From 4c2874a32b08001e27feb1d2b1970bdaca4a58ec Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 11 Aug 2025 15:37:01 -0500
Subject: [PATCH 1/6] [esphome] Fix OTA watchdog resets during port scanning
 and network delays (#10152)

---
 .../components/esphome/ota/ota_esphome.cpp    | 227 ++++++++++++------
 esphome/components/esphome/ota/ota_esphome.h  |   9 +-
 2 files changed, 158 insertions(+), 78 deletions(-)

diff --git a/esphome/components/esphome/ota/ota_esphome.cpp b/esphome/components/esphome/ota/ota_esphome.cpp
index 4cc82b9094..5217e9c61f 100644
--- a/esphome/components/esphome/ota/ota_esphome.cpp
+++ b/esphome/components/esphome/ota/ota_esphome.cpp
@@ -19,7 +19,9 @@
 namespace esphome {
 
 static const char *const TAG = "esphome.ota";
-static constexpr u_int16_t OTA_BLOCK_SIZE = 8192;
+static constexpr uint16_t OTA_BLOCK_SIZE = 8192;
+static constexpr uint32_t OTA_SOCKET_TIMEOUT_HANDSHAKE = 10000;  // milliseconds for initial handshake
+static constexpr uint32_t OTA_SOCKET_TIMEOUT_DATA = 90000;       // milliseconds for data transfer
 
 void ESPHomeOTAComponent::setup() {
 #ifdef USE_OTA_STATE_CALLBACK
@@ -28,19 +30,19 @@ void ESPHomeOTAComponent::setup() {
 
   this->server_ = socket::socket_ip_loop_monitored(SOCK_STREAM, 0);  // monitored for incoming connections
   if (this->server_ == nullptr) {
-    ESP_LOGW(TAG, "Could not create socket");
+    this->log_socket_error_("creation");
     this->mark_failed();
     return;
   }
   int enable = 1;
   int err = this->server_->setsockopt(SOL_SOCKET, SO_REUSEADDR, &enable, sizeof(int));
   if (err != 0) {
-    ESP_LOGW(TAG, "Socket unable to set reuseaddr: errno %d", err);
+    this->log_socket_error_("reuseaddr");
     // we can still continue
   }
   err = this->server_->setblocking(false);
   if (err != 0) {
-    ESP_LOGW(TAG, "Socket unable to set nonblocking mode: errno %d", err);
+    this->log_socket_error_("non-blocking");
     this->mark_failed();
     return;
   }
@@ -49,21 +51,21 @@ void ESPHomeOTAComponent::setup() {
 
   socklen_t sl = socket::set_sockaddr_any((struct sockaddr *) &server, sizeof(server), this->port_);
   if (sl == 0) {
-    ESP_LOGW(TAG, "Socket unable to set sockaddr: errno %d", errno);
+    this->log_socket_error_("set sockaddr");
     this->mark_failed();
     return;
   }
 
   err = this->server_->bind((struct sockaddr *) &server, sizeof(server));
   if (err != 0) {
-    ESP_LOGW(TAG, "Socket unable to bind: errno %d", errno);
+    this->log_socket_error_("bind");
     this->mark_failed();
     return;
   }
 
   err = this->server_->listen(4);
   if (err != 0) {
-    ESP_LOGW(TAG, "Socket unable to listen: errno %d", errno);
+    this->log_socket_error_("listen");
     this->mark_failed();
     return;
   }
@@ -83,17 +85,93 @@ void ESPHomeOTAComponent::dump_config() {
 }
 
 void ESPHomeOTAComponent::loop() {
-  // Skip handle_() call if no client connected and no incoming connections
+  // Skip handle_handshake_() call if no client connected and no incoming connections
   // This optimization reduces idle loop overhead when OTA is not active
-  // Note: No need to check server_ for null as the component is marked failed in setup() if server_ creation fails
+  // Note: No need to check server_ for null as the component is marked failed in setup()
+  // if server_ creation fails
   if (this->client_ != nullptr || this->server_->ready()) {
-    this->handle_();
+    this->handle_handshake_();
   }
 }
 
 static const uint8_t FEATURE_SUPPORTS_COMPRESSION = 0x01;
 
-void ESPHomeOTAComponent::handle_() {
+void ESPHomeOTAComponent::handle_handshake_() {
+  /// Handle the initial OTA handshake.
+  ///
+  /// This method is non-blocking and will return immediately if no data is available.
+  /// It waits for the first magic byte (0x6C) before proceeding to handle_data_().
+  /// A 10-second timeout is enforced from initial connection.
+
+  if (this->client_ == nullptr) {
+    // We already checked server_->ready() in loop(), so we can accept directly
+    struct sockaddr_storage source_addr;
+    socklen_t addr_len = sizeof(source_addr);
+    int enable = 1;
+
+    this->client_ = this->server_->accept_loop_monitored((struct sockaddr *) &source_addr, &addr_len);
+    if (this->client_ == nullptr)
+      return;
+    int err = this->client_->setsockopt(IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(int));
+    if (err != 0) {
+      this->log_socket_error_("nodelay");
+      this->cleanup_connection_();
+      return;
+    }
+    err = this->client_->setblocking(false);
+    if (err != 0) {
+      this->log_socket_error_("non-blocking");
+      this->cleanup_connection_();
+      return;
+    }
+    this->log_start_("handshake");
+    this->client_connect_time_ = App.get_loop_component_start_time();
+  }
+
+  // Check for handshake timeout
+  uint32_t now = App.get_loop_component_start_time();
+  if (now - this->client_connect_time_ > OTA_SOCKET_TIMEOUT_HANDSHAKE) {
+    ESP_LOGW(TAG, "Handshake timeout");
+    this->cleanup_connection_();
+    return;
+  }
+
+  // Try to read first byte of magic bytes
+  uint8_t first_byte;
+  ssize_t read = this->client_->read(&first_byte, 1);
+
+  if (read == -1 && (errno == EAGAIN || errno == EWOULDBLOCK)) {
+    return;  // No data yet, try again next loop
+  }
+
+  if (read <= 0) {
+    // Error or connection closed
+    if (read == -1) {
+      this->log_socket_error_("reading first byte");
+    } else {
+      ESP_LOGW(TAG, "Remote closed during handshake");
+    }
+    this->cleanup_connection_();
+    return;
+  }
+
+  // Got first byte, check if it's the magic byte
+  if (first_byte != 0x6C) {
+    ESP_LOGW(TAG, "Invalid initial byte: 0x%02X", first_byte);
+    this->cleanup_connection_();
+    return;
+  }
+
+  // First byte is valid, continue with data handling
+  this->handle_data_();
+}
+
+void ESPHomeOTAComponent::handle_data_() {
+  /// Handle the OTA data transfer and update process.
+  ///
+  /// This method is blocking and will not return until the OTA update completes,
+  /// fails, or times out. It handles authentication, receives the firmware data,
+  /// writes it to flash, and reboots on success.
   ota::OTAResponseTypes error_code = ota::OTA_RESPONSE_ERROR_UNKNOWN;
   bool update_started = false;
   size_t total = 0;
@@ -108,38 +186,14 @@ void ESPHomeOTAComponent::handle_() {
   size_t size_acknowledged = 0;
 #endif
 
