->has_state() ? obj->current_option() : StringRef(), detail);
+      auto data = this->select_json_(obj, obj->has_state() ? obj->current_option() : StringRef(), detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1419,15 +1420,15 @@ void WebServer::handle_select_request(AsyncWebServerRequest *request, const UrlM
   }
   request->send(404);
 }
-std::string WebServer::select_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::select_state_json_generator(WebServer *web_server, void *source) {
   auto *obj = (select::Select *) (source);
   return web_server->select_json_(obj, obj->has_state() ? obj->current_option() : StringRef(), DETAIL_STATE);
 }
-std::string WebServer::select_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::select_all_json_generator(WebServer *web_server, void *source) {
   auto *obj = (select::Select *) (source);
   return web_server->select_json_(obj, obj->has_state() ? obj->current_option() : StringRef(), DETAIL_ALL);
 }
-std::string WebServer::select_json_(select::Select *obj, StringRef value, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::select_json_(select::Select *obj, StringRef value, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1459,7 +1460,7 @@ void WebServer::handle_climate_request(AsyncWebServerRequest *request, const Url
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->climate_json_(obj, detail);
+      auto data = this->climate_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1488,15 +1489,15 @@ void WebServer::handle_climate_request(AsyncWebServerRequest *request, const Url
   }
   request->send(404);
 }
-std::string WebServer::climate_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::climate_state_json_generator(WebServer *web_server, void *source) {
   // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   return web_server->climate_json_((climate::Climate *) (source), DETAIL_STATE);
 }
-std::string WebServer::climate_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::climate_all_json_generator(WebServer *web_server, void *source) {
   // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   return web_server->climate_json_((climate::Climate *) (source), DETAIL_ALL);
 }
-std::string WebServer::climate_json_(climate::Climate *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::climate_json_(climate::Climate *obj, JsonDetail start_config) {
   // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   json::JsonBuilder builder;
   JsonObject root = builder.root();
@@ -1629,7 +1630,7 @@ void WebServer::handle_lock_request(AsyncWebServerRequest *request, const UrlMat
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->lock_json_(obj, obj->state, detail);
+      auto data = this->lock_json_(obj, obj->state, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1658,13 +1659,13 @@ void WebServer::handle_lock_request(AsyncWebServerRequest *request, const UrlMat
   }
   request->send(404);
 }
-std::string WebServer::lock_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::lock_state_json_generator(WebServer *web_server, void *source) {
   return web_server->lock_json_((lock::Lock *) (source), ((lock::Lock *) (source))->state, DETAIL_STATE);
 }
-std::string WebServer::lock_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::lock_all_json_generator(WebServer *web_server, void *source) {
   return web_server->lock_json_((lock::Lock *) (source), ((lock::Lock *) (source))->state, DETAIL_ALL);
 }
-std::string WebServer::lock_json_(lock::Lock *obj, lock::LockState value, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::lock_json_(lock::Lock *obj, lock::LockState value, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1692,7 +1693,7 @@ void WebServer::handle_valve_request(AsyncWebServerRequest *request, const UrlMa
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->valve_json_(obj, detail);
+      auto data = this->valve_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1738,13 +1739,13 @@ void WebServer::handle_valve_request(AsyncWebServerRequest *request, const UrlMa
   }
   request->send(404);
 }
-std::string WebServer::valve_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::valve_state_json_generator(WebServer *web_server, void *source) {
   return web_server->valve_json_((valve::Valve *) (source), DETAIL_STATE);
 }
-std::string WebServer::valve_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::valve_all_json_generator(WebServer *web_server, void *source) {
   return web_server->valve_json_((valve::Valve *) (source), DETAIL_ALL);
 }
-std::string WebServer::valve_json_(valve::Valve *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::valve_json_(valve::Valve *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1777,7 +1778,7 @@ void WebServer::handle_alarm_control_panel_request(AsyncWebServerRequest *reques
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->alarm_control_panel_json_(obj, obj->get_state(), detail);
+      auto data = this->alarm_control_panel_json_(obj, obj->get_state(), detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1817,19 +1818,19 @@ void WebServer::handle_alarm_control_panel_request(AsyncWebServerRequest *reques
   }
   request->send(404);
 }
-std::string WebServer::alarm_control_panel_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::alarm_control_panel_state_json_generator(WebServer *web_server, void *source) {
   return web_server->alarm_control_panel_json_((alarm_control_panel::AlarmControlPanel *) (source),
                                                ((alarm_control_panel::AlarmControlPanel *) (source))->get_state(),
                                                DETAIL_STATE);
 }
-std::string WebServer::alarm_control_panel_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::alarm_control_panel_all_json_generator(WebServer *web_server, void *source) {
   return web_server->alarm_control_panel_json_((alarm_control_panel::AlarmControlPanel *) (source),
                                                ((alarm_control_panel::AlarmControlPanel *) (source))->get_state(),
                                                DETAIL_ALL);
 }
-std::string WebServer::alarm_control_panel_json_(alarm_control_panel::AlarmControlPanel *obj,
+json::SerializationBuffer<> WebServer::alarm_control_panel_json_(alarm_control_panel::AlarmControlPanel *obj,
-                                                 alarm_control_panel::AlarmControlPanelState value,
+                                                                 alarm_control_panel::AlarmControlPanelState value,
-                                                 JsonDetail start_config) {
+                                                                 JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -1858,7 +1859,7 @@ void WebServer::handle_water_heater_request(AsyncWebServerRequest *request, cons
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->water_heater_json_(obj, detail);
+      auto data = this->water_heater_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -1894,14 +1895,14 @@ void WebServer::handle_water_heater_request(AsyncWebServerRequest *request, cons
   request->send(404);
 }
 
