Merge branch 'esp8266-native-build-surgery' into esp8266-native-toolchain-plumbing

esphome/components/api/api_connection.cpp

@@ -412,15 +412,15 @@ void APIConnection::finalize_iterator_sync_() {
 }
 
 void APIConnection::process_iterator_batch_(ComponentIterator &iterator) {
-  size_t initial_size = this->deferred_batch_.size();
-  size_t max_batch = MAX_INITIAL_PER_BATCH;
-  while (!iterator.completed() && (this->deferred_batch_.size() - initial_size) < max_batch) {
-    iterator.advance();
-  }
+  // Budget by remaining batch capacity so a pass cannot overfill the batch;
+  // stops early on a refused send and resumes next loop pass
+  size_t batch_size = this->deferred_batch_.size();
+  if (batch_size < MAX_INITIAL_BATCH_SIZE)
+    iterator.try_advance(MAX_INITIAL_BATCH_SIZE - batch_size);
 
-  // If the batch is full, process it immediately
-  // Note: iterator.advance() already calls schedule_batch_() via schedule_message_()
-  if (this->deferred_batch_.size() >= max_batch) {
+  // Flush immediately once enough is queued (not guaranteed every pass);
+  // partial batches go out via the batch timer or finalize_iterator_sync_()
+  if (this->deferred_batch_.size() >= MAX_INITIAL_BATCH_SIZE) {
     this->process_batch_();
   }
 }

esphome/components/api/api_connection.h

@@ -53,11 +53,11 @@ void log_dropped_message(const char *tag, int line, const LogString *what);
 
 // Keepalive timeout in milliseconds
 static constexpr uint32_t KEEPALIVE_TIMEOUT_MS = 60000;
-// Maximum number of entities to process in a single batch during initial state/info sending
-static constexpr size_t MAX_INITIAL_PER_BATCH = 34;
+// Deferred batch size cap during initial state/info sync
+static constexpr size_t MAX_INITIAL_BATCH_SIZE = 34;
 // Verify MAX_MESSAGES_PER_BATCH (defined in api_frame_helper.h) can hold the initial batch
-static_assert(MAX_MESSAGES_PER_BATCH >= MAX_INITIAL_PER_BATCH,
-              "MAX_MESSAGES_PER_BATCH must be >= MAX_INITIAL_PER_BATCH");
+static_assert(MAX_MESSAGES_PER_BATCH >= MAX_INITIAL_BATCH_SIZE,
+              "MAX_MESSAGES_PER_BATCH must be >= MAX_INITIAL_BATCH_SIZE");
 
 #ifdef USE_BENCHMARK
 class APIConnection;

esphome/components/api/api_frame_helper.h

@@ -36,7 +36,7 @@ static constexpr uint16_t MAX_MESSAGE_SIZE = 32768;  // 32 KiB for ESP32 and oth
 static constexpr uint16_t RX_BUF_NULL_TERMINATOR = 1;
 
 // Maximum number of messages to batch in a single write operation
-// Must be >= MAX_INITIAL_PER_BATCH in api_connection.h (enforced by static_assert there)
+// Must be >= MAX_INITIAL_BATCH_SIZE in api_connection.h (enforced by static_assert there)
 static constexpr size_t MAX_MESSAGES_PER_BATCH = 34;
 
 // Max client name length (e.g., "Home Assistant 2026.1.0.dev0" = 28 chars)

esphome/components/api/list_entities.cpp

@@ -95,9 +95,17 @@ bool ListEntitiesIterator::on_end() { return this->client_->send_list_info_done(
 ListEntitiesIterator::ListEntitiesIterator(APIConnection *client) : client_(client) {}
 
 #ifdef USE_API_USER_DEFINED_ACTIONS
+// Yield after every Nth service; bounds direct (non-batched) writes per loop pass
+static constexpr uint8_t SERVICE_YIELD_INTERVAL = 3;
+
 bool ListEntitiesIterator::on_service(UserServiceDescriptor *service) {
   auto resp = service->encode_list_service_response();
-  return this->client_->send_message(resp);
+  if (!this->client_->send_message(resp))
+    return false;
+  // at_ is this service's index
+  if ((this->at_ + 1) % SERVICE_YIELD_INTERVAL == 0)
+    this->yield_after_step_();
+  return true;
 }
 #endif
 

esphome/components/ble_device_base/__init__.py

@@ -206,32 +206,36 @@ def validate_scan_parameters(config: ConfigType) -> ConfigType:
     interval = config[CONF_INTERVAL]
     window = config[CONF_WINDOW]
 
-    if window > interval:
-        raise cv.Invalid(
-            f"Scan window ({window}) needs to be smaller than scan interval ({interval})"
-        )
+    # Labels are reused in every error below; the optional one names its key.
+    windows = [("Scan window", window)]
+    if (connection_window := config.get(CONF_CONNECTION_SCAN_WINDOW)) is not None:
+        windows.append((CONF_CONNECTION_SCAN_WINDOW, connection_window))
+
+    for name, value in windows:
+        if value > interval:
+            raise cv.Invalid(
+                f"{name} ({value}) needs to be smaller than scan interval ({interval})"
+            )
 
     # BLE scan interval/window are programmed in 0.625 ms units as a 16-bit value; the
     # controller only accepts 2.5 ms .. 10240 ms (0x0004 .. 0x4000). Reject out-of-range
     # values here instead of letting the unit conversion silently overflow.
-    for name, value in (("interval", interval), ("window", window)):
+    for name, value in (("Scan interval", interval), *windows):
         if value.total_microseconds < 2500 or value.total_microseconds > 10_240_000:
-            raise cv.Invalid(
-                f"Scan {name} ({value}) must be between 2.5 ms and 10240 ms"
-            )
+            raise cv.Invalid(f"{name} ({value}) must be between 2.5 ms and 10240 ms")
 
     # Validate what actually reaches the controller: both values are truncated to
     # whole 0.625 ms units, so a window/interval pair that differs by less than one
     # unit collapses to the same value — silently programming a 100 % duty cycle
     # (radio permanently on) from a config that asked for less.
     interval_units = to_ble_units(interval)
-    window_units = to_ble_units(window)
-    if window_units == interval_units and window < interval:
-        raise cv.Invalid(
-            f"Scan window ({window}) and interval ({interval}) both truncate to "
-            f"{interval_units} x 0.625 ms, which the controller scans at a 100 % duty "
-            f"cycle. Separate them by at least 0.625 ms."
-        )
+    for name, value in windows:
+        if to_ble_units(value) == interval_units and value < interval:
+            raise cv.Invalid(
+                f"{name} ({value}) and interval ({interval}) both truncate to "
+                f"{interval_units} x 0.625 ms, which the controller scans at a 100 % duty "
+                f"cycle. Separate them by at least 0.625 ms."
+            )
 
     if interval.total_microseconds * 3 > duration.total_microseconds:
         raise cv.Invalid(
@@ -247,11 +251,14 @@ def validate_scan_parameters(config: ConfigType) -> ConfigType:
 # their own; also the fallback for esp32's conditional default.
 DEFAULT_SCAN_WINDOW = "30ms"
 
+CONF_CONNECTION_SCAN_WINDOW = "connection_scan_window"
+
 
 def scan_parameters_schema(
     interval_default: str,
     *,
     window_default: str | Callable[[], TimePeriod] = DEFAULT_SCAN_WINDOW,
+    connection_window: bool = False,
 ) -> cv.All:
     """Build the scan_parameters value schema shared by all BLE trackers.
 
@@ -263,7 +270,9 @@ def scan_parameters_schema(
     can adjust it once sibling keys are resolved). The `active` option
     (default on) is unconditional: active scanning is part of the tracker
     contract — every current proxy client assumes it, so a passive-only
-    tracker must not share this schema.
+    tracker must not share this schema. connection_window opts in to the
+    `connection_scan_window` option for trackers that can fall back to a
+    smaller window while a GATT connection is active.
     """
     schema = {
         cv.Optional(CONF_DURATION, default="5min"): cv.positive_time_period_seconds,
@@ -272,6 +281,8 @@ def scan_parameters_schema(
         cv.Optional(CONF_CONTINUOUS, default=True): cv.boolean,
         cv.Optional(CONF_ACTIVE, default=True): cv.boolean,
     }
+    if connection_window:
+        schema[cv.Optional(CONF_CONNECTION_SCAN_WINDOW)] = cv.positive_time_period
     return cv.All(cv.Schema(schema), validate_scan_parameters)
 
 

esphome/components/esp32_ble_tracker/__init__.py

@@ -7,6 +7,7 @@ import logging
 from esphome import automation
 import esphome.codegen as cg
 from esphome.components import ble_device_base, esp32_ble, ota
+from esphome.components.ble_device_base import CONF_CONNECTION_SCAN_WINDOW
 from esphome.components.const import CONF_ON_SCAN_END, CONF_SCAN_PARAMETERS, CONF_WINDOW
 from esphome.components.esp32 import (
     add_idf_sdkconfig_option,
@@ -73,8 +74,9 @@ def _get_required_features() -> set[BLEFeatures]:
 
 # Slot counters sizing the tracker's StaticVector storage; one request per
 # registered listener or client.
+CLIENT_COUNT_DEFINE = "ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT"
 _request_listener_slot = cg.slot_counter("ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT")
-_request_client_slot = cg.slot_counter("ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT")
+_request_client_slot = cg.slot_counter(CLIENT_COUNT_DEFINE)
 
 
 def register_ble_features(features: set[BLEFeatures]) -> None:
@@ -147,6 +149,7 @@ class TrackerData:
     """Per-run validation state, namespaced under DOMAIN in CORE.data."""
 
     scan_window_defaulted: bool = False
+    connection_window_injected: bool = False
 
 
 def _get_data() -> TrackerData:
@@ -175,17 +178,34 @@ def _raise_defaulted_scan_window(config: ConfigType) -> ConfigType:
     honors the window strictly (>= 5.5.5); without the arbiter a full-duty
     scan would starve wifi outright, and a user-set window is never touched.
     Raising to the interval cannot invalidate the already-validated
-    parameters, so no re-validation is needed.
+    parameters, so no re-validation is needed. The connection window is
+    checked against the window here, after the raise.
     """
+    params = config[CONF_SCAN_PARAMETERS]
     if (
         _get_data().scan_window_defaulted
         and config.get(CONF_SOFTWARE_COEXISTENCE)
         and idf_version() >= IDF_SCAN_WINDOW_FIX_VERSION
     ):
-        params = config[CONF_SCAN_PARAMETERS]
         # Copy so the config dump shows a plain value instead of a YAML
         # anchor/alias pair pointing at the interval.
         params[CONF_WINDOW] = copy.copy(params[CONF_INTERVAL])
+        # Arm the connection-time fallback unless the user set one. Injected
+        # after validation; safe because it equals the validated window default.
+        if CONF_CONNECTION_SCAN_WINDOW not in params:
+            params[CONF_CONNECTION_SCAN_WINDOW] = cv.positive_time_period(
+                ble_device_base.DEFAULT_SCAN_WINDOW
+            )
+            _get_data().connection_window_injected = True
+    if (
+        connection_window := params.get(CONF_CONNECTION_SCAN_WINDOW)
+    ) is not None and connection_window > params[CONF_WINDOW]:
+        # A larger value would widen the scan during connections.
+        raise cv.Invalid(
+            f"{CONF_CONNECTION_SCAN_WINDOW} ({connection_window}) needs to be "
+            f"smaller than the scan window ({params[CONF_WINDOW]})",
+            path=[CONF_SCAN_PARAMETERS, CONF_CONNECTION_SCAN_WINDOW],
+        )
     return config
 
 
@@ -194,7 +214,7 @@ def _raise_defaulted_scan_window(config: ConfigType) -> ConfigType:
 # window/interval pairs that collapse to the same 0.625 ms unit count.
 # The window default is conditional (see _scan_window_default above).
 SCAN_PARAMETERS_SCHEMA = ble_device_base.scan_parameters_schema(
-    "320ms", window_default=_scan_window_default
+    "320ms", window_default=_scan_window_default, connection_window=True
 )
 
 # Codegen helpers are owned by ble_device_base; kept under the historical names
@@ -288,6 +308,25 @@ async def to_code(config: ConfigType) -> None:
     cg.add(var.set_scan_duration(params[CONF_DURATION]))
     cg.add(var.set_scan_interval(ble_device_base.to_ble_units(params[CONF_INTERVAL])))
     cg.add(var.set_scan_window(ble_device_base.to_ble_units(params[CONF_WINDOW])))
+    if (connection_window := params.get(CONF_CONNECTION_SCAN_WINDOW)) is not None:
+        # Emitted at FINAL so a scan-only build, where the guarded C++ path
+        # compiles out, skips the call entirely.
+        window_units = ble_device_base.to_ble_units(connection_window)
+
+        @coroutine_with_priority(CoroPriority.FINAL)
+        async def _emit_connection_scan_window() -> None:
+            if cg.get_slot_count(CLIENT_COUNT_DEFINE):
+                cg.add(var.set_connection_scan_window(window_units))
+            elif not _get_data().connection_window_injected:
+                # Warn only for a user-set value; the injected default drops silently.
+                _LOGGER.warning(
+                    "'%s' has no effect because this build has no BLE client "
+                    "components (for example bluetooth_proxy with active "
+                    "connections, or ble_client)",
+                    CONF_CONNECTION_SCAN_WINDOW,
+                )
+
+        CORE.add_job(_emit_connection_scan_window)
     cg.add(var.set_scan_active(params[CONF_ACTIVE]))
     cg.add(var.set_scan_continuous(params[CONF_CONTINUOUS]))
 

esphome/components/esp32_ble_tracker/esp32_ble_tracker.cpp

@@ -122,6 +122,9 @@ void ESP32BLETracker::loop() {
   // - start_scan_(): scanner_state_ becomes IDLE via set_scanner_state_() in cleanup_scan_state_()
   // - try_promote_discovered_clients_(): client enters DISCOVERED via set_state(), or
   //   connecting client finishes (state change), or scanner reaches RUNNING/IDLE
+  // - connection-window restart: scan_params_ is only written in start_scan_()
+  //   (which changes scanner state via set_scanner_state_()), and
+  //   counts.active/disconnecting only change on client state changes
   //
   // All conditions that affect the logic below are tied to state changes that increment
   // state_version_, so the fast path is safe.
@@ -144,6 +147,19 @@ void ESP32BLETracker::loop() {
       (this->scan_set_param_failed_ && this->scanner_state_ == ScannerState::RUNNING)) {
     this->handle_scanner_failure_();
   }
+
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  // The programmed window no longer matches the connection state (typically
+  // the last connection dropped): restart so the right window applies now
+  // instead of at the end of the scan period. Continuous only (a user-started
+  // scan would not restart); !disconnecting matches the restart gate below.
+  if (this->scanner_state_ == ScannerState::RUNNING && this->scan_continuous_ && !counts.disconnecting &&
+      this->scan_params_.scan_window != this->desired_scan_window_(counts.active)) {
+    // Same logical scan period continues: no on_scan_end sweeps for this
+    // restart. Only armed when the stop was issued.
+    this->skip_next_scan_end_ = this->stop_scan_();
+  }
+#endif
   /*
 
     Avoid starting the scanner if:
@@ -195,19 +211,23 @@ void ESP32BLETracker::stop_scan() {
   // reason at D themselves, and the user-facing stop action is deliberate.
   ESP_LOGV(TAG, "Stopping scan.");
   this->scan_continuous_ = false;
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  // The window-change restart is abandoned with continuous scanning.
+  this->skip_next_scan_end_ = false;
+#endif
   this->stop_scan_();
 }
 
 void ESP32BLETracker::ble_before_disabled_event_handler() { this->stop_scan_(); }
 
-void ESP32BLETracker::stop_scan_() {
+bool ESP32BLETracker::stop_scan_() {
   if (this->scanner_state_ != ScannerState::RUNNING && this->scanner_state_ != ScannerState::FAILED) {
     // IDLE means there is nothing to stop; STOPPING means a stop is already in
     // flight and will finish on its own. Neither is an error.
     if (this->scanner_state_ != ScannerState::IDLE && this->scanner_state_ != ScannerState::STOPPING) {
       ESP_LOGE(TAG, "Cannot stop scan: %s", this->scanner_state_to_string_(this->scanner_state_));
     }
-    return;
+    return false;
   }
   // Reset timeout state machine when stopping scan
   this->scan_timeout_state_ = ScanTimeoutState::INACTIVE;
@@ -215,8 +235,9 @@ void ESP32BLETracker::stop_scan_() {
   esp_err_t err = esp_ble_gap_stop_scanning();
   if (err != ESP_OK) {
     ESP_LOGE(TAG, "esp_ble_gap_stop_scanning failed: %d", err);
-    return;
+    return false;
   }
+  return true;
 }
 
 void ESP32BLETracker::start_scan_(bool first) {
@@ -230,16 +251,11 @@ void ESP32BLETracker::start_scan_(bool first) {
   }
   this->set_scanner_state_(ScannerState::STARTING);
   ESP_LOGV(TAG, "Starting scan, set scanner state to STARTING.");
-  if (!first) {
-#ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
-    for (auto *listener : this->listeners_)
-      listener->on_scan_end();
+  if (!first)
+    this->notify_scan_end_();
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  this->skip_next_scan_end_ = false;
 #endif
-#ifdef ESPHOME_BLE_DEVICE_BASE_LISTENER_COUNT
-    for (auto *listener : this->neutral_listeners_)
-      listener->on_scan_end();
-#endif
-  }
 #ifdef USE_ESP32_BLE_DEVICE
   this->discovered_log_.clear();
 #endif
@@ -247,7 +263,17 @@ void ESP32BLETracker::start_scan_(bool first) {
   this->scan_params_.own_addr_type = BLE_ADDR_TYPE_PUBLIC;
   this->scan_params_.scan_filter_policy = BLE_SCAN_FILTER_ALLOW_ALL;
   this->scan_params_.scan_interval = this->scan_interval_;
-  this->scan_params_.scan_window = this->scan_window_;
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  // Count fresh: an automation can start a scan before loop() refreshes the counts.
+  const uint32_t window = this->desired_scan_window_(this->count_client_states_().active);
+  if (window != this->scan_window_) {
+    // Guarantee the connection airtime instead of scanning wall to wall.
+    ESP_LOGV(TAG, "Connection active, using %" PRIu32 " unit scan window", window);
+  }
+#else
+  const uint32_t window = this->scan_window_;
+#endif
+  this->scan_params_.scan_window = window;
 
   // Start timeout monitoring in loop() instead of using scheduler
   // This prevents false reboots when the loop is blocked
@@ -408,6 +434,11 @@ void ESP32BLETracker::dump_config() {
                 "  Continuous Scanning: %s",
                 this->scan_duration_, this->scan_interval_ * 0.625f, this->scan_window_ * 0.625f,
                 this->scan_active_ ? "ACTIVE" : "PASSIVE", YESNO(this->scan_continuous_));
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  if (this->connection_scan_window_ != 0) {
+    ESP_LOGCONFIG(TAG, "  Connection Scan Window: %.1f ms", this->connection_scan_window_ * 0.625f);
+  }
+#endif
   ESP_LOGCONFIG(TAG,
                 "  Scanner State: %s\n"
                 "  Connecting: %d, discovered: %d, disconnecting: %d, active: %d",
@@ -487,6 +518,18 @@ void ESP32BLETracker::cleanup_scan_state_(bool is_stop_complete) {
   // Reset timeout state machine instead of cancelling scheduler timeout
   this->scan_timeout_state_ = ScanTimeoutState::INACTIVE;
 
+  this->notify_scan_end_();
+
+  this->set_scanner_state_(ScannerState::IDLE);
+}
+
+void ESP32BLETracker::notify_scan_end_() {
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  // Window-change restart continues the same scan period; the flag stays set
+  // across the stop and is cleared by the restart in start_scan_.
+  if (this->skip_next_scan_end_)
+    return;
+#endif
 #ifdef ESPHOME_ESP32_BLE_TRACKER_LISTENER_COUNT
   for (auto *listener : this->listeners_)
     listener->on_scan_end();
@@ -495,8 +538,6 @@ void ESP32BLETracker::cleanup_scan_state_(bool is_stop_complete) {
   for (auto *listener : this->neutral_listeners_)
     listener->on_scan_end();
 #endif
-
-  this->set_scanner_state_(ScannerState::IDLE);
 }
 
 void ESP32BLETracker::handle_scanner_failure_() {
@@ -534,6 +575,8 @@ void ESP32BLETracker::try_promote_discovered_clients_() {
     }
 