-  if (this->client_ == nullptr) {
-    // We already checked server_->ready() in loop(), so we can accept directly
-    struct sockaddr_storage source_addr;
-    socklen_t addr_len = sizeof(source_addr);
-    this->client_ = this->server_->accept((struct sockaddr *) &source_addr, &addr_len);
-    if (this->client_ == nullptr)
-      return;
-  }
-
-  int enable = 1;
-  int err = this->client_->setsockopt(IPPROTO_TCP, TCP_NODELAY, &enable, sizeof(int));
-  if (err != 0) {
-    ESP_LOGW(TAG, "Socket could not enable TCP nodelay, errno %d", errno);
-    this->client_->close();
-    this->client_ = nullptr;
-    return;
-  }
-
-  ESP_LOGD(TAG, "Starting update from %s", this->client_->getpeername().c_str());
-  this->status_set_warning();
-#ifdef USE_OTA_STATE_CALLBACK
-  this->state_callback_.call(ota::OTA_STARTED, 0.0f, 0);
-#endif
-
-  if (!this->readall_(buf, 5)) {
-    ESP_LOGW(TAG, "Reading magic bytes failed");
+  // Read remaining 4 bytes of magic (we already read the first byte 0x6C in handle_handshake_)
+  if (!this->readall_(buf, 4)) {
+    this->log_read_error_("magic bytes");
     goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
   }
-  // 0x6C, 0x26, 0xF7, 0x5C, 0x45
-  if (buf[0] != 0x6C || buf[1] != 0x26 || buf[2] != 0xF7 || buf[3] != 0x5C || buf[4] != 0x45) {
-    ESP_LOGW(TAG, "Magic bytes do not match! 0x%02X-0x%02X-0x%02X-0x%02X-0x%02X", buf[0], buf[1], buf[2], buf[3],
-             buf[4]);
+  // Check remaining magic bytes: 0x26, 0xF7, 0x5C, 0x45
+  if (buf[0] != 0x26 || buf[1] != 0xF7 || buf[2] != 0x5C || buf[3] != 0x45) {
+    ESP_LOGW(TAG, "Magic bytes mismatch! 0x6C-0x%02X-0x%02X-0x%02X-0x%02X", buf[0], buf[1], buf[2], buf[3]);
     error_code = ota::OTA_RESPONSE_ERROR_MAGIC;
     goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
   }
@@ -153,7 +207,7 @@ void ESPHomeOTAComponent::handle_() {
 
   // Read features - 1 byte
   if (!this->readall_(buf, 1)) {
-    ESP_LOGW(TAG, "Reading features failed");
+    this->log_read_error_("features");
     goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
   }
   ota_features = buf[0];  // NOLINT
@@ -232,7 +286,7 @@ void ESPHomeOTAComponent::handle_() {
 
   // Read size, 4 bytes MSB first
   if (!this->readall_(buf, 4)) {
-    ESP_LOGW(TAG, "Reading size failed");
+    this->log_read_error_("size");
     goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
   }
   ota_size = 0;
@@ -242,6 +296,17 @@ void ESPHomeOTAComponent::handle_() {
   }
   ESP_LOGV(TAG, "Size is %u bytes", ota_size);
 
+  // Now that we've passed authentication and are actually
+  // starting the update, set the warning status and notify
+  // listeners. This ensures that port scanners do not
+  // accidentally trigger the update process.
+  this->log_start_("update");
+  this->status_set_warning();
+#ifdef USE_OTA_STATE_CALLBACK
+  this->state_callback_.call(ota::OTA_STARTED, 0.0f, 0);
+#endif
+
+  // This will block for a few seconds as it locks flash
   error_code = backend->begin(ota_size);
   if (error_code != ota::OTA_RESPONSE_OK)
     goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
@@ -253,7 +318,7 @@ void ESPHomeOTAComponent::handle_() {
 
   // Read binary MD5, 32 bytes
   if (!this->readall_(buf, 32)) {
-    ESP_LOGW(TAG, "Reading binary MD5 checksum failed");
+    this->log_read_error_("MD5 checksum");
     goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
   }
   sbuf[32] = '\0';
@@ -270,23 +335,22 @@ void ESPHomeOTAComponent::handle_() {
     ssize_t read = this->client_->read(buf, requested);
     if (read == -1) {
       if (errno == EAGAIN || errno == EWOULDBLOCK) {
-        App.feed_wdt();
-        delay(1);
+        this->yield_and_feed_watchdog_();
         continue;
       }
-      ESP_LOGW(TAG, "Error receiving data for update, errno %d", errno);
+      ESP_LOGW(TAG, "Read error, errno %d", errno);
       goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
     } else if (read == 0) {
       // $ man recv
       // "When  a  stream socket peer has performed an orderly shutdown, the return value will
       // be 0 (the traditional "end-of-file" return)."
-      ESP_LOGW(TAG, "Remote end closed connection");
+      ESP_LOGW(TAG, "Remote closed connection");
       goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
     }
 
     error_code = backend->write(buf, read);
     if (error_code != ota::OTA_RESPONSE_OK) {
-      ESP_LOGW(TAG, "Error writing binary data to flash!, error_code: %d", error_code);
+      ESP_LOGW(TAG, "Flash write error, code: %d", error_code);
       goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
     }
     total += read;
@@ -307,8 +371,7 @@ void ESPHomeOTAComponent::handle_() {
       this->state_callback_.call(ota::OTA_IN_PROGRESS, percentage, 0);
 #endif
       // feed watchdog and give other tasks a chance to run
-      App.feed_wdt();
-      yield();
+      this->yield_and_feed_watchdog_();
     }
   }
 
@@ -318,7 +381,7 @@ void ESPHomeOTAComponent::handle_() {
 
   error_code = backend->end();
   if (error_code != ota::OTA_RESPONSE_OK) {
-    ESP_LOGW(TAG, "Error ending update! error_code: %d", error_code);
+    ESP_LOGW(TAG, "Error ending update! code: %d", error_code);
     goto error;  // NOLINT(cppcoreguidelines-avoid-goto)
   }
 
@@ -328,12 +391,11 @@ void ESPHomeOTAComponent::handle_() {
 
   // Read ACK
   if (!this->readall_(buf, 1) || buf[0] != ota::OTA_RESPONSE_OK) {
-    ESP_LOGW(TAG, "Reading back acknowledgement failed");
+    this->log_read_error_("ack");
     // do not go to error, this is not fatal
   }
 
-  this->client_->close();
-  this->client_ = nullptr;
+  this->cleanup_connection_();
   delay(10);
   ESP_LOGI(TAG, "Update complete");
   this->status_clear_warning();
@@ -346,8 +408,7 @@ void ESPHomeOTAComponent::handle_() {
 error:
   buf[0] = static_cast<uint8_t>(error_code);
   this->writeall_(buf, 1);
-  this->client_->close();
-  this->client_ = nullptr;
+  this->cleanup_connection_();
 
   if (backend != nullptr && update_started) {
     backend->abort();
@@ -364,28 +425,24 @@ bool ESPHomeOTAComponent::readall_(uint8_t *buf, size_t len) {
   uint32_t at = 0;
   while (len - at > 0) {
     uint32_t now = millis();
-    if (now - start > 1000) {
-      ESP_LOGW(TAG, "Timed out reading %d bytes of data", len);
+    if (now - start > OTA_SOCKET_TIMEOUT_DATA) {
+      ESP_LOGW(TAG, "Timeout reading %d bytes", len);
       return false;
     }
 
     ssize_t read = this->client_->read(buf + at, len - at);
     if (read == -1) {
-      if (errno == EAGAIN || errno == EWOULDBLOCK) {
-        App.feed_wdt();
-        delay(1);
-        continue;
+      if (errno != EAGAIN && errno != EWOULDBLOCK) {
+        ESP_LOGW(TAG, "Error reading %d bytes, errno %d", len, errno);
+        return false;
       }
-      ESP_LOGW(TAG, "Failed to read %d bytes of data, errno %d", len, errno);
-      return false;
     } else if (read == 0) {
       ESP_LOGW(TAG, "Remote closed connection");
       return false;
     } else {
       at += read;
     }
-    App.feed_wdt();
-    delay(1);
+    this->yield_and_feed_watchdog_();
   }
 
   return true;
@@ -395,25 +452,21 @@ bool ESPHomeOTAComponent::writeall_(const uint8_t *buf, size_t len) {
   uint32_t at = 0;
   while (len - at > 0) {
     uint32_t now = millis();
-    if (now - start > 1000) {
-      ESP_LOGW(TAG, "Timed out writing %d bytes of data", len);
+    if (now - start > OTA_SOCKET_TIMEOUT_DATA) {
+      ESP_LOGW(TAG, "Timeout writing %d bytes", len);
       return false;
     }
 
