Merge branch 'dev' into str_sprintf

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

esphome/components/esp32_hosted/update/esp32_hosted_update.cpp

@@ -11,6 +11,7 @@
 #include <esp_ota_ops.h>
 
 #ifdef USE_ESP32_HOSTED_HTTP_UPDATE
+#include "esphome/components/http_request/http_request.h"
 #include "esphome/components/json/json_util.h"
 #include "esphome/components/network/util.h"
 #endif
@@ -184,15 +185,23 @@ bool Esp32HostedUpdate::fetch_manifest_() {
   }
 
   // Read manifest JSON into string (manifest is small, ~1KB max)
+  // NOTE: HttpContainer::read() has non-BSD socket semantics - see http_request.h
+  // Use http_read_loop_result() helper instead of checking return values directly
   std::string json_str;
   json_str.reserve(container->content_length);
   uint8_t buf[256];
+  uint32_t last_data_time = millis();
+  const uint32_t read_timeout = this->http_request_parent_->get_timeout();
   while (container->get_bytes_read() < container->content_length) {
-    int read = container->read(buf, sizeof(buf));
-    if (read > 0) {
-      json_str.append(reinterpret_cast<char *>(buf), read);
-    }
+    int read_or_error = container->read(buf, sizeof(buf));
+    App.feed_wdt();
     yield();
+    auto result = http_request::http_read_loop_result(read_or_error, last_data_time, read_timeout);
+    if (result == http_request::HttpReadLoopResult::RETRY)
+      continue;
+    if (result != http_request::HttpReadLoopResult::DATA)
+      break;  // ERROR or TIMEOUT
+    json_str.append(reinterpret_cast<char *>(buf), read_or_error);
   }
   container->end();
 
@@ -297,32 +306,38 @@ bool Esp32HostedUpdate::stream_firmware_to_coprocessor_() {
   }
 
   // Stream firmware to coprocessor while computing SHA256
+  // NOTE: HttpContainer::read() has non-BSD socket semantics - see http_request.h
+  // Use http_read_loop_result() helper instead of checking return values directly
   sha256::SHA256 hasher;
   hasher.init();
 
   uint8_t buffer[CHUNK_SIZE];
+  uint32_t last_data_time = millis();
+  const uint32_t read_timeout = this->http_request_parent_->get_timeout();
   while (container->get_bytes_read() < total_size) {
-    int read = container->read(buffer, sizeof(buffer));
+    int read_or_error = container->read(buffer, sizeof(buffer));
 
     // Feed watchdog and give other tasks a chance to run
     App.feed_wdt();
     yield();
 
-    // Exit loop if no data available (stream closed or end of data)
-    if (read <= 0) {
-      if (read < 0) {
-        ESP_LOGE(TAG, "Stream closed with error");
-        esp_hosted_slave_ota_end();  // NOLINT
-        container->end();
-        this->status_set_error(LOG_STR("Download failed"));
-        return false;
+    auto result = http_request::http_read_loop_result(read_or_error, last_data_time, read_timeout);
+    if (result == http_request::HttpReadLoopResult::RETRY)
+      continue;
+    if (result != http_request::HttpReadLoopResult::DATA) {
+      if (result == http_request::HttpReadLoopResult::TIMEOUT) {
+        ESP_LOGE(TAG, "Timeout reading firmware data");
+      } else {
+        ESP_LOGE(TAG, "Error reading firmware data: %d", read_or_error);
       }
-      // read == 0: no more data available, exit loop
-      break;
+      esp_hosted_slave_ota_end();  // NOLINT
+      container->end();
+      this->status_set_error(LOG_STR("Download failed"));
+      return false;
     }
 
-    hasher.add(buffer, read);
-    err = esp_hosted_slave_ota_write(buffer, read);  // NOLINT
+    hasher.add(buffer, read_or_error);
+    err = esp_hosted_slave_ota_write(buffer, read_or_error);  // NOLINT
     if (err != ESP_OK) {
       ESP_LOGE(TAG, "Failed to write OTA data: %s", esp_err_to_name(err));
       esp_hosted_slave_ota_end();  // NOLINT

esphome/components/http_request/http_request.h

@@ -79,6 +79,81 @@ inline bool is_redirect(int const status) {
  */
 inline bool is_success(int const status) { return status >= HTTP_STATUS_OK && status < HTTP_STATUS_MULTIPLE_CHOICES; }
 