-std::string WebServer::water_heater_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::water_heater_state_json_generator(WebServer *web_server, void *source) {
   return web_server->water_heater_json_(static_cast<water_heater::WaterHeater *>(source), DETAIL_STATE);
 }
-std::string WebServer::water_heater_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::water_heater_all_json_generator(WebServer *web_server, void *source) {
   // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   return web_server->water_heater_json_(static_cast<water_heater::WaterHeater *>(source), DETAIL_ALL);
 }
-std::string WebServer::water_heater_json_(water_heater::WaterHeater *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::water_heater_json_(water_heater::WaterHeater *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
   char buf[PSTR_LOCAL_SIZE];
@@ -1964,7 +1965,7 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->infrared_json_(obj, detail);
+      auto data = this->infrared_json_(obj, detail);
       request->send(200, ESPHOME_F("application/json"), data.c_str());
       return;
     }
@@ -2035,12 +2036,12 @@ void WebServer::handle_infrared_request(AsyncWebServerRequest *request, const Ur
   request->send(404);
 }
 
-std::string WebServer::infrared_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::infrared_all_json_generator(WebServer *web_server, void *source) {
   // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   return web_server->infrared_json_(static_cast<infrared::Infrared *>(source), DETAIL_ALL);
 }
 
-std::string WebServer::infrared_json_(infrared::Infrared *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::infrared_json_(infrared::Infrared *obj, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -2075,7 +2076,7 @@ void WebServer::handle_event_request(AsyncWebServerRequest *request, const UrlMa
     // Note: request->method() is always HTTP_GET here (canHandle ensures this)
     if (entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->event_json_(obj, StringRef(), detail);
+      auto data = this->event_json_(obj, StringRef(), detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -2085,16 +2086,16 @@ void WebServer::handle_event_request(AsyncWebServerRequest *request, const UrlMa
 
 static StringRef get_event_type(event::Event *event) { return event ? event->get_last_event_type() : StringRef(); }
 
-std::string WebServer::event_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::event_state_json_generator(WebServer *web_server, void *source) {
   auto *event = static_cast<event::Event *>(source);
   return web_server->event_json_(event, get_event_type(event), DETAIL_STATE);
 }
 // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
-std::string WebServer::event_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::event_all_json_generator(WebServer *web_server, void *source) {
   auto *event = static_cast<event::Event *>(source);
   return web_server->event_json_(event, get_event_type(event), DETAIL_ALL);
 }
-std::string WebServer::event_json_(event::Event *obj, StringRef event_type, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::event_json_(event::Event *obj, StringRef event_type, JsonDetail start_config) {
   json::JsonBuilder builder;
   JsonObject root = builder.root();
 
@@ -2141,7 +2142,7 @@ void WebServer::handle_update_request(AsyncWebServerRequest *request, const UrlM
 
     if (request->method() == HTTP_GET && entity_match.action_is_empty) {
       auto detail = get_request_detail(request);
-      std::string data = this->update_json_(obj, detail);
+      auto data = this->update_json_(obj, detail);
       request->send(200, "application/json", data.c_str());
       return;
     }
@@ -2157,15 +2158,15 @@ void WebServer::handle_update_request(AsyncWebServerRequest *request, const UrlM
   }
   request->send(404);
 }
-std::string WebServer::update_state_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::update_state_json_generator(WebServer *web_server, void *source) {
   // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   return web_server->update_json_((update::UpdateEntity *) (source), DETAIL_STATE);
 }
-std::string WebServer::update_all_json_generator(WebServer *web_server, void *source) {
+json::SerializationBuffer<> WebServer::update_all_json_generator(WebServer *web_server, void *source) {
   // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   return web_server->update_json_((update::UpdateEntity *) (source), DETAIL_STATE);
 }
-std::string WebServer::update_json_(update::UpdateEntity *obj, JsonDetail start_config) {
+json::SerializationBuffer<> WebServer::update_json_(update::UpdateEntity *obj, JsonDetail start_config) {
   // NOLINTBEGIN(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
   json::JsonBuilder builder;
   JsonObject root = builder.root();

esphome/components/web_server/web_server.h

@@ -2,6 +2,7 @@
 
 #include "list_entities.h"
 
+#include "esphome/components/json/json_util.h"
 #include "esphome/components/web_server_base/web_server_base.h"
 #ifdef USE_WEBSERVER
 #include "esphome/core/component.h"
@@ -104,7 +105,7 @@ enum JsonDetail { DETAIL_ALL, DETAIL_STATE };
   can be forgotten.
 */
 #if !defined(USE_ESP32) && defined(USE_ARDUINO)
-using message_generator_t = std::string(WebServer *, void *);
+using message_generator_t = json::SerializationBuffer<>(WebServer *, void *);
 
 class DeferredUpdateEventSourceList;
 class DeferredUpdateEventSource : public AsyncEventSource {
@@ -263,7 +264,7 @@ class WebServer : public Controller,
   void handle_index_request(AsyncWebServerRequest *request);
 
   /// Return the webserver configuration as JSON.
-  std::string get_config_json();
+  json::SerializationBuffer<> get_config_json();
 