     ssize_t written = this->client_->write(buf + at, len - at);
     if (written == -1) {
-      if (errno == EAGAIN || errno == EWOULDBLOCK) {
-        App.feed_wdt();
-        delay(1);
-        continue;
+      if (errno != EAGAIN && errno != EWOULDBLOCK) {
+        ESP_LOGW(TAG, "Error writing %d bytes, errno %d", len, errno);
+        return false;
       }
-      ESP_LOGW(TAG, "Failed to write %d bytes of data, errno %d", len, errno);
-      return false;
     } else {
       at += written;
     }
-    App.feed_wdt();
-    delay(1);
+    this->yield_and_feed_watchdog_();
   }
   return true;
 }
@@ -421,5 +474,25 @@ bool ESPHomeOTAComponent::writeall_(const uint8_t *buf, size_t len) {
 float ESPHomeOTAComponent::get_setup_priority() const { return setup_priority::AFTER_WIFI; }
 uint16_t ESPHomeOTAComponent::get_port() const { return this->port_; }
 void ESPHomeOTAComponent::set_port(uint16_t port) { this->port_ = port; }
+
+void ESPHomeOTAComponent::log_socket_error_(const char *msg) { ESP_LOGW(TAG, "Socket %s: errno %d", msg, errno); }
+
+void ESPHomeOTAComponent::log_read_error_(const char *what) { ESP_LOGW(TAG, "Read %s failed", what); }
+
+void ESPHomeOTAComponent::log_start_(const char *phase) {
+  ESP_LOGD(TAG, "Starting %s from %s", phase, this->client_->getpeername().c_str());
+}
+
+void ESPHomeOTAComponent::cleanup_connection_() {
+  this->client_->close();
+  this->client_ = nullptr;
+  this->client_connect_time_ = 0;
+}
+
+void ESPHomeOTAComponent::yield_and_feed_watchdog_() {
+  App.feed_wdt();
+  delay(1);
+}
+
 }  // namespace esphome
 #endif
diff --git a/esphome/components/esphome/ota/ota_esphome.h b/esphome/components/esphome/ota/ota_esphome.h
index e0d09ff37e..8397b86528 100644
--- a/esphome/components/esphome/ota/ota_esphome.h
+++ b/esphome/components/esphome/ota/ota_esphome.h
@@ -27,15 +27,22 @@ class ESPHomeOTAComponent : public ota::OTAComponent {
   uint16_t get_port() const;
 
  protected:
-  void handle_();
+  void handle_handshake_();
+  void handle_data_();
   bool readall_(uint8_t *buf, size_t len);
   bool writeall_(const uint8_t *buf, size_t len);
+  void log_socket_error_(const char *msg);
+  void log_read_error_(const char *what);
+  void log_start_(const char *phase);
+  void cleanup_connection_();
+  void yield_and_feed_watchdog_();
 
 #ifdef USE_OTA_PASSWORD
   std::string password_;
 #endif  // USE_OTA_PASSWORD
 
   uint16_t port_;
+  uint32_t client_connect_time_{0};
 
   std::unique_ptr<socket::Socket> server_;
   std::unique_ptr<socket::Socket> client_;

From 9aa21956c8af931f529d51bfb972d49292daa375 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 11 Aug 2025 15:41:08 -0500
Subject: [PATCH 2/6] [api] Optimize single vector writes to use write()
 instead of writev() (#10193)

---
 esphome/components/api/api_frame_helper.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/esphome/components/api/api_frame_helper.cpp b/esphome/components/api/api_frame_helper.cpp
index 6ca38e80ed..dee3af2ac3 100644
--- a/esphome/components/api/api_frame_helper.cpp
+++ b/esphome/components/api/api_frame_helper.cpp
@@ -156,7 +156,9 @@ APIError APIFrameHelper::write_raw_(const struct iovec *iov, int iovcnt, uint16_
   }
 
   // Try to send directly if no buffered data
-  ssize_t sent = this->socket_->writev(iov, iovcnt);
+  // Optimize for single iovec case (common for plaintext API)
+  ssize_t sent =
+      (iovcnt == 1) ? this->socket_->write(iov[0].iov_base, iov[0].iov_len) : this->socket_->writev(iov, iovcnt);
 
   if (sent == -1) {
     APIError err = this->handle_socket_write_error_();

From 42aee53dde435611cf152f5fc88d53bf60ca9d48 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 11 Aug 2025 15:47:46 -0500
Subject: [PATCH 3/6] [bluetooth_proxy] Replace dynamic vector with fixed array
 for BLE advertisements (#10174)

---
 esphome/components/api/api.proto              |   2 +-
 esphome/components/api/api_options.proto      |   1 +
 esphome/components/api/api_pb2.cpp            |   8 +-
 esphome/components/api/api_pb2.h              |   5 +-
 esphome/components/api/api_pb2_dump.cpp       |   4 +-
 .../components/bluetooth_proxy/__init__.py    |   6 +
 .../bluetooth_proxy/bluetooth_proxy.cpp       |  57 ++--------
 .../bluetooth_proxy/bluetooth_proxy.h         |   4 +-
 esphome/core/defines.h                        |   1 +
 script/api_protobuf/api_protobuf.py           | 106 +++++++++++++++---
 10 files changed, 124 insertions(+), 70 deletions(-)

diff --git a/esphome/components/api/api.proto b/esphome/components/api/api.proto
index 9d77ecdfa8..6b19f2026a 100644
--- a/esphome/components/api/api.proto
+++ b/esphome/components/api/api.proto
@@ -1438,7 +1438,7 @@ message BluetoothLERawAdvertisementsResponse {
   option (ifdef) = "USE_BLUETOOTH_PROXY";
   option (no_delay) = true;
 
-  repeated BluetoothLERawAdvertisement advertisements = 1;
+  repeated BluetoothLERawAdvertisement advertisements = 1 [(fixed_array_with_length_define) = "BLUETOOTH_PROXY_ADVERTISEMENT_BATCH_SIZE"];
 }
 
 enum BluetoothDeviceRequestType {
diff --git a/esphome/components/api/api_options.proto b/esphome/components/api/api_options.proto
index ed0e0d7455..50c43b96fd 100644
--- a/esphome/components/api/api_options.proto
+++ b/esphome/components/api/api_options.proto
@@ -30,6 +30,7 @@ extend google.protobuf.FieldOptions {
     optional bool no_zero_copy = 50008 [default=false];
     optional bool fixed_array_skip_zero = 50009 [default=false];
     optional string fixed_array_size_define = 50010;
+    optional string fixed_array_with_length_define = 50011;
 
     // container_pointer: Zero-copy optimization for repeated fields.
     //
diff --git a/esphome/components/api/api_pb2.cpp b/esphome/components/api/api_pb2.cpp
index 5dddc79b49..476e3c88d0 100644
--- a/esphome/components/api/api_pb2.cpp
+++ b/esphome/components/api/api_pb2.cpp
@@ -1843,12 +1843,14 @@ void BluetoothLERawAdvertisement::calculate_size(ProtoSize &size) const {
   size.add_length(1, this->data_len);
 }
 void BluetoothLERawAdvertisementsResponse::encode(ProtoWriteBuffer buffer) const {
-  for (auto &it : this->advertisements) {
-    buffer.encode_message(1, it, true);
+  for (uint16_t i = 0; i < this->advertisements_len; i++) {
+    buffer.encode_message(1, this->advertisements[i], true);
   }
 }
 void BluetoothLERawAdvertisementsResponse::calculate_size(ProtoSize &size) const {
-  size.add_repeated_message(1, this->advertisements);
+  for (uint16_t i = 0; i < this->advertisements_len; i++) {
+    size.add_message_object_force(1, this->advertisements[i]);
+  }
 }
 bool BluetoothDeviceRequest::decode_varint(uint32_t field_id, ProtoVarInt value) {
   switch (field_id) {
diff --git a/esphome/components/api/api_pb2.h b/esphome/components/api/api_pb2.h
index d43d3c61b7..edf839be55 100644
--- a/esphome/components/api/api_pb2.h
+++ b/esphome/components/api/api_pb2.h
@@ -1788,11 +1788,12 @@ class BluetoothLERawAdvertisement : public ProtoMessage {
 class BluetoothLERawAdvertisementsResponse : public ProtoMessage {
  public:
   static constexpr uint8_t MESSAGE_TYPE = 93;
-  static constexpr uint8_t ESTIMATED_SIZE = 34;
+  static constexpr uint8_t ESTIMATED_SIZE = 136;
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "bluetooth_le_raw_advertisements_response"; }
 #endif
-  std::vector<BluetoothLERawAdvertisement> advertisements{};
+  std::array<BluetoothLERawAdvertisement, BLUETOOTH_PROXY_ADVERTISEMENT_BATCH_SIZE> advertisements{};
+  uint16_t advertisements_len{0};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
 #ifdef HAS_PROTO_MESSAGE_DUMP
diff --git a/esphome/components/api/api_pb2_dump.cpp b/esphome/components/api/api_pb2_dump.cpp
index b212353ad8..7af322f96d 100644
--- a/esphome/components/api/api_pb2_dump.cpp
+++ b/esphome/components/api/api_pb2_dump.cpp
@@ -1534,9 +1534,9 @@ void BluetoothLERawAdvertisement::dump_to(std::string &out) const {
 }
 void BluetoothLERawAdvertisementsResponse::dump_to(std::string &out) const {
   MessageDumpHelper helper(out, "BluetoothLERawAdvertisementsResponse");
-  for (const auto &it : this->advertisements) {
+  for (uint16_t i = 0; i < this->advertisements_len; i++) {
     out.append("  advertisements: ");
-    it.dump_to(out);
+    this->advertisements[i].dump_to(out);
     out.append("\n");
   }
 }
diff --git a/esphome/components/bluetooth_proxy/__init__.py b/esphome/components/bluetooth_proxy/__init__.py
index fb7f7a37c0..112faa27e5 100644
--- a/esphome/components/bluetooth_proxy/__init__.py
+++ b/esphome/components/bluetooth_proxy/__init__.py
@@ -118,6 +118,12 @@ async def to_code(config):
     connection_count = len(config.get(CONF_CONNECTIONS, []))
     cg.add_define("BLUETOOTH_PROXY_MAX_CONNECTIONS", connection_count)
 