+/*
+ * HTTP Container Read Semantics
+ * =============================
+ *
+ * IMPORTANT: These semantics differ from standard BSD sockets!
+ *
+ * BSD socket read() returns:
+ *   > 0: bytes read
+ *   == 0: connection closed (EOF)
+ *   < 0: error (check errno)
+ *
+ * HttpContainer::read() returns:
+ *   > 0: bytes read successfully
+ *   == 0: no data available yet OR all content read
+ *         (caller should check bytes_read vs content_length)
+ *   < 0: error or connection closed (caller should EXIT)
+ *        HTTP_ERROR_CONNECTION_CLOSED (-1) = connection closed prematurely
+ *        other negative values = platform-specific errors
+ *
+ * Platform behaviors:
+ *   - ESP-IDF: blocking reads, 0 only returned when all content read
+ *   - Arduino: non-blocking, 0 means "no data yet" or "all content read"
+ *
+ * Use the helper functions below instead of checking return values directly:
+ *   - http_read_loop_result(): for manual loops with per-chunk processing
+ *   - http_read_fully(): for simple "read N bytes into buffer" operations
+ */
+
+/// Error code returned by HttpContainer::read() when connection closed prematurely
+/// NOTE: Unlike BSD sockets where 0 means EOF, here 0 means "no data yet, retry"
+static constexpr int HTTP_ERROR_CONNECTION_CLOSED = -1;
+
+/// Status of a read operation
+enum class HttpReadStatus : uint8_t {
+  OK,       ///< Read completed successfully
+  ERROR,    ///< Read error occurred
+  TIMEOUT,  ///< Timeout waiting for data
+};
+
+/// Result of an HTTP read operation
+struct HttpReadResult {
+  HttpReadStatus status;  ///< Status of the read operation
+  int error_code;         ///< Error code from read() on failure, 0 on success
+};
+
+/// Result of processing a non-blocking read with timeout (for manual loops)
+enum class HttpReadLoopResult : uint8_t {
+  DATA,     ///< Data was read, process it
+  RETRY,    ///< No data yet, already delayed, caller should continue loop
+  ERROR,    ///< Read error, caller should exit loop
+  TIMEOUT,  ///< Timeout waiting for data, caller should exit loop
+};
+
+/// Process a read result with timeout tracking and delay handling
+/// @param bytes_read_or_error Return value from read() - positive for bytes read, negative for error
+/// @param last_data_time Time of last successful read, updated when data received
+/// @param timeout_ms Maximum time to wait for data
+/// @return DATA if data received, RETRY if should continue loop, ERROR/TIMEOUT if should exit
+inline HttpReadLoopResult http_read_loop_result(int bytes_read_or_error, uint32_t &last_data_time,
+                                                uint32_t timeout_ms) {
+  if (bytes_read_or_error > 0) {
+    last_data_time = millis();
+    return HttpReadLoopResult::DATA;
+  }
+  if (bytes_read_or_error < 0) {
+    return HttpReadLoopResult::ERROR;
+  }
+  // bytes_read_or_error == 0: no data available yet
+  if (millis() - last_data_time >= timeout_ms) {
+    return HttpReadLoopResult::TIMEOUT;
+  }
+  delay(1);  // Small delay to prevent tight spinning
+  return HttpReadLoopResult::RETRY;
+}
+
 class HttpRequestComponent;
 
 class HttpContainer : public Parented<HttpRequestComponent> {
@@ -88,6 +163,33 @@ class HttpContainer : public Parented<HttpRequestComponent> {
   int status_code;
   uint32_t duration_ms;
 
+  /**
+   * @brief Read data from the HTTP response body.
+   *
+   * WARNING: These semantics differ from BSD sockets!
+   * BSD sockets: 0 = EOF (connection closed)
+   * This method: 0 = no data yet OR all content read, negative = error/closed
+   *
+   * @param buf Buffer to read data into
+   * @param max_len Maximum number of bytes to read
+   * @return
+   *   - > 0: Number of bytes read successfully
+   *   - 0: No data available yet OR all content read
+   *        (check get_bytes_read() >= content_length to distinguish)
+   *   - HTTP_ERROR_CONNECTION_CLOSED (-1): Connection closed prematurely
+   *   - < -1: Other error (platform-specific error code)
+   *
+   * Platform notes:
+   *   - ESP-IDF: blocking read, 0 only when all content read
+   *   - Arduino: non-blocking, 0 can mean "no data yet" or "all content read"
+   *
+   * Use get_bytes_read() and content_length to track progress.
+   * When get_bytes_read() >= content_length, all data has been received.
+   *
+   * IMPORTANT: Do not use raw return values directly. Use these helpers:
+   *   - http_read_loop_result(): for loops with per-chunk processing
+   *   - http_read_fully(): for simple "read N bytes" operations
+   */
   virtual int read(uint8_t *buf, size_t max_len) = 0;
   virtual void end() = 0;
 