 #ifdef USE_WEBSERVER_CSS_INCLUDE
   /// Handle included css request under '/0.css'.
@@ -285,8 +286,8 @@ class WebServer : public Controller,
   /// Handle a sensor request under '/sensor/<id>'.
   void handle_sensor_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string sensor_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> sensor_state_json_generator(WebServer *web_server, void *source);
-  static std::string sensor_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> sensor_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_SWITCH
@@ -295,8 +296,8 @@ class WebServer : public Controller,
   /// Handle a switch request under '/switch/<id>/</turn_on/turn_off/toggle>'.
   void handle_switch_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string switch_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> switch_state_json_generator(WebServer *web_server, void *source);
-  static std::string switch_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> switch_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_BUTTON
@@ -304,7 +305,7 @@ class WebServer : public Controller,
   void handle_button_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
   // Buttons are stateless, so there is no button_state_json_generator
-  static std::string button_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> button_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_BINARY_SENSOR
@@ -313,8 +314,8 @@ class WebServer : public Controller,
   /// Handle a binary sensor request under '/binary_sensor/<id>'.
   void handle_binary_sensor_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string binary_sensor_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> binary_sensor_state_json_generator(WebServer *web_server, void *source);
-  static std::string binary_sensor_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> binary_sensor_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_FAN
@@ -323,8 +324,8 @@ class WebServer : public Controller,
   /// Handle a fan request under '/fan/<id>/</turn_on/turn_off/toggle>'.
   void handle_fan_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string fan_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> fan_state_json_generator(WebServer *web_server, void *source);
-  static std::string fan_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> fan_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_LIGHT
@@ -333,8 +334,8 @@ class WebServer : public Controller,
   /// Handle a light request under '/light/<id>/</turn_on/turn_off/toggle>'.
   void handle_light_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string light_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> light_state_json_generator(WebServer *web_server, void *source);
-  static std::string light_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> light_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_TEXT_SENSOR
@@ -343,8 +344,8 @@ class WebServer : public Controller,
   /// Handle a text sensor request under '/text_sensor/<id>'.
   void handle_text_sensor_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string text_sensor_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> text_sensor_state_json_generator(WebServer *web_server, void *source);
-  static std::string text_sensor_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> text_sensor_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_COVER
@@ -353,8 +354,8 @@ class WebServer : public Controller,
   /// Handle a cover request under '/cover/<id>/<open/close/stop/set>'.
   void handle_cover_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string cover_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> cover_state_json_generator(WebServer *web_server, void *source);
-  static std::string cover_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> cover_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_NUMBER
@@ -362,8 +363,8 @@ class WebServer : public Controller,
   /// Handle a number request under '/number/<id>'.
   void handle_number_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string number_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> number_state_json_generator(WebServer *web_server, void *source);
-  static std::string number_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> number_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_DATETIME_DATE
@@ -371,8 +372,8 @@ class WebServer : public Controller,
   /// Handle a date request under '/date/<id>'.
   void handle_date_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string date_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> date_state_json_generator(WebServer *web_server, void *source);
-  static std::string date_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> date_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_DATETIME_TIME
@@ -380,8 +381,8 @@ class WebServer : public Controller,
   /// Handle a time request under '/time/<id>'.
   void handle_time_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string time_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> time_state_json_generator(WebServer *web_server, void *source);
-  static std::string time_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> time_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_DATETIME_DATETIME
@@ -389,8 +390,8 @@ class WebServer : public Controller,
   /// Handle a datetime request under '/datetime/<id>'.
   void handle_datetime_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string datetime_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> datetime_state_json_generator(WebServer *web_server, void *source);
-  static std::string datetime_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> datetime_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_TEXT
@@ -398,8 +399,8 @@ class WebServer : public Controller,
   /// Handle a text input request under '/text/<id>'.
   void handle_text_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string text_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> text_state_json_generator(WebServer *web_server, void *source);
-  static std::string text_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> text_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_SELECT
@@ -407,8 +408,8 @@ class WebServer : public Controller,
   /// Handle a select request under '/select/<id>'.
   void handle_select_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string select_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> select_state_json_generator(WebServer *web_server, void *source);
-  static std::string select_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> select_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_CLIMATE
@@ -416,8 +417,8 @@ class WebServer : public Controller,
   /// Handle a climate request under '/climate/<id>'.
   void handle_climate_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string climate_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> climate_state_json_generator(WebServer *web_server, void *source);
-  static std::string climate_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> climate_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_LOCK
@@ -426,8 +427,8 @@ class WebServer : public Controller,
   /// Handle a lock request under '/lock/<id>/</lock/unlock/open>'.
   void handle_lock_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string lock_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> lock_state_json_generator(WebServer *web_server, void *source);
-  static std::string lock_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> lock_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_VALVE
@@ -436,8 +437,8 @@ class WebServer : public Controller,
   /// Handle a valve request under '/valve/<id>/<open/close/stop/set>'.
   void handle_valve_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string valve_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> valve_state_json_generator(WebServer *web_server, void *source);
-  static std::string valve_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> valve_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_ALARM_CONTROL_PANEL
@@ -446,8 +447,8 @@ class WebServer : public Controller,
   /// Handle a alarm_control_panel request under '/alarm_control_panel/<id>'.
   void handle_alarm_control_panel_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string alarm_control_panel_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> alarm_control_panel_state_json_generator(WebServer *web_server, void *source);
-  static std::string alarm_control_panel_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> alarm_control_panel_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_WATER_HEATER
@@ -456,22 +457,22 @@ class WebServer : public Controller,
   /// Handle a water_heater request under '/water_heater/<id>/<mode/set>'.
   void handle_water_heater_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string water_heater_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> water_heater_state_json_generator(WebServer *web_server, void *source);
-  static std::string water_heater_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> water_heater_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_INFRARED
   /// Handle an infrared request under '/infrared/<id>/transmit'.
   void handle_infrared_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string infrared_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> infrared_all_json_generator(WebServer *web_server, void *source);
 #endif
 
 #ifdef USE_EVENT
   void on_event(event::Event *obj) override;
 
-  static std::string event_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> event_state_json_generator(WebServer *web_server, void *source);
-  static std::string event_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> event_all_json_generator(WebServer *web_server, void *source);
 
   /// Handle a event request under '/event<id>'.
   void handle_event_request(AsyncWebServerRequest *request, const UrlMatch &match);
@@ -483,8 +484,8 @@ class WebServer : public Controller,
   /// Handle a update request under '/update/<id>'.
   void handle_update_request(AsyncWebServerRequest *request, const UrlMatch &match);
 
-  static std::string update_state_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> update_state_json_generator(WebServer *web_server, void *source);
-  static std::string update_all_json_generator(WebServer *web_server, void *source);
+  static json::SerializationBuffer<> update_all_json_generator(WebServer *web_server, void *source);
 #endif
 
