[api] Reduce heap allocations in DeviceInfoResponse

2025.11.0b3

esphome/components/api/api_connection.cpp

@@ -1451,8 +1451,11 @@ bool APIConnection::send_device_info_response(const DeviceInfoRequest &msg) {
 #ifdef USE_AREAS
   resp.set_suggested_area(StringRef(App.get_area()));
 #endif
-  // mac_address must store temporary string - will be valid during send_message call
-  std::string mac_address = get_mac_address_pretty();
+  // Stack buffer for MAC address (XX:XX:XX:XX:XX:XX\0 = 18 bytes)
+  char mac_address[18];
+  uint8_t mac[6];
+  get_mac_address_raw(mac);
+  format_mac_addr_upper(mac, mac_address);
   resp.set_mac_address(StringRef(mac_address));
 
   resp.set_esphome_version(ESPHOME_VERSION_REF);
@@ -1493,8 +1496,9 @@ bool APIConnection::send_device_info_response(const DeviceInfoRequest &msg) {
 #endif
 #ifdef USE_BLUETOOTH_PROXY
   resp.bluetooth_proxy_feature_flags = bluetooth_proxy::global_bluetooth_proxy->get_feature_flags();
-  // bt_mac must store temporary string - will be valid during send_message call
-  std::string bluetooth_mac = bluetooth_proxy::global_bluetooth_proxy->get_bluetooth_mac_address_pretty();
+  // Stack buffer for Bluetooth MAC address (XX:XX:XX:XX:XX:XX\0 = 18 bytes)
+  char bluetooth_mac[18];
+  bluetooth_proxy::global_bluetooth_proxy->get_bluetooth_mac_address_pretty(bluetooth_mac);
   resp.set_bluetooth_mac_address(StringRef(bluetooth_mac));
 #endif
 #ifdef USE_VOICE_ASSISTANT

esphome/components/bh1750/bh1750.cpp

@@ -1,8 +1,8 @@
 #include "bh1750.h"
 #include "esphome/core/log.h"
-#include "esphome/core/application.h"
 
-namespace esphome::bh1750 {
+namespace esphome {
+namespace bh1750 {
 
 static const char *const TAG = "bh1750.sensor";
 
@@ -13,31 +13,6 @@ static const uint8_t BH1750_COMMAND_ONE_TIME_L = 0b00100011;
 static const uint8_t BH1750_COMMAND_ONE_TIME_H = 0b00100000;
 static const uint8_t BH1750_COMMAND_ONE_TIME_H2 = 0b00100001;
 
-static constexpr uint32_t MEASUREMENT_TIMEOUT_MS = 2000;
-static constexpr float HIGH_LIGHT_THRESHOLD_LX = 7000.0f;
-
-// Measurement time constants (datasheet values)
-static constexpr uint16_t MTREG_DEFAULT = 69;
-static constexpr uint16_t MTREG_MIN = 31;
-static constexpr uint16_t MTREG_MAX = 254;
-static constexpr uint16_t MEAS_TIME_L_MS = 24;   // L-resolution max measurement time @ mtreg=69
-static constexpr uint16_t MEAS_TIME_H_MS = 180;  // H/H2-resolution max measurement time @ mtreg=69
-
-// Conversion constants (datasheet formulas)
-static constexpr float RESOLUTION_DIVISOR = 1.2f;  // counts to lux conversion divisor
-static constexpr float MODE_H2_DIVISOR = 2.0f;     // H2 mode has 2x higher resolution
-
-// MTreg calculation constants
-static constexpr int COUNTS_TARGET = 50000;  // Target counts for optimal range (avoid saturation)
-static constexpr int COUNTS_NUMERATOR = 10;
-static constexpr int COUNTS_DENOMINATOR = 12;
-
-// MTreg register bit manipulation constants
-static constexpr uint8_t MTREG_HI_SHIFT = 5;       // High 3 bits start at bit 5
-static constexpr uint8_t MTREG_HI_MASK = 0b111;    // 3-bit mask for high bits
-static constexpr uint8_t MTREG_LO_SHIFT = 0;       // Low 5 bits start at bit 0
-static constexpr uint8_t MTREG_LO_MASK = 0b11111;  // 5-bit mask for low bits
-
 /*
 bh1750 properties:
 