     ESP_LOGD(TAG, "Promoting client to connect");
+    // A connect ends the scan period a window-change restart was continuing.
+    this->skip_next_scan_end_ = false;
 #ifdef USE_ESP32_BLE_SOFTWARE_COEXISTENCE
     this->update_coex_preference_(true);
 #endif

esphome/components/esp32_ble_tracker/esp32_ble_tracker.h

@@ -169,6 +169,9 @@ class ESP32BLETracker final : public Component,
   void set_scan_duration(uint32_t scan_duration) { scan_duration_ = scan_duration; }
   void set_scan_interval(uint32_t scan_interval) { scan_interval_ = scan_interval; }
   void set_scan_window(uint32_t scan_window) { scan_window_ = scan_window; }
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  void set_connection_scan_window(uint32_t scan_window) { connection_scan_window_ = scan_window; }
+#endif
   void set_scan_active(bool scan_active) { scan_active_ = scan_active; }
   bool get_scan_active() const { return scan_active_; }
   void set_scan_continuous(bool scan_continuous) { scan_continuous_ = scan_continuous; }
@@ -226,7 +229,10 @@ class ESP32BLETracker final : public Component,
   ScannerState get_scanner_state() const { return this->scanner_state_; }
 
  protected:
-  void stop_scan_();
+  /// Returns true when a stop was issued to the controller.
+  bool stop_scan_();
+  /// Fire on_scan_end on every listener unless a window-change restart suppressed it.
+  void notify_scan_end_();
   /// Start a single scan by setting up the parameters and doing some esp-idf calls.
   void start_scan_(bool first);
   /// Called when a `ESP_GAP_BLE_SCAN_RESULT_EVT` event is received.
@@ -313,6 +319,15 @@ class ESP32BLETracker final : public Component,
   uint32_t scan_duration_;
   uint32_t scan_interval_;
   uint32_t scan_window_;
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  /// Window used while a GATT connection is active; set by the user, or
+  /// defaulted when the window was raised to full duty (0 = no fallback).
+  uint32_t connection_scan_window_{0};
+  /// The window to scan at for the given number of active GATT connections.
+  uint32_t desired_scan_window_(uint8_t active) const {
+    return (this->connection_scan_window_ != 0 && active > 0) ? this->connection_scan_window_ : this->scan_window_;
+  }
+#endif
   esp_bt_status_t scan_start_failed_{ESP_BT_STATUS_SUCCESS};
   esp_bt_status_t scan_set_param_failed_{ESP_BT_STATUS_SUCCESS};
 
@@ -330,15 +345,20 @@ class ESP32BLETracker final : public Component,
   /// state_version_ to detect if any state changed since last iteration.
   uint8_t last_processed_version_{0};
   ScannerState scanner_state_{ScannerState::IDLE};
-  bool scan_continuous_;
-  bool scan_active_;
+  // Packed 1-bit flags.
+  bool scan_continuous_ : 1;
+  bool scan_active_ : 1;
 #ifdef USE_OTA_STATE_LISTENER
-  bool scan_continuous_before_ota_{false};
+  bool scan_continuous_before_ota_ : 1 {false};
+#endif
+  bool ble_was_disabled_ : 1 {true};
+  bool parse_advertisements_ : 1 {false};
+#ifdef ESPHOME_ESP32_BLE_TRACKER_CLIENT_COUNT
+  /// Suppress the window-change restart's on_scan_end sweeps (stop and start).
+  bool skip_next_scan_end_ : 1 {false};
 #endif
-  bool ble_was_disabled_{true};
-  bool parse_advertisements_{false};
 #ifdef USE_ESP32_BLE_SOFTWARE_COEXISTENCE
-  bool coex_prefer_ble_{false};
+  bool coex_prefer_ble_ : 1 {false};
 #endif
   // Scan timeout state machine
   enum class ScanTimeoutState : uint8_t {
@@ -346,10 +366,10 @@ class ESP32BLETracker final : public Component,
     MONITORING,     // Actively monitoring for timeout
     EXCEEDED_WAIT,  // Timeout exceeded, waiting one loop before reboot
   };
+  ScanTimeoutState scan_timeout_state_{ScanTimeoutState::INACTIVE};
   uint32_t scan_start_time_{0};
   /// Precomputed timeout value: scan_duration_ * 2000
   uint32_t scan_timeout_ms_{0};
-  ScanTimeoutState scan_timeout_state_{ScanTimeoutState::INACTIVE};
 };
 
 // NOLINTNEXTLINE

esphome/components/http_request/http_request_idf.cpp

@@ -196,6 +196,9 @@ std::shared_ptr<HttpContainer> HttpRequestIDF::perform(const std::string &url, c
       }
 
       container->feed_wdt();
+      // IDF is the only backend reusing the container across redirect hops;
+      // drop the previous hop's headers (Arduino/host collect only the final response)
+      container->response_headers_.clear();
       container->content_length = esp_http_client_fetch_headers(client);
       container->set_chunked(esp_http_client_is_chunked_response(client));
       container->feed_wdt();

esphome/components/mitsubishi_cn105/automation.h

@@ -9,7 +9,7 @@
 namespace esphome::mitsubishi_cn105 {
 
 template<typename... Ts>
-class SetRemoteTemperatureAction : public Action<Ts...>, public Parented<MitsubishiCN105Component> {
+class SetRemoteTemperatureAction final : public Action<Ts...>, public Parented<MitsubishiCN105Component> {
  public:
   TEMPLATABLE_VALUE(float, temperature)
 
@@ -17,12 +17,12 @@ class SetRemoteTemperatureAction : public Action<Ts...>, public Parented<Mitsubi
 };
 
 template<typename... Ts>
-class ClearRemoteTemperatureAction : public Action<Ts...>, public Parented<MitsubishiCN105Component> {
+class ClearRemoteTemperatureAction final : public Action<Ts...>, public Parented<MitsubishiCN105Component> {
  public:
   void play(const Ts &...x) override { this->parent_->clear_remote_temperature(); }
 };
 
-template<typename... Ts> class VaneControlAction : public Action<Ts...> {
+template<typename... Ts> class VaneControlAction final : public Action<Ts...> {
  public:
   using ApplyFn = void (*)(VaneCall &, const std::remove_cvref_t<Ts> &...);
 

esphome/components/mitsubishi_cn105/mitsubishi_cn105_climate.cpp

@@ -74,7 +74,7 @@ climate::ClimateTraits MitsubishiCN105Climate::traits() {
     traits.add_supported_fan_mode(p.second);
   }
 
-  traits.set_supported_swing_modes(this->supported_swing_modes_);
+  traits.set_supported_swing_modes(this->swing_mode_manager_.supported_swing_modes());
 
   const bool use_fahrenheit = this->parent_->get_temperature_mapping().get_use_fahrenheit();
   traits.set_temperature_unit(use_fahrenheit ? TemperatureUnit::FAHRENHEIT : TemperatureUnit::CELSIUS);
@@ -109,33 +109,11 @@ void MitsubishiCN105Climate::control(const climate::ClimateCall &call) {
   }
 
   if (const auto swing_mode = call.get_swing_mode()) {
-    auto vane = this->last_non_swing_vane_mode_;
-    auto wide = this->last_non_swing_wide_vane_mode_;
-
-    switch (*swing_mode) {
-      case climate::CLIMATE_SWING_BOTH:
-        vane = MitsubishiCN105::VaneMode::SWING;
-        wide = MitsubishiCN105::WideVaneMode::SWING;
-        break;
-
-      case climate::CLIMATE_SWING_VERTICAL:
-        vane = MitsubishiCN105::VaneMode::SWING;
-        break;
-
-      case climate::CLIMATE_SWING_HORIZONTAL:
-        wide = MitsubishiCN105::WideVaneMode::SWING;
-        break;
-
-      case climate::CLIMATE_SWING_OFF:
-      default:
-        break;
+    if (const auto vane = this->swing_mode_manager_.vane_from(*swing_mode)) {
+      this->parent_->set_vane_mode(*vane);
     }
-
-    if (this->supported_swing_modes_.count(climate::CLIMATE_SWING_VERTICAL)) {
-      this->parent_->set_vane_mode(vane);
-    }
-    if (this->supported_swing_modes_.count(climate::CLIMATE_SWING_HORIZONTAL)) {
-      this->parent_->set_wide_vane_mode(wide);
+    if (const auto wide = this->swing_mode_manager_.wide_vane_from(*swing_mode)) {
+      this->parent_->set_wide_vane_mode(*wide);
     }
   }
 
@@ -166,64 +144,39 @@ void MitsubishiCN105Climate::apply_values_() {
     ESP_LOGD(TAG, "Unable to map fan mode");
   }
 
-  if (!this->supported_swing_modes_.empty()) {
-    bool vertical_swinging = false;
-    bool horizontal_swinging = false;
-
-    if (this->supported_swing_modes_.count(climate::CLIMATE_SWING_VERTICAL)) {
-      if (status.vane_mode == MitsubishiCN105::VaneMode::SWING) {
-        vertical_swinging = true;
-      } else if (status.vane_mode != MitsubishiCN105::VaneMode::UNKNOWN) {
-        this->last_non_swing_vane_mode_ = status.vane_mode;
-      }
-    }
-
-    if (this->supported_swing_modes_.count(climate::CLIMATE_SWING_HORIZONTAL)) {
-      if (status.wide_vane_mode == MitsubishiCN105::WideVaneMode::SWING) {
-        horizontal_swinging = true;
-      } else if (status.wide_vane_mode != MitsubishiCN105::WideVaneMode::UNKNOWN) {
-        this->last_non_swing_wide_vane_mode_ = status.wide_vane_mode;
-      }
-    }
-
-    if (vertical_swinging && horizontal_swinging) {
-      this->swing_mode = climate::CLIMATE_SWING_BOTH;
-    } else if (vertical_swinging) {
-      this->swing_mode = climate::CLIMATE_SWING_VERTICAL;
-    } else if (horizontal_swinging) {
-      this->swing_mode = climate::CLIMATE_SWING_HORIZONTAL;
-    } else {
-      this->swing_mode = climate::CLIMATE_SWING_OFF;
-    }
+  if (const auto swing_mode =
+          this->swing_mode_manager_.update_and_get_swing_mode(status.vane_mode, status.wide_vane_mode)) {
+    this->swing_mode = *swing_mode;
   }
 
   this->publish_state();
 }
 
 void MitsubishiCN105Climate::set_supported_swing_mode(climate::ClimateSwingMode mode) {
-  this->supported_swing_modes_.clear();
+  climate::ClimateSwingModeMask supported_swing_modes;
   switch (mode) {
     case climate::CLIMATE_SWING_VERTICAL:
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_OFF);
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_VERTICAL);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_OFF);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_VERTICAL);
       break;
 
     case climate::CLIMATE_SWING_HORIZONTAL:
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_OFF);
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_HORIZONTAL);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_OFF);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_HORIZONTAL);
       break;
 
     case climate::CLIMATE_SWING_BOTH:
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_OFF);
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_VERTICAL);
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_HORIZONTAL);
-      this->supported_swing_modes_.insert(climate::CLIMATE_SWING_BOTH);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_OFF);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_VERTICAL);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_HORIZONTAL);
+      supported_swing_modes.insert(climate::CLIMATE_SWING_BOTH);
       break;
 
     case climate::CLIMATE_SWING_OFF:
     default:
       break;
   }
+  this->swing_mode_manager_.set_supported_swing_modes(supported_swing_modes);
 }
 
 }  // namespace esphome::mitsubishi_cn105

esphome/components/mitsubishi_cn105/mitsubishi_cn105_climate.h

@@ -6,10 +6,13 @@
 #include "esphome/core/automation.h"
 #include "esphome/core/component.h"
 #include "esphome/components/climate/climate.h"
+#include "mitsubishi_cn105_swing_mode_manager.h"
 
 namespace esphome::mitsubishi_cn105 {
 
-class MitsubishiCN105Climate : public climate::Climate, public Component, public Parented<MitsubishiCN105Component> {
+class MitsubishiCN105Climate final : public climate::Climate,
+                                     public Component,
+                                     public Parented<MitsubishiCN105Component> {
  public:
   void setup() override;
   void dump_config() override;
@@ -25,14 +28,12 @@ class MitsubishiCN105Climate : public climate::Climate, public Component, public
  protected:
   void apply_values_();
 
-  climate::ClimateSwingModeMask supported_swing_modes_{};
-  MitsubishiCN105::VaneMode last_non_swing_vane_mode_{MitsubishiCN105::VaneMode::AUTO};
-  MitsubishiCN105::WideVaneMode last_non_swing_wide_vane_mode_{MitsubishiCN105::WideVaneMode::CENTER};
+  SwingModeManager swing_mode_manager_;
 };
 
 // Legacy climate action compatibility. Remove in 2027.2.0.
 template<typename... Ts>
-class LegacySetRemoteTemperatureAction : public Action<Ts...>, public Parented<MitsubishiCN105Climate> {
+class LegacySetRemoteTemperatureAction final : public Action<Ts...>, public Parented<MitsubishiCN105Climate> {
  public:
   TEMPLATABLE_VALUE(float, temperature)
 
@@ -41,7 +42,7 @@ class LegacySetRemoteTemperatureAction : public Action<Ts...>, public Parented<M
 
 // Legacy climate action compatibility. Remove in 2027.2.0.
 template<typename... Ts>
-class LegacyClearRemoteTemperatureAction : public Action<Ts...>, public Parented<MitsubishiCN105Climate> {
+class LegacyClearRemoteTemperatureAction final : public Action<Ts...>, public Parented<MitsubishiCN105Climate> {
  public:
   void play(const Ts &...x) override { this->parent_->clear_remote_temperature(); }
 };

esphome/components/mitsubishi_cn105/mitsubishi_cn105_component.h

@@ -80,7 +80,7 @@ struct VaneCall {
   MitsubishiCN105Component *parent_;
 };
 
-class MitsubishiCN105Component : public Component, public uart::UARTDevice {
+class MitsubishiCN105Component final : public Component, public uart::UARTDevice {
  public:
   explicit MitsubishiCN105Component() : hp_(*this) {}
 

esphome/components/mitsubishi_cn105/mitsubishi_cn105_swing_mode_manager.h

@@ -0,0 +1,86 @@
+#pragma once
+
+#include <optional>
+
+#include "esphome/components/climate/climate.h"
+#include "mitsubishi_cn105.h"
+
+namespace esphome::mitsubishi_cn105 {
+
+class SwingModeManager final {
+ public:
+  const climate::ClimateSwingModeMask &supported_swing_modes() const { return this->supported_swing_modes_; }
+  void set_supported_swing_modes(const climate::ClimateSwingModeMask &supported_swing_modes) {
+    this->supported_swing_modes_ = supported_swing_modes;
+  }
+
+  std::optional<MitsubishiCN105::VaneMode> vane_from(climate::ClimateSwingMode swing_mode) const {
+    if (!this->supported_swing_modes_.count(climate::CLIMATE_SWING_VERTICAL)) {
+      return std::nullopt;
+    }
+
+    switch (swing_mode) {
+      case climate::CLIMATE_SWING_BOTH:
+      case climate::CLIMATE_SWING_VERTICAL:
+        return MitsubishiCN105::VaneMode::SWING;
+      default:
+        return this->last_non_swing_vane_mode_;
+    }
+  }
+
+  std::optional<MitsubishiCN105::WideVaneMode> wide_vane_from(climate::ClimateSwingMode swing_mode) const {
+    if (!this->supported_swing_modes_.count(climate::CLIMATE_SWING_HORIZONTAL)) {
+      return std::nullopt;
+    }
+
+    switch (swing_mode) {
+      case climate::CLIMATE_SWING_BOTH:
+      case climate::CLIMATE_SWING_HORIZONTAL:
+        return MitsubishiCN105::WideVaneMode::SWING;
+      default:
+        return this->last_non_swing_wide_vane_mode_;
+    }
+  }
+
+  std::optional<climate::ClimateSwingMode> update_and_get_swing_mode(MitsubishiCN105::VaneMode vane_mode,
+                                                                     MitsubishiCN105::WideVaneMode wide_vane_mode) {
+    if (this->supported_swing_modes_.empty()) {
+      return std::nullopt;
+    }
+
+    bool vertical_swinging = false;
+    bool horizontal_swinging = false;
+    if (this->supported_swing_modes_.count(climate::CLIMATE_SWING_VERTICAL)) {
+      if (vane_mode == MitsubishiCN105::VaneMode::SWING) {
+        vertical_swinging = true;
+      } else if (vane_mode != MitsubishiCN105::VaneMode::UNKNOWN) {
+        this->last_non_swing_vane_mode_ = vane_mode;
+      }
+    }
+    if (this->supported_swing_modes_.count(climate::CLIMATE_SWING_HORIZONTAL)) {
+      if (wide_vane_mode == MitsubishiCN105::WideVaneMode::SWING) {
+        horizontal_swinging = true;
+      } else if (wide_vane_mode != MitsubishiCN105::WideVaneMode::UNKNOWN) {
+        this->last_non_swing_wide_vane_mode_ = wide_vane_mode;
+      }
+    }
+
+    if (vertical_swinging && horizontal_swinging) {
+      return climate::CLIMATE_SWING_BOTH;
+    }
+    if (vertical_swinging) {
+      return climate::CLIMATE_SWING_VERTICAL;
+    }
+    if (horizontal_swinging) {
+      return climate::CLIMATE_SWING_HORIZONTAL;
+    }
+    return climate::CLIMATE_SWING_OFF;
+  }
+
+ private:
+  climate::ClimateSwingModeMask supported_swing_modes_{};
+  MitsubishiCN105::VaneMode last_non_swing_vane_mode_{MitsubishiCN105::VaneMode::AUTO};
+  MitsubishiCN105::WideVaneMode last_non_swing_wide_vane_mode_{MitsubishiCN105::WideVaneMode::CENTER};
+};
+
+}  // namespace esphome::mitsubishi_cn105

esphome/components/mitsubishi_cn105/select/mitsubishi_cn105_vane_select_vertical.h

@@ -7,9 +7,9 @@
 
 namespace esphome::mitsubishi_cn105 {
 
-class MitsubishiCN105VerticalVaneDirectionSelect : public select::Select,
-                                                   public Component,
-                                                   public Parented<MitsubishiCN105Component> {
+class MitsubishiCN105VerticalVaneDirectionSelect final : public select::Select,
+                                                         public Component,
+                                                         public Parented<MitsubishiCN105Component> {
  public:
   void setup() override;
   void publish_vane_state(MitsubishiCN105::VaneMode mode);

esphome/components/online_image/image.py

@@ -4,8 +4,16 @@ from esphome.components import runtime_image
 from esphome.components.const import CONF_REQUEST_HEADERS
 from esphome.components.http_request import CONF_HTTP_REQUEST_ID, HttpRequestComponent
 from esphome.components.image import CONF_TRANSPARENCY, add_metadata
+from esphome.components.runtime_image import IMAGE_FORMATS
 import esphome.config_validation as cv
-from esphome.const import CONF_BUFFER_SIZE, CONF_ID, CONF_ON_ERROR, CONF_TYPE, CONF_URL
+from esphome.const import (
+    CONF_BUFFER_SIZE,
+    CONF_FORMAT,
+    CONF_ID,
+    CONF_ON_ERROR,
+    CONF_TYPE,
+    CONF_URL,
+)
 from esphome.core import ID, Lambda
 from esphome.cpp_generator import MockObj, TemplateArgsType
 from esphome.types import ConfigType
@@ -31,7 +39,6 @@ ReleaseImageAction = online_image_ns.class_(
     "OnlineImageReleaseAction", automation.Action, cg.Parented.template(OnlineImage)
 )
 