   /// Override the web handler's canHandle method.
@@ -609,71 +610,74 @@ class WebServer : public Controller,
 
  private:
 #ifdef USE_SENSOR
-  std::string sensor_json_(sensor::Sensor *obj, float value, JsonDetail start_config);
+  json::SerializationBuffer<> sensor_json_(sensor::Sensor *obj, float value, JsonDetail start_config);
 #endif
 #ifdef USE_SWITCH
-  std::string switch_json_(switch_::Switch *obj, bool value, JsonDetail start_config);
+  json::SerializationBuffer<> switch_json_(switch_::Switch *obj, bool value, JsonDetail start_config);
 #endif
 #ifdef USE_BUTTON
-  std::string button_json_(button::Button *obj, JsonDetail start_config);
+  json::SerializationBuffer<> button_json_(button::Button *obj, JsonDetail start_config);
 #endif
 #ifdef USE_BINARY_SENSOR
-  std::string binary_sensor_json_(binary_sensor::BinarySensor *obj, bool value, JsonDetail start_config);
+  json::SerializationBuffer<> binary_sensor_json_(binary_sensor::BinarySensor *obj, bool value,
+                                                  JsonDetail start_config);
 #endif
 #ifdef USE_FAN
-  std::string fan_json_(fan::Fan *obj, JsonDetail start_config);
+  json::SerializationBuffer<> fan_json_(fan::Fan *obj, JsonDetail start_config);
 #endif
 #ifdef USE_LIGHT
-  std::string light_json_(light::LightState *obj, JsonDetail start_config);
+  json::SerializationBuffer<> light_json_(light::LightState *obj, JsonDetail start_config);
 #endif
 #ifdef USE_TEXT_SENSOR
-  std::string text_sensor_json_(text_sensor::TextSensor *obj, const std::string &value, JsonDetail start_config);
+  json::SerializationBuffer<> text_sensor_json_(text_sensor::TextSensor *obj, const std::string &value,
+                                                JsonDetail start_config);
 #endif
 #ifdef USE_COVER
-  std::string cover_json_(cover::Cover *obj, JsonDetail start_config);
+  json::SerializationBuffer<> cover_json_(cover::Cover *obj, JsonDetail start_config);
 #endif
 #ifdef USE_NUMBER
-  std::string number_json_(number::Number *obj, float value, JsonDetail start_config);
+  json::SerializationBuffer<> number_json_(number::Number *obj, float value, JsonDetail start_config);
 #endif
 #ifdef USE_DATETIME_DATE
-  std::string date_json_(datetime::DateEntity *obj, JsonDetail start_config);
+  json::SerializationBuffer<> date_json_(datetime::DateEntity *obj, JsonDetail start_config);
 #endif
 #ifdef USE_DATETIME_TIME
-  std::string time_json_(datetime::TimeEntity *obj, JsonDetail start_config);
+  json::SerializationBuffer<> time_json_(datetime::TimeEntity *obj, JsonDetail start_config);
 #endif
 #ifdef USE_DATETIME_DATETIME
-  std::string datetime_json_(datetime::DateTimeEntity *obj, JsonDetail start_config);
+  json::SerializationBuffer<> datetime_json_(datetime::DateTimeEntity *obj, JsonDetail start_config);
 #endif
 #ifdef USE_TEXT
-  std::string text_json_(text::Text *obj, const std::string &value, JsonDetail start_config);
+  json::SerializationBuffer<> text_json_(text::Text *obj, const std::string &value, JsonDetail start_config);
 #endif
 #ifdef USE_SELECT
-  std::string select_json_(select::Select *obj, StringRef value, JsonDetail start_config);
+  json::SerializationBuffer<> select_json_(select::Select *obj, StringRef value, JsonDetail start_config);
 #endif
 #ifdef USE_CLIMATE
-  std::string climate_json_(climate::Climate *obj, JsonDetail start_config);
+  json::SerializationBuffer<> climate_json_(climate::Climate *obj, JsonDetail start_config);
 #endif
 #ifdef USE_LOCK
-  std::string lock_json_(lock::Lock *obj, lock::LockState value, JsonDetail start_config);
+  json::SerializationBuffer<> lock_json_(lock::Lock *obj, lock::LockState value, JsonDetail start_config);
 #endif
 #ifdef USE_VALVE
-  std::string valve_json_(valve::Valve *obj, JsonDetail start_config);
+  json::SerializationBuffer<> valve_json_(valve::Valve *obj, JsonDetail start_config);
 #endif
 #ifdef USE_ALARM_CONTROL_PANEL
-  std::string alarm_control_panel_json_(alarm_control_panel::AlarmControlPanel *obj,
+  json::SerializationBuffer<> alarm_control_panel_json_(alarm_control_panel::AlarmControlPanel *obj,
-                                        alarm_control_panel::AlarmControlPanelState value, JsonDetail start_config);
+                                                        alarm_control_panel::AlarmControlPanelState value,
+                                                        JsonDetail start_config);
 #endif
 #ifdef USE_EVENT
-  std::string event_json_(event::Event *obj, StringRef event_type, JsonDetail start_config);
+  json::SerializationBuffer<> event_json_(event::Event *obj, StringRef event_type, JsonDetail start_config);
 #endif
 #ifdef USE_WATER_HEATER
-  std::string water_heater_json_(water_heater::WaterHeater *obj, JsonDetail start_config);
+  json::SerializationBuffer<> water_heater_json_(water_heater::WaterHeater *obj, JsonDetail start_config);
 #endif
 #ifdef USE_INFRARED
-  std::string infrared_json_(infrared::Infrared *obj, JsonDetail start_config);
+  json::SerializationBuffer<> infrared_json_(infrared::Infrared *obj, JsonDetail start_config);
 #endif
 #ifdef USE_UPDATE
-  std::string update_json_(update::UpdateEntity *obj, JsonDetail start_config);
+  json::SerializationBuffer<> update_json_(update::UpdateEntity *obj, JsonDetail start_config);
 #endif
 };
 

esphome/components/web_server_base/__init__.py

@@ -53,4 +53,4 @@ async def to_code(config):
                 "lib_ignore", ["ESPAsyncTCP", "AsyncTCP", "AsyncTCP_RP2040W"]
             )
         # https://github.com/ESP32Async/ESPAsyncWebServer/blob/main/library.json
-        cg.add_library("ESP32Async/ESPAsyncWebServer", "3.9.6")
+        cg.add_library("ESP32Async/ESPAsyncWebServer", "3.9.5")

esphome/components/web_server_idf/web_server_idf.cpp

@@ -507,7 +507,7 @@ AsyncEventSourceResponse::AsyncEventSourceResponse(const AsyncWebServerRequest *
 
   // Configure reconnect timeout and send config
   // this should always go through since the tcp send buffer is empty on connect
-  std::string message = ws->get_config_json();
+  auto message = ws->get_config_json();
   this->try_send_nodefer(message.c_str(), "ping", millis(), 30000);
 