@@ -68,7 +43,74 @@ void BH1750Sensor::setup() {
     this->mark_failed();
     return;
   }
-  this->state_ = IDLE;
+}
+
+void BH1750Sensor::read_lx_(BH1750Mode mode, uint8_t mtreg, const std::function<void(float)> &f) {
+  // turn on (after one-shot sensor automatically powers down)
+  uint8_t turn_on = BH1750_COMMAND_POWER_ON;
+  if (this->write(&turn_on, 1) != i2c::ERROR_OK) {
+    ESP_LOGW(TAG, "Power on failed");
+    f(NAN);
+    return;
+  }
+
+  if (active_mtreg_ != mtreg) {
+    // set mtreg
+    uint8_t mtreg_hi = BH1750_COMMAND_MT_REG_HI | ((mtreg >> 5) & 0b111);
+    uint8_t mtreg_lo = BH1750_COMMAND_MT_REG_LO | ((mtreg >> 0) & 0b11111);
+    if (this->write(&mtreg_hi, 1) != i2c::ERROR_OK || this->write(&mtreg_lo, 1) != i2c::ERROR_OK) {
+      ESP_LOGW(TAG, "Set measurement time failed");
+      active_mtreg_ = 0;
+      f(NAN);
+      return;
+    }
+    active_mtreg_ = mtreg;
+  }
+
+  uint8_t cmd;
+  uint16_t meas_time;
+  switch (mode) {
+    case BH1750_MODE_L:
+      cmd = BH1750_COMMAND_ONE_TIME_L;
+      meas_time = 24 * mtreg / 69;
+      break;
+    case BH1750_MODE_H:
+      cmd = BH1750_COMMAND_ONE_TIME_H;
+      meas_time = 180 * mtreg / 69;
+      break;
+    case BH1750_MODE_H2:
+      cmd = BH1750_COMMAND_ONE_TIME_H2;
+      meas_time = 180 * mtreg / 69;
+      break;
+    default:
+      f(NAN);
+      return;
+  }
+  if (this->write(&cmd, 1) != i2c::ERROR_OK) {
+    ESP_LOGW(TAG, "Start measurement failed");
+    f(NAN);
+    return;
+  }
+
+  // probably not needed, but adjust for rounding
+  meas_time++;
+
+  this->set_timeout("read", meas_time, [this, mode, mtreg, f]() {
+    uint16_t raw_value;
+    if (this->read(reinterpret_cast<uint8_t *>(&raw_value), 2) != i2c::ERROR_OK) {
+      ESP_LOGW(TAG, "Read data failed");
+      f(NAN);
+      return;
+    }
+    raw_value = i2c::i2ctohs(raw_value);
+
+    float lx = float(raw_value) / 1.2f;
+    lx *= 69.0f / mtreg;
+    if (mode == BH1750_MODE_H2)
+      lx /= 2.0f;
+
+    f(lx);
+  });
 }
 
 void BH1750Sensor::dump_config() {
@@ -82,189 +124,45 @@ void BH1750Sensor::dump_config() {
 }
 
 void BH1750Sensor::update() {
-  const uint32_t now = millis();
-
-  // Start coarse measurement to determine optimal mode/mtreg
-  if (this->state_ != IDLE) {
-    // Safety timeout: reset if stuck
-    if (now - this->measurement_start_time_ > MEASUREMENT_TIMEOUT_MS) {
-      ESP_LOGW(TAG, "Measurement timeout, resetting state");
-      this->state_ = IDLE;
-    } else {
-      ESP_LOGW(TAG, "Previous measurement not complete, skipping update");
+  // first do a quick measurement in L-mode with full range
+  // to find right range
+  this->read_lx_(BH1750_MODE_L, 31, [this](float val) {
+    if (std::isnan(val)) {
+      this->status_set_warning();
+      this->publish_state(NAN);
       return;
     }
-  }
 