-
 ONLINE_IMAGE_SCHEMA = (
     runtime_image.runtime_image_schema(OnlineImage)
     .extend(
@@ -39,6 +46,8 @@ ONLINE_IMAGE_SCHEMA = (
             # Online Image specific options
             cv.GenerateID(CONF_HTTP_REQUEST_ID): cv.use_id(HttpRequestComponent),
             cv.Required(CONF_URL): cv.url,
+            # AUTO (Content-Type detection) is online_image specific; not in the shared registry
+            cv.Required(CONF_FORMAT): cv.one_of(*IMAGE_FORMATS, "AUTO", upper=True),
             cv.Optional(CONF_BUFFER_SIZE, default=65536): cv.int_range(256, 65536),
             cv.Optional(CONF_REQUEST_HEADERS): cv.All(
                 cv.Schema({cv.string: cv.templatable(cv.string)})

esphome/components/online_image/online_image.cpp

@@ -1,9 +1,11 @@
 #include "online_image.h"
 #include "esphome/components/runtime_image/image_decoder.h"
+#include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include <algorithm>
 
 static const char *const TAG = "online_image";
+static const char *const CONTENT_TYPE_HEADER_NAME = "content-type";
 static const char *const ETAG_HEADER_NAME = "etag";
 static const char *const IF_NONE_MATCH_HEADER_NAME = "if-none-match";
 static const char *const LAST_MODIFIED_HEADER_NAME = "last-modified";
@@ -62,7 +64,8 @@ void OnlineImage::update() {
 
   // Add Accept header based on image format
   const char *accept_mime_type;
-  switch (this->get_format()) {
+  runtime_image::ImageFormat format = this->get_format();
+  switch (format) {
 #ifdef USE_RUNTIME_IMAGE_BMP
     case runtime_image::BMP:
       accept_mime_type = "image/bmp,*/*;q=0.8";
@@ -89,8 +92,8 @@ void OnlineImage::update() {
     headers.push_back(http_request::Header{header.first, header.second.value()});
   }
 
-  this->downloader_ = this->parent_->get(this->url_, headers, {ETAG_HEADER_NAME, LAST_MODIFIED_HEADER_NAME});
-
+  this->downloader_ =
+      this->parent_->get(this->url_, headers, {ETAG_HEADER_NAME, LAST_MODIFIED_HEADER_NAME, CONTENT_TYPE_HEADER_NAME});
   if (this->downloader_ == nullptr) {
     ESP_LOGE(TAG, "Download failed.");
     this->end_connection_();
@@ -115,17 +118,54 @@ void OnlineImage::update() {
 
   ESP_LOGD(TAG, "Starting download");
   size_t total_size = this->downloader_->content_length;
+  ESP_LOGV(TAG, "Content-Length: %zu", total_size);
+
+  if (format == runtime_image::AUTO) {
+    // Try to auto-detect format from Content-Type header
+    auto content_type_header = this->downloader_->get_response_header(CONTENT_TYPE_HEADER_NAME);
+    const char *content_type = content_type_header.c_str();
+    ESP_LOGV(TAG, "Content-Type: %s", content_type);
+    // Includes aliases seen from real servers (older IIS, CDNs, S3)
+    if (str_contains_ignore_case(content_type, "image/bmp") ||
+        str_contains_ignore_case(content_type, "image/x-ms-bmp") ||
+        str_contains_ignore_case(content_type, "image/x-bmp")) {
+      format = runtime_image::BMP;
+    } else if (str_contains_ignore_case(content_type, "image/jpeg") ||
+               str_contains_ignore_case(content_type, "image/jpg")) {
+      format = runtime_image::JPEG;
+    } else if (str_contains_ignore_case(content_type, "image/png") ||
+               str_contains_ignore_case(content_type, "image/x-png")) {
+      format = runtime_image::PNG;
+    } else if (str_contains_ignore_case(content_type, "image/")) {
+      ESP_LOGW(TAG, "Unsupported image type: '%s'", content_type);
+      this->end_connection_();
+      this->download_error_callback_.call();
+      return;
+    } else {
+      // TODO: implement auto-detection in runtime_image by sniffing the first few bytes of the image data
+      if (content_type_header.empty()) {
+        ESP_LOGW(TAG, "Server sent no Content-Type header; cannot determine image format. Set `format:` explicitly");
+      } else {
+        ESP_LOGE(TAG, "Could not determine image format from Content-Type: '%s'. Set `format:` explicitly",
+                 content_type);
+      }
+      this->end_connection_();
+      this->download_error_callback_.call();
+      return;
+    }
+  }
+  ESP_LOGD(TAG, "Using image format: %d", format);
 
   // Initialize decoder with the known format
-  if (!this->begin_decode(total_size)) {
-    ESP_LOGE(TAG, "Failed to initialize decoder for format %d", this->get_format());
+  if (!this->begin_decode(total_size, format)) {
+    ESP_LOGE(TAG, "Failed to initialize decoder for format %d", format);
     this->end_connection_();
     this->download_error_callback_.call();
     return;
   }
 
   // JPEG requires the complete image in the download buffer before decoding
-  if (this->get_format() == runtime_image::JPEG && total_size > this->download_buffer_.size()) {
+  if (format == runtime_image::JPEG && total_size > this->download_buffer_.size()) {
     this->download_buffer_.resize(total_size);
   }
 

esphome/components/runtime_image/__init__.py

@@ -58,6 +58,18 @@ class Format:
         """Add defines and libraries needed for this format."""
 
 
+class AUTOFormat(Format):
+    """AUTO format - detect from MIME type."""
+
+    def __init__(self):
+        super().__init__("AUTO", None)
+
+    def actions(self) -> None:
+        # dict.fromkeys dedupes the JPG/JPEG alias so each format runs once
+        for image_format in dict.fromkeys(IMAGE_FORMATS.values()):
+            image_format.actions()
+
+
 class BMPFormat(Format):
     """BMP format decoder configuration."""
 
@@ -102,18 +114,25 @@ class PNGFormat(Format):
         cg.add_library("pngle", "1.1.0")
 
 
-# Registry of available formats
+# Decodable formats only; platforms that support runtime detection accept
+# "AUTO" in their own schema and get_format() resolves it
+_JPEG_FORMAT = JPEGFormat()
 IMAGE_FORMATS = {
     "BMP": BMPFormat(),
-    "JPEG": JPEGFormat(),
+    "JPEG": _JPEG_FORMAT,
+    "JPG": _JPEG_FORMAT,  # Alias for JPEG
     "PNG": PNGFormat(),
-    "JPG": JPEGFormat(),  # Alias for JPEG
 }
 
+AUTO_FORMAT = AUTOFormat()
+
 
 def get_format(format_name: str) -> Format | None:
     """Get a format instance by name."""
-    return IMAGE_FORMATS.get(format_name.upper())
+    name = format_name.upper()
+    if name == "AUTO":
+        return AUTO_FORMAT
+    return IMAGE_FORMATS.get(name)
 
 
 def enable_format(format_name: str) -> Format | None:

esphome/components/runtime_image/image_format.h

@@ -6,7 +6,8 @@ namespace esphome::runtime_image {
  * @brief Image format types that can be decoded dynamically.
  */
 enum ImageFormat {
-  /** Automatically detect from data. Not implemented yet. */
+  /** Format is supplied per decode, e.g. detected from the Content-Type header
+   *  by online_image; sniffing the image data is not implemented. */
   AUTO,
   /** JPEG format. */
   JPEG,

esphome/components/runtime_image/runtime_image.cpp

@@ -171,22 +171,27 @@ void RuntimeImage::draw(int x, int y, display::Display *display, Color color_on,
   // If no image is loaded and no placeholder, nothing to draw
 }
 
-bool RuntimeImage::begin_decode(size_t expected_size) {
+bool RuntimeImage::begin_decode(size_t expected_size, ImageFormat format) {
   if (this->is_decoding()) {
     ESP_LOGW(TAG, "Decoding already in progress");
     return false;
   }
 
+  if (format == AUTO && this->format_ != AUTO) {
+    // Fall back to the configured format before the reuse check below
+    format = this->format_;
+  }
+
   // An idle decoder for a different format cannot be reused
-  if (this->decoder_ != nullptr && this->decoder_->get_format() != this->format_) {
-    ESP_LOGD(TAG, "Decoder format mismatch: current: %d, new: %d", this->decoder_->get_format(), this->format_);
+  if (this->decoder_ != nullptr && this->decoder_->get_format() != format) {
+    ESP_LOGD(TAG, "Decoder format mismatch: current: %d, new: %d", this->decoder_->get_format(), format);
     this->decoder_ = nullptr;
   }
 
   if (!this->decoder_) {
-    this->decoder_ = this->create_decoder_(this->format_);
+    this->decoder_ = this->create_decoder_(format);
     if (!this->decoder_) {
-      ESP_LOGE(TAG, "Failed to create decoder for format %d", this->format_);
+      ESP_LOGE(TAG, "Failed to create decoder for format %d", format);
       return false;
     }
   }
@@ -364,6 +369,9 @@ std::unique_ptr<ImageDecoder> RuntimeImage::create_decoder_(ImageFormat format)
     case PNG:
       return make_unique<PngDecoder>(this);
 #endif
+    case AUTO:
+      ESP_LOGE(TAG, "Image format could not be determined; set `format:` explicitly in the configuration");
+      return nullptr;
     default:
       ESP_LOGE(TAG, "Unsupported image format: %d", format);
       return nullptr;

esphome/components/runtime_image/runtime_image.h

@@ -62,9 +62,10 @@ class RuntimeImage : public image::Image {
    * @brief Begin decoding an image.
    *
    * @param expected_size Optional hint about the expected data size.
+   * @param format The image format to decode (defaults to AUTO, which uses the value set at construction).
    * @return true if decoder was successfully initialized.
    */
-  bool begin_decode(size_t expected_size = 0);
+  bool begin_decode(size_t expected_size = 0, ImageFormat format = AUTO);
 
   /**
    * @brief Feed data to the decoder.
@@ -103,6 +104,7 @@ class RuntimeImage : public image::Image {
   /**
    * @brief Get the image format.
    */
+  /// Configured format; a format resolved per decode lives on the active decoder
   ImageFormat get_format() const { return this->format_; }
 
   /**

esphome/components/web_server/list_entities.h

@@ -35,7 +35,6 @@ class ListEntitiesIterator final : public ComponentIterator {
 #undef ENTITY_TYPE_
 #undef ENTITY_CONTROLLER_TYPE_
   // NOLINTEND(bugprone-macro-parentheses)
-  bool completed() { return this->state_ == IteratorState::NONE; }
 
  protected:
   const WebServer *web_server_;

esphome/components/web_server/web_server.cpp

@@ -214,8 +214,8 @@ void DeferredUpdateEventSource::process_deferred_queue_() {
 
 void DeferredUpdateEventSource::loop() {
   process_deferred_queue_();
-  if (!this->entities_iterator_.completed())
-    this->entities_iterator_.advance();
+  // One step per loop; refusals retry next pass
+  this->entities_iterator_.try_advance(1);
 }
 
 void DeferredUpdateEventSource::deferrable_send_state(void *source, const char *event_type,
@@ -321,12 +321,6 @@ void DeferredUpdateEventSourceList::on_client_connect_(DeferredUpdateEventSource
 #endif
 
     source->entities_iterator_.begin(ws->include_internal_);
-
-    // just dump them all up-front and take advantage of the deferred queue
-    //     on second thought that takes too long, but leaving the commented code here for debug purposes
-    // while(!source->entities_iterator_.completed()) {
-    //  source->entities_iterator_.advance();
-    //}
   });
 }
 

esphome/components/web_server_idf/web_server_idf.cpp

@@ -935,8 +935,8 @@ void AsyncEventSourceResponse::process_buffer_() {
 void AsyncEventSourceResponse::loop() {
   process_buffer_();
   process_deferred_queue_();
-  if (!this->entities_iterator_.completed())
-    this->entities_iterator_.advance();
+  // One step per loop; refusals retry next pass
+  this->entities_iterator_.try_advance(1);
 }
 
 bool AsyncEventSourceResponse::try_send_nodefer(const char *message, size_t message_len, const char *event, uint32_t id,

esphome/core/component_iterator.cpp

@@ -22,23 +22,23 @@ void ComponentIterator::advance_platform_() {
   this->at_ = 0;
 }
 
-void ComponentIterator::advance() {
+bool ComponentIterator::advance_step_() {
   switch (this->state_) {
     case IteratorState::NONE:
       // not started
-      return;
+      return false;
     case IteratorState::BEGIN:
       if (this->on_begin()) {
         advance_platform_();
+        return true;
       }
-      break;
+      return false;
 
 // Entity iterator cases (generated from entity_types.h)
 // NOLINTBEGIN(bugprone-macro-parentheses)
 #define ENTITY_TYPE_(type, singular, plural, count, upper) \
   case IteratorState::upper: \
-    this->process_platform_item_(App.get_##plural(), &ComponentIterator::on_##singular); \
-    break;
+    return this->process_platform_item_(App.get_##plural(), &ComponentIterator::on_##singular);
 #define ENTITY_CONTROLLER_TYPE_(type, singular, plural, count, upper, callback) \
   ENTITY_TYPE_(type, singular, plural, count, upper)
 #include "esphome/core/entity_types.h"
@@ -48,26 +48,29 @@ void ComponentIterator::advance() {
 
 #ifdef USE_API_USER_DEFINED_ACTIONS
     case IteratorState::SERVICE:
-      this->process_platform_item_(api::global_api_server->get_user_services(), &ComponentIterator::on_service);
-      break;
+      return this->process_platform_item_(api::global_api_server->get_user_services(), &ComponentIterator::on_service);
 #endif
 
 #ifdef USE_CAMERA
     case IteratorState::CAMERA: {
       camera::Camera *camera_instance = camera::Camera::instance();
-      if (camera_instance != nullptr && (!camera_instance->is_internal() || this->include_internal_)) {
-        this->on_camera(camera_instance);
+      if (camera_instance != nullptr && (!camera_instance->is_internal() || this->include_internal_) &&
+          !this->on_camera(camera_instance)) {
+        return false;
       }
       advance_platform_();
-    } break;
+      return true;
+    }
 #endif
 
     case IteratorState::MAX:
       if (this->on_end()) {
         this->state_ = IteratorState::NONE;
+        return true;
       }
-      return;
+      return false;
   }
+  return false;
 }
 
 bool ComponentIterator::on_end() { return true; }

esphome/core/component_iterator.h

@@ -30,7 +30,23 @@ class RadioFrequency;
 class ComponentIterator {
  public:
   void begin(bool include_internal = false);
-  void advance();
+  /// Run up to max_steps iteration steps; stops early when iteration
+  /// completes or a callback refuses (that step is retried on the next
+  /// call). Inline so an idle (completed) iterator costs one compare, no call.
+  ESPHOME_ALWAYS_INLINE void try_advance(size_t max_steps) {
+    size_t steps = 0;
+    while (steps < max_steps && !this->completed()) {
+      this->yield_requested_ = false;
+      if (!this->advance_step_())
+        break;
+      steps++;
+      if (this->yield_requested_)
+        break;
+    }
+  }
+  // Remove before 2027.3.0
+  ESPDEPRECATED("Use try_advance() instead. Removed in 2027.3.0", "2026.8.1")
+  void advance() { this->try_advance(1); }
   bool completed() const { return this->state_ == IteratorState::NONE; }
   virtual bool on_begin();
 // Pure virtual entity callbacks (generated from entity_types.h)
@@ -73,23 +89,34 @@ class ComponentIterator {
 #endif
     MAX,
   };
+  /// End the current try_advance() pass after this step; lets callbacks
+  /// that write directly to the socket cap direct writes per pass.
+  void yield_after_step_() { this->yield_requested_ = true; }
+
   uint16_t at_{0};  // Supports up to 65,535 entities per type
   IteratorState state_{IteratorState::NONE};
-  bool include_internal_{false};
+  bool yield_requested_ : 1 {false};
+  bool include_internal_ : 1 {false};
 
   template<typename Container>
-  void process_platform_item_(const Container &items,
+  bool process_platform_item_(const Container &items,
                               bool (ComponentIterator::*on_item)(typename Container::value_type)) {
     if (this->at_ >= items.size()) {
       this->advance_platform_();
-    } else {
-      typename Container::value_type item = items[this->at_];
-      if ((item->is_internal() && !this->include_internal_) || (this->*on_item)(item)) {
-        this->at_++;
-      }
+      return true;
     }
+    typename Container::value_type item = items[this->at_];
+    if ((item->is_internal() && !this->include_internal_) || (this->*on_item)(item)) {
+      this->at_++;
+      return true;
+    }
+    return false;
   }
 
+  /// One iteration step; false if no progress was made (callback refused
+  /// or iterator not running).
+  bool advance_step_();
+
   void advance_platform_();
 };
 

esphome/external_files.py

@@ -16,6 +16,7 @@ from esphome.const import CONF_FILE, CONF_TYPE, CONF_URL, __version__
 from esphome.core import CORE, EsphomeError, TimePeriodSeconds
 from esphome.happy_eyeballs import ensure_happy_eyeballs
 from esphome.helpers import write_file
+from esphome.net_retry import fetch_with_retry
 from esphome.types import ConfigType
 
 _LOGGER = logging.getLogger(__name__)
@@ -157,8 +158,17 @@ def has_remote_file_changed(
             }
             if etag := _read_etag(local_file_path):
                 headers[IF_NONE_MATCH] = etag
-            response = requests.head(
-                url, headers=headers, timeout=timeout, allow_redirects=True
+            # Retried so allow_stale=False consumers don't hard-fail on a
+            # healed flake. Only connection-level failures retry: HEAD
+            # never raises on HTTP status (servers rejecting HEAD with
+            # 405/501 must fall through to the GET), so 5xx is handled by
+            # the GET's own retry.
+            response = fetch_with_retry(
+                url,
+                lambda: requests.head(
+                    url, headers=headers, timeout=timeout, allow_redirects=True
+                ),
+                what="Revalidation",
             )
 
             _LOGGER.debug(
@@ -293,7 +303,7 @@ def download_content(
     _LOGGER.info("Downloading %s", url)
     _LOGGER.debug("Saving to %s", path)
 
-    try:
+    def _fetch() -> tuple[requests.Response, bytes]:
         req = requests.get(
             url,
             timeout=timeout,
@@ -304,7 +314,10 @@ def download_content(
         # and mid-stream connection errors all surface here as
         # RequestException subclasses, so this needs the same fall-back
         # treatment as the request itself.
-        data = req.content
+        return req, req.content
+
+    try:
+        req, data = fetch_with_retry(url, _fetch)
     except requests.exceptions.RequestException as e:
         if path.exists():
             # Memoized so a flaky host warns once per run, not per consumer.

esphome/framework_helpers.py

@@ -17,6 +17,7 @@ from typing import IO, TYPE_CHECKING
 
 from esphome.happy_eyeballs import ensure_happy_eyeballs
 from esphome.helpers import ProgressBar, rmtree
+from esphome.net_retry import NETWORK_MAX_ATTEMPTS, is_transient_download_error
 
 if TYPE_CHECKING:
     import requests
@@ -32,8 +33,9 @@ _LOGGER = logging.getLogger(__name__)
 _MIRROR_ATTEMPTS = 3
 
 # Passes over the whole mirror list when a transient network error is in
-# the mix; matches git.py's _NETWORK_MAX_ATTEMPTS (3 tries, 2s/4s backoff).
-_MIRROR_SWEEP_ATTEMPTS = 3
+# the mix; shares net_retry's policy (3 tries, 2s/4s backoff), which in
+# turn matches git.py's _NETWORK_MAX_ATTEMPTS.
+_MIRROR_SWEEP_ATTEMPTS = NETWORK_MAX_ATTEMPTS
 
 
 def get_project_link_flags() -> list[str]:
@@ -1081,30 +1083,6 @@ def _spent_attempts_error(e: Exception, attempts: int) -> Exception:
     return err
 