@@ -110,6 +212,38 @@ class HttpContainer : public Parented<HttpRequestComponent> {
   std::map<std::string, std::list<std::string>> response_headers_{};
 };
 
+/// Read data from HTTP container into buffer with timeout handling
+/// Handles feed_wdt, yield, and timeout checking internally
+/// @param container The HTTP container to read from
+/// @param buffer Buffer to read into
+/// @param total_size Total bytes to read
+/// @param chunk_size Maximum bytes per read call
+/// @param timeout_ms Read timeout in milliseconds
+/// @return HttpReadResult with status and error_code on failure
+inline HttpReadResult http_read_fully(HttpContainer *container, uint8_t *buffer, size_t total_size, size_t chunk_size,
+                                      uint32_t timeout_ms) {
+  size_t read_index = 0;
+  uint32_t last_data_time = millis();
+
+  while (read_index < total_size) {
+    int read_bytes_or_error = container->read(buffer + read_index, std::min(chunk_size, total_size - read_index));
+
+    App.feed_wdt();
+    yield();
+
+    auto result = http_read_loop_result(read_bytes_or_error, last_data_time, timeout_ms);
+    if (result == HttpReadLoopResult::RETRY)
+      continue;
+    if (result == HttpReadLoopResult::ERROR)
+      return {HttpReadStatus::ERROR, read_bytes_or_error};
+    if (result == HttpReadLoopResult::TIMEOUT)
+      return {HttpReadStatus::TIMEOUT, 0};
+
+    read_index += read_bytes_or_error;
+  }
+  return {HttpReadStatus::OK, 0};
+}
+
 class HttpRequestResponseTrigger : public Trigger<std::shared_ptr<HttpContainer>, std::string &> {
  public:
   void process(const std::shared_ptr<HttpContainer> &container, std::string &response_body) {
@@ -124,6 +258,7 @@ class HttpRequestComponent : public Component {
 
   void set_useragent(const char *useragent) { this->useragent_ = useragent; }
   void set_timeout(uint32_t timeout) { this->timeout_ = timeout; }
+  uint32_t get_timeout() const { return this->timeout_; }
   void set_watchdog_timeout(uint32_t watchdog_timeout) { this->watchdog_timeout_ = watchdog_timeout; }
   uint32_t get_watchdog_timeout() const { return this->watchdog_timeout_; }
   void set_follow_redirects(bool follow_redirects) { this->follow_redirects_ = follow_redirects; }
@@ -249,15 +384,21 @@ template<typename... Ts> class HttpRequestSendAction : public Action<Ts...> {
       RAMAllocator<uint8_t> allocator;
       uint8_t *buf = allocator.allocate(max_length);
       if (buf != nullptr) {
+        // NOTE: HttpContainer::read() has non-BSD socket semantics - see top of this file
+        // Use http_read_loop_result() helper instead of checking return values directly
         size_t read_index = 0;
+        uint32_t last_data_time = millis();
+        const uint32_t read_timeout = this->parent_->get_timeout();
         while (container->get_bytes_read() < max_length) {
-          int read = container->read(buf + read_index, std::min<size_t>(max_length - read_index, 512));
-          if (read <= 0) {
-            break;
-          }
+          int read_or_error = container->read(buf + read_index, std::min<size_t>(max_length - read_index, 512));
           App.feed_wdt();
           yield();
-          read_index += read;
+          auto result = http_read_loop_result(read_or_error, last_data_time, read_timeout);
+          if (result == HttpReadLoopResult::RETRY)
+            continue;
+          if (result != HttpReadLoopResult::DATA)
+            break;  // ERROR or TIMEOUT
+          read_index += read_or_error;
         }
         response_body.reserve(read_index);
         response_body.assign((char *) buf, read_index);

esphome/components/http_request/http_request_arduino.cpp

@@ -139,6 +139,23 @@ std::shared_ptr<HttpContainer> HttpRequestArduino::perform(const std::string &ur
   return container;
 }
 