-  if (!this->start_measurement_(BH1750_MODE_L, MTREG_MIN, now)) {
-    this->status_set_warning();
-    this->publish_state(NAN);
-    return;
-  }
-
-  this->state_ = WAITING_COARSE_MEASUREMENT;
-  this->enable_loop();  // Enable loop while measurement in progress
-}
-
-void BH1750Sensor::loop() {
-  const uint32_t now = App.get_loop_component_start_time();
-
-  switch (this->state_) {
-    case IDLE:
-      // Disable loop when idle to save cycles
-      this->disable_loop();
-      break;
-
-    case WAITING_COARSE_MEASUREMENT:
-      if (now - this->measurement_start_time_ >= this->measurement_duration_) {
-        this->state_ = READING_COARSE_RESULT;
-      }
-      break;
-
-    case READING_COARSE_RESULT: {
-      float lx;
-      if (!this->read_measurement_(lx)) {
-        this->fail_and_reset_();
-        break;
-      }
-
-      this->process_coarse_result_(lx);
-
-      // Start fine measurement with optimal settings
-      // fetch millis() again since the read can take a bit
-      if (!this->start_measurement_(this->fine_mode_, this->fine_mtreg_, millis())) {
-        this->fail_and_reset_();
-        break;
-      }
-
-      this->state_ = WAITING_FINE_MEASUREMENT;
-      break;
+    BH1750Mode use_mode;
+    uint8_t use_mtreg;
+    if (val <= 7000) {
+      use_mode = BH1750_MODE_H2;
+      use_mtreg = 254;
+    } else {
+      use_mode = BH1750_MODE_H;
+      // lx = counts / 1.2 * (69 / mtreg)
+      // -> mtreg = counts / 1.2 * (69 / lx)
+      // calculate for counts=50000 (allow some range to not saturate, but maximize mtreg)
+      // -> mtreg = 50000*(10/12)*(69/lx)
+      int ideal_mtreg = 50000 * 10 * 69 / (12 * (int) val);
+      use_mtreg = std::min(254, std::max(31, ideal_mtreg));
     }
+    ESP_LOGV(TAG, "L result: %f -> Calculated mode=%d, mtreg=%d", val, (int) use_mode, use_mtreg);
 