 
-def _is_transient_download_error(e: Exception) -> bool:
-    """Return True when a download failure is worth retrying.
-
-    Connection-level failures and HTTP 429/5xx are transient. Other HTTP
-    errors, local errors, and exhausted-attempts EsphomeError wrappers
-    (their per-mirror retries are already spent) are permanent.
-    """
-    # Imported lazily: requests is a heavy import (~85ms) and is only
-    # needed when actually downloading, never during config validation.
-    import requests
-
-    if isinstance(e, requests.exceptions.HTTPError):
-        resp = e.response
-        return resp is not None and (resp.status_code == 429 or resp.status_code >= 500)
-    return isinstance(
-        e,
-        (
-            requests.exceptions.ConnectionError,
-            requests.exceptions.Timeout,
-            requests.exceptions.ChunkedEncodingError,
-        ),
-    )
-
-
 def _try_mirrors_once(
     urls: list[str],
     path_target: Path | None,
@@ -1316,7 +1294,7 @@ def download_from_mirrors(
         # Permanent failures (404, verification mismatch) won't heal;
         # only retry when a transient error is in the mix (as git.py does).
         transient = next(
-            ((u, e) for u, e in sweep_failures if _is_transient_download_error(e)),
+            ((u, e) for u, e in sweep_failures if is_transient_download_error(e)),
             None,
         )
         if transient is None:

esphome/net_retry.py

@@ -0,0 +1,114 @@
+"""Retry policy for HTTP downloads.
+
+Kept import-light on purpose: this module is imported at config time, so it
+must not pull in requests (a heavy import, ~85ms) at module scope.
+"""
+
+from __future__ import annotations
+
+from collections.abc import Callable
+import logging
+import time
+
+_LOGGER = logging.getLogger(__name__)
+
+# 3 tries with 2s/4s backoff, matching git.py's _NETWORK_MAX_ATTEMPTS.
+# Callers memoize failures so a flaky host pays this once per file per run.
+NETWORK_MAX_ATTEMPTS = 3
+
+
+def _is_permanent_dns_failure(e: BaseException) -> bool:
+    """Whether a hard socket.gaierror hides in ``e``'s exception chain.
+
+    EAI_AGAIN (flaky resolver) stays retryable; anything else is permanent
+    so offline builds fall back to their cache without sleeping first.
+    Narrower than git.py, which retries NXDOMAIN too.
+
+    Walks ``__cause__``, ``args`` (requests wraps MaxRetryError without
+    ``from``) and MaxRetryError's ``reason``, but not implicit
+    ``__context__``: an unrelated earlier attempt's resolution failure
+    must not reclassify an error it did not cause.
+    """
+    import socket
+
+    seen: set[int] = set()
+    stack: list[BaseException] = [e]
+    while stack:
+        exc = stack.pop()
+        if id(exc) in seen:
+            continue
+        if (
+            isinstance(exc, socket.gaierror)
+            and exc.errno is not None
+            and exc.errno != socket.EAI_AGAIN
+        ):
+            return True
+        seen.add(id(exc))
+        stack.extend(
+            nxt
+            for nxt in (
+                exc.__cause__,
+                getattr(exc, "reason", None),  # urllib3 MaxRetryError
+                *exc.args,
+            )
+            if isinstance(nxt, BaseException)
+        )
+    return False
+
+
+def is_transient_download_error(e: Exception) -> bool:
+    """Return True when a download failure is worth retrying.
+
+    Connection-level failures and HTTP 429/5xx are transient; hard DNS
+    failures, other HTTP errors, and local errors are permanent.
+    """
+    # Imported lazily: requests is a heavy import (~85ms) and is only
+    # needed when actually downloading, never during config validation.
+    import requests
+
+    if isinstance(e, requests.exceptions.HTTPError):
+        resp = e.response
+        return resp is not None and (resp.status_code == 429 or resp.status_code >= 500)
+    if isinstance(e, requests.exceptions.ConnectionError) and _is_permanent_dns_failure(
+        e
+    ):
+        return False
+    # SSLError (a ConnectionError subclass) stays transient on purpose: it
+    # also covers mid-handshake connection drops, not just bad certificates.
+    return isinstance(
+        e,
+        (
+            requests.exceptions.ConnectionError,
+            requests.exceptions.Timeout,
+            requests.exceptions.ChunkedEncodingError,
+            requests.exceptions.ContentDecodingError,
+        ),
+    )
+
+
+def fetch_with_retry[T](url: str, fetch: Callable[[], T], what: str = "Download") -> T:
+    """Run ``fetch``, retrying transient failures with 2s/4s backoff.
+
+    Permanent failures and the final attempt propagate to the caller;
+    ``what`` names the operation in the retry warning.
+    """
+    import requests
+
+    for attempt in range(1, NETWORK_MAX_ATTEMPTS):
+        try:
+            return fetch()
+        except requests.exceptions.RequestException as e:
+            if not is_transient_download_error(e):
+                raise
+            delay = 2**attempt
+            _LOGGER.warning(
+                "%s of %s failed: %s. Retrying in %d seconds... (attempt %d/%d)",
+                what,
+                url,
+                e,
+                delay,
+                attempt + 1,
+                NETWORK_MAX_ATTEMPTS,
+            )
+            time.sleep(delay)
+    return fetch()

esphome/platformio/extra_script.py

@@ -14,7 +14,7 @@ import logging
 import os
 from pathlib import Path
 import shlex
-from typing import TYPE_CHECKING, Any
+from typing import TYPE_CHECKING, Any, NamedTuple
 
 from esphome.core import EsphomeError
 from esphome.platformio.library import ESPHOME_DATA_KEY, ESPHOME_DATA_LINK_FLAGS_KEY
@@ -99,20 +99,47 @@ class ExtraScriptResult:
     cpppath: list[str] = field(default_factory=list)
     libpath: list[str] = field(default_factory=list)
     libs: list[str] = field(default_factory=list)
-    cppdefines: list[str | tuple[str, str]] = field(default_factory=list)
+    cppdefines: list[CppDefine] = field(default_factory=list)
     linkflags: list[str] = field(default_factory=list)
     cppflags: list[str] = field(default_factory=list)
 
 
-def _cppdefines_items(value: Any) -> list:
-    """Normalize SCons ``processDefines`` spellings: a bare 2-tuple is one
-    ``name=value`` pair, a dict maps names to values, a list is
-    element-wise."""
+class CppDefine(NamedTuple):
+    """One normalized CPPDEFINES entry; a ``value`` of None is a bare -DNAME."""
+
+    name: str
+    value: str | None = None
+
+
+def _cppdefine(entry: Any) -> CppDefine | None:
+    """Normalize one CPPDEFINES element, or warn and drop an unsupported
+    shape; formatting those blind would hand the compiler garbage like
+    ``-D{'FOO': '1'}``."""
+    if isinstance(entry, str):
+        return CppDefine(entry)
+    if (
+        isinstance(entry, (tuple, list))
+        and len(entry) == 2
+        and isinstance(entry[0], (str, int))
+        and isinstance(entry[1], (str, int, type(None)))
+    ):
+        value = entry[1]
+        return CppDefine(str(entry[0]), None if value is None else str(value))
+    _LOGGER.warning("Ignoring unsupported CPPDEFINES entry %r", entry)
+    return None
+
+
+def _cppdefines_items(value: Any) -> list[CppDefine]:
+    """Normalize SCons ``processDefines`` spellings into ``CppDefine``s: a
+    bare 2-tuple is one ``name=value`` pair, a dict maps names to values, a
+    list is element-wise."""
     if isinstance(value, tuple) and len(value) == 2:
-        return [value]
-    if isinstance(value, dict):
-        return list(value.items())
-    return list(value) if isinstance(value, (list, tuple)) else [value]
+        elements: list[Any] = [value]
+    elif isinstance(value, dict):
+        elements = list(value.items())
+    else:
+        elements = list(value) if isinstance(value, (list, tuple)) else [value]
+    return [d for e in elements if (d := _cppdefine(e)) is not None]
 
 
 class _FakeSConsEnv:
@@ -316,23 +343,11 @@ def captured_as_build_flags(
     )
     flags.extend(f"-l{shlex.quote(lib)}" for lib in _str_entries(result.libs, "LIBS"))
     for define in result.cppdefines:
-        # SCons also accepts nested containers; formatting those blind
-        # would hand the compiler garbage like -D{'FOO': '1'}
-        if (
-            isinstance(define, (tuple, list))
-            and len(define) == 2
-            and isinstance(define[0], (str, int))
-            and isinstance(define[1], (str, int, type(None)))
-        ):
-            if define[1] is None:
-                # {"FOO": None} / ("FOO", None) is a bare -DFOO in SCons
-                flags.append(shlex.quote(f"-D{define[0]}"))
-            else:
-                flags.append(shlex.quote(f"-D{define[0]}={define[1]}"))
-        elif isinstance(define, str):
-            flags.append(shlex.quote(f"-D{define}"))
+        if define.value is None:
+            # {"FOO": None} / ("FOO", None) is a bare -DFOO in SCons
+            flags.append(shlex.quote(f"-D{define.name}"))
         else:
-            _LOGGER.warning("Ignoring unsupported CPPDEFINES entry %r", define)
+            flags.append(shlex.quote(f"-D{define.name}={define.value}"))
     # Each captured entry is one argv token in SCons; quote so the
     # lex_build_flags round-trip cannot split a spaced value into two.
     # LINKFLAGS are deliberately absent: they travel via

tests/component_tests/esp32_ble_tracker/config/scan_window_explicit.yaml

@@ -0,0 +1,19 @@
+esphome:
+  name: scan-window-explicit
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: MySSID
+
+esp32_ble_tracker:
+  scan_parameters:
+    window: 30ms
+
+bluetooth_proxy:
+  active: true
+
+api:

tests/component_tests/esp32_ble_tracker/config/scan_window_raised.yaml

@@ -0,0 +1,17 @@
+esphome:
+  name: scan-window-raised
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: MySSID
+
+esp32_ble_tracker:
+
+bluetooth_proxy:
+  active: true
+
+api:

tests/component_tests/esp32_ble_tracker/config/scan_window_scan_only.yaml

@@ -0,0 +1,12 @@
+esphome:
+  name: scan-window-scan-only
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: MySSID
+
+esp32_ble_tracker:

tests/component_tests/esp32_ble_tracker/config/scan_window_user_set_scan_only.yaml

@@ -0,0 +1,14 @@
+esphome:
+  name: scan-window-user-scan-only
+
+esp32:
+  board: esp32dev
+  framework:
+    type: esp-idf
+
+wifi:
+  ssid: MySSID
+
+esp32_ble_tracker:
+  scan_parameters:
+    connection_scan_window: 20ms

tests/component_tests/esp32_ble_tracker/test_scan_window_default.py

@@ -12,11 +12,12 @@ arbiter a full-duty scan would starve wifi, so the 30 ms default is kept.
 from __future__ import annotations
 
 from collections.abc import Callable
+from pathlib import Path
 
 import pytest
 
 from esphome import config_validation as cv
-from esphome.components.ble_device_base import to_ble_units
+from esphome.components.ble_device_base import CONF_CONNECTION_SCAN_WINDOW, to_ble_units
 from esphome.components.const import CONF_SCAN_PARAMETERS, CONF_WINDOW
 from esphome.components.esp32 import KEY_IDF_VERSION
 from esphome.components.esp32_ble_tracker import (
@@ -120,3 +121,103 @@ def test_short_interval_without_window_still_rejected(
     stage_esp32("5.5.5", wifi=True)
     with pytest.raises(cv.Invalid, match="needs to be smaller than scan interval"):
         _scan_params({"scan_parameters": {"interval": "20ms"}})
+
+
+# The connection-time fallback window: while a GATT connection is active the
+# scanner drops from a raised full-duty window back to this value so the
+# connection gets guaranteed airtime.
+
+
+def test_raise_arms_connection_scan_window_default(
+    stage_esp32: Callable[..., None],
+) -> None:
+    stage_esp32("5.5.5", wifi=True)
+    params = _scan_params({})
+    assert params[CONF_WINDOW] == params[CONF_INTERVAL]
+    assert to_ble_units(params[CONF_CONNECTION_SCAN_WINDOW]) == 48
+
+
+def test_user_connection_scan_window_survives_raise(
+    stage_esp32: Callable[..., None],
+) -> None:
+    stage_esp32("5.5.5", wifi=True)
+    params = _scan_params({"scan_parameters": {"connection_scan_window": "60ms"}})
+    assert params[CONF_WINDOW] == params[CONF_INTERVAL]
+    assert to_ble_units(params[CONF_CONNECTION_SCAN_WINDOW]) == 96
+
+
+def test_unraised_window_gets_no_connection_scan_window_default(
+    stage_esp32: Callable[..., None],
+) -> None:
+    stage_esp32("5.5.4", wifi=True)
+    assert CONF_CONNECTION_SCAN_WINDOW not in _scan_params({})
+
+
+def test_connection_scan_window_above_interval_rejected(
+    stage_esp32: Callable[..., None],
+) -> None:
+    stage_esp32("5.5.5", wifi=True)
+    with pytest.raises(
+        cv.Invalid, match="connection_scan_window .* needs to be smaller"
+    ):
+        _scan_params({"scan_parameters": {"connection_scan_window": "400ms"}})
+
+
+def test_connection_scan_window_above_window_rejected(
+    stage_esp32: Callable[..., None],
+) -> None:
+    """A connection window above the (post-raise) window would widen the scan
+    during connections; the reject runs after the raise so a fallback below a
+    raised window still validates (covered by the survives-raise test)."""
+    stage_esp32("5.5.5", wifi=True)
+    with pytest.raises(
+        cv.Invalid, match="connection_scan_window .* needs to be smaller"
+    ):
+        _scan_params(
+            {"scan_parameters": {"window": "30ms", "connection_scan_window": "300ms"}}
+        )
+
+
+def test_connection_scan_window_truncation_collapse_rejected(
+    stage_esp32: Callable[..., None],
+) -> None:
+    """A connection window that truncates into the interval's 0.625 ms unit
+    would silently program a full-duty scan during connections."""
+    stage_esp32("5.5.5", wifi=True)
+    with pytest.raises(cv.Invalid, match="connection_scan_window .* both truncate"):
+        _scan_params(
+            {
+                "scan_parameters": {
+                    "interval": "320.5ms",
+                    "connection_scan_window": "320.2ms",
+                }
+            }
+        )
+
+
+@pytest.mark.parametrize(
+    ("config_file", "window_call", "connection_call", "warns"),
+    [
+        # Raised window with GATT clients: the injected fallback is emitted.
+        ("scan_window_raised.yaml", "set_scan_window(512)", True, False),
+        # Explicit window: nothing injected.
+        ("scan_window_explicit.yaml", "set_scan_window(48)", False, False),
+        # Scan-only build compiles the path out: the injected default is
+        # dropped silently, a user-set value warns.
+        ("scan_window_scan_only.yaml", "set_scan_window(512)", False, False),
+        ("scan_window_user_set_scan_only.yaml", "set_scan_window(512)", False, True),
+    ],
+)
+def test_connection_scan_window_codegen(
+    generate_main: Callable[[str | Path], str],
+    component_config_path: Callable[[str], Path],
+    caplog: pytest.LogCaptureFixture,
+    config_file: str,
+    window_call: str,
+    connection_call: bool,
+    warns: bool,
+) -> None:
+    main_cpp = generate_main(component_config_path(config_file))
+    assert window_call in main_cpp
+    assert ("set_connection_scan_window(48)" in main_cpp) == connection_call
+    assert ("'connection_scan_window' has no effect" in caplog.text) == warns

tests/components/camera/__init__.py

@@ -0,0 +1,11 @@
+import esphome.codegen as cg
+from tests.testing_helpers import ComponentManifestOverride
+
+
+def override_manifest(manifest: ComponentManifestOverride) -> None:
+    # No host camera platform exists to emit USE_CAMERA; define it here so
+    # the iterator CAMERA state compiles into the test binary.
+    async def to_code_testing(config):
+        cg.add_define("USE_CAMERA")
+
+    manifest.to_code = to_code_testing

tests/components/camera/test_component_iterator_camera.cpp

@@ -0,0 +1,79 @@
+#include <gtest/gtest.h>
+
+#include "esphome/core/component_iterator.h"
+
+#ifdef USE_CAMERA
+#include "esphome/components/camera/camera.h"
+
+namespace esphome::testing {
+
+class StubCamera : public camera::Camera {
+ public:
+  void add_listener(camera::CameraListener *listener) override {}
+  camera::CameraImageReader *create_image_reader() override { return nullptr; }
+  void request_image(camera::CameraRequester requester) override {}
+  void start_stream(camera::CameraRequester requester) override {}
+  void stop_stream(camera::CameraRequester requester) override {}
+};
+
+// Iterator that accepts everything except the camera, which can refuse a
+// configurable number of times. The CAMERA state is a singleton path
+// distinct from process_platform_item_; this pins the same contract:
+// a refused camera is re-offered, never skipped.
+class CameraRefusingIterator : public ComponentIterator {
+ public:
+// NOLINTBEGIN(bugprone-macro-parentheses)
+#define ENTITY_TYPE_(type, singular, plural, count, upper) \
+  bool on_##singular(type *obj) override { return true; }
+#define ENTITY_CONTROLLER_TYPE_(type, singular, plural, count, upper, callback) \
+  ENTITY_TYPE_(type, singular, plural, count, upper)
+#include "esphome/core/entity_types.h"
+#undef ENTITY_TYPE_
+#undef ENTITY_CONTROLLER_TYPE_
+  // NOLINTEND(bugprone-macro-parentheses)
+
+  bool on_camera(camera::Camera *obj) override {
+    this->camera_calls++;
+    if (this->camera_refusals > 0) {
+      this->camera_refusals--;
+      return false;
+    }
+    return true;
+  }
+
+  int camera_calls{0};
+  int camera_refusals{0};
+};
+
+// Far above the fixed number of iterator states
+static constexpr size_t BIG_BUDGET = 1000;
+
+class ComponentIteratorCameraTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    // Constructing a Camera installs the process-wide singleton
+    static StubCamera stub_camera;
+    ASSERT_EQ(camera::Camera::instance(), &stub_camera);
+  }
+};
+
+TEST_F(ComponentIteratorCameraTest, RefusedCameraIsReofferedNotSkipped) {
+  CameraRefusingIterator it;
+  it.camera_refusals = 2;
+  it.begin();
+  // Runs until the camera refuses, which stops the pass
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.camera_calls, 1);
+  EXPECT_FALSE(it.completed());
+  // The camera is re-offered once per call, not skipped
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.camera_calls, 2);
+  EXPECT_FALSE(it.completed());
+  // Once accepted, the iteration completes
+  it.try_advance(BIG_BUDGET);
+  EXPECT_TRUE(it.completed());
+  EXPECT_EQ(it.camera_calls, 3);
+}
+
+}  // namespace esphome::testing
+#endif  // USE_CAMERA

tests/components/core/benchmark.yaml

@@ -0,0 +1,11 @@
+# Pulls in sensor so entity iteration paths compile (USE_SENSOR);
+# tests register their own instances. Plain yaml.safe_load, no ESPHome tags.
+# An alphabetically-earlier component's sensor: block shadows this one in
+# combined builds; the tests' sensor-count ASSERT catches a capacity drop.
+sensor:
+  - platform: template
+    id: bench_sensor_a
+    name: "Bench A"
+  - platform: template
+    id: bench_sensor_b
+    name: "Bench B"