+// Arduino HTTP read implementation
+//
+// WARNING: Return values differ from BSD sockets! See http_request.h for full documentation.
+//
+// Arduino's WiFiClient is inherently non-blocking - available() returns 0 when
+// no data is ready. We use connected() to distinguish "no data yet" from
+// "connection closed".
+//
+// WiFiClient behavior:
+//   available() > 0: data ready to read
+//   available() == 0 && connected(): no data yet, still connected
+//   available() == 0 && !connected(): connection closed
+//
+// We normalize to HttpContainer::read() contract (NOT BSD socket semantics!):
+//   > 0: bytes read
+//   0: no data yet, retry            <-- NOTE: 0 means retry, NOT EOF!
+//   < 0: error/connection closed     <-- connection closed returns -1, not 0
 int HttpContainerArduino::read(uint8_t *buf, size_t max_len) {
   const uint32_t start = millis();
   watchdog::WatchdogManager wdm(this->parent_->get_watchdog_timeout());
@@ -146,7 +163,7 @@ int HttpContainerArduino::read(uint8_t *buf, size_t max_len) {
   WiFiClient *stream_ptr = this->client_.getStreamPtr();
   if (stream_ptr == nullptr) {
     ESP_LOGE(TAG, "Stream pointer vanished!");
-    return -1;
+    return HTTP_ERROR_CONNECTION_CLOSED;
   }
 
   int available_data = stream_ptr->available();
@@ -154,7 +171,15 @@ int HttpContainerArduino::read(uint8_t *buf, size_t max_len) {
 
   if (bufsize == 0) {
     this->duration_ms += (millis() - start);
-    return 0;
+    // Check if we've read all expected content
+    if (this->bytes_read_ >= this->content_length) {
+      return 0;  // All content read successfully
+    }
+    // No data available - check if connection is still open
+    if (!stream_ptr->connected()) {
+      return HTTP_ERROR_CONNECTION_CLOSED;  // Connection closed prematurely
+    }
+    return 0;  // No data yet, caller should retry
   }
 
   App.feed_wdt();

esphome/components/http_request/http_request_idf.cpp

@@ -209,26 +209,57 @@ std::shared_ptr<HttpContainer> HttpRequestIDF::perform(const std::string &url, c
   return container;
 }
 
+// ESP-IDF HTTP read implementation (blocking mode)
+//
+// WARNING: Return values differ from BSD sockets! See http_request.h for full documentation.
+//
+// esp_http_client_read() in blocking mode returns:
+//   > 0: bytes read
+//   0: connection closed (end of stream)
+//   < 0: error
+//
+// We normalize to HttpContainer::read() contract:
+//   > 0: bytes read
+//   0: no data yet / all content read (caller should check bytes_read vs content_length)
+//   < 0: error/connection closed
 int HttpContainerIDF::read(uint8_t *buf, size_t max_len) {
   const uint32_t start = millis();
   watchdog::WatchdogManager wdm(this->parent_->get_watchdog_timeout());
 
-  this->feed_wdt();
-  int read_len = esp_http_client_read(this->client_, (char *) buf, max_len);
-  this->feed_wdt();
-  if (read_len > 0) {
-    this->bytes_read_ += read_len;
+  // Check if we've already read all expected content
+  if (this->bytes_read_ >= this->content_length) {
+    return 0;  // All content read successfully
   }
+
+  this->feed_wdt();
+  int read_len_or_error = esp_http_client_read(this->client_, (char *) buf, max_len);
+  this->feed_wdt();
+
   this->duration_ms += (millis() - start);
 
-  return read_len;
+  if (read_len_or_error > 0) {
+    this->bytes_read_ += read_len_or_error;
+    return read_len_or_error;
+  }
+
+  // Connection closed by server before all content received
+  if (read_len_or_error == 0) {
+    return HTTP_ERROR_CONNECTION_CLOSED;
+  }
+
+  // Negative value - error, return the actual error code for debugging
+  return read_len_or_error;
 }
 
 void HttpContainerIDF::end() {
+  if (this->client_ == nullptr) {
+    return;  // Already cleaned up
+  }
   watchdog::WatchdogManager wdm(this->parent_->get_watchdog_timeout());
 
   esp_http_client_close(this->client_);
   esp_http_client_cleanup(this->client_);
+  this->client_ = nullptr;
 }
 
 void HttpContainerIDF::feed_wdt() {

esphome/components/http_request/ota/ota_http_request.cpp

@@ -115,39 +115,47 @@ uint8_t OtaHttpRequestComponent::do_ota_() {
     return error_code;
   }
 