+    # Define batch size for BLE advertisements
+    # Each advertisement is up to 80 bytes when packaged (including protocol overhead)
+    # 16 advertisements × 80 bytes (worst case) = 1280 bytes out of ~1320 bytes usable payload
+    # This achieves ~97% WiFi MTU utilization while staying under the limit
+    cg.add_define("BLUETOOTH_PROXY_ADVERTISEMENT_BATCH_SIZE", 16)
+
     for connection_conf in config.get(CONF_CONNECTIONS, []):
         connection_var = cg.new_Pvariable(connection_conf[CONF_ID])
         await cg.register_component(connection_var, connection_conf)
diff --git a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
index 04b85fc3f0..723466a5ff 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
+++ b/esphome/components/bluetooth_proxy/bluetooth_proxy.cpp
@@ -11,12 +11,8 @@ namespace esphome::bluetooth_proxy {
 
 static const char *const TAG = "bluetooth_proxy";
 
-// Batch size for BLE advertisements to maximize WiFi efficiency
-// Each advertisement is up to 80 bytes when packaged (including protocol overhead)
-// Most advertisements are 20-30 bytes, allowing even more to fit per packet
-// 16 advertisements × 80 bytes (worst case) = 1280 bytes out of ~1320 bytes usable payload
-// This achieves ~97% WiFi MTU utilization while staying under the limit
-static constexpr size_t FLUSH_BATCH_SIZE = 16;
+// BLUETOOTH_PROXY_ADVERTISEMENT_BATCH_SIZE is defined during code generation
+// It sets the batch size for BLE advertisements to maximize WiFi efficiency
 
 // Verify BLE advertisement data array size matches the BLE specification (31 bytes adv + 31 bytes scan response)
 static_assert(sizeof(((api::BluetoothLERawAdvertisement *) nullptr)->data) == 62,
@@ -25,13 +21,6 @@ static_assert(sizeof(((api::BluetoothLERawAdvertisement *) nullptr)->data) == 62
 BluetoothProxy::BluetoothProxy() { global_bluetooth_proxy = this; }
 
 void BluetoothProxy::setup() {
-  // Reserve capacity but start with size 0
-  // Reserve 50% since we'll grow naturally and flush at FLUSH_BATCH_SIZE
-  this->response_.advertisements.reserve(FLUSH_BATCH_SIZE / 2);
-
-  // Don't pre-allocate pool - let it grow only if needed in busy environments
-  // Many devices in quiet areas will never need the overflow pool
-
   this->connections_free_response_.limit = BLUETOOTH_PROXY_MAX_CONNECTIONS;
   this->connections_free_response_.free = BLUETOOTH_PROXY_MAX_CONNECTIONS;
 
@@ -88,33 +77,21 @@ bool BluetoothProxy::parse_devices(const esp32_ble::BLEScanResult *scan_results,
     auto &result = scan_results[i];
     uint8_t length = result.adv_data_len + result.scan_rsp_len;
 
-    // Check if we need to expand the vector
-    if (this->advertisement_count_ >= advertisements.size()) {
-      if (this->advertisement_pool_.empty()) {
-        // No room in pool, need to allocate
-        advertisements.emplace_back();
-      } else {
-        // Pull from pool
-        advertisements.push_back(std::move(this->advertisement_pool_.back()));
-        this->advertisement_pool_.pop_back();
-      }
-    }
-
     // Fill in the data directly at current position
-    auto &adv = advertisements[this->advertisement_count_];
+    auto &adv = advertisements[this->response_.advertisements_len];
     adv.address = esp32_ble::ble_addr_to_uint64(result.bda);
     adv.rssi = result.rssi;
     adv.address_type = result.ble_addr_type;
     adv.data_len = length;
     std::memcpy(adv.data, result.ble_adv, length);
 
-    this->advertisement_count_++;
+    this->response_.advertisements_len++;
 
     ESP_LOGV(TAG, "Queuing raw packet from %02X:%02X:%02X:%02X:%02X:%02X, length %d. RSSI: %d dB", result.bda[0],
              result.bda[1], result.bda[2], result.bda[3], result.bda[4], result.bda[5], length, result.rssi);
 
-    // Flush if we have reached FLUSH_BATCH_SIZE
-    if (this->advertisement_count_ >= FLUSH_BATCH_SIZE) {
+    // Flush if we have reached BLUETOOTH_PROXY_ADVERTISEMENT_BATCH_SIZE
+    if (this->response_.advertisements_len >= BLUETOOTH_PROXY_ADVERTISEMENT_BATCH_SIZE) {
       this->flush_pending_advertisements();
     }
   }
@@ -123,27 +100,17 @@ bool BluetoothProxy::parse_devices(const esp32_ble::BLEScanResult *scan_results,
 }
 
 void BluetoothProxy::flush_pending_advertisements() {
-  if (this->advertisement_count_ == 0 || !api::global_api_server->is_connected() || this->api_connection_ == nullptr)
+  if (this->response_.advertisements_len == 0 || !api::global_api_server->is_connected() ||
+      this->api_connection_ == nullptr)
     return;
 
-  auto &advertisements = this->response_.advertisements;
-
-  // Return any items beyond advertisement_count_ to the pool
-  if (advertisements.size() > this->advertisement_count_) {
-    // Move unused items back to pool
-    this->advertisement_pool_.insert(this->advertisement_pool_.end(),
-                                     std::make_move_iterator(advertisements.begin() + this->advertisement_count_),
-                                     std::make_move_iterator(advertisements.end()));
-
-    // Resize to actual count
-    advertisements.resize(this->advertisement_count_);
-  }
-
   // Send the message
   this->api_connection_->send_message(this->response_, api::BluetoothLERawAdvertisementsResponse::MESSAGE_TYPE);
 
-  // Reset count - existing items will be overwritten in next batch
-  this->advertisement_count_ = 0;
+  ESP_LOGV(TAG, "Sent batch of %u BLE advertisements", this->response_.advertisements_len);
+
+  // Reset the length for the next batch
+  this->response_.advertisements_len = 0;
 }
 
 void BluetoothProxy::dump_config() {
diff --git a/esphome/components/bluetooth_proxy/bluetooth_proxy.h b/esphome/components/bluetooth_proxy/bluetooth_proxy.h
index 21695d9819..bc8d3ed762 100644
--- a/esphome/components/bluetooth_proxy/bluetooth_proxy.h
+++ b/esphome/components/bluetooth_proxy/bluetooth_proxy.h
@@ -150,7 +150,6 @@ class BluetoothProxy : public esp32_ble_tracker::ESPBTDeviceListener, public Com
   std::array<BluetoothConnection *, BLUETOOTH_PROXY_MAX_CONNECTIONS> connections_{};
 