tests/components/core/test_component_iterator.cpp

@@ -0,0 +1,195 @@
+#include <gtest/gtest.h>
+
+#include "esphome/core/component_iterator.h"
+
+#ifdef USE_SENSOR
+#include "esphome/components/sensor/sensor.h"
+#include "esphome/core/application.h"
+#endif
+
+namespace esphome::testing {
+
+// Iterator whose begin/end callbacks can refuse a configurable number of
+// times; all entity callbacks accept (any registered entities are accepted).
+class RefusingIterator : public ComponentIterator {
+ public:
+// NOLINTBEGIN(bugprone-macro-parentheses)
+#define ENTITY_TYPE_(type, singular, plural, count, upper) \
+  bool on_##singular(type *obj) override { return true; }
+#define ENTITY_CONTROLLER_TYPE_(type, singular, plural, count, upper, callback) \
+  ENTITY_TYPE_(type, singular, plural, count, upper)
+#include "esphome/core/entity_types.h"
+#undef ENTITY_TYPE_
+#undef ENTITY_CONTROLLER_TYPE_
+  // NOLINTEND(bugprone-macro-parentheses)
+
+  bool on_begin() override { return step(this->begin_calls, this->begin_refusals); }
+  bool on_end() override { return step(this->end_calls, this->end_refusals); }
+
+  int begin_calls{0};
+  int end_calls{0};
+  int begin_refusals{0};
+  int end_refusals{0};
+
+ protected:
+  static bool step(int &calls, int &refusals) {
+    calls++;
+    if (refusals > 0) {
+      refusals--;
+      return false;
+    }
+    return true;
+  }
+};
+
+// Far above the fixed number of iterator states
+static constexpr size_t BIG_BUDGET = 1000;
+
+TEST(ComponentIterator, NotRunningMakesNoProgress) {
+  RefusingIterator it;
+  it.try_advance(BIG_BUDGET);
+  EXPECT_TRUE(it.completed());
+  EXPECT_EQ(it.begin_calls, 0);
+  EXPECT_EQ(it.end_calls, 0);
+}
+
+TEST(ComponentIterator, CompletesInOneCallWithoutRefusals) {
+  RefusingIterator it;
+  it.begin();
+  it.try_advance(BIG_BUDGET);
+  EXPECT_TRUE(it.completed());
+  EXPECT_EQ(it.begin_calls, 1);
+  EXPECT_EQ(it.end_calls, 1);
+}
+
+TEST(ComponentIterator, StepBudgetIsHonored) {
+  RefusingIterator it;
+  it.begin();
+  it.try_advance(1);
+  EXPECT_EQ(it.begin_calls, 1);
+  EXPECT_EQ(it.end_calls, 0);
+  EXPECT_FALSE(it.completed());
+}
+
+TEST(ComponentIterator, RefusedStepStopsBatchAndRetriesSameStep) {
+  RefusingIterator it;
+  it.end_refusals = 3;
+  it.begin();
+  // First call runs until the refused end step, which stops the pass
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.end_calls, 1);
+  EXPECT_FALSE(it.completed());
+  // The refused step is retried once per call, not skipped
+  it.try_advance(BIG_BUDGET);
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.end_calls, 3);
+  EXPECT_FALSE(it.completed());
+  // Once accepted, the iteration completes
+  it.try_advance(BIG_BUDGET);
+  EXPECT_TRUE(it.completed());
+  EXPECT_EQ(it.end_calls, 4);
+}
+
+TEST(ComponentIterator, RefusedBeginStopsBatchAndRetries) {
+  RefusingIterator it;
+  it.begin_refusals = 2;
+  it.begin();
+  it.try_advance(BIG_BUDGET);
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.begin_calls, 2);
+  EXPECT_FALSE(it.completed());
+  it.try_advance(BIG_BUDGET);
+  EXPECT_TRUE(it.completed());
+  EXPECT_EQ(it.begin_calls, 3);
+}
+
+// The deprecated advance() wrapper must keep the legacy once-per-loop
+// pattern working during the deprecation window.
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wdeprecated-declarations"
+TEST(ComponentIterator, DeprecatedAdvanceKeepsLegacyPatternWorking) {
+  RefusingIterator it;
+  it.end_refusals = 2;
+  it.begin();
+  size_t guard = 0;
+  while (!it.completed() && guard++ < BIG_BUDGET) {
+    it.advance();
+  }
+  EXPECT_TRUE(it.completed());
+  // Two refused end steps were retried, then accepted
+  EXPECT_EQ(it.end_calls, 3);
+}
+#pragma GCC diagnostic pop
+
+#ifdef USE_SENSOR
+// Iterator whose sensor callback can refuse or yield; pins the per-item
+// contract: a refused item is re-offered with at_ unchanged, never skipped.
+class ItemRefusingIterator : public RefusingIterator {
+ public:
+  bool on_sensor(sensor::Sensor *obj) override {
+    this->last_sensor = obj;
+    if (!step(this->sensor_calls, this->sensor_refusals))
+      return false;
+    if (this->yield_on_sensor)
+      this->yield_after_step_();
+    return true;
+  }
+  sensor::Sensor *last_sensor{nullptr};
+  int sensor_calls{0};
+  int sensor_refusals{0};
+  bool yield_on_sensor{false};
+};
+
+class ComponentIteratorSensorTest : public ::testing::Test {
+ protected:
+  void SetUp() override {
+    static sensor::Sensor sensor_a;
+    static sensor::Sensor sensor_b;
+    static bool registered = false;
+    if (!registered) {
+      App.register_sensor(&sensor_a);
+      App.register_sensor(&sensor_b);
+      registered = true;
+    }
+    // StaticVector drops silently when full; fail the fixture, not the contract
+    ASSERT_EQ(App.get_sensors().size(), 2u) << "benchmark.yaml sensor count too small";
+  }
+};
+
+TEST_F(ComponentIteratorSensorTest, RefusedItemIsReofferedNotSkipped) {
+  ItemRefusingIterator it;
+  it.sensor_refusals = 2;
+  it.begin();
+  // Runs until the first sensor refuses
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.sensor_calls, 1);
+  EXPECT_FALSE(it.completed());
+  // The refused item is re-offered, not skipped
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.sensor_calls, 2);
+  sensor::Sensor *refused = it.last_sensor;
+  // Once accepted, iteration continues through the second sensor to the end
+  it.try_advance(BIG_BUDGET);
+  EXPECT_TRUE(it.completed());
+  EXPECT_NE(it.last_sensor, refused);
+  EXPECT_EQ(it.sensor_calls, 4);
+}
+
+TEST_F(ComponentIteratorSensorTest, YieldAfterStepEndsPassAndResumes) {
+  ItemRefusingIterator it;
+  it.yield_on_sensor = true;
+  it.begin();
+  // The pass ends right after the first sensor despite a big budget
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.sensor_calls, 1);
+  EXPECT_FALSE(it.completed());
+  // The next pass ends after the second sensor
+  it.try_advance(BIG_BUDGET);
+  EXPECT_EQ(it.sensor_calls, 2);
+  // Remaining states then run to completion in one pass
+  it.try_advance(BIG_BUDGET);
+  EXPECT_TRUE(it.completed());
+}
+#endif  // USE_SENSOR
+
+}  // namespace esphome::testing

tests/components/mitsubishi_cn105/climate/mitsubishi_cn105_climate_tests.cpp

@@ -2,10 +2,19 @@
 #include <utility>
 #include "../common.h"
 
+#include "esphome/components/mitsubishi_cn105/mitsubishi_cn105_climate.h"
+
 namespace esphome::mitsubishi_cn105::testing {
 
+struct MitsubishiCN105ClimateTestContext {
+  MitsubishiCN105Component component;
+  MitsubishiCN105Climate sut;
+
+  MitsubishiCN105ClimateTestContext() { this->sut.set_parent(&this->component); }
+};
+
 TEST(MitsubishiCN105ClimateTests, CelsiusTemperatureMappingAndTraitsMatchExpectedValues) {
-  TestableMitsubishiCN105Climate sut;
+  MitsubishiCN105ClimateTestContext context;
   const auto mapping = TemperatureMapping();
 
   for (int temperature = 16; temperature <= 31; ++temperature) {
@@ -13,7 +22,7 @@ TEST(MitsubishiCN105ClimateTests, CelsiusTemperatureMappingAndTraitsMatchExpecte
     EXPECT_EQ(mapping.from_mitsubishi(temperature), temperature);
   }
 
-  const auto traits = sut.traits();
+  const auto traits = context.sut.traits();
   EXPECT_EQ(traits.get_temperature_unit(), TemperatureUnit::CELSIUS);
   EXPECT_FLOAT_EQ(traits.get_visual_min_temperature(), 16.0f);
   EXPECT_FLOAT_EQ(traits.get_visual_max_temperature(), 31.0f);
@@ -22,10 +31,10 @@ TEST(MitsubishiCN105ClimateTests, CelsiusTemperatureMappingAndTraitsMatchExpecte
 }
 
 TEST(MitsubishiCN105ClimateTests, FahrenheitTemperatureMappingAndTraitsMatchExpectedValues) {
-  TestableMitsubishiCN105Climate sut;
+  MitsubishiCN105ClimateTestContext context;
   auto mapping = TemperatureMapping();
   mapping.set_use_fahrenheit(true);
-  sut.set_use_fahrenheit(true);
+  context.component.set_use_fahrenheit(true);
 
   const std::array cases{
       std::pair{61, 16.0f}, std::pair{62, 16.5f}, std::pair{63, 17.0f}, std::pair{64, 17.5f}, std::pair{65, 18.0f},
@@ -40,7 +49,7 @@ TEST(MitsubishiCN105ClimateTests, FahrenheitTemperatureMappingAndTraitsMatchExpe
     EXPECT_FLOAT_EQ(mapping.to_mitsubishi(fahrenheit), mitsubishi_celsius);
     EXPECT_FLOAT_EQ(mapping.from_mitsubishi(mitsubishi_celsius), fahrenheit);
   }
-  const auto traits = sut.traits();
+  const auto traits = context.sut.traits();
   EXPECT_EQ(traits.get_temperature_unit(), TemperatureUnit::FAHRENHEIT);
   EXPECT_FLOAT_EQ(traits.get_visual_min_temperature(), 61.0f);
   EXPECT_FLOAT_EQ(traits.get_visual_max_temperature(), 88.0f);
@@ -63,163 +72,44 @@ TEST(MitsubishiCN105ClimateTests, FahrenheitTemperatureMappingUsesLinearConversi
 }
 
 TEST(MitsubishiCN105ClimateTests, SupportedSwingModeOffLeavesTraitsEmpty) {
-  TestableMitsubishiCN105Climate sut;
+  MitsubishiCN105ClimateTestContext context;
 
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_OFF);
+  context.sut.set_supported_swing_mode(climate::CLIMATE_SWING_OFF);
 
-  EXPECT_FALSE(sut.traits().get_supports_swing_modes());
+  EXPECT_FALSE(context.sut.traits().get_supports_swing_modes());
 }
 
 TEST(MitsubishiCN105ClimateTests, SupportedSwingModeVerticalExposesOffAndVertical) {
-  TestableMitsubishiCN105Climate sut;
+  MitsubishiCN105ClimateTestContext context;
 
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_VERTICAL);
+  context.sut.set_supported_swing_mode(climate::CLIMATE_SWING_VERTICAL);
 
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_OFF));
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_VERTICAL));
-  EXPECT_FALSE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_HORIZONTAL));
-  EXPECT_FALSE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_BOTH));
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_OFF));
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_VERTICAL));
+  EXPECT_FALSE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_HORIZONTAL));
+  EXPECT_FALSE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_BOTH));
 }
 
 TEST(MitsubishiCN105ClimateTests, SupportedSwingModeHorizontalExposesOffAndHorizontal) {
-  TestableMitsubishiCN105Climate sut;
+  MitsubishiCN105ClimateTestContext context;
 
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_HORIZONTAL);
+  context.sut.set_supported_swing_mode(climate::CLIMATE_SWING_HORIZONTAL);
 
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_OFF));
-  EXPECT_FALSE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_VERTICAL));
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_HORIZONTAL));
-  EXPECT_FALSE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_BOTH));
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_OFF));
+  EXPECT_FALSE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_VERTICAL));
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_HORIZONTAL));
+  EXPECT_FALSE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_BOTH));
 }
 
 TEST(MitsubishiCN105ClimateTests, SupportedSwingModeBothExposesAllExpectedModes) {
-  TestableMitsubishiCN105Climate sut;
+  MitsubishiCN105ClimateTestContext context;
 
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_BOTH);
+  context.sut.set_supported_swing_mode(climate::CLIMATE_SWING_BOTH);
 
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_OFF));
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_VERTICAL));
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_HORIZONTAL));
-  EXPECT_TRUE(sut.traits().supports_swing_mode(climate::CLIMATE_SWING_BOTH));
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesMapsVerticalSwingWhenSupported) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_VERTICAL);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::SWING;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::CENTER;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_VERTICAL);
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesMapsHorizontalSwingWhenSupported) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_HORIZONTAL);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::AUTO;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::SWING;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_HORIZONTAL);
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesMapsBothSwingWhenSupported) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_BOTH);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::SWING;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::SWING;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_BOTH);
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesMapsSwingOffWhenNoSwingActive) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_BOTH);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::POSITION_3;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::CENTER;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_OFF);
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesRemembersLastNonSwingPositions) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_BOTH);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::POSITION_4;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::RIGHT;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.last_non_swing_vane_mode_, MitsubishiCN105::VaneMode::POSITION_4);
-  EXPECT_EQ(sut.last_non_swing_wide_vane_mode_, MitsubishiCN105::WideVaneMode::RIGHT);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::SWING;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::SWING;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.last_non_swing_vane_mode_, MitsubishiCN105::VaneMode::POSITION_4);
-  EXPECT_EQ(sut.last_non_swing_wide_vane_mode_, MitsubishiCN105::WideVaneMode::RIGHT);
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_BOTH);
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesDoesNotOverwriteRememberedPositionWithUnknownValues) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_BOTH);
-
-  sut.last_non_swing_vane_mode_ = MitsubishiCN105::VaneMode::POSITION_2;
-  sut.last_non_swing_wide_vane_mode_ = MitsubishiCN105::WideVaneMode::LEFT;
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::UNKNOWN;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::UNKNOWN;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.last_non_swing_vane_mode_, MitsubishiCN105::VaneMode::POSITION_2);
-  EXPECT_EQ(sut.last_non_swing_wide_vane_mode_, MitsubishiCN105::WideVaneMode::LEFT);
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_OFF);
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesIgnoresUnsupportedVerticalSwingState) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_HORIZONTAL);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::SWING;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::CENTER;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_OFF);
-}
-
-TEST(MitsubishiCN105ClimateTests, ApplyValuesIgnoresUnsupportedHorizontalSwingState) {
-  TestableMitsubishiCN105Climate sut;
-
-  sut.set_supported_swing_mode(climate::CLIMATE_SWING_VERTICAL);
-
-  sut.status().vane_mode = MitsubishiCN105::VaneMode::AUTO;
-  sut.status().wide_vane_mode = MitsubishiCN105::WideVaneMode::SWING;
-
-  sut.apply_values_();
-
-  EXPECT_EQ(sut.swing_mode, climate::CLIMATE_SWING_OFF);
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_OFF));
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_VERTICAL));
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_HORIZONTAL));
+  EXPECT_TRUE(context.sut.traits().supports_swing_mode(climate::CLIMATE_SWING_BOTH));
 }
 
 }  // namespace esphome::mitsubishi_cn105::testing

tests/components/mitsubishi_cn105/climate/mitsubishi_cn105_swing_mode_manager_tests.cpp

@@ -0,0 +1,99 @@
+#include "../common.h"
+
+#include "esphome/components/mitsubishi_cn105/mitsubishi_cn105_swing_mode_manager.h"
+
+namespace esphome::mitsubishi_cn105::testing {
+
+static SwingModeManager make_swing_mode_manager(std::initializer_list<climate::ClimateSwingMode> supported_modes) {
+  SwingModeManager manager;
+  climate::ClimateSwingModeMask supported_swing_modes;
+  for (const auto mode : supported_modes)
+    supported_swing_modes.insert(mode);
+  manager.set_supported_swing_modes(supported_swing_modes);
+  return manager;
+}
+
+TEST(SwingModeManagerTests, StatusMapsVerticalSwingWhenSupported) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL});
+  EXPECT_EQ(manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::SWING, MitsubishiCN105::WideVaneMode::CENTER),
+            std::optional{climate::CLIMATE_SWING_VERTICAL});
+}
+
+TEST(SwingModeManagerTests, StatusMapsHorizontalSwingWhenSupported) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_HORIZONTAL});
+  EXPECT_EQ(manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::AUTO, MitsubishiCN105::WideVaneMode::SWING),
+            std::optional{climate::CLIMATE_SWING_HORIZONTAL});
+}
+
+TEST(SwingModeManagerTests, StatusMapsBothSwingWhenSupported) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL,
+                                          climate::CLIMATE_SWING_HORIZONTAL, climate::CLIMATE_SWING_BOTH});
+  EXPECT_EQ(manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::SWING, MitsubishiCN105::WideVaneMode::SWING),
+            std::optional{climate::CLIMATE_SWING_BOTH});
+}
+
+TEST(SwingModeManagerTests, StatusMapsSwingOffWhenNoSwingActive) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL,
+                                          climate::CLIMATE_SWING_HORIZONTAL, climate::CLIMATE_SWING_BOTH});
+  EXPECT_EQ(
+      manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::POSITION_3, MitsubishiCN105::WideVaneMode::CENTER),
+      std::optional{climate::CLIMATE_SWING_OFF});
+}
+
+TEST(SwingModeManagerTests, RemembersLastNonSwingPositions) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL,
+                                          climate::CLIMATE_SWING_HORIZONTAL, climate::CLIMATE_SWING_BOTH});
+  manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::POSITION_4, MitsubishiCN105::WideVaneMode::RIGHT);
+  manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::SWING, MitsubishiCN105::WideVaneMode::SWING);
+  EXPECT_EQ(manager.vane_from(climate::CLIMATE_SWING_OFF), std::optional{MitsubishiCN105::VaneMode::POSITION_4});
+  EXPECT_EQ(manager.wide_vane_from(climate::CLIMATE_SWING_OFF), std::optional{MitsubishiCN105::WideVaneMode::RIGHT});
+}
+
+TEST(SwingModeManagerTests, UnknownValuesDoNotOverwriteRememberedPositions) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL,
+                                          climate::CLIMATE_SWING_HORIZONTAL, climate::CLIMATE_SWING_BOTH});
+  manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::POSITION_2, MitsubishiCN105::WideVaneMode::LEFT);
+  manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::UNKNOWN, MitsubishiCN105::WideVaneMode::UNKNOWN);
+  EXPECT_EQ(manager.vane_from(climate::CLIMATE_SWING_OFF), std::optional{MitsubishiCN105::VaneMode::POSITION_2});
+  EXPECT_EQ(manager.wide_vane_from(climate::CLIMATE_SWING_OFF), std::optional{MitsubishiCN105::WideVaneMode::LEFT});
+}
+
+TEST(SwingModeManagerTests, UnsupportedVerticalSwingStateIsIgnored) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_HORIZONTAL});
+  EXPECT_EQ(manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::SWING, MitsubishiCN105::WideVaneMode::CENTER),
+            std::optional{climate::CLIMATE_SWING_OFF});
+}
+
+TEST(SwingModeManagerTests, UnsupportedHorizontalSwingStateIsIgnored) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL});
+  EXPECT_EQ(manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::AUTO, MitsubishiCN105::WideVaneMode::SWING),
+            std::optional{climate::CLIMATE_SWING_OFF});
+}
+
+TEST(SwingModeManagerTests, SwingModeFromReturnsNulloptWhenNoSwingModesSupported) {
+  auto manager = make_swing_mode_manager({});
+  EXPECT_FALSE(manager.update_and_get_swing_mode(MitsubishiCN105::VaneMode::SWING, MitsubishiCN105::WideVaneMode::SWING)
+                   .has_value());
+}
+
+TEST(SwingModeManagerTests, VaneFromSwingModeReturnsNulloptWhenVerticalUnsupported) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_HORIZONTAL});
+  EXPECT_FALSE(manager.vane_from(climate::CLIMATE_SWING_VERTICAL).has_value());
+}
+
+TEST(SwingModeManagerTests, WideVaneFromSwingModeReturnsNulloptWhenHorizontalUnsupported) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL});
+  EXPECT_FALSE(manager.wide_vane_from(climate::CLIMATE_SWING_HORIZONTAL).has_value());
+}
+
+TEST(SwingModeManagerTests, VaneAndWideVaneFromSwingModeMapSwingModes) {
+  auto manager = make_swing_mode_manager({climate::CLIMATE_SWING_OFF, climate::CLIMATE_SWING_VERTICAL,
+                                          climate::CLIMATE_SWING_HORIZONTAL, climate::CLIMATE_SWING_BOTH});
+  EXPECT_EQ(manager.vane_from(climate::CLIMATE_SWING_VERTICAL), std::optional{MitsubishiCN105::VaneMode::SWING});
+  EXPECT_EQ(manager.vane_from(climate::CLIMATE_SWING_BOTH), std::optional{MitsubishiCN105::VaneMode::SWING});
+  EXPECT_EQ(manager.wide_vane_from(climate::CLIMATE_SWING_HORIZONTAL),
+            std::optional{MitsubishiCN105::WideVaneMode::SWING});
+  EXPECT_EQ(manager.wide_vane_from(climate::CLIMATE_SWING_BOTH), std::optional{MitsubishiCN105::WideVaneMode::SWING});
+}
+
+}  // namespace esphome::mitsubishi_cn105::testing

tests/components/mitsubishi_cn105/common.h

@@ -64,26 +64,4 @@ class TestableMitsubishiCN105 : public MitsubishiCN105 {
   void set_current_time(uint32_t ms) { test_loop_time_ms = ms; }
 };
 