 #ifdef USE_WEBSERVER_SORTING
@@ -561,7 +561,7 @@ void AsyncEventSourceResponse::deq_push_back_with_dedup_(void *source, message_g
 void AsyncEventSourceResponse::process_deferred_queue_() {
   while (!deferred_queue_.empty()) {
     DeferredEvent &de = deferred_queue_.front();
-    std::string message = de.message_generator_(web_server_, de.source_);
+    auto message = de.message_generator_(web_server_, de.source_);
     if (this->try_send_nodefer(message.c_str(), "state")) {
       // O(n) but memory efficiency is more important than speed here which is why std::vector was chosen
       deferred_queue_.erase(deferred_queue_.begin());
@@ -798,7 +798,7 @@ void AsyncEventSourceResponse::deferrable_send_state(void *source, const char *e
     // trying to send first
     deq_push_back_with_dedup_(source, message_generator);
   } else {
-    std::string message = message_generator(web_server_, source);
+    auto message = message_generator(web_server_, source);
     if (!this->try_send_nodefer(message.c_str(), "state")) {
       deq_push_back_with_dedup_(source, message_generator);
     }

esphome/components/web_server_idf/web_server_idf.h

@@ -16,6 +16,7 @@
 #include <vector>
 
 #ifdef USE_WEBSERVER
+#include "esphome/components/json/json_util.h"
 #include "esphome/components/web_server/list_entities.h"
 #endif
 
@@ -250,7 +251,7 @@ class AsyncWebHandler {
 class AsyncEventSource;
 class AsyncEventSourceResponse;
 
-using message_generator_t = std::string(esphome::web_server::WebServer *, void *);
+using message_generator_t = json::SerializationBuffer<>(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

esphome/core/__init__.py

@@ -278,13 +278,9 @@ LAMBDA_PROG = re.compile(r"\bid\(\s*([a-zA-Z_][a-zA-Z0-9_]*)\s*\)(\.?)")
 
 class Lambda:
     def __init__(self, value):
-        from esphome.cpp_generator import Expression, statement
-
         # pylint: disable=protected-access
         if isinstance(value, Lambda):
             self._value = value._value
-        elif isinstance(value, Expression):
-            self._value = str(statement(value))
         else:
             self._value = value
         self._parts = None

esphome/core/application.cpp

@@ -210,7 +210,7 @@ void Application::loop() {
 #ifdef USE_ESP32
       esp_chip_info_t chip_info;
       esp_chip_info(&chip_info);
-      ESP_LOGI(TAG, "ESP32 Chip: %s rev%d.%d, %d core(s)", ESPHOME_VARIANT, chip_info.revision / 100,
+      ESP_LOGI(TAG, "ESP32 Chip: %s r%d.%d, %d core(s)", ESPHOME_VARIANT, chip_info.revision / 100,
                chip_info.revision % 100, chip_info.cores);
 #if defined(USE_ESP32_VARIANT_ESP32) && !defined(USE_ESP32_MIN_CHIP_REVISION_SET)
       // Suggest optimization for chips that don't need the PSRAM cache workaround

esphome/core/task_priorities.h

@@ -1,61 +0,0 @@
-#pragma once
-
-#ifdef USE_ESP32
-
-#include <freertos/FreeRTOS.h>
-
-namespace esphome {
-
-/// @brief FreeRTOS task priority definitions for ESPHome
-///
-/// All priorities use relative values based on configMAX_PRIORITIES so they
-/// scale automatically if CONFIG_FREERTOS_MAX_PRIORITIES changes.
-///
-/// Priority hierarchy (with CONFIG_FREERTOS_MAX_PRIORITIES = 16):
-///
-///   14: Audio capture (I2S microphone) - highest, real-time audio input
-///   10: Audio output (I2S speaker) - real-time audio output
-///    8: Network stack (LWIP TCP/IP) - set via CONFIG_LWIP_TCPIP_TASK_PRIO
-///    6: Audio mixing - buffered audio processing
-///    5: Protocol tasks (MQTT, USB host, OpenThread) - communication
-///    4: USB serial TX - serial communication
-///    3: ML inference (wake word) - background ML processing
-///    1: Application (main loop, media pipelines, camera, UART RX) - baseline
-///    0: Idle task (FreeRTOS system)
-///
-/// Guidelines:
-/// - Real-time audio I/O tasks need highest priorities to prevent glitches
-/// - Network/protocol tasks should be above application but below audio
-/// - Background processing (ML, media decoding) can run at low priority
-
-/// Audio capture task priority (I2S microphone)
-/// Highest application priority - audio input cannot tolerate delays
-static constexpr UBaseType_t TASK_PRIORITY_AUDIO_CAPTURE = configMAX_PRIORITIES - 2;
-
-/// Audio output task priority (I2S speaker)
-/// High priority - audio output needs consistent timing
-static constexpr UBaseType_t TASK_PRIORITY_AUDIO_OUTPUT = configMAX_PRIORITIES - 6;
-
-/// Audio mixer task priority
-/// Medium-high - mixing is buffered but feeds real-time output
-static constexpr UBaseType_t TASK_PRIORITY_AUDIO_MIXER = configMAX_PRIORITIES - 10;
-
-/// Protocol/communication task priority (MQTT, USB host, OpenThread)
-/// Above application tasks for responsive network handling
-static constexpr UBaseType_t TASK_PRIORITY_PROTOCOL = configMAX_PRIORITIES - 11;
-
-/// USB serial TX task priority
-/// Slightly below protocol tasks
-static constexpr UBaseType_t TASK_PRIORITY_USB_SERIAL = configMAX_PRIORITIES - 12;
-
-/// ML inference task priority (wake word detection)
-/// Background processing - can yield to communication tasks
-static constexpr UBaseType_t TASK_PRIORITY_INFERENCE = configMAX_PRIORITIES - 13;
-
-/// Application task priority (main loop, media pipelines, camera, etc.)
-/// Baseline priority - just above idle task
-static constexpr UBaseType_t TASK_PRIORITY_APPLICATION = tskIDLE_PRIORITY + 1;
-
-}  // namespace esphome
-
-#endif  // USE_ESP32

esphome/cpp_generator.py

@@ -462,16 +462,6 @@ def statement(expression: Expression | Statement) -> Statement:
     return ExpressionStatement(expression)
 