+  // NOTE: HttpContainer::read() has non-BSD socket semantics - see http_request.h
+  // Use http_read_loop_result() helper instead of checking return values directly
+  uint32_t last_data_time = millis();
+  const uint32_t read_timeout = this->parent_->get_timeout();
+
   while (container->get_bytes_read() < container->content_length) {
-    // read a maximum of chunk_size bytes into buf. (real read size returned)
-    int bufsize = container->read(buf, OtaHttpRequestComponent::HTTP_RECV_BUFFER);
-    ESP_LOGVV(TAG, "bytes_read_ = %u, body_length_ = %u, bufsize = %i", container->get_bytes_read(),
-              container->content_length, bufsize);
+    // read a maximum of chunk_size bytes into buf. (real read size returned, or negative error code)
+    int bufsize_or_error = container->read(buf, OtaHttpRequestComponent::HTTP_RECV_BUFFER);
+    ESP_LOGVV(TAG, "bytes_read_ = %u, body_length_ = %u, bufsize_or_error = %i", container->get_bytes_read(),
+              container->content_length, bufsize_or_error);
 
     // feed watchdog and give other tasks a chance to run
     App.feed_wdt();
     yield();
 
-    // Exit loop if no data available (stream closed or end of data)
-    if (bufsize <= 0) {
-      if (bufsize < 0) {
-        ESP_LOGE(TAG, "Stream closed with error");
-        this->cleanup_(std::move(backend), container);
-        return OTA_CONNECTION_ERROR;
+    auto result = http_read_loop_result(bufsize_or_error, last_data_time, read_timeout);
+    if (result == HttpReadLoopResult::RETRY)
+      continue;
+    if (result != HttpReadLoopResult::DATA) {
+      if (result == HttpReadLoopResult::TIMEOUT) {
+        ESP_LOGE(TAG, "Timeout reading data");
+      } else {
+        ESP_LOGE(TAG, "Error reading data: %d", bufsize_or_error);
       }
-      // bufsize == 0: no more data available, exit loop
-      break;
+      this->cleanup_(std::move(backend), container);
+      return OTA_CONNECTION_ERROR;
     }
 
-    if (bufsize <= OtaHttpRequestComponent::HTTP_RECV_BUFFER) {
+    // At this point bufsize_or_error > 0, so it's a valid size
+    if (bufsize_or_error <= OtaHttpRequestComponent::HTTP_RECV_BUFFER) {
       // add read bytes to MD5
-      md5_receive.add(buf, bufsize);
+      md5_receive.add(buf, bufsize_or_error);
 
       // write bytes to OTA backend
       this->update_started_ = true;
-      error_code = backend->write(buf, bufsize);
+      error_code = backend->write(buf, bufsize_or_error);
       if (error_code != ota::OTA_RESPONSE_OK) {
         // error code explanation available at
         // https://github.com/esphome/esphome/blob/dev/esphome/components/ota/ota_backend.h
         ESP_LOGE(TAG, "Error code (%02X) writing binary data to flash at offset %d and size %d", error_code,
-                 container->get_bytes_read() - bufsize, container->content_length);
+                 container->get_bytes_read() - bufsize_or_error, container->content_length);
         this->cleanup_(std::move(backend), container);
         return error_code;
       }
@@ -244,19 +252,19 @@ bool OtaHttpRequestComponent::http_get_md5_() {
   }
 
   this->md5_expected_.resize(MD5_SIZE);
-  int read_len = 0;
-  while (container->get_bytes_read() < MD5_SIZE) {
-    read_len = container->read((uint8_t *) this->md5_expected_.data(), MD5_SIZE);
-    if (read_len <= 0) {
-      break;
-    }
-    App.feed_wdt();
-    yield();
-  }
+  auto result = http_read_fully(container.get(), (uint8_t *) this->md5_expected_.data(), MD5_SIZE, MD5_SIZE,
+                                this->parent_->get_timeout());
   container->end();
 
-  ESP_LOGV(TAG, "Read len: %u, MD5 expected: %u