-    case WAITING_FINE_MEASUREMENT:
-      if (now - this->measurement_start_time_ >= this->measurement_duration_) {
-        this->state_ = READING_FINE_RESULT;
+    this->read_lx_(use_mode, use_mtreg, [this](float val) {
+      if (std::isnan(val)) {
+        this->status_set_warning();
+        this->publish_state(NAN);
+        return;
       }
-      break;
-
-    case READING_FINE_RESULT: {
-      float lx;
-      if (!this->read_measurement_(lx)) {
-        this->fail_and_reset_();
-        break;
-      }
-
-      ESP_LOGD(TAG, "'%s': Illuminance=%.1flx", this->get_name().c_str(), lx);
+      ESP_LOGD(TAG, "'%s': Illuminance=%.1flx", this->get_name().c_str(), val);
       this->status_clear_warning();
-      this->publish_state(lx);
-      this->state_ = IDLE;
-      break;
-    }
-  }
-}
-
-bool BH1750Sensor::start_measurement_(BH1750Mode mode, uint8_t mtreg, uint32_t now) {
-  // Power on
-  uint8_t turn_on = BH1750_COMMAND_POWER_ON;
-  if (this->write(&turn_on, 1) != i2c::ERROR_OK) {
-    ESP_LOGW(TAG, "Power on failed");
-    return false;
-  }
-
-  // Set MTreg if changed
-  if (this->active_mtreg_ != mtreg) {
-    uint8_t mtreg_hi = BH1750_COMMAND_MT_REG_HI | ((mtreg >> MTREG_HI_SHIFT) & MTREG_HI_MASK);
-    uint8_t mtreg_lo = BH1750_COMMAND_MT_REG_LO | ((mtreg >> MTREG_LO_SHIFT) & MTREG_LO_MASK);
-    if (this->write(&mtreg_hi, 1) != i2c::ERROR_OK || this->write(&mtreg_lo, 1) != i2c::ERROR_OK) {
-      ESP_LOGW(TAG, "Set measurement time failed");
-      this->active_mtreg_ = 0;
-      return false;
-    }
-    this->active_mtreg_ = mtreg;
-  }
-
-  // Start measurement
-  uint8_t cmd;
-  uint16_t meas_time;
-  switch (mode) {
-    case BH1750_MODE_L:
-      cmd = BH1750_COMMAND_ONE_TIME_L;
-      meas_time = MEAS_TIME_L_MS * mtreg / MTREG_DEFAULT;
-      break;
-    case BH1750_MODE_H:
-      cmd = BH1750_COMMAND_ONE_TIME_H;
-      meas_time = MEAS_TIME_H_MS * mtreg / MTREG_DEFAULT;
-      break;
-    case BH1750_MODE_H2:
-      cmd = BH1750_COMMAND_ONE_TIME_H2;
-      meas_time = MEAS_TIME_H_MS * mtreg / MTREG_DEFAULT;
-      break;
-    default:
-      return false;
-  }
-
-  if (this->write(&cmd, 1) != i2c::ERROR_OK) {
-    ESP_LOGW(TAG, "Start measurement failed");
-    return false;
-  }
-
-  // Store current measurement parameters
-  this->current_mode_ = mode;
-  this->current_mtreg_ = mtreg;
-  this->measurement_start_time_ = now;
-  this->measurement_duration_ = meas_time + 1;  // Add 1ms for safety
-
-  return true;
-}
-
-bool BH1750Sensor::read_measurement_(float &lx_out) {
-  uint16_t raw_value;
-  if (this->read(reinterpret_cast<uint8_t *>(&raw_value), 2) != i2c::ERROR_OK) {
-    ESP_LOGW(TAG, "Read data failed");
-    return false;
-  }
-  raw_value = i2c::i2ctohs(raw_value);
-
-  float lx = float(raw_value) / RESOLUTION_DIVISOR;
-  lx *= float(MTREG_DEFAULT) / this->current_mtreg_;
-  if (this->current_mode_ == BH1750_MODE_H2) {
-    lx /= MODE_H2_DIVISOR;
-  }
-
-  lx_out = lx;
-  return true;
-}
-
-void BH1750Sensor::process_coarse_result_(float lx) {
-  if (std::isnan(lx)) {
-    // Use defaults if coarse measurement failed
-    this->fine_mode_ = BH1750_MODE_H2;
-    this->fine_mtreg_ = MTREG_MAX;
-    return;
-  }
-
-  if (lx <= HIGH_LIGHT_THRESHOLD_LX) {
-    this->fine_mode_ = BH1750_MODE_H2;
-    this->fine_mtreg_ = MTREG_MAX;
-  } else {
-    this->fine_mode_ = BH1750_MODE_H;
-    // lx = counts / 1.2 * (69 / mtreg)
-    // -> mtreg = counts / 1.2 * (69 / lx)
-    // calculate for counts=50000 (allow some range to not saturate, but maximize mtreg)
-    // -> mtreg = 50000*(10/12)*(69/lx)
-    int ideal_mtreg = COUNTS_TARGET * COUNTS_NUMERATOR * MTREG_DEFAULT / (COUNTS_DENOMINATOR * (int) lx);
-    this->fine_mtreg_ = std::min((int) MTREG_MAX, std::max((int) MTREG_MIN, ideal_mtreg));
-  }
-
-  ESP_LOGV(TAG, "L result: %.1f -> Calculated mode=%d, mtreg=%d", lx, (int) this->fine_mode_, this->fine_mtreg_);
-}
-
-void BH1750Sensor::fail_and_reset_() {
-  this->status_set_warning();
-  this->publish_state(NAN);
-  this->state_ = IDLE;
+      this->publish_state(val);
+    });
+  });
 }
 
 float BH1750Sensor::get_setup_priority() const { return setup_priority::DATA; }
 
-}  // namespace esphome::bh1750
+}  // namespace bh1750
+}  // namespace esphome

esphome/components/bh1750/bh1750.h

@@ -4,9 +4,10 @@
 #include "esphome/components/sensor/sensor.h"
 #include "esphome/components/i2c/i2c.h"
 