-class TestableMitsubishiCN105Climate : public MitsubishiCN105Climate {
- public:
-  TestableMitsubishiCN105Climate() { this->set_parent(&this->component_); }
-
-  using MitsubishiCN105Climate::apply_values_;
-  using MitsubishiCN105Climate::last_non_swing_vane_mode_;
-  using MitsubishiCN105Climate::last_non_swing_wide_vane_mode_;
-
-  MitsubishiCN105::Status &status() { return const_cast<MitsubishiCN105::Status &>(this->component_.status()); }
-  void set_use_fahrenheit(bool value) { this->component_.set_use_fahrenheit(value); }
-
- protected:
-  MitsubishiCN105Component component_;
-};
-
-class TestableMitsubishiCN105Component : public MitsubishiCN105Component {
- public:
-  MitsubishiCN105::Status &mutable_status() { return const_cast<MitsubishiCN105::Status &>(this->status()); }
-
-  void notify_status() { this->status_callback_.call(); }
-};
-
 }  // namespace esphome::mitsubishi_cn105::testing

tests/components/mitsubishi_cn105/mitsubishi_cn105_component_tests.cpp

@@ -3,7 +3,7 @@
 namespace esphome::mitsubishi_cn105::testing {
 
 TEST(MitsubishiCN105ComponentTests, PublishesVaneStateForEveryValidSnapshot) {
-  TestableMitsubishiCN105Component hub;
+  MitsubishiCN105Component hub;
   size_t callback_count = 0;
   std::optional<VerticalVaneMode> callback_direction;
   hub.add_on_vane_state_callback([&](const VaneState &state) {
@@ -11,8 +11,9 @@ TEST(MitsubishiCN105ComponentTests, PublishesVaneStateForEveryValidSnapshot) {
     callback_direction = state.vertical.direction;
   });
 
-  hub.mutable_status().room_temperature = 20.0f;
-  hub.mutable_status().vane_mode = MitsubishiCN105::VaneMode::POSITION_4;
+  hub.set_telemetry_request_min_interval(SCHEDULER_DONT_RUN);
+  hub.set_target_temperature(20.0f);
+  hub.set_vane_mode(MitsubishiCN105::VaneMode::POSITION_4);
   hub.publish_status();
 
   EXPECT_EQ(callback_count, 1);
@@ -25,7 +26,7 @@ TEST(MitsubishiCN105ComponentTests, PublishesVaneStateForEveryValidSnapshot) {
 }
 
 TEST(MitsubishiCN105ComponentTests, PublishesUnknownVaneState) {
-  TestableMitsubishiCN105Component hub;
+  MitsubishiCN105Component hub;
   size_t status_callback_count = 0;
   size_t vane_callback_count = 0;
   std::optional<VerticalVaneMode> callback_direction;
@@ -35,15 +36,16 @@ TEST(MitsubishiCN105ComponentTests, PublishesUnknownVaneState) {
     callback_direction = state.vertical.direction;
   });
 
-  hub.mutable_status().room_temperature = 20.0f;
-  hub.mutable_status().vane_mode = MitsubishiCN105::VaneMode::UNKNOWN;
+  hub.set_telemetry_request_min_interval(SCHEDULER_DONT_RUN);
+  hub.set_target_temperature(20.0f);
+  ASSERT_EQ(hub.status().vane_mode, MitsubishiCN105::VaneMode::UNKNOWN);
   hub.publish_status();
 
   EXPECT_EQ(status_callback_count, 1);
   EXPECT_EQ(vane_callback_count, 1);
   EXPECT_EQ(callback_direction, std::optional{VERTICAL_VANE_MODE_UNKNOWN});
 
-  hub.mutable_status().vane_mode = MitsubishiCN105::VaneMode::POSITION_4;
+  hub.set_vane_mode(MitsubishiCN105::VaneMode::POSITION_4);
   hub.publish_status();
 
   EXPECT_EQ(status_callback_count, 2);
@@ -52,7 +54,7 @@ TEST(MitsubishiCN105ComponentTests, PublishesUnknownVaneState) {
 }
 
 TEST(MitsubishiCN105ComponentTests, VaneCallAppliesVerticalDirection) {
-  TestableMitsubishiCN105Component hub;
+  MitsubishiCN105Component hub;
 
   auto call = hub.make_vane_call();
   call.vertical.set_direction(VERTICAL_VANE_MODE_POSITION_5);
@@ -62,12 +64,11 @@ TEST(MitsubishiCN105ComponentTests, VaneCallAppliesVerticalDirection) {
 }
 
 TEST(MitsubishiCN105ComponentTests, VaneControlActionAppliesConfiguredFields) {
-  TestableMitsubishiCN105Component hub;
+  MitsubishiCN105Component hub;
   VaneControlAction<> action(&hub, [](VaneCall &call) { call.vertical.set_direction(VERTICAL_VANE_MODE_SWING); });
 
   action.play();
 
   EXPECT_EQ(hub.status().vane_mode, MitsubishiCN105::VaneMode::SWING);
 }
-
 }  // namespace esphome::mitsubishi_cn105::testing

tests/components/mitsubishi_cn105/select/mitsubishi_cn105_vane_select_vertical_tests.cpp

@@ -3,14 +3,9 @@
 
 namespace esphome::mitsubishi_cn105::testing {
 
-class TestableMitsubishiCN105VerticalVaneDirectionSelect : public MitsubishiCN105VerticalVaneDirectionSelect {
- public:
-  using MitsubishiCN105VerticalVaneDirectionSelect::control;
-};
-
 struct VerticalVaneDirectionSelectTestContext {
-  TestableMitsubishiCN105Component hub;
-  TestableMitsubishiCN105VerticalVaneDirectionSelect select;
+  MitsubishiCN105Component hub;
+  MitsubishiCN105VerticalVaneDirectionSelect select;
 
   VerticalVaneDirectionSelectTestContext() {
     this->select.traits.set_options({"Auto", "1", "2", "3", "4", "5", "Swing"});
@@ -31,13 +26,15 @@ TEST(MitsubishiCN105VerticalVaneDirectionSelectTests, MapsIndexesToVaneModes) {
 
   for (size_t i = 0; i < expected_modes.size(); ++i) {
     SCOPED_TRACE(i);
-    ctx.select.control(i);
+    ctx.select.make_call().set_index(i).perform();
     EXPECT_EQ(ctx.hub.status().vane_mode, expected_modes[i]);
   }
 }
 
 TEST(MitsubishiCN105VerticalVaneDirectionSelectTests, PublishesIncomingVaneModes) {
   VerticalVaneDirectionSelectTestContext ctx;
+  ctx.hub.set_telemetry_request_min_interval(SCHEDULER_DONT_RUN);
+  ctx.hub.set_target_temperature(20.0f);
 
   constexpr std::array modes{
       MitsubishiCN105::VaneMode::AUTO,       MitsubishiCN105::VaneMode::POSITION_1,
@@ -48,13 +45,12 @@ TEST(MitsubishiCN105VerticalVaneDirectionSelectTests, PublishesIncomingVaneModes
 
   for (size_t i = 0; i < modes.size(); ++i) {
     SCOPED_TRACE(i);
-    ctx.hub.mutable_status().vane_mode = modes[i];
-    ctx.hub.notify_status();
+    ctx.hub.set_vane_mode(modes[i]);
+    ctx.hub.publish_status();
     EXPECT_EQ(ctx.select.active_index(), std::optional{i});
   }
 
-  ctx.hub.mutable_status().vane_mode = MitsubishiCN105::VaneMode::UNKNOWN;
-  ctx.hub.notify_status();
+  ctx.select.publish_vane_state(MitsubishiCN105::VaneMode::UNKNOWN);
   EXPECT_EQ(ctx.select.active_index(), std::optional{modes.size() - 1});
 }
 
@@ -64,14 +60,15 @@ TEST(MitsubishiCN105VerticalVaneDirectionSelectTests, ControlPublishesSelectAndC
   climate_entity.set_parent(&ctx.hub);
   climate_entity.set_supported_swing_mode(climate::CLIMATE_SWING_VERTICAL);
 
-  ctx.hub.mutable_status().room_temperature = 20.0f;
+  ctx.hub.set_telemetry_request_min_interval(SCHEDULER_DONT_RUN);
+  ctx.hub.set_target_temperature(20.0f);
   climate_entity.setup();
 
-  ctx.select.control(6);
+  ctx.select.make_call().set_index(6).perform();
   EXPECT_EQ(ctx.select.active_index(), std::optional<size_t>{6});
   EXPECT_EQ(climate_entity.swing_mode, climate::CLIMATE_SWING_VERTICAL);
 
-  ctx.select.control(3);
+  ctx.select.make_call().set_index(3).perform();
   EXPECT_EQ(ctx.select.active_index(), std::optional<size_t>{3});
   EXPECT_EQ(climate_entity.swing_mode, climate::CLIMATE_SWING_OFF);
 }
@@ -82,7 +79,8 @@ TEST(MitsubishiCN105VerticalVaneDirectionSelectTests, ClimateControlPublishesSel
   climate_entity.set_parent(&ctx.hub);
   climate_entity.set_supported_swing_mode(climate::CLIMATE_SWING_VERTICAL);
 
-  ctx.hub.mutable_status().room_temperature = 20.0f;
+  ctx.hub.set_telemetry_request_min_interval(SCHEDULER_DONT_RUN);
+  ctx.hub.set_target_temperature(20.0f);
   climate_entity.setup();
 
   climate_entity.make_call().set_swing_mode(climate::CLIMATE_SWING_VERTICAL).perform();
@@ -95,10 +93,9 @@ TEST(MitsubishiCN105VerticalVaneDirectionSelectTests, ClimateControlPublishesSel
 TEST(MitsubishiCN105VerticalVaneDirectionSelectTests, BeforeInitializationDoesNotPublishSelectState) {
   VerticalVaneDirectionSelectTestContext ctx;
 
-  ctx.select.control(3);
+  ctx.select.make_call().set_index(3).perform();
 
   EXPECT_EQ(ctx.hub.status().vane_mode, MitsubishiCN105::VaneMode::POSITION_3);
   EXPECT_FALSE(ctx.select.has_state());
 }
-
 }  // namespace esphome::mitsubishi_cn105::testing

tests/components/online_image/common.yaml

@@ -57,6 +57,11 @@ image:
     url: http://www.faqs.org/images/library.jpg
     format: JPG
     type: RGB565
+  - platform: online_image
+    id: online_auto_image
+    url: http://www.faqs.org/images/library.jpg
+    format: AUTO
+    type: RGB565
 
 # Check the set_url action
 esphome:

tests/components/runtime_image/test_decoder_reuse.cpp

@@ -77,18 +77,12 @@ class TestableRuntimeImage : public RuntimeImage {
       : RuntimeImage(format, image::IMAGE_TYPE_RGB, image::TRANSPARENCY_OPAQUE, nullptr, false, 0, 0) {}
 
   ImageDecoder *decoder() { return this->decoder_.get(); }
-
-  /// Simulates the state a dynamic-format producer (PR #16337) would leave behind:
-  /// a cached decoder whose format no longer matches the image's format.
-  /// TODO: once #16337 adds a public way to change the format, drive the mismatch
-  /// through it and delete this seam.
-  void plant_decoder(ImageFormat format) { this->decoder_ = this->create_decoder_(format); }
 };
 
 /// Runs one full decode session. Returns true when every stage succeeded.
-static bool decode_all(TestableRuntimeImage &img, const uint8_t *data, size_t len) {
+static bool decode_all(TestableRuntimeImage &img, const uint8_t *data, size_t len, ImageFormat format = AUTO) {
   std::vector<uint8_t> buffer(data, data + len);  // feed_data needs mutable bytes
-  if (!img.begin_decode(len)) {
+  if (!img.begin_decode(len, format)) {
     return false;
   }
   size_t offset = 0;
@@ -203,25 +197,51 @@ TEST(RuntimeImageDecoder, ChunkedFeedDecodesLikeDownloadLoop) {
 }
 
 TEST(RuntimeImageDecoder, FormatSwitchEvictsMismatchedDecoder) {
-  // PNG image holding a stale BMP decoder: begin_decode must evict and recreate.
-  TestableRuntimeImage png_img(PNG);
-  png_img.plant_decoder(BMP);
-  ASSERT_NE(png_img.decoder(), nullptr);
-  ASSERT_EQ(png_img.decoder()->get_format(), BMP);
+  // Drive the format switch through begin_decode()'s format parameter, the way
+  // a dynamic-format producer (online_image MIME detection) does.
+  TestableRuntimeImage img(AUTO);
 
-  ASSERT_TRUE(decode_all(png_img, PNG_RGB, sizeof(PNG_RGB)));
-  EXPECT_EQ(png_img.decoder()->get_format(), PNG);
-  expect_pixels(png_img, PNG_RGB_EXPECTED);
+  ASSERT_TRUE(decode_all(img, BMP_24BPP, sizeof(BMP_24BPP), BMP));
+  ASSERT_NE(img.decoder(), nullptr);
+  ASSERT_EQ(img.decoder()->get_format(), BMP);
+  expect_pixels(img, BMP_24BPP_EXPECTED);
 
-  // And the other direction: BMP image holding a stale PNG decoder.
-  TestableRuntimeImage bmp_img(BMP);
-  bmp_img.plant_decoder(PNG);
-  ASSERT_NE(bmp_img.decoder(), nullptr);
-  ASSERT_EQ(bmp_img.decoder()->get_format(), PNG);
+  // Same explicit format again: the decoder must stay warm.
+  ImageDecoder *bmp_decoder = img.decoder();
+  ASSERT_TRUE(decode_all(img, BMP_8BPP, sizeof(BMP_8BPP), BMP));
+  expect_pixels(img, BMP_8BPP_EXPECTED);
+  EXPECT_EQ(img.decoder(), bmp_decoder);
 
-  ASSERT_TRUE(decode_all(bmp_img, BMP_24BPP, sizeof(BMP_24BPP)));
-  EXPECT_EQ(bmp_img.decoder()->get_format(), BMP);
-  expect_pixels(bmp_img, BMP_24BPP_EXPECTED);
+  // Different format: the stale decoder must be evicted and recreated.
+  ASSERT_TRUE(decode_all(img, PNG_RGB, sizeof(PNG_RGB), PNG));
+  EXPECT_EQ(img.decoder()->get_format(), PNG);
+  expect_pixels(img, PNG_RGB_EXPECTED);
+
+  // And back again.
+  ASSERT_TRUE(decode_all(img, BMP_24BPP, sizeof(BMP_24BPP), BMP));
+  EXPECT_EQ(img.decoder()->get_format(), BMP);
+  expect_pixels(img, BMP_24BPP_EXPECTED);
+}
+
+TEST(RuntimeImageDecoder, AutoFormatFallsBackToConfiguredAndKeepsDecoderWarm) {
+  // With a configured format, an AUTO begin_decode() must resolve to the
+  // configured format before the reuse check instead of evicting the decoder.
+  TestableRuntimeImage img(BMP);
+
+  ASSERT_TRUE(decode_all(img, BMP_24BPP, sizeof(BMP_24BPP), AUTO));
+  ImageDecoder *first = img.decoder();
+  ASSERT_NE(first, nullptr);
+  EXPECT_EQ(first->get_format(), BMP);
+
+  ASSERT_TRUE(decode_all(img, BMP_24BPP, sizeof(BMP_24BPP), AUTO));
+  expect_pixels(img, BMP_24BPP_EXPECTED);
+  EXPECT_EQ(img.decoder(), first) << "AUTO must not evict the configured-format decoder";
+}
+
+TEST(RuntimeImageDecoder, AutoWithoutConfiguredFormatFails) {
+  // Neither a configured format nor an explicit one: there is nothing to decode with.
+  TestableRuntimeImage img(AUTO);
+  EXPECT_FALSE(img.begin_decode(64));
 }
 
 TEST(RuntimeImageDecoder, ReleaseKeepsDecoderWarm) {

tests/integration/README.md

@@ -7,6 +7,7 @@ This directory contains end-to-end integration tests for ESPHome, focusing on te
 - `conftest.py` - Common fixtures and utilities
 - `const.py` - Constants used throughout the integration tests
 - `types.py` - Type definitions for fixtures and functions
+- `raw_api_client.py` - Minimal plaintext api client whose reads happen only on request (for backpressure tests)
 - `state_utils.py` - State handling utilities (e.g., `InitialStateHelper`, `find_entity`, `require_entity`)
 - `fixtures/` - YAML configuration files for tests
 - `test_*.py` - Individual test files
@@ -347,6 +348,7 @@ Create C++ components in `fixtures/external_components/` for:
 - Custom entity behaviors
 - Scheduler testing
 - Memory management tests
+- Deterministic network backpressure (`sndbuf_pin_component` pins socket send buffers; assert on its log line to prove the pin took effect)
 