   // BLE advertisement batching
-  std::vector<api::BluetoothLERawAdvertisement> advertisement_pool_;
   api::BluetoothLERawAdvertisementsResponse response_;
 
   // Group 3: 4-byte types
@@ -161,9 +160,8 @@ class BluetoothProxy : public esp32_ble_tracker::ESPBTDeviceListener, public Com
 
   // Group 4: 1-byte types grouped together
   bool active_;
-  uint8_t advertisement_count_{0};
   uint8_t connection_count_{0};
-  // 3 bytes used, 1 byte padding
+  // 2 bytes used, 2 bytes padding
 };
 
 extern BluetoothProxy *global_bluetooth_proxy;  // NOLINT(cppcoreguidelines-avoid-non-const-global-variables)
diff --git a/esphome/core/defines.h b/esphome/core/defines.h
index 7631ff54f3..01f6811e05 100644
--- a/esphome/core/defines.h
+++ b/esphome/core/defines.h
@@ -148,6 +148,7 @@
 
 #define USE_BLUETOOTH_PROXY
 #define BLUETOOTH_PROXY_MAX_CONNECTIONS 3
+#define BLUETOOTH_PROXY_ADVERTISEMENT_BATCH_SIZE 16
 #define USE_CAPTIVE_PORTAL
 #define USE_ESP32_BLE
 #define USE_ESP32_BLE_CLIENT
diff --git a/script/api_protobuf/api_protobuf.py b/script/api_protobuf/api_protobuf.py
index fa2f87d98d..3396e5ad05 100755
--- a/script/api_protobuf/api_protobuf.py
+++ b/script/api_protobuf/api_protobuf.py
@@ -339,6 +339,11 @@ def create_field_type_info(
 ) -> TypeInfo:
     """Create the appropriate TypeInfo instance for a field, handling repeated fields and custom options."""
     if field.label == 3:  # repeated
+        # Check if this repeated field has fixed_array_with_length_define option
+        if (
+            fixed_size := get_field_opt(field, pb.fixed_array_with_length_define)
+        ) is not None:
+            return FixedArrayWithLengthRepeatedType(field, fixed_size)
         # Check if this repeated field has fixed_array_size option
         if (fixed_size := get_field_opt(field, pb.fixed_array_size)) is not None:
             return FixedArrayRepeatedType(field, fixed_size)
@@ -1052,7 +1057,7 @@ def _generate_array_dump_content(
     """
     o = f"for (const auto {'' if is_bool else '&'}it : {field_name}) {{\n"
     # Check if underlying type can use dump_field
-    if type(ti).can_use_dump_field():
+    if ti.can_use_dump_field():
         # For types that have dump_field overloads, use them with extra indent
         o += f'  dump_field(out, "{name}", {ti.dump_field_value("it")}, 4);\n'
     else:
@@ -1084,6 +1089,12 @@ class FixedArrayRepeatedType(TypeInfo):
         validate_field_type(field.type, field.name)
         self._ti: TypeInfo = TYPE_INFO[field.type](field)
 
+    def _encode_element(self, element: str) -> str:
+        """Helper to generate encode statement for a single element."""
+        if isinstance(self._ti, EnumType):
+            return f"buffer.{self._ti.encode_func}({self.number}, static_cast<uint32_t>({element}), true);"
+        return f"buffer.{self._ti.encode_func}({self.number}, {element}, true);"
+
     @property
     def cpp_type(self) -> str:
         return f"std::array<{self._ti.cpp_type}, {self.array_size}>"
@@ -1111,19 +1122,13 @@ class FixedArrayRepeatedType(TypeInfo):
 
     @property
     def encode_content(self) -> str:
-        # Helper to generate encode statement for a single element
-        def encode_element(element: str) -> str:
-            if isinstance(self._ti, EnumType):
-                return f"buffer.{self._ti.encode_func}({self.number}, static_cast<uint32_t>({element}), true);"
-            return f"buffer.{self._ti.encode_func}({self.number}, {element}, true);"
-
         # If skip_zero is enabled, wrap encoding in a zero check
         if self.skip_zero:
             if self.is_define:
                 # When using a define, we need to use a loop-based approach
                 o = f"for (const auto &it : this->{self.field_name}) {{\n"
                 o += "  if (it != 0) {\n"
-                o += f"    {encode_element('it')}\n"
+                o += f"    {self._encode_element('it')}\n"
                 o += "  }\n"
                 o += "}"
                 return o
@@ -1132,7 +1137,7 @@ class FixedArrayRepeatedType(TypeInfo):
                 [f"this->{self.field_name}[{i}] != 0" for i in range(self.array_size)]
             )
             encode_lines = [
-                f"  {encode_element(f'this->{self.field_name}[{i}]')}"
+                f"  {self._encode_element(f'this->{self.field_name}[{i}]')}"
                 for i in range(self.array_size)
             ]
             return f"if ({non_zero_checks}) {{\n" + "\n".join(encode_lines) + "\n}"
@@ -1140,23 +1145,23 @@ class FixedArrayRepeatedType(TypeInfo):
         # When using a define, always use loop-based approach
         if self.is_define:
             o = f"for (const auto &it : this->{self.field_name}) {{\n"
-            o += f"  {encode_element('it')}\n"
+            o += f"  {self._encode_element('it')}\n"
             o += "}"
             return o
 
         # Unroll small arrays for efficiency
         if self.array_size == 1:
-            return encode_element(f"this->{self.field_name}[0]")
+            return self._encode_element(f"this->{self.field_name}[0]")
         if self.array_size == 2:
             return (
-                encode_element(f"this->{self.field_name}[0]")
+                self._encode_element(f"this->{self.field_name}[0]")
                 + "\n  "
-                + encode_element(f"this->{self.field_name}[1]")
+                + self._encode_element(f"this->{self.field_name}[1]")
             )
 
         # Use loops for larger arrays
         o = f"for (const auto &it : this->{self.field_name}) {{\n"
-        o += f"  {encode_element('it')}\n"
+        o += f"  {self._encode_element('it')}\n"
         o += "}"
         return o
 
@@ -1230,6 +1235,66 @@ class FixedArrayRepeatedType(TypeInfo):
         return underlying_size * self.array_size
 
 
+class FixedArrayWithLengthRepeatedType(FixedArrayRepeatedType):
+    """Special type for fixed-size repeated fields with variable length tracking.
+
+    Similar to FixedArrayRepeatedType but generates an additional length field
+    to track how many elements are actually in use. Only encodes/sends elements
+    up to the current length.
+
+    Fixed arrays with length are only supported for encoding (SOURCE_SERVER) since
+    we cannot control how many items we receive when decoding.
+    """
+
+    @property
+    def public_content(self) -> list[str]:
+        # Return both the array and the length field
+        return [
+            f"{self.cpp_type} {self.field_name}{{}};",
+            f"uint16_t {self.field_name}_len{{0}};",
+        ]
+
+    @property
+    def encode_content(self) -> str:
+        # Always use a loop up to the current length
+        o = f"for (uint16_t i = 0; i < this->{self.field_name}_len; i++) {{\n"
+        o += f"  {self._encode_element(f'this->{self.field_name}[i]')}\n"
+        o += "}"
+        return o
+
+    @property
+    def dump_content(self) -> str:
+        # Dump only the active elements
+        o = f"for (uint16_t i = 0; i < this->{self.field_name}_len; i++) {{\n"
+        # Check if underlying type can use dump_field
+        if self._ti.can_use_dump_field():
+            o += f'  dump_field(out, "{self.name}", {self._ti.dump_field_value(f"this->{self.field_name}[i]")}, 4);\n'
+        else:
+            o += f'  out.append("  {self.name}: ");\n'
+            o += indent(self._ti.dump(f"this->{self.field_name}[i]")) + "\n"
+            o += '  out.append("\\n");\n'
+        o += "}"
+        return o
+
+    def get_size_calculation(self, name: str, force: bool = False) -> str:
+        # Calculate size only for active elements
+        o = f"for (uint16_t i = 0; i < {name}_len; i++) {{\n"
+        o += f"  {self._ti.get_size_calculation(f'{name}[i]', True)}\n"
+        o += "}"
+        return o
+
+    def get_estimated_size(self) -> int:
+        # For fixed arrays with length, estimate based on typical usage
+        # Assume on average half the array is used
+        underlying_size = self._ti.get_estimated_size()
+        if self.is_define:
+            # When using a define, estimate 8 elements as typical
+            return underlying_size * 8
+        return underlying_size * (
+            self.array_size // 2 if self.array_size > 2 else self.array_size
+        )
+
+
 class RepeatedTypeInfo(TypeInfo):
     def __init__(self, field: descriptor.FieldDescriptorProto) -> None:
         super().__init__(field)
@@ -1711,6 +1776,19 @@ def build_message_type(
                 f"since we cannot trust or control the number of items received from clients."
             )
 