-namespace esphome::bh1750 {
+namespace esphome {
+namespace bh1750 {
 
-enum BH1750Mode : uint8_t {
+enum BH1750Mode {
   BH1750_MODE_L,
   BH1750_MODE_H,
   BH1750_MODE_H2,
@@ -20,36 +21,13 @@ class BH1750Sensor : public sensor::Sensor, public PollingComponent, public i2c:
   void setup() override;
   void dump_config() override;
   void update() override;
-  void loop() override;
   float get_setup_priority() const override;
 
  protected:
-  // State machine states
-  enum State : uint8_t {
-    IDLE,
-    WAITING_COARSE_MEASUREMENT,
-    READING_COARSE_RESULT,
-    WAITING_FINE_MEASUREMENT,
-    READING_FINE_RESULT,
-  };
+  void read_lx_(BH1750Mode mode, uint8_t mtreg, const std::function<void(float)> &f);
 
-  // 4-byte aligned members
-  uint32_t measurement_start_time_{0};
-  uint32_t measurement_duration_{0};
-
-  // 1-byte members grouped together to minimize padding
-  State state_{IDLE};
-  BH1750Mode current_mode_{BH1750_MODE_L};
-  uint8_t current_mtreg_{31};
-  BH1750Mode fine_mode_{BH1750_MODE_H2};
-  uint8_t fine_mtreg_{254};
   uint8_t active_mtreg_{0};
-
-  // Helper methods
-  bool start_measurement_(BH1750Mode mode, uint8_t mtreg, uint32_t now);
-  bool read_measurement_(float &lx_out);
-  void process_coarse_result_(float lx);
-  void fail_and_reset_();
 };
 
-}  // namespace esphome::bh1750
+}  // namespace bh1750
+}  // namespace esphome

esphome/components/bluetooth_proxy/bluetooth_proxy.h

@@ -130,11 +130,9 @@ class BluetoothProxy final : public esp32_ble_tracker::ESPBTDeviceListener, publ
     return flags;
   }
 
-  std::string get_bluetooth_mac_address_pretty() {
+  void get_bluetooth_mac_address_pretty(std::span<char, 18> output) {
     const uint8_t *mac = esp_bt_dev_get_address();
-    char buf[18];
-    format_mac_addr_upper(mac, buf);
-    return std::string(buf);
+    format_mac_addr_upper(mac, output.data());
   }
 
  protected:

esphome/config.py

@@ -338,21 +338,44 @@ def check_replaceme(value):
         )
 