 
-def literal(name: str) -> "MockObj":
-    """Create a literal name that will appear in the generated code
-    not surrounded by quotes.
-
-    :param name: The name of the literal.
-    :return: The literal as a MockObj.
-    """
-    return MockObj(name, "")
-
-
 def variable(
     id_: ID, rhs: SafeExpType, type_: "MockObj" = None, register=True
 ) -> "MockObj":
@@ -675,7 +665,7 @@ async def get_variable_with_full_id(id_: ID) -> tuple[ID, "MockObj"]:
 
 
 async def process_lambda(
-    value: Lambda | Expression,
+    value: Lambda,
     parameters: TemplateArgsType,
     capture: str = "",
     return_type: SafeExpType = None,
@@ -699,14 +689,6 @@ async def process_lambda(
 
     if value is None:
         return None
-    # Inadvertently passing a malformed parameters value will lead to the build process mysteriously hanging at the
-    # "Generating C++ source..." stage, so check here to save the developer's hair.
-    assert isinstance(parameters, list) and all(
-        isinstance(p, tuple) and len(p) == 2 for p in parameters
-    )
-    if isinstance(value, Expression):
-        value = Lambda(value)
-
     parts = value.parts[:]
     for i, id in enumerate(value.requires_ids):
         full_id, var = await get_variable_with_full_id(id)

platformio.ini

@@ -114,7 +114,7 @@ lib_deps =
     ESP8266WiFi                           ; wifi (Arduino built-in)
     Update                                ; ota (Arduino built-in)
     ESP32Async/ESPAsyncTCP@2.0.0          ; async_tcp
-    ESP32Async/ESPAsyncWebServer@3.9.6    ; web_server_base
+    ESP32Async/ESPAsyncWebServer@3.9.5    ; web_server_base
     makuna/NeoPixelBus@2.7.3              ; neopixelbus
     ESP8266HTTPClient                     ; http_request (Arduino built-in)
     ESP8266mDNS                           ; mdns (Arduino built-in)
@@ -202,7 +202,7 @@ lib_deps =
     ${common:arduino.lib_deps}
     ayushsharma82/RPAsyncTCP@1.3.2        ; async_tcp
     bblanchon/ArduinoJson@7.4.2           ; json
-    ESP32Async/ESPAsyncWebServer@3.9.6    ; web_server_base
+    ESP32Async/ESPAsyncWebServer@3.9.5    ; web_server_base
 build_flags =
     ${common:arduino.build_flags}
     -DUSE_RP2040
@@ -218,7 +218,7 @@ framework = arduino
 lib_compat_mode = soft
 lib_deps =
     bblanchon/ArduinoJson@7.4.2           ; json
-    ESP32Async/ESPAsyncWebServer@3.9.6    ; web_server_base
+    ESP32Async/ESPAsyncWebServer@3.9.5    ; web_server_base
     droscy/esp_wireguard@0.4.2            ; wireguard
 build_flags =
     ${common:arduino.build_flags}

tests/components/dlms_meter/common-generic.yaml

@@ -1,11 +0,0 @@
-dlms_meter:
-  decryption_key: "36C66639E48A8CA4D6BC8B282A793BBB"   # change this to your decryption key!
-
-sensor:
-  - platform: dlms_meter
-    reactive_energy_plus:
-      name: "Reactive energy taken from grid"
-    reactive_energy_minus:
-      name: "Reactive energy put into grid"
-
-<<: !include common.yaml

tests/components/dlms_meter/common-netznoe.yaml

@@ -1,17 +0,0 @@
-dlms_meter:
-  decryption_key: "36C66639E48A8CA4D6BC8B282A793BBB"  # change this to your decryption key!
-  provider: netznoe                                   # (optional) key - only set if using evn
-
-sensor:
-  - platform: dlms_meter
-    # EVN
-    power_factor:
-      name: "Power Factor"
-
-text_sensor:
-  - platform: dlms_meter
-    # EVN
-    meternumber:
-      name: "meterNumber"
-
-<<: !include common.yaml

tests/components/dlms_meter/common.yaml

@@ -1,27 +0,0 @@
-sensor:
-  - platform: dlms_meter
-    voltage_l1:
-      name: "Voltage L1"
-    voltage_l2:
-      name: "Voltage L2"
-    voltage_l3:
-      name: "Voltage L3"
-    current_l1:
-      name: "Current L1"
-    current_l2:
-      name: "Current L2"
-    current_l3:
-      name: "Current L3"
-    active_power_plus:
-      name: "Active power taken from grid"
-    active_power_minus:
-      name: "Active power put into grid"
-    active_energy_plus:
-      name: "Active energy taken from grid"
-    active_energy_minus:
-      name: "Active energy put into grid"
-
-text_sensor:
-  - platform: dlms_meter
-    timestamp:
-      name: "timestamp"

tests/components/dlms_meter/test.esp32-ard.yaml

@@ -1,4 +0,0 @@
-packages:
-  uart: !include ../../test_build_components/common/uart_2400/esp32-ard.yaml
-
-<<: !include common-generic.yaml

tests/components/dlms_meter/test.esp32-idf.yaml

@@ -1,4 +0,0 @@
-packages:
-  uart: !include ../../test_build_components/common/uart_2400/esp32-idf.yaml
-
-<<: !include common-netznoe.yaml

tests/components/dlms_meter/test.esp8266-ard.yaml

@@ -1,4 +0,0 @@
-packages:
-  uart: !include ../../test_build_components/common/uart_2400/esp8266-ard.yaml
-
-<<: !include common-generic.yaml

tests/components/json/common.yaml

@@ -4,15 +4,16 @@ interval:
   - interval: 60s
     then:
       - lambda: |-
-          // Test build_json
+          // Test build_json - returns SerializationBuffer, use auto to avoid heap allocation
-          std::string json_str = esphome::json::build_json([](JsonObject root) {
+          auto json_buf = esphome::json::build_json([](JsonObject root) {
             root["sensor"] = "temperature";
             root["value"] = 23.5;
             root["unit"] = "°C";
           });
-          ESP_LOGD("test", "Built JSON: %s", json_str.c_str());
+          ESP_LOGD("test", "Built JSON: %s", json_buf.c_str());
 