 ##### Log Line Monitoring
 ```python

tests/integration/fixtures/api_list_entities_backpressure.yaml

@@ -0,0 +1,23 @@
+esphome:
+  name: api-backpressure-test
+
+host:
+
+api:
+  # Smallest queue so a non-draining client blocks the send path quickly
+  max_send_queue: 1
+  actions:
+# GENERATED_ACTIONS
+
+external_components:
+  - source:
+      type: local
+      path: EXTERNAL_COMPONENT_PATH
+    components: [sndbuf_pin_component]
+
+# Pins the device's socket send buffers for deterministic TCP backpressure
+sndbuf_pin_component:
+  buffer_size: SERVER_SNDBUF
+
+logger:
+  level: DEBUG

tests/integration/fixtures/external_components/sndbuf_pin_component/__init__.py

@@ -0,0 +1,20 @@
+import esphome.codegen as cg
+import esphome.config_validation as cv
+from esphome.const import CONF_BUFFER_SIZE, CONF_ID
+
+DEPENDENCIES = ["api"]
+
+sndbuf_pin_ns = cg.esphome_ns.namespace("sndbuf_pin")
+SndbufPinComponent = sndbuf_pin_ns.class_("SndbufPinComponent", cg.Component)
+
+CONFIG_SCHEMA = cv.Schema(
+    {
+        cv.GenerateID(): cv.declare_id(SndbufPinComponent),
+        cv.Required(CONF_BUFFER_SIZE): cv.int_range(min=1),
+    }
+).extend(cv.COMPONENT_SCHEMA)
+
+
+async def to_code(config):
+    var = cg.new_Pvariable(config[CONF_ID], config[CONF_BUFFER_SIZE])
+    await cg.register_component(var, config)

tests/integration/fixtures/external_components/sndbuf_pin_component/sndbuf_pin_component.cpp

@@ -0,0 +1,55 @@
+#include "sndbuf_pin_component.h"
+
+#include <netinet/in.h>
+#include <sys/socket.h>
+#include <cerrno>
+
+#include "esphome/components/api/api_server.h"
+#include "esphome/core/log.h"
+
+namespace esphome::sndbuf_pin {
+
+static const char *const TAG = "sndbuf_pin";
+
+// Skip stdio; scan the low fd range where the listeners land
+static constexpr int FIRST_USER_FD = 3;
+static constexpr int MAX_FD_SCAN = 128;
+
+void SndbufPinComponent::setup() {
+  int pinned = 0;
+  for (int fd = FIRST_USER_FD; fd < MAX_FD_SCAN; fd++) {
+    int type = 0;
+    socklen_t len = sizeof(type);
+    if (::getsockopt(fd, SOL_SOCKET, SO_TYPE, &type, &len) != 0 || type != SOCK_STREAM)
+      continue;
+    struct sockaddr_in addr {};
+    socklen_t addr_len = sizeof(addr);
+    if (::getsockname(fd, reinterpret_cast<struct sockaddr *>(&addr), &addr_len) != 0) {
+      ESP_LOGW(TAG, "fd %d: getsockname failed, errno %d", fd, errno);
+      continue;
+    }
+    if (ntohs(addr.sin_port) != api::global_api_server->get_port())
+      continue;
+    if (::setsockopt(fd, SOL_SOCKET, SO_SNDBUF, &this->buffer_size_, sizeof(this->buffer_size_)) != 0) {
+      ESP_LOGW(TAG, "fd %d: SO_SNDBUF pin failed, errno %d", fd, errno);
+      continue;
+    }
+    int applied = 0;
+    len = sizeof(applied);
+    if (::getsockopt(fd, SOL_SOCKET, SO_SNDBUF, &applied, &len) != 0 || applied < this->buffer_size_) {
+      // Linux doubles the requested value; anything below it means clamped
+      ESP_LOGW(TAG, "fd %d: SO_SNDBUF readback %d below requested %d", fd, applied, this->buffer_size_);
+      continue;
+    }
+    // Tests assert on this line; accepted sockets inherit the pinned size
+    ESP_LOGD(TAG, "fd %d port %d: SO_SNDBUF pinned to %d (effective %d)", fd, ntohs(addr.sin_port), this->buffer_size_,
+             applied);
+    pinned++;
+  }
+  if (pinned == 0) {
+    ESP_LOGE(TAG, "api listener socket was not pinned");
+    this->mark_failed();
+  }
+}
+
+}  // namespace esphome::sndbuf_pin

tests/integration/fixtures/external_components/sndbuf_pin_component/sndbuf_pin_component.h

@@ -0,0 +1,21 @@
+#pragma once
+
+#include "esphome/core/component.h"
+
+namespace esphome::sndbuf_pin {
+
+// Test-only (host): pins SO_SNDBUF on every open TCP socket so integration
+// tests get deterministic backpressure; an explicit SO_SNDBUF also disables
+// kernel autotuning, and accepted sockets inherit it from the listener.
+class SndbufPinComponent : public Component {
+ public:
+  explicit SndbufPinComponent(int buffer_size) : buffer_size_(buffer_size) {}
+  void setup() override;
+  // After the api server so its listening socket exists
+  float get_setup_priority() const override { return setup_priority::LATE; }
+
+ protected:
+  int buffer_size_;
+};
+
+}  // namespace esphome::sndbuf_pin

tests/integration/fixtures/online_image_auto_detects_image_bmp_mime.yaml

@@ -0,0 +1,28 @@
+esphome:
+  name: online-image-bmp
+
+host:
+
+http_request:
+
+display:
+
+image:
+  - platform: online_image
+    url: http://127.0.0.1:HTTP_PORT/foo.bmp
+    format: AUTO
+    id: myimg
+    type: RGB
+    on_download_finished:
+      logger.log:
+        format: "download finished. cache hit: %u"
+        args: [cached]
+
+api:
+  actions:
+    - action: fetch_image
+      then:
+        - component.update: myimg
+
+logger:
+  level: DEBUG

tests/integration/fixtures/online_image_auto_detects_redirected_image_bmp_mime.yaml

@@ -0,0 +1,28 @@
+esphome:
+  name: online-image-bmp
+
+host:
+
+http_request:
+
+display:
+
+image:
+  - platform: online_image
+    url: http://127.0.0.1:HTTP_PORT/foo.bmp
+    id: myimg
+    format: AUTO
+    type: RGB
+    on_download_finished:
+      logger.log:
+        format: "download finished. cache hit: %u"
+        args: [cached]
+
+api:
+  actions:
+    - action: fetch_image
+      then:
+        - component.update: myimg
+
+logger:
+  level: DEBUG

tests/integration/fixtures/online_image_bmp.yaml

@@ -7,8 +7,9 @@ http_request:
 
 display:
 
-online_image:
-  - url: http://127.0.0.1:HTTP_PORT/foo.bmp
+image:
+  - platform: online_image
+    url: http://127.0.0.1:HTTP_PORT/foo.bmp
     id: myimg
     format: BMP
     type: RGB

tests/integration/online_image_utils.py

@@ -0,0 +1,158 @@
+"""Shared fixture server and log helpers for the online_image integration tests."""
+
+from __future__ import annotations
+
+import asyncio
+from collections.abc import Callable
+import re
+
+# black 8x8 RGB BMP, generated with
+#   from PIL import Image
+#   from io import BytesIO
+#   b = BytesIO()
+#   img = Image.new("RGB", (8, 8))
+#   img.save(b, format="BMP")
+#   b.getvalue()
+BMP_IMAGE = b"BM\xf6\x00\x00\x00\x00\x00\x00\x006\x00\x00\x00(\x00\x00\x00\x08\x00\x00\x00\x08\x00\x00\x00\x01\x00\x18\x00\x00\x00\x00\x00\xc0\x00\x00\x00\xc4\x0e\x00\x00\xc4\x0e\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
+LEN_BMP_IMAGE = len(BMP_IMAGE)
+
+
+async def wait_for_download(
+    downloaded_bytes_future: asyncio.Future,
+    server_error_future: asyncio.Future,
+) -> int:
+    """Await the downloaded byte count, raising a server handler error first."""
+    await asyncio.wait(
+        {downloaded_bytes_future, server_error_future},
+        return_when=asyncio.FIRST_COMPLETED,
+    )
+    if server_error_future.done() and (exc := server_error_future.exception()):
+        raise exc
+    # Retrieve a late teardown error so asyncio does not log it at GC
+    server_error_future.add_done_callback(lambda f: f.exception())
+    return downloaded_bytes_future.result()
+
+
+def make_download_watcher(
+    downloaded_bytes_future: asyncio.Future,
+    download_finished_future: asyncio.Future,
+) -> Callable[[str], None]:
+    """Build a line callback resolving the futures from the device log."""
+
+    def check_output(line: str) -> None:
+        if (
+            match := re.search(r"Image fully downloaded, (\d+) bytes", line)
+        ) and not downloaded_bytes_future.done():
+            downloaded_bytes_future.set_result(int(match.group(1)))
+        if "download finished" in line and not download_finished_future.done():
+            download_finished_future.set_result(True)
+
+    return check_output
+
+
+def handle_http(
+    http_request_future,
+    content_type: str = "text/plain",
+    *,
+    request_path: str = "/foo.bmp",
+    request_line_consumed: bool = False,
+    server_error_future: asyncio.Future | None = None,
+):
+    async def handler(reader, writer):
+        try:
+            # Only read the request line if it hasn't been consumed by a caller
+            if not request_line_consumed:
+                async with asyncio.timeout(1.0):
+                    data = await reader.readuntil(b"\r\n")
+
+                expected_request = f"GET {request_path} HTTP/1.1\r\n".encode()
+                assert data[: len(expected_request)] == expected_request
+
+            async with asyncio.timeout(1.0):
+                await reader.readuntil(b"\r\n\r\n")
+
+            if not http_request_future.done():
+                http_request_future.set_result(True)
+
+            http_response = [
+                b"HTTP/1.1 200 OK",
+                b"Content-Length: %d" % LEN_BMP_IMAGE,
+                f"Content-Type: {content_type}".encode(),
+                b"Connection: close",
+                b"",
+                b"",
+            ]
+            writer.write(b"\r\n".join(http_response))
+            await writer.drain()
+
+            writer.write(BMP_IMAGE)
+
+            await writer.drain()
+        except Exception as exc:
+            if server_error_future is not None and not server_error_future.done():
+                server_error_future.set_exception(exc)
+            if not http_request_future.done():
+                http_request_future.set_exception(exc)
+            raise
+        finally:
+            writer.close()
+
+    return handler
+
+
+def handle_http_redirect(
+    http_request_future, final_request_future, server_error_future, port_holder
+):
+    async def handler(reader, writer):
+        try:
+            async with asyncio.timeout(1.0):
+                request = await reader.readuntil(b"\r\n")
+
+            if (
+                request[: len(b"GET /foo.bmp HTTP/1.1\r\n")]
+                == b"GET /foo.bmp HTTP/1.1\r\n"
+            ):
+                if not http_request_future.done():
+                    http_request_future.set_result(True)
+                async with asyncio.timeout(1.0):
+                    await reader.readuntil(b"\r\n\r\n")
+
+                http_response = [
+                    b"HTTP/1.1 302 Found",
+                    f"Location: http://127.0.0.1:{port_holder['port']}/final.bmp".encode(),
+                    b"Content-Type: text/html",
+                    b"Content-Length: 0",
+                    b"Connection: close",
+                    b"",
+                    b"",
+                ]
+                writer.write(b"\r\n".join(http_response))
+                await writer.drain()
+                return
+
+            assert (
+                request[: len(b"GET /final.bmp HTTP/1.1\r\n")]
+                == b"GET /final.bmp HTTP/1.1\r\n"
+            )
+            if not final_request_future.done():
+                final_request_future.set_result(True)
+            await handle_http(
+                final_request_future,
+                "image/bmp",
+                request_path="/final.bmp",
+                request_line_consumed=True,
+                server_error_future=server_error_future,
+            )(reader, writer)
+        except Exception as exc:
+            # Route handler failures to the dedicated error future so they're not silently lost
+            if not server_error_future.done():
+                server_error_future.set_exception(exc)
+            if not http_request_future.done():
+                http_request_future.set_exception(exc)
+            if not final_request_future.done():
+                final_request_future.set_exception(exc)
+            raise
+        finally:
+            writer.close()
+
+    return handler

tests/integration/raw_api_client.py

@@ -0,0 +1,148 @@
+"""Minimal plaintext native-api client over a raw socket.
+
+Reads only when told to, so tests control when the TCP pipe backs up toward
+the device; payloads are skipped and only message types are counted.
+"""
+
+from __future__ import annotations
+
+import asyncio
+from collections import Counter
+import socket
+from typing import Self
+
+from aioesphomeapi import api_pb2
+import aioesphomeapi.core as api_core
+from google.protobuf import message
+
+from .const import LOCALHOST
+
+# Message type ids are protocol constants; derive them from aioesphomeapi so
+# they cannot drift from the client library in use.
+MESSAGE_TYPE_OF = {cls: num for num, cls in api_core.MESSAGE_TYPE_TO_PROTO.items()}
+
+_READ_CHUNK = 4096
+
+
+def encode_varint(value: int) -> bytes:
+    out = bytearray()
+    while True:
+        byte = value & 0x7F
+        value >>= 7
+        if value:
+            out.append(byte | 0x80)
+        else:
+            out.append(byte)
+            return bytes(out)
+
+
+def decode_varint(buf: bytearray, pos: int) -> tuple[int, int] | None:
+    """Decode one varint at pos; return (value, new_pos) or None if short."""
+    value = shift = 0
+    while pos < len(buf):
+        byte = buf[pos]
+        pos += 1
+        value |= (byte & 0x7F) << shift
+        if not byte & 0x80:
+            return value, pos
+        shift += 7
+    return None
+
+
+def encode_frame(msg_type: int, payload: bytes) -> bytes:
+    """Encode one plaintext api frame: 0x00, payload length, message type."""
+    return b"\x00" + encode_varint(len(payload)) + encode_varint(msg_type) + payload
+
+
+class FrameParser:
+    """Incremental parser for the plaintext api frame stream."""
+
+    def __init__(self) -> None:
+        self._buf = bytearray()
+
+    def feed(self, data: bytes) -> list[int]:
+        self._buf.extend(data)
+        types: list[int] = []
+        while (msg_type := self._try_parse()) is not None:
+            types.append(msg_type)
+        return types
+
+    def _try_parse(self) -> int | None:
+        buf = self._buf
+        if not buf:
+            return None
+        assert buf[0] == 0, f"expected plaintext frame, got indicator {buf[0]}"
+        if (size_decoded := decode_varint(buf, 1)) is None:
+            return None
+        size, pos = size_decoded
+        if (type_decoded := decode_varint(buf, pos)) is None:
+            return None
+        msg_type, pos = type_decoded
+        if len(buf) - pos < size:
+            return None
+        del buf[: pos + size]
+        return msg_type
+
+
+class RawApiClient:
+    """Plaintext api client whose reads happen only on request."""
+
+    def __init__(self, port: int, recv_buffer_size: int | None = None) -> None:
+        self._port = port
+        self._parser = FrameParser()
+        self.bytes_received = 0
+        self.frame_counts: Counter[int] = Counter()
+        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
+        try:
+            if recv_buffer_size is not None:
+                sock.setsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF, recv_buffer_size)
+                # Kernels may round up (Linux doubles) but must not clamp below
+                applied = sock.getsockopt(socket.SOL_SOCKET, socket.SO_RCVBUF)
+                assert applied >= recv_buffer_size, (
+                    f"SO_RCVBUF clamped to {applied}, requested {recv_buffer_size}"
+                )
+            sock.setblocking(False)
+        except Exception:
+            sock.close()
+            raise
+        self._sock = sock
+
+    async def __aenter__(self) -> Self:
+        return self
+
+    async def __aexit__(self, *exc_info: object) -> None:
+        self.close()
+
+    async def connect(self, client_info: str = "raw-api-client") -> None:
+        """Connect and complete the Hello handshake (no auth step since 2026.1.0)."""
+        loop = asyncio.get_running_loop()
+        await loop.sock_connect(self._sock, (LOCALHOST, self._port))
+        hello = api_pb2.HelloRequest()
+        hello.client_info = client_info
+        hello.api_version_major = 1
+        hello.api_version_minor = 10
+        await self.send_message(hello)
+        await self.read_until_frame(MESSAGE_TYPE_OF[api_pb2.HelloResponse])
+
+    async def send_message(self, msg: message.Message) -> None:
+        loop = asyncio.get_running_loop()
+        await loop.sock_sendall(
+            self._sock,
+            encode_frame(MESSAGE_TYPE_OF[type(msg)], msg.SerializeToString()),
+        )
+
+    async def read_until_frame(self, msg_type: int, timeout: float = 10.0) -> None:
+        """Read until at least one frame of msg_type has been received."""
+        loop = asyncio.get_running_loop()
+
+        async def _read_loop() -> None:
+            while not self.frame_counts[msg_type]:
+                data = await loop.sock_recv(self._sock, _READ_CHUNK)
+                assert data, "server closed the connection unexpectedly"
+                self.bytes_received += len(data)
+                self.frame_counts.update(self._parser.feed(data))
+
+        await asyncio.wait_for(_read_loop(), timeout)
+
+    def close(self) -> None:
+        self._sock.close()

tests/integration/test_api_list_entities_backpressure.py

@@ -0,0 +1,110 @@
+"""A client that stops reading the entity listing must not starve other clients.
+
+Service responses are sent directly (not via the deferred batch), so a full
+TCP pipe makes the send path refuse; the drive loop now lives in
+try_advance(), which stops on refusal instead of retrying forever. Not a
+before/after regression test: pre-fix builds survive here because the
+refusal path yields and pumps the socket each retry.
+
+The sndbuf_pin_component fixture pins the device's send buffers so the pipe
+fills deterministically regardless of kernel autotuning; the test waits for
+its log line before proceeding.
+"""
+
+from __future__ import annotations
+
+import asyncio
+
+from aioesphomeapi import api_pb2
+import pytest
+
+from .raw_api_client import MESSAGE_TYPE_OF, RawApiClient
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+SERVICES_RESPONSE = MESSAGE_TYPE_OF[api_pb2.ListEntitiesServicesResponse]
+LIST_DONE_RESPONSE = MESSAGE_TYPE_OF[api_pb2.ListEntitiesDoneResponse]
+
+# Both ends of the pipe are pinned small; only tens of KB fit in the kernel
+RECV_BUFFER_SIZE = 4096
+SERVER_SNDBUF = 8192  # substituted into the fixture yaml
+# Logged by the sndbuf_pin_component fixture when it pins a socket
+SNDBUF_PIN_LOG = "SO_SNDBUF pinned to"
+# One response (~6.4 KB) must stay smaller than the pinned send buffer; an
+# oversized message parks in the overflow buffer and reports as sent.
+ARGS_PER_SERVICE = 8
+ARG_NAME_LEN = 800
+# ~160 KB listing versus a tens-of-KB pipe guarantees a mid-services block
+NUM_SERVICES = 25
+assert ARGS_PER_SERVICE * ARG_NAME_LEN < SERVER_SNDBUF
+# The pipe fills in well under a second
+STALL_SECONDS = 0.5
+# Well above pipe capacity, well below the listing size
+MIN_DRAINED_BYTES = 60_000
+
+
+def _generated_actions() -> str:
+    """Build the api actions block: services with long argument names."""
+    lines: list[str] = []
+    for i in range(NUM_SERVICES):
+        lines.append(f"    - action: backpressure_service_{i:04d}")
+        lines.append("      variables:")
+        for j in range(ARGS_PER_SERVICE):
+            prefix = f"arg_{i:04d}_{j:02d}_"
+            lines.append(
+                f"        {prefix}{'x' * (ARG_NAME_LEN - len(prefix))}: string"
+            )
+        lines.append("      then:")
+        lines.append("        - logger.log: service called")
+    return "\n".join(lines)
+
+
+@pytest.mark.asyncio
+async def test_api_list_entities_backpressure(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+    unused_tcp_port: int,
+) -> None:
+    """A stalled reader mid-services must not block other api clients."""
+    assert "# GENERATED_ACTIONS" in yaml_config
+    config = yaml_config.replace("# GENERATED_ACTIONS", _generated_actions())
+    config = config.replace("SERVER_SNDBUF", str(SERVER_SNDBUF))
+
+    pin_applied = asyncio.Event()
+
+    def _on_log_line(line: str) -> None:
+        if SNDBUF_PIN_LOG in line:
+            pin_applied.set()
+
+    async with run_compiled(config, line_callback=_on_log_line):
+        # Fails loudly if the pin never applied
+        await asyncio.wait_for(pin_applied.wait(), 10)
+
+        async with RawApiClient(
+            unused_tcp_port, recv_buffer_size=RECV_BUFFER_SIZE
+        ) as stalled:
+            await stalled.connect(client_info="backpressure-stall-client")
+            await stalled.send_message(api_pb2.ListEntitiesRequest())
+            # The client now stops reading entirely.
+
+            # Let the server run against the full pipe
+            await asyncio.sleep(STALL_SECONDS)
+
+            # Other clients must still be served while the first is blocked
+            async with api_client_connected(timeout=20) as client:
+                device_info = await asyncio.wait_for(client.device_info(), 20)
+                assert device_info.name == "api-backpressure-test"
+                _, services = await asyncio.wait_for(
+                    client.list_entities_services(), 30
+                )
+                assert len(services) == NUM_SERVICES
+
+            # Fixture-size guard: the listing must dwarf the pinned pipe
+            before = stalled.bytes_received
+            await stalled.read_until_frame(LIST_DONE_RESPONSE, timeout=60)
+            drained = stalled.bytes_received - before
+            assert drained > MIN_DRAINED_BYTES, (
+                f"only {drained} bytes drained; the listing never backed up"
+            )
+            assert stalled.frame_counts[SERVICES_RESPONSE] == NUM_SERVICES
+            assert stalled.frame_counts[LIST_DONE_RESPONSE] == 1

tests/integration/test_online_image_auto_detects_image_bmp_mime.py

@@ -0,0 +1,71 @@
+"""Test that online_image AUTO format detection reads the Content-Type header."""
+
+from __future__ import annotations
+
+import asyncio
+
+import pytest
+
+from .online_image_utils import (
+    LEN_BMP_IMAGE,
+    handle_http,
+    make_download_watcher,
+    wait_for_download,
+)
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_online_image_auto_detects_image_bmp_mime(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """AUTO format detection should honor the final response MIME type without explicit format."""
+    loop = asyncio.get_running_loop()
+    http_request_future = loop.create_future()
+    server_error_future = loop.create_future()
+    download_finished_future = loop.create_future()
+    downloaded_bytes_future = loop.create_future()
+
+    check_output = make_download_watcher(