 
-def _build_list_index(lst):
+def _get_item_id(item: Any) -> str | Extend | Remove | None:
+    """Attempts to get a list item's ID"""
+    if not isinstance(item, dict):
+        return None  # not a dict, can't have ID
+    # 1.- Check regular case:
+    # - id: my_id
+    item_id = item.get(CONF_ID)
+    if item_id is None and len(item) == 1:
+        # 2.- Check single-key dict case:
+        # - obj:
+        #     id: my_id
+        item = next(iter(item.values()))
+        if isinstance(item, dict):
+            item_id = item.get(CONF_ID)
+    if isinstance(item_id, Extend):
+        # Remove instances of Extend so they don't overwrite the original item when merging:
+        del item[CONF_ID]
+    return item_id
+
+
+def _build_list_index(
+    lst: list[Any],
+) -> tuple[
+    OrderedDict[str | Extend | Remove, Any], list[tuple[int, str, Any]], set[str]
+]:
     index = OrderedDict()
     extensions, removals = [], set()
-    for item in lst:
+    for pos, item in enumerate(lst):
         if item is None:
             removals.add(None)
             continue
-        item_id = None
-        if isinstance(item, dict) and (item_id := item.get(CONF_ID)):
-            if isinstance(item_id, Extend):
-                extensions.append(item)
-                continue
-            if isinstance(item_id, Remove):
-                removals.add(item_id.value)
-                continue
+        item_id = _get_item_id(item)
+        if isinstance(item_id, Extend):
+            extensions.append((pos, item_id.value, item))
+            continue
+        if isinstance(item_id, Remove):
+            removals.add(item_id.value)
+            continue
         if not item_id or item_id in index:
             # no id or duplicate -> pass through with identity-based key
             item_id = id(item)
@@ -360,7 +383,7 @@ def _build_list_index(lst):
     return index, extensions, removals
 
 
-def resolve_extend_remove(value, is_key=None):
+def resolve_extend_remove(value: Any, is_key: bool = False) -> None:
     if isinstance(value, ESPLiteralValue):
         return  # do not check inside literal blocks
     if isinstance(value, list):
@@ -368,26 +391,16 @@ def resolve_extend_remove(value, is_key=None):
         if extensions or removals:
             # Rebuild the original list after
             # processing all extensions and removals
-            for item in extensions:
-                item_id = item[CONF_ID].value
+            for pos, item_id, item in extensions:
                 if item_id in removals:
                     continue
                 old = index.get(item_id)
                 if old is None:
                     # Failed to find source for extension
-                    # Find index of item to show error at correct position
-                    i = next(
-                        (
-                            i
-                            for i, d in enumerate(value)
-                            if d.get(CONF_ID) == item[CONF_ID]
-                        )
-                    )
-                    with cv.prepend_path(i):
+                    with cv.prepend_path(pos):
                         raise cv.Invalid(
                             f"Source for extension of ID '{item_id}' was not found."
                         )
-                item[CONF_ID] = item_id
                 index[item_id] = merge_config(old, item)
             for item_id in removals:
                 index.pop(item_id, None)

tests/unit_tests/fixtures/substitutions/05-extend-remove.approved.yaml

@@ -7,3 +7,27 @@ some_component:
     value: 2
   - id: component2
     value: 5
+lvgl:
+  pages:
+    - id: page1
+      widgets:
+        - obj:
+            id: object1
+            x: 3
+            y: 2
+            width: 4
+        - obj:
+            id: object3
+            x: 6
+            y: 12
+            widgets:
+              - obj:
+                  id: object4
+                  x: 14
+                  y: 9
+                  width: 15
+            height: 13
+        - obj:
+            id: object5
+            x: 10
+            y: 11

tests/unit_tests/fixtures/substitutions/05-extend-remove.input.yaml

@@ -13,6 +13,30 @@ packages:
         value: 5
       - id: component3
         value: 6
+  - lvgl:
+      pages:
+        - id: page1
+          widgets:
+            - obj:
+                id: object1
+                x: 1
+                y: 2
+            - obj:
+                id: object2
+                x: 5
+            - obj:
+                id: object3
+                x: 6
+                y: 7
+                widgets:
+                  - obj:
+                      id: object4
+                      x: 8
+                      y: 9
+            - obj:
+                id: object5
+                x: 10
+                y: 11
 
 some_component:
   - id: !extend ${A}
@@ -20,3 +44,23 @@ some_component:
   - id: component2
     value: 3
   - id: !remove ${C}
+
+lvgl:
+  pages:
+    - id: !extend page1
+      widgets:
+        - obj:
+            id: !extend object1
+            x: 3
+            width: 4
+        - obj:
+            id: !remove object2
+        - obj:
+            id: !extend object3
+            y: 12
+            height: 13
+            widgets:
+              - obj:
+                  id: !extend object4
+                  x: 14
+                  width: 15