-          // Test parse_json
+          // Test parse_json - implicit conversion to std::string for backward compatibility
+          std::string json_str = json_buf;
           bool parse_ok = esphome::json::parse_json(json_str, [](JsonObject root) {
             if (root["sensor"].is<const char*>() && root["value"].is<float>()) {
               const char* sensor = root["sensor"];
@@ -26,10 +27,10 @@ interval:
           });
           ESP_LOGD("test", "Parse result (JSON syntax only): %s", parse_ok ? "success" : "failed");
 
-          // Test JsonBuilder class
+          // Test JsonBuilder class - returns SerializationBuffer
           esphome::json::JsonBuilder builder;
           JsonObject obj = builder.root();
           obj["test"] = "direct_builder";
           obj["count"] = 42;
-          std::string result = builder.serialize();
+          auto result = builder.serialize();
           ESP_LOGD("test", "JsonBuilder result: %s", result.c_str());

tests/components/mipi_spi/test.esp8266-ard.yaml

@@ -1,10 +0,0 @@
-substitutions:
-  dc_pin: GPIO15
-  cs_pin: GPIO5
-  enable_pin: GPIO4
-  reset_pin: GPIO16
-
-packages:
-  spi: !include ../../test_build_components/common/spi/esp8266-ard.yaml
-
-<<: !include common.yaml

tests/components/pmsx003/common.yaml

@@ -8,11 +8,11 @@ sensor:
     pm_10_0:
       name: PM 10.0 Concentration
     pm_1_0_std:
-      name: PM 1.0 Standard Atmospheric Concentration
+      name: PM 1.0 Standard Atmospher Concentration
     pm_2_5_std:
-      name: PM 2.5 Standard Atmospheric Concentration
+      name: PM 2.5 Standard Atmospher Concentration
     pm_10_0_std:
-      name: PM 10.0 Standard Atmospheric Concentration
+      name: PM 10.0 Standard Atmospher Concentration
     pm_0_3um:
       name: Particulate Count >0.3um
     pm_0_5um:

tests/test_build_components/common/uart_2400/esp32-ard.yaml

@@ -1,11 +0,0 @@
-# Common UART configuration for ESP32 Arduino tests - 2400 baud
-
-substitutions:
-  tx_pin: GPIO17
-  rx_pin: GPIO16
-
-uart:
-  - id: uart_bus
-    tx_pin: ${tx_pin}
-    rx_pin: ${rx_pin}
-    baud_rate: 2400

tests/test_build_components/common/uart_2400/esp32-idf.yaml

@@ -1,11 +0,0 @@
-# Common UART configuration for ESP32 IDF tests - 2400 baud
-
-substitutions:
-  tx_pin: GPIO17
-  rx_pin: GPIO16
-
-uart:
-  - id: uart_bus
-    tx_pin: ${tx_pin}
-    rx_pin: ${rx_pin}
-    baud_rate: 2400

tests/test_build_components/common/uart_2400/esp8266-ard.yaml

@@ -1,11 +0,0 @@
-# Common UART configuration for ESP8266 Arduino tests - 2400 baud
-
-substitutions:
-  tx_pin: GPIO4
-  rx_pin: GPIO5
-
-uart:
-  - id: uart_bus
-    tx_pin: ${tx_pin}
-    rx_pin: ${rx_pin}
-    baud_rate: 2400