+        # Validate that fixed_array_with_length_define is only used in encode-only messages
+        if (
+            needs_decode
+            and field.label == 3
+            and get_field_opt(field, pb.fixed_array_with_length_define) is not None
+        ):
+            raise ValueError(
+                f"Message '{desc.name}' uses fixed_array_with_length_define on field '{field.name}' "
+                f"but has source={SOURCE_NAMES[source]}. "
+                f"Fixed arrays with length are only supported for SOURCE_SERVER (encode-only) messages "
+                f"since we cannot trust or control the number of items received from clients."
+            )
+
         ti = create_field_type_info(field, needs_decode, needs_encode)
 
         # Skip field declarations for fields that are in the base class

From c14c4fb658dae18deb53fe425ea18a476f5572e9 Mon Sep 17 00:00:00 2001
From: Jesse Hills <3060199+jesserockz@users.noreply.github.com>
Date: Tue, 12 Aug 2025 09:12:54 +1200
Subject: [PATCH 4/6] [substitutions] Add some safe built-in functions to jinja
 parsing (#10178)

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 esphome/components/substitutions/jinja.py | 24 ++++++++++++++++++++++-
 1 file changed, 23 insertions(+), 1 deletion(-)

diff --git a/esphome/components/substitutions/jinja.py b/esphome/components/substitutions/jinja.py
index cf393d2a5d..c6e40a668d 100644
--- a/esphome/components/substitutions/jinja.py
+++ b/esphome/components/substitutions/jinja.py
@@ -25,6 +25,24 @@ def has_jinja(st):
     return detect_jinja_re.search(st) is not None
 
 
+# SAFE_GLOBAL_FUNCTIONS defines a allowlist of built-in functions that are considered safe to expose
+# in Jinja templates or other sandboxed evaluation contexts. Only functions that do not allow
+# arbitrary code execution, file access, or other security risks are included.
+#
+# The following functions are considered safe:
+#   - ord: Converts a character to its Unicode code point integer.
+#   - chr: Converts an integer to its corresponding Unicode character.
+#   - len: Returns the length of a sequence or collection.
+#
+# These functions were chosen because they are pure, have no side effects, and do not provide access
+# to the file system, environment, or other potentially sensitive resources.
+SAFE_GLOBAL_FUNCTIONS = {
+    "ord": ord,
+    "chr": chr,
+    "len": len,
+}
+
+
 class JinjaStr(str):
     """
     Wraps a string containing an unresolved Jinja expression,
@@ -66,7 +84,11 @@ class Jinja:
         self.env.add_extension("jinja2.ext.do")
         self.env.globals["math"] = math  # Inject entire math module
         self.context_vars = {**context_vars}
-        self.env.globals = {**self.env.globals, **self.context_vars}
+        self.env.globals = {
+            **self.env.globals,
+            **self.context_vars,
+            **SAFE_GLOBAL_FUNCTIONS,
+        }
 
     def expand(self, content_str):
         """

From 82b7c1224c17d533db47c92ace97e27a11433eed Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 11 Aug 2025 16:58:51 -0500
Subject: [PATCH 5/6] [core] Improve entity duplicate validation error messages
 (#10184)

---
 esphome/config.py                             |  4 +-
 esphome/core/__init__.py                      | 22 +++++--
 esphome/core/entity_helpers.py                | 37 ++++++++++-
 esphome/types.py                              | 12 ++++
 tests/unit_tests/core/test_entity_helpers.py  | 66 ++++++++++++++++++-
 .../entity_conflict_components.yaml           | 20 ++++++
 6 files changed, 151 insertions(+), 10 deletions(-)
 create mode 100644 tests/unit_tests/fixtures/core/entity_helpers/entity_conflict_components.yaml

diff --git a/esphome/config.py b/esphome/config.py
index cf7a232d8e..ecd0cbb048 100644
--- a/esphome/config.py
+++ b/esphome/config.py
@@ -627,13 +627,15 @@ class SchemaValidationStep(ConfigValidationStep):
     def __init__(
         self, domain: str, path: ConfigPath, conf: ConfigType, comp: ComponentManifest
     ):
+        self.domain = domain
         self.path = path
         self.conf = conf
         self.comp = comp
 
     def run(self, result: Config) -> None:
         token = path_context.set(self.path)
-        with result.catch_error(self.path):
+        # The domain already contains the full component path (e.g., "sensor.template", "sensor.uptime")
+        with CORE.component_context(self.domain), result.catch_error(self.path):
             if self.comp.is_platform:
                 # Remove 'platform' key for validation
                 input_conf = OrderedDict(self.conf)
diff --git a/esphome/core/__init__.py b/esphome/core/__init__.py
index 39c6c3def1..9df5da1c78 100644
--- a/esphome/core/__init__.py
+++ b/esphome/core/__init__.py
@@ -1,4 +1,5 @@
 from collections import defaultdict
+from contextlib import contextmanager
 import logging
 import math
 import os
@@ -38,7 +39,7 @@ from esphome.util import OrderedDict
 
 if TYPE_CHECKING:
     from ..cpp_generator import MockObj, MockObjClass, Statement
-    from ..types import ConfigType
+    from ..types import ConfigType, EntityMetadata
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -571,14 +572,16 @@ class EsphomeCore:
         # Key: platform name (e.g. "sensor", "binary_sensor"), Value: count
         self.platform_counts: defaultdict[str, int] = defaultdict(int)
         # Track entity unique IDs to handle duplicates
-        # Set of (device_id, platform, sanitized_name) tuples
-        self.unique_ids: set[tuple[str, str, str]] = set()
+        # Dict mapping (device_id, platform, sanitized_name) -> entity metadata
+        self.unique_ids: dict[tuple[str, str, str], EntityMetadata] = {}
         # Whether ESPHome was started in verbose mode
         self.verbose = False
         # Whether ESPHome was started in quiet mode
         self.quiet = False
         # A list of all known ID classes
         self.id_classes = {}
+        # The current component being processed during validation
+        self.current_component: str | None = None
 
     def reset(self):
         from esphome.pins import PIN_SCHEMA_REGISTRY
@@ -604,9 +607,20 @@ class EsphomeCore:
         self.loaded_integrations = set()
         self.component_ids = set()
         self.platform_counts = defaultdict(int)
-        self.unique_ids = set()
+        self.unique_ids = {}
+        self.current_component = None
         PIN_SCHEMA_REGISTRY.reset()
 
+    @contextmanager
+    def component_context(self, component: str):
+        """Context manager to set the current component being processed."""
+        old_component = self.current_component
+        self.current_component = component
+        try:
+            yield
+        finally:
+            self.current_component = old_component
+
     @property
     def address(self) -> str | None:
         if self.config is None:
diff --git a/esphome/core/entity_helpers.py b/esphome/core/entity_helpers.py
index cc388ffb4c..107b9fd739 100644
--- a/esphome/core/entity_helpers.py
+++ b/esphome/core/entity_helpers.py
@@ -16,7 +16,7 @@ from esphome.core import CORE, ID
 from esphome.cpp_generator import MockObj, add, get_variable
 import esphome.final_validate as fv
 from esphome.helpers import sanitize, snake_case
-from esphome.types import ConfigType
+from esphome.types import ConfigType, EntityMetadata
 