+        downloaded_bytes_future, download_finished_future
+    )
+
+    server = await asyncio.start_server(
+        handle_http(
+            http_request_future,
+            "image/bmp",
+            server_error_future=server_error_future,
+        ),
+        "127.0.0.1",
+        0,
+    )
+    http_server_port = server.sockets[0].getsockname()[1]
+
+    config = yaml_config.replace("HTTP_PORT", str(http_server_port))
+
+    async with (
+        server,
+        run_compiled(config, line_callback=check_output),
+        api_client_connected() as client,
+    ):
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == "online-image-bmp"
+
+        _, services = await client.list_entities_services()
+        request_service = next((s for s in services if s.name == "fetch_image"), None)
+        assert request_service is not None
+
+        await client.execute_service(request_service, {})
+
+        async with asyncio.timeout(0.1):
+            await http_request_future
+
+        async with asyncio.timeout(0.5):
+            numbytes = await wait_for_download(
+                downloaded_bytes_future, server_error_future
+            )
+            assert numbytes == LEN_BMP_IMAGE
+            await download_finished_future

tests/integration/test_online_image_auto_detects_redirected_image_bmp_mime.py

@@ -0,0 +1,71 @@
+"""Test that AUTO format detection uses the final Content-Type after redirects."""
+
+from __future__ import annotations
+
+import asyncio
+
+import pytest
+
+from .online_image_utils import (
+    LEN_BMP_IMAGE,
+    handle_http_redirect,
+    make_download_watcher,
+    wait_for_download,
+)
+from .types import APIClientConnectedFactory, RunCompiledFunction
+
+
+@pytest.mark.asyncio
+async def test_online_image_auto_detects_redirected_image_bmp_mime(
+    yaml_config: str,
+    run_compiled: RunCompiledFunction,
+    api_client_connected: APIClientConnectedFactory,
+) -> None:
+    """Redirect hops should not leave the 302 HTML Content-Type in place for the final image."""
+    loop = asyncio.get_running_loop()
+    http_request_future = loop.create_future()
+    final_request_future = loop.create_future()
+    server_error_future = loop.create_future()
+    download_finished_future = loop.create_future()
+    downloaded_bytes_future = loop.create_future()
+
+    check_output = make_download_watcher(
+        downloaded_bytes_future, download_finished_future
+    )
+
+    port_holder = {}
+    server = await asyncio.start_server(
+        handle_http_redirect(
+            http_request_future, final_request_future, server_error_future, port_holder
+        ),
+        "127.0.0.1",
+        0,
+    )
+    port_holder["port"] = server.sockets[0].getsockname()[1]
+
+    config = yaml_config.replace("HTTP_PORT", str(port_holder["port"]))
+
+    async with (
+        server,
+        run_compiled(config, line_callback=check_output),
+        api_client_connected() as client,
+    ):
+        device_info = await client.device_info()
+        assert device_info is not None
+        assert device_info.name == "online-image-bmp"
+
+        _, services = await client.list_entities_services()
+        request_service = next((s for s in services if s.name == "fetch_image"), None)
+        assert request_service is not None
+
+        await client.execute_service(request_service, {})
+
+        async with asyncio.timeout(0.1):
+            await http_request_future
+        async with asyncio.timeout(0.5):
+            await final_request_future
+            numbytes = await wait_for_download(
+                downloaded_bytes_future, server_error_future
+            )
+            assert numbytes == LEN_BMP_IMAGE
+            await download_finished_future

tests/integration/test_online_image_bmp.py

@@ -1,62 +1,12 @@
 from __future__ import annotations
 
 import asyncio
-import re
 
 import pytest
 
+from .online_image_utils import LEN_BMP_IMAGE, handle_http, make_download_watcher
 from .types import APIClientConnectedFactory, RunCompiledFunction
 
-# black 8x8 RGB BMP, generated with
-#   from PIL import Image
-#   from io import BytesIO
-#   b = BytesIO()
-#   img = Image.new("RGB", (8, 8))
-#   img.save(b, format="BMP")
-#   b.getvalue()
-BMP_IMAGE = b"BM\xf6\x00\x00\x00\x00\x00\x00\x006\x00\x00\x00(\x00\x00\x00\x08\x00\x00\x00\x08\x00\x00\x00\x01\x00\x18\x00\x00\x00\x00\x00\xc0\x00\x00\x00\xc4\x0e\x00\x00\xc4\x0e\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00\x00"
-LEN_BMP_IMAGE = len(BMP_IMAGE)
-
-
-def handle_http(http_request_future):
-    async def handler(reader, writer):
-        try:
-            async with asyncio.timeout(1.0):
-                data = await reader.readuntil(b"\r\n")
-
-            # ensure our request matches the expectation
-            expected_request = b"GET /foo.bmp HTTP/1.1\r\n"
-            assert data[: len(expected_request)] == expected_request
-
-            # consume rest of request
-            async with asyncio.timeout(1.0):
-                data = await reader.readuntil(b"\r\n\r\n")
-
-            http_request_future.set_result(True)
-
-            http_response = [
-                b"HTTP/1.1 200 OK",
-                b"Content-Length: %d" % LEN_BMP_IMAGE,
-                b"Content-Type: text/plain",
-                b"Connection: close",
-                b"",
-                b"",
-            ]
-            writer.write(b"\r\n".join(http_response))
-            await writer.drain()
-
-            writer.write(BMP_IMAGE)
-
-            await writer.drain()
-        except Exception as exc:
-            if not http_request_future.done():
-                http_request_future.set_exception(exc)
-            raise
-        finally:
-            writer.close()
-
-    return handler
-
 
 @pytest.mark.asyncio
 async def test_online_image_bmp(
@@ -72,14 +22,9 @@ async def test_online_image_bmp(
     download_finished_future = loop.create_future()
     downloaded_bytes_future = loop.create_future()
 
-    def check_output(line: str) -> None:
-        """Check log output for expected messages."""
-
-        if match := re.search(r"Image fully downloaded, (\d+) bytes", line):
-            downloaded_bytes_future.set_result(int(match.group(1)))
-
-        if "download finished" in line:
-            download_finished_future.set_result(True)
+    check_output = make_download_watcher(
+        downloaded_bytes_future, download_finished_future
+    )
 
     server = await asyncio.start_server(
         handle_http(http_request_future), "127.0.0.1", 0

tests/unit_tests/test_external_files.py

@@ -4,7 +4,7 @@ import os
 from pathlib import Path
 import time
 from typing import Any
-from unittest.mock import MagicMock, patch
+from unittest.mock import MagicMock, call, patch
 
 import pytest
 import requests
@@ -81,6 +81,15 @@ def mock_download_content_many() -> MagicMock:
         yield m
 
 
+@pytest.fixture
+def mock_retry_sleep() -> MagicMock:
+    """Patch the retry backoff sleep (process-wide; net_retry.time is the
+    global module) so transient-error tests don't really wait 2s/4s.
+    """
+    with patch("esphome.net_retry.time.sleep") as m:
+        yield m
+
+
 def test_compute_local_file_dir(setup_core: Path) -> None:
     """Test compute_local_file_dir creates and returns correct path."""
     domain = "font"
@@ -495,6 +504,7 @@ class _BodyReadErrorResponse:
 def test_download_content_with_body_read_error_uses_cache(
     mock_has_remote_file_changed: MagicMock,
     mock_requests_get: MagicMock,
+    mock_retry_sleep: MagicMock,
     setup_core: Path,
 ) -> None:
     """Body-read errors (chunked-decode/gzip-decode/mid-stream connection
@@ -519,6 +529,7 @@ def test_download_content_with_body_read_error_uses_cache(
 def test_download_content_with_body_read_error_no_cache_fails(
     mock_has_remote_file_changed: MagicMock,
     mock_requests_get: MagicMock,
+    mock_retry_sleep: MagicMock,
     setup_core: Path,
 ) -> None:
     """A body-read failure with no cache available must surface as a
@@ -535,6 +546,131 @@ def test_download_content_with_body_read_error_no_cache_fails(
         external_files.download_content("https://example.com/file.txt", test_file)
 
 
+def test_download_content_retries_transient_error_then_succeeds(
+    mock_has_remote_file_changed: MagicMock,
+    mock_requests_get: MagicMock,
+    mock_retry_sleep: MagicMock,
+    setup_core: Path,
+) -> None:
+    """Transient failures (connection reset, timeout) are retried with 2s/4s
+    backoff before giving up; a late success downloads normally."""
+    test_file = setup_core / "downloads" / "file.txt"
+    mock_has_remote_file_changed.return_value = True
+
+    ok = MagicMock()
+    ok.content = b"downloaded"
+    ok.headers = {}
+    mock_requests_get.side_effect = [
+        requests.exceptions.ConnectionError("reset by peer"),
+        requests.exceptions.Timeout("timed out"),
+        ok,
+    ]
+
+    result = external_files.download_content("https://example.com/file.txt", test_file)
+
+    assert result == b"downloaded"
+    assert test_file.read_bytes() == b"downloaded"
+    assert mock_retry_sleep.call_args_list == [call(2), call(4)]
+
+
+def test_download_content_transient_error_exhausts_attempts(
+    mock_has_remote_file_changed: MagicMock,
+    mock_requests_get: MagicMock,
+    mock_retry_sleep: MagicMock,
+    setup_core: Path,
+) -> None:
+    """A persistent transient failure gives up after three attempts and then
+    follows the normal no-cache error path."""
+    test_file = setup_core / "nonexistent.txt"
+    mock_has_remote_file_changed.return_value = True
+    mock_requests_get.side_effect = requests.exceptions.ConnectionError("reset by peer")
+
+    with pytest.raises(Invalid, match="Could not download from.*reset by peer"):
+        external_files.download_content("https://example.com/file.txt", test_file)
+
+    assert mock_retry_sleep.call_args_list == [call(2), call(4)]
+
+
+def test_download_content_non_transient_error_not_retried(
+    mock_has_remote_file_changed: MagicMock,
+    mock_requests_get: MagicMock,
+    mock_retry_sleep: MagicMock,
+    setup_core: Path,
+) -> None:
+    """Permanent failures like a 404 fail on the first attempt."""
+    test_file = setup_core / "nonexistent.txt"
+    mock_has_remote_file_changed.return_value = True
+
+    response = MagicMock()
+    response.status_code = 404
+    mock_requests_get.side_effect = requests.exceptions.HTTPError(
+        "404 Client Error", response=response
+    )
+
+    with pytest.raises(Invalid, match="Could not download from.*404"):
+        external_files.download_content("https://example.com/file.txt", test_file)
+
+    assert mock_requests_get.call_count == 1
+    mock_retry_sleep.assert_not_called()
+
+
+def test_download_content_retries_body_read_error(
+    mock_has_remote_file_changed: MagicMock,
+    mock_requests_get: MagicMock,
+    mock_retry_sleep: MagicMock,
+    setup_core: Path,
+) -> None:
+    """Mid-stream failures surfacing from `.content` are retried too."""
+    test_file = setup_core / "downloads" / "file.txt"
+    mock_has_remote_file_changed.return_value = True
+
+    ok = MagicMock()
+    ok.content = b"downloaded"
+    ok.headers = {}
+    mock_requests_get.side_effect = [
+        _BodyReadErrorResponse(
+            requests.exceptions.ChunkedEncodingError("body truncated")
+        ),
+        ok,
+    ]
+
+    result = external_files.download_content("https://example.com/file.txt", test_file)
+
+    assert result == b"downloaded"
+    assert mock_requests_get.call_count == 2
+    assert mock_retry_sleep.call_args_list == [call(2)]
+
+
+def test_has_remote_file_changed_retries_transient_error(
+    mock_requests_head: MagicMock,
+    mock_retry_sleep: MagicMock,
+    setup_core: Path,
+    caplog: pytest.LogCaptureFixture,
+) -> None:
+    """A HEAD revalidation that fails transiently then returns 304 does not
+    mark the cached copy stale, and the retry warning names the operation."""
+    test_file = setup_core / "cached.txt"
+    test_file.write_bytes(b"cached content")
+
+    ok = MagicMock()
+    ok.status_code = 304
+    ok.headers = {}
+    mock_requests_head.side_effect = [
+        requests.exceptions.ConnectionError("reset by peer"),
+        ok,
+    ]
+
+    changed = external_files.has_remote_file_changed(
+        "https://example.com/file.txt", test_file
+    )
+
+    assert changed is False
+    assert test_file not in external_files._run_data().stale_paths
+    assert mock_requests_head.call_count == 2
+    assert mock_retry_sleep.call_args_list == [call(2)]
+    assert "Revalidation of" in caplog.text
+
+
 def test_download_content_skip_external_update_uses_cache(
     mock_has_remote_file_changed: MagicMock,
     mock_requests_get: MagicMock,

tests/unit_tests/test_framework_helpers.py

@@ -26,7 +26,6 @@ from esphome.framework_helpers import (
     _7z_extract_all,
     _BatchDownloadProgress,
     _detect_archive_root,
-    _is_transient_download_error,
     _rename_with_retry,
     _tar_extract_all,
     _zip_extract_all,
@@ -1849,43 +1848,6 @@ class TestDownloadFromMirrors:
         mock_sleep.assert_not_called()
 
 
-def _http_error(status: int) -> req.HTTPError:
-    """An HTTPError carrying a response with the given status, as raised by
-    ``raise_for_status`` on a real response."""
-    resp = MagicMock()
-    resp.status_code = status
-    return req.HTTPError(str(status), response=resp)
-
-
-class TestIsTransientDownloadError:
-    def test_connection_errors_are_transient(self) -> None:
-        assert _is_transient_download_error(req.ConnectionError("reset"))
-        assert _is_transient_download_error(req.Timeout("timed out"))
-        assert _is_transient_download_error(
-            req.exceptions.ChunkedEncodingError("dropped")
-        )
-
-    def test_http_statuses(self) -> None:
-        assert not _is_transient_download_error(_http_error(404))
-        assert not _is_transient_download_error(_http_error(403))
-        assert _is_transient_download_error(_http_error(429))
-        assert _is_transient_download_error(_http_error(503))
-
-    def test_http_error_without_response_is_permanent(self) -> None:
-        assert not _is_transient_download_error(req.HTTPError("boom"))
-
-    def test_exhausted_resume_attempts_are_permanent(self) -> None:
-        """download_with_resume already spent its own resume attempts; its
-        EsphomeError wrapper is not retried again at the sweep level."""
-        wrapped = EsphomeError("Failed to download after 3 attempts")
-        wrapped.__cause__ = req.ConnectionError("down")
-        assert not _is_transient_download_error(wrapped)
-
-    def test_unrelated_errors_are_permanent(self) -> None:
-        assert not _is_transient_download_error(OSError("disk full"))
-        assert not _is_transient_download_error(EsphomeError("size mismatch"))
-
-
 def test_importing_framework_helpers_does_not_import_requests() -> None:
     """Importing framework_helpers must not drag in requests.
 

tests/unit_tests/test_net_retry.py

@@ -0,0 +1,143 @@
+"""Tests for esphome.net_retry."""
+
+import socket
+from unittest.mock import MagicMock, call, patch
+
+import pytest
+import requests as req
+
+from esphome.core import EsphomeError
+from esphome.net_retry import fetch_with_retry, is_transient_download_error
+
+
+def _http_error(status: int) -> req.HTTPError:
+    """An HTTPError carrying a response with the given status, as raised by
+    ``raise_for_status`` on a real response."""
+    resp = MagicMock()
+    resp.status_code = status
+    return req.HTTPError(str(status), response=resp)
+
+
+class TestIsTransientDownloadError:
+    def test_connection_errors_are_transient(self) -> None:
+        assert is_transient_download_error(req.ConnectionError("reset"))
+        assert is_transient_download_error(req.Timeout("timed out"))
+        assert is_transient_download_error(
+            req.exceptions.ChunkedEncodingError("dropped")
+        )
+        assert is_transient_download_error(
+            req.exceptions.ContentDecodingError("gzip stream truncated")
+        )
+
+    def test_http_statuses(self) -> None:
+        assert not is_transient_download_error(_http_error(404))
+        assert not is_transient_download_error(_http_error(403))
+        assert is_transient_download_error(_http_error(429))
+        assert is_transient_download_error(_http_error(503))
+
+    def test_http_error_without_response_is_permanent(self) -> None:
+        assert not is_transient_download_error(req.HTTPError("boom"))
+
+    def test_hard_dns_failures_are_permanent(self) -> None:
+        """Hard resolution failures are permanent via both the cause chain
+        and MaxRetryError.reason."""
+        from urllib3.exceptions import MaxRetryError, NameResolutionError
+
+        gai = socket.gaierror(socket.EAI_NONAME, "nodename nor servname provided")
+
+        chained = req.ConnectionError("resolution failed")
+        chained.__cause__ = gai
+        assert not is_transient_download_error(chained)
+
+        # The real urllib3 shape: gaierror on NameResolutionError.__cause__,
+        # carried by MaxRetryError.reason.
+        try:
+            raise NameResolutionError("example.invalid", None, gai) from gai
+        except NameResolutionError as nre:
+            wrapped = req.ConnectionError(
+                MaxRetryError(None, "http://example.invalid/", reason=nre)
+            )
+        assert not is_transient_download_error(wrapped)
+
+        # A garden-variety connection reset stays transient.
+        assert is_transient_download_error(req.ConnectionError("reset by peer"))
+
+    def test_temporary_dns_failure_stays_transient(self) -> None:
+        """EAI_AGAIN (flaky resolver) stays retryable."""
+        gai = socket.gaierror(socket.EAI_AGAIN, "temporary failure in name resolution")
+        chained = req.ConnectionError("resolution failed")
+        chained.__cause__ = gai
+
+        assert is_transient_download_error(chained)
+
+    def test_implicit_context_does_not_reclassify(self) -> None:
+        """A gaierror riding along as implicit __context__ must not turn a
+        genuine connection reset permanent."""
+        try:
+            try:
+                raise socket.gaierror(socket.EAI_NONAME, "first attempt")
+            except socket.gaierror:
+                raise req.ConnectionError("reset by peer") from None
+        except req.ConnectionError as reset:
+            assert reset.__context__ is not None
+            assert is_transient_download_error(reset)
+
+    def test_gaierror_without_errno_stays_transient(self) -> None:
+        """A gaierror carrying no EAI code cannot prove a hard failure."""
+        chained = req.ConnectionError("resolution failed")
+        chained.__cause__ = socket.gaierror("no errno")
+
+        assert is_transient_download_error(chained)
+
+    def test_mixed_chain_hard_failure_wins(self) -> None:
+        """EAI_AGAIN in the chain does not mask a hard failure elsewhere."""
+        again = socket.gaierror(socket.EAI_AGAIN, "temporary failure")
+        hard = socket.gaierror(socket.EAI_NONAME, "unknown host")
+
+        outer = req.ConnectionError(hard)
+        outer.__cause__ = again
+        assert not is_transient_download_error(outer)
+
+        outer = req.ConnectionError(again)
+        outer.__cause__ = hard
+        assert not is_transient_download_error(outer)
+
+    def test_dns_walk_survives_exception_cycles(self) -> None:
+        """A cyclic cause chain must terminate (and stay transient when no
+        resolution failure is present)."""
+        outer = req.ConnectionError("a")
+        inner = ValueError("b")
+        outer.__cause__ = inner
+        inner.__cause__ = outer
+
+        assert is_transient_download_error(outer)
+
+    def test_exhausted_resume_attempts_are_permanent(self) -> None:
+        """download_with_resume already spent its own resume attempts; its
+        EsphomeError wrapper is not retried again at the sweep level."""
+        wrapped = EsphomeError("Failed to download after 3 attempts")
+        wrapped.__cause__ = req.ConnectionError("down")
+        assert not is_transient_download_error(wrapped)
+
+    def test_unrelated_errors_are_permanent(self) -> None:
+        assert not is_transient_download_error(OSError("disk full"))
+        assert not is_transient_download_error(EsphomeError("size mismatch"))
+
+
+class TestFetchWithRetry:
+    def test_logs_the_upcoming_attempt_number(
+        self, caplog: pytest.LogCaptureFixture
+    ) -> None:
+        """The warning names the attempt about to run, not the failed one."""
+        with (
+            patch("esphome.net_retry.time.sleep") as mock_sleep,
+            pytest.raises(req.ConnectionError),
+        ):
+            fetch_with_retry(
+                "https://example.com/f",
+                lambda: (_ for _ in ()).throw(req.ConnectionError("reset")),
+            )
+
+        assert mock_sleep.call_args_list == [call(2), call(4)]
+        assert "(attempt 2/3)" in caplog.text
+        assert "(attempt 3/3)" in caplog.text

tests/unit_tests/test_platformio_extra_script.py

@@ -11,6 +11,7 @@ import pytest
 
 from esphome.core import EsphomeError
 from esphome.platformio.extra_script import (
+    CppDefine,
     ExtraScriptResult,
     _FakeSConsEnv,
     apply_extra_script,
@@ -51,8 +52,8 @@ def test_extra_script_captures_libpath_libs_and_defines(tmp_path):
 
     assert result.libpath == [str(Path("src") / "esp32")]
     assert result.libs == ["algobsec"]
-    assert ("BAR", "1") in result.cppdefines
-    assert "FOO" in result.cppdefines
+    assert CppDefine("BAR", "1") in result.cppdefines
+    assert CppDefine("FOO") in result.cppdefines
     assert result.linkflags == ["-Wl,--gc-sections"]
 
     # Lex like the consumer does: quoting makes raw strings platform-varying
@@ -476,7 +477,7 @@ def test_spaced_cppflag_survives_relexing(tmp_path) -> None:
     """A captured argv token with a space stays one token after lexing."""
     result = ExtraScriptResult(
         cppflags=["-include my hdr.h"],
-        cppdefines=[("MSG", '"hello world"'), "PLAIN"],
+        cppdefines=[CppDefine("MSG", '"hello world"'), CppDefine("PLAIN")],
     )
     flags = captured_as_build_flags(result, library_dir=tmp_path)
     assert lex_build_flags(flags, "test") == [