tests/unit_tests/test_cpp_generator.py

@@ -347,280 +347,3 @@ class TestMockObj:
         assert isinstance(actual, cg.MockObj)
         assert actual.base == "foo.eek"
         assert actual.op == "."
-
-
-class TestStatementFunction:
-    """Tests for the statement() function."""
-
-    def test_statement__expression_converted_to_statement(self):
-        """Test that expressions are converted to ExpressionStatement."""
-        expr = cg.RawExpression("foo()")
-        result = cg.statement(expr)
-
-        assert isinstance(result, cg.ExpressionStatement)
-        assert str(result) == "foo();"
-
-    def test_statement__statement_unchanged(self):
-        """Test that statements are returned unchanged."""
-        stmt = cg.RawStatement("foo()")
-        result = cg.statement(stmt)
-
-        assert result is stmt
-        assert str(result) == "foo()"
-
-    def test_statement__expression_statement_unchanged(self):
-        """Test that ExpressionStatement is returned unchanged."""
-        stmt = cg.ExpressionStatement(42)
-        result = cg.statement(stmt)
-
-        assert result is stmt
-        assert str(result) == "42;"
-
-    def test_statement__line_comment_unchanged(self):
-        """Test that LineComment is returned unchanged."""
-        stmt = cg.LineComment("This is a comment")
-        result = cg.statement(stmt)
-
-        assert result is stmt
-        assert str(result) == "// This is a comment"
-
-
-class TestLiteralFunction:
-    """Tests for the literal() function."""
-
-    def test_literal__creates_mockobj(self):
-        """Test that literal() creates a MockObj."""
-        result = cg.literal("MY_CONSTANT")
-
-        assert isinstance(result, cg.MockObj)
-        assert result.base == "MY_CONSTANT"
-        assert result.op == ""
-
-    def test_literal__string_representation(self):
-        """Test that literal names appear unquoted in generated code."""
-        result = cg.literal("nullptr")
-
-        assert str(result) == "nullptr"
-
-    def test_literal__can_be_used_in_expressions(self):
-        """Test that literals can be used as part of larger expressions."""
-        null_lit = cg.literal("nullptr")
-        expr = cg.CallExpression(cg.RawExpression("my_func"), null_lit)
-
-        assert str(expr) == "my_func(nullptr)"
-
-    def test_literal__common_cpp_literals(self):
-        """Test common C++ literal values."""
-        test_cases = [
-            ("nullptr", "nullptr"),
-            ("true", "true"),
-            ("false", "false"),
-            ("NULL", "NULL"),
-            ("NAN", "NAN"),
-        ]
-
-        for name, expected in test_cases:
-            result = cg.literal(name)
-            assert str(result) == expected
-
-
-class TestLambdaConstructor:
-    """Tests for the Lambda class constructor in core/__init__.py."""
-
-    def test_lambda__from_string(self):
-        """Test Lambda constructor with string argument."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return x + 1;")
-
-        assert lambda_obj.value == "return x + 1;"
-        assert str(lambda_obj) == "return x + 1;"
-
-    def test_lambda__from_expression(self):
-        """Test Lambda constructor with Expression argument."""
-        from esphome.core import Lambda
-
-        expr = cg.RawExpression("x + 1")
-        lambda_obj = Lambda(expr)
-
-        # Expression should be converted to statement (with semicolon)
-        assert lambda_obj.value == "x + 1;"
-
-    def test_lambda__from_lambda(self):
-        """Test Lambda constructor with another Lambda argument."""
-        from esphome.core import Lambda
-
-        original = Lambda("return x + 1;")
-        copy = Lambda(original)
-
-        assert copy.value == original.value
-        assert copy.value == "return x + 1;"
-
-    def test_lambda__parts_parsing(self):
-        """Test that Lambda correctly parses parts with id() references."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return id(my_sensor).state;")
-        parts = lambda_obj.parts
-
-        # Parts should be split by LAMBDA_PROG regex: text, id, op, text
-        assert len(parts) == 4
-        assert parts[0] == "return "
-        assert parts[1] == "my_sensor"
-        assert parts[2] == "."
-        assert parts[3] == "state;"
-
-    def test_lambda__requires_ids(self):
-        """Test that Lambda correctly extracts required IDs."""
-        from esphome.core import ID, Lambda
-
-        lambda_obj = Lambda("return id(sensor1).state + id(sensor2).value;")
-        ids = lambda_obj.requires_ids
-
-        assert len(ids) == 2
-        assert all(isinstance(id_obj, ID) for id_obj in ids)
-        assert ids[0].id == "sensor1"
-        assert ids[1].id == "sensor2"
-
-    def test_lambda__no_ids(self):
-        """Test Lambda with no id() references."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return 42;")
-        ids = lambda_obj.requires_ids
-
-        assert len(ids) == 0
-
-    def test_lambda__comment_removal(self):
-        """Test that comments are removed when parsing parts."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return id(sensor).state; // Get sensor state")
-        parts = lambda_obj.parts
-
-        # Comment should be replaced with space, not affect parsing
-        assert "my_sensor" not in str(parts)
-
-    def test_lambda__multiline_string(self):
-        """Test Lambda with multiline string."""
-        from esphome.core import Lambda
-
-        code = """if (id(sensor).state > 0) {
-  return true;
-}
-return false;"""
-        lambda_obj = Lambda(code)
-
-        assert lambda_obj.value == code
-        assert "sensor" in [id_obj.id for id_obj in lambda_obj.requires_ids]
-
-
-@pytest.mark.asyncio
-class TestProcessLambda:
-    """Tests for the process_lambda() async function."""
-
-    async def test_process_lambda__none_value(self):
-        """Test that None returns None."""
-        result = await cg.process_lambda(None, [])
-
-        assert result is None
-
-    async def test_process_lambda__with_expression(self):
-        """Test process_lambda with Expression argument."""
-
-        expr = cg.RawExpression("return x + 1")
-        result = await cg.process_lambda(expr, [(int, "x")])
-
-        assert isinstance(result, cg.LambdaExpression)
-        assert "x + 1" in str(result)
-
-    async def test_process_lambda__simple_lambda_no_ids(self):
-        """Test process_lambda with simple Lambda without id() references."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return x + 1;")
-        result = await cg.process_lambda(lambda_obj, [(int, "x")])
-
-        assert isinstance(result, cg.LambdaExpression)
-        # Should have parameter
-        lambda_str = str(result)
-        assert "int32_t x" in lambda_str
-        assert "return x + 1;" in lambda_str
-
-    async def test_process_lambda__with_return_type(self):
-        """Test process_lambda with return type specified."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return x > 0;")
-        result = await cg.process_lambda(lambda_obj, [(int, "x")], return_type=bool)
-
-        assert isinstance(result, cg.LambdaExpression)
-        lambda_str = str(result)
-        assert "-> bool" in lambda_str
-
-    async def test_process_lambda__with_capture(self):
-        """Test process_lambda with capture specified."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return captured + x;")
-        result = await cg.process_lambda(lambda_obj, [(int, "x")], capture="captured")
-
-        assert isinstance(result, cg.LambdaExpression)
-        lambda_str = str(result)
-        assert "[captured]" in lambda_str
-
-    async def test_process_lambda__empty_capture(self):
-        """Test process_lambda with empty capture (stateless lambda)."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return x + 1;")
-        result = await cg.process_lambda(lambda_obj, [(int, "x")], capture="")
-
-        assert isinstance(result, cg.LambdaExpression)
-        lambda_str = str(result)
-        assert "[]" in lambda_str
-
-    async def test_process_lambda__no_parameters(self):
-        """Test process_lambda with no parameters."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return 42;")
-        result = await cg.process_lambda(lambda_obj, [])
-
-        assert isinstance(result, cg.LambdaExpression)
-        lambda_str = str(result)
-        # Should have empty parameter list
-        assert "()" in lambda_str
-
-    async def test_process_lambda__multiple_parameters(self):
-        """Test process_lambda with multiple parameters."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return x + y + z;")
-        result = await cg.process_lambda(
-            lambda_obj, [(int, "x"), (float, "y"), (bool, "z")]
-        )
-
-        assert isinstance(result, cg.LambdaExpression)
-        lambda_str = str(result)
-        assert "int32_t x" in lambda_str
-        assert "float y" in lambda_str
-        assert "bool z" in lambda_str
-
-    async def test_process_lambda__parameter_validation(self):
-        """Test that malformed parameters raise assertion error."""
-        from esphome.core import Lambda
-
-        lambda_obj = Lambda("return x;")
-
-        # Test invalid parameter format (not list of tuples)
-        with pytest.raises(AssertionError):
-            await cg.process_lambda(lambda_obj, "invalid")
-
-        # Test invalid tuple format (not 2-element tuples)
-        with pytest.raises(AssertionError):
-            await cg.process_lambda(lambda_obj, [(int, "x", "extra")])
-
-        # Test invalid tuple format (single element)
-        with pytest.raises(AssertionError):
-            await cg.process_lambda(lambda_obj, [(int,)])