 _LOGGER = logging.getLogger(__name__)
 
@@ -214,14 +214,45 @@ def entity_duplicate_validator(platform: str) -> Callable[[ConfigType], ConfigTy
         # Check for duplicates
         unique_key = (device_id, platform, name_key)
         if unique_key in CORE.unique_ids:
+            # Get the existing entity metadata
+            existing = CORE.unique_ids[unique_key]
+            existing_name = existing.get("name", entity_name)
+            existing_device = existing.get("device_id", "")
+            existing_id = existing.get("entity_id", "unknown")
+
+            # Build detailed error message
             device_prefix = f" on device '{device_id}'" if device_id else ""
+            existing_device_prefix = (
+                f" on device '{existing_device}'" if existing_device else ""
+            )
+            existing_component = existing.get("component", "unknown")
+
+            # Provide more context about where the duplicate was found
+            conflict_msg = (
+                f"Conflicts with entity '{existing_name}'{existing_device_prefix}"
+            )
+            if existing_id != "unknown":
+                conflict_msg += f" (id: {existing_id})"
+            if existing_component != "unknown":
+                conflict_msg += f" from component '{existing_component}'"
+
             raise cv.Invalid(
                 f"Duplicate {platform} entity with name '{entity_name}' found{device_prefix}. "
+                f"{conflict_msg}. "
                 f"Each entity on a device must have a unique name within its platform."
             )
 
-        # Add to tracking set
-        CORE.unique_ids.add(unique_key)
+        # Store metadata about this entity
+        entity_metadata: EntityMetadata = {
+            "name": entity_name,
+            "device_id": device_id,
+            "platform": platform,
+            "entity_id": str(config.get(CONF_ID, "unknown")),
+            "component": CORE.current_component or "unknown",
+        }
+
+        # Add to tracking dict
+        CORE.unique_ids[unique_key] = entity_metadata
         return config
 
     return validator
diff --git a/esphome/types.py b/esphome/types.py
index f68f503993..62499a953c 100644
--- a/esphome/types.py
+++ b/esphome/types.py
@@ -1,5 +1,7 @@
 """This helper module tracks commonly used types in the esphome python codebase."""
 
+from typing import TypedDict
+
 from esphome.core import ID, EsphomeCore, Lambda
 
 ConfigFragmentType = (
@@ -16,3 +18,13 @@ ConfigFragmentType = (
 ConfigType = dict[str, ConfigFragmentType]
 CoreType = EsphomeCore
 ConfigPathType = str | int
+
+
+class EntityMetadata(TypedDict):
+    """Metadata stored for each entity to help with duplicate detection."""
+
+    name: str
+    device_id: str
+    platform: str
+    entity_id: str
+    component: str
diff --git a/tests/unit_tests/core/test_entity_helpers.py b/tests/unit_tests/core/test_entity_helpers.py
index c639ad94b2..2157bc20a9 100644
--- a/tests/unit_tests/core/test_entity_helpers.py
+++ b/tests/unit_tests/core/test_entity_helpers.py
@@ -12,6 +12,7 @@ from esphome.const import (
     CONF_DEVICE_ID,
     CONF_DISABLED_BY_DEFAULT,
     CONF_ICON,
+    CONF_ID,
     CONF_INTERNAL,
     CONF_NAME,
 )
@@ -511,12 +512,18 @@ def test_entity_duplicate_validator() -> None:
     validated1 = validator(config1)
     assert validated1 == config1
     assert ("", "sensor", "temperature") in CORE.unique_ids
+    # Check metadata was stored
+    metadata = CORE.unique_ids[("", "sensor", "temperature")]
+    assert metadata["name"] == "Temperature"
+    assert metadata["platform"] == "sensor"
 
     # Second entity with different name should pass
     config2 = {CONF_NAME: "Humidity"}
     validated2 = validator(config2)
     assert validated2 == config2
     assert ("", "sensor", "humidity") in CORE.unique_ids
+    metadata2 = CORE.unique_ids[("", "sensor", "humidity")]
+    assert metadata2["name"] == "Humidity"
 
     # Duplicate entity should fail
     config3 = {CONF_NAME: "Temperature"}
@@ -540,11 +547,15 @@ def test_entity_duplicate_validator_with_devices() -> None:
     validated1 = validator(config1)
     assert validated1 == config1
     assert ("device1", "sensor", "temperature") in CORE.unique_ids
+    metadata1 = CORE.unique_ids[("device1", "sensor", "temperature")]
+    assert metadata1["device_id"] == "device1"
 
     config2 = {CONF_NAME: "Temperature", CONF_DEVICE_ID: device2}
     validated2 = validator(config2)
     assert validated2 == config2
     assert ("device2", "sensor", "temperature") in CORE.unique_ids
+    metadata2 = CORE.unique_ids[("device2", "sensor", "temperature")]
+    assert metadata2["device_id"] == "device2"
 
     # Duplicate on same device should fail
     config3 = {CONF_NAME: "Temperature", CONF_DEVICE_ID: device1}
@@ -595,6 +606,54 @@ def test_entity_different_platforms_yaml_validation(
     assert result is not None
 
 
+def test_entity_duplicate_validator_error_message() -> None:
+    """Test that duplicate entity error messages include helpful metadata."""
+    # Create validator for sensor platform
+    validator = entity_duplicate_validator("sensor")
+
+    # Set current component to simulate validation context for uptime sensor
+    CORE.current_component = "sensor.uptime"
+
+    # First entity should pass
+    config1 = {CONF_NAME: "Battery", CONF_ID: ID("battery_1")}
+    validated1 = validator(config1)
+    assert validated1 == config1
+
+    # Reset component to simulate template sensor
+    CORE.current_component = "sensor.template"
+
+    # Duplicate entity should fail with detailed error
+    config2 = {CONF_NAME: "Battery", CONF_ID: ID("battery_2")}
+    with pytest.raises(
+        Invalid,
+        match=r"Duplicate sensor entity with name 'Battery' found.*"
+        r"Conflicts with entity 'Battery' \(id: battery_1\) from component 'sensor\.uptime'",
+    ):
+        validator(config2)
+
+    # Clean up
+    CORE.current_component = None
+
+
+def test_entity_conflict_between_components_yaml(
+    yaml_file: Callable[[str], str], capsys: pytest.CaptureFixture[str]
+) -> None:
+    """Test that conflicts between different components show helpful error messages."""
+    result = load_config_from_fixture(
+        yaml_file, "entity_conflict_components.yaml", FIXTURES_DIR
+    )
+    assert result is None
+
+    # Check for the enhanced error message
+    captured = capsys.readouterr()
+    # The error should mention both the conflict and which component created it
+    assert "Duplicate sensor entity with name 'Battery' found" in captured.out
+    # Should mention it conflicts with an entity from a specific sensor platform
+    assert "from component 'sensor." in captured.out
+    # Should show it's a conflict between wifi_signal and template
+    assert "sensor.wifi_signal" in captured.out or "sensor.template" in captured.out
+
+
 def test_entity_duplicate_validator_internal_entities() -> None:
     """Test that internal entities are excluded from duplicate name validation."""
     # Create validator for sensor platform
@@ -612,14 +671,17 @@ def test_entity_duplicate_validator_internal_entities() -> None:
     validated2 = validator(config2)
     assert validated2 == config2
     # Internal entity should not be added to unique_ids
-    assert len([k for k in CORE.unique_ids if k == ("", "sensor", "temperature")]) == 1
+    # Count how many times the key appears (should still be 1)
+    count = sum(1 for k in CORE.unique_ids if k == ("", "sensor", "temperature"))
+    assert count == 1
 
     # Another internal entity with same name should also pass
     config3 = {CONF_NAME: "Temperature", CONF_INTERNAL: True}
     validated3 = validator(config3)
     assert validated3 == config3
     # Still only one entry in unique_ids (from the non-internal entity)
-    assert len([k for k in CORE.unique_ids if k == ("", "sensor", "temperature")]) == 1
+    count = sum(1 for k in CORE.unique_ids if k == ("", "sensor", "temperature"))
+    assert count == 1
 
     # Non-internal entity with same name should fail
     config4 = {CONF_NAME: "Temperature"}
diff --git a/tests/unit_tests/fixtures/core/entity_helpers/entity_conflict_components.yaml b/tests/unit_tests/fixtures/core/entity_helpers/entity_conflict_components.yaml
new file mode 100644
index 0000000000..6a1df0f7b4
--- /dev/null
+++ b/tests/unit_tests/fixtures/core/entity_helpers/entity_conflict_components.yaml
@@ -0,0 +1,20 @@
+esphome:
+  name: test-device
+
+esp32:
+  board: esp32dev
+
+# Uptime sensor
+sensor:
+  - platform: uptime
+    name: "Battery"
+    id: uptime_battery
+
+# Template sensor also named "Battery" - this should conflict
+  - platform: template
+    name: "Battery"
+    id: template_battery
+    lambda: |-
+      return 95.0;
+    unit_of_measurement: "%"
+    update_interval: 60s

From ff52869b4c0d6552d17187fe773a702a8f162677 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 11 Aug 2025 17:10:38 -0500
Subject: [PATCH 6/6] [api] Add constexpr optimizations to protobuf encoding
 (#10192)

---
 esphome/components/api/proto.h | 76 ++++++++++++++++------------------
 1 file changed, 36 insertions(+), 40 deletions(-)

diff --git a/esphome/components/api/proto.h b/esphome/components/api/proto.h
index 5c174b679c..0e5ec61050 100644
--- a/esphome/components/api/proto.h
+++ b/esphome/components/api/proto.h
@@ -15,6 +15,23 @@
 
 namespace esphome::api {
 
+// Helper functions for ZigZag encoding/decoding
+inline constexpr uint32_t encode_zigzag32(int32_t value) {
+  return (static_cast<uint32_t>(value) << 1) ^ (static_cast<uint32_t>(value >> 31));
+}
+
+inline constexpr uint64_t encode_zigzag64(int64_t value) {
+  return (static_cast<uint64_t>(value) << 1) ^ (static_cast<uint64_t>(value >> 63));
+}
+
+inline constexpr int32_t decode_zigzag32(uint32_t value) {
+  return (value & 1) ? static_cast<int32_t>(~(value >> 1)) : static_cast<int32_t>(value >> 1);
+}
+
+inline constexpr int64_t decode_zigzag64(uint64_t value) {
+  return (value & 1) ? static_cast<int64_t>(~(value >> 1)) : static_cast<int64_t>(value >> 1);
+}
+
 /*
  * StringRef Ownership Model for API Protocol Messages
  * ===================================================
@@ -87,33 +104,25 @@ class ProtoVarInt {
     return {};  // Incomplete or invalid varint
   }
 
-  uint16_t as_uint16() const { return this->value_; }
-  uint32_t as_uint32() const { return this->value_; }
-  uint64_t as_uint64() const { return this->value_; }
-  bool as_bool() const { return this->value_; }
-  int32_t as_int32() const {
+  constexpr uint16_t as_uint16() const { return this->value_; }
+  constexpr uint32_t as_uint32() const { return this->value_; }
+  constexpr uint64_t as_uint64() const { return this->value_; }
+  constexpr bool as_bool() const { return this->value_; }
+  constexpr int32_t as_int32() const {
     // Not ZigZag encoded
     return static_cast<int32_t>(this->as_int64());
   }
-  int64_t as_int64() const {
+  constexpr int64_t as_int64() const {
     // Not ZigZag encoded
     return static_cast<int64_t>(this->value_);
   }
-  int32_t as_sint32() const {
+  constexpr int32_t as_sint32() const {
     // with ZigZag encoding
-    if (this->value_ & 1) {
-      return static_cast<int32_t>(~(this->value_ >> 1));
-    } else {
-      return static_cast<int32_t>(this->value_ >> 1);
-    }
+    return decode_zigzag32(static_cast<uint32_t>(this->value_));
   }
-  int64_t as_sint64() const {
+  constexpr int64_t as_sint64() const {
     // with ZigZag encoding
-    if (this->value_ & 1) {
-      return static_cast<int64_t>(~(this->value_ >> 1));
-    } else {
-      return static_cast<int64_t>(this->value_ >> 1);
-    }
+    return decode_zigzag64(this->value_);
   }
   /**
    * Encode the varint value to a pre-allocated buffer without bounds checking.
@@ -309,22 +318,10 @@ class ProtoWriteBuffer {
     this->encode_uint64(field_id, static_cast<uint64_t>(value), force);
   }
   void encode_sint32(uint32_t field_id, int32_t value, bool force = false) {
-    uint32_t uvalue;
-    if (value < 0) {
-      uvalue = ~(value << 1);
-    } else {
-      uvalue = value << 1;
-    }
-    this->encode_uint32(field_id, uvalue, force);
+    this->encode_uint32(field_id, encode_zigzag32(value), force);
   }
   void encode_sint64(uint32_t field_id, int64_t value, bool force = false) {
-    uint64_t uvalue;
-    if (value < 0) {
-      uvalue = ~(value << 1);
-    } else {
-      uvalue = value << 1;
-    }
-    this->encode_uint64(field_id, uvalue, force);
+    this->encode_uint64(field_id, encode_zigzag64(value), force);
   }
   void encode_message(uint32_t field_id, const ProtoMessage &value, bool force = false);
   std::vector<uint8_t> *get_buffer() const { return buffer_; }
@@ -395,7 +392,7 @@ class ProtoSize {
    * @param value The uint32_t value to calculate size for
    * @return The number of bytes needed to encode the value
    */
-  static inline uint32_t varint(uint32_t value) {
+  static constexpr uint32_t varint(uint32_t value) {
     // Optimized varint size calculation using leading zeros
     // Each 7 bits requires one byte in the varint encoding
     if (value < 128)
@@ -419,7 +416,7 @@ class ProtoSize {
    * @param value The uint64_t value to calculate size for
    * @return The number of bytes needed to encode the value
    */
-  static inline uint32_t varint(uint64_t value) {
+  static constexpr uint32_t varint(uint64_t value) {
     // Handle common case of values fitting in uint32_t (vast majority of use cases)
     if (value <= UINT32_MAX) {
       return varint(static_cast<uint32_t>(value));
@@ -450,7 +447,7 @@ class ProtoSize {
    * @param value The int32_t value to calculate size for
    * @return The number of bytes needed to encode the value
    */
-  static inline uint32_t varint(int32_t value) {
+  static constexpr uint32_t varint(int32_t value) {
     // Negative values are sign-extended to 64 bits in protocol buffers,
     // which always results in a 10-byte varint for negative int32
     if (value < 0) {
@@ -466,7 +463,7 @@ class ProtoSize {
    * @param value The int64_t value to calculate size for
    * @return The number of bytes needed to encode the value
    */
-  static inline uint32_t varint(int64_t value) {
+  static constexpr uint32_t varint(int64_t value) {
     // For int64_t, we convert to uint64_t and calculate the size
     // This works because the bit pattern determines the encoding size,
     // and we've handled negative int32 values as a special case above
@@ -480,7 +477,7 @@ class ProtoSize {
    * @param type The wire type value (from the WireType enum in the protobuf spec)
    * @return The number of bytes needed to encode the field ID and wire type
    */
-  static inline uint32_t field(uint32_t field_id, uint32_t type) {
+  static constexpr uint32_t field(uint32_t field_id, uint32_t type) {
     uint32_t tag = (field_id << 3) | (type & 0b111);
     return varint(tag);
   }
@@ -607,9 +604,8 @@ class ProtoSize {
    */
   inline void add_sint32_force(uint32_t field_id_size, int32_t value) {
     // Always calculate size when force is true
-    // ZigZag encoding for sint32: (n << 1) ^ (n >> 31)
-    uint32_t zigzag = (static_cast<uint32_t>(value) << 1) ^ (static_cast<uint32_t>(value >> 31));
-    total_size_ += field_id_size + varint(zigzag);
+    // ZigZag encoding for sint32
+    total_size_ += field_id_size + varint(encode_zigzag32(value));
   }
 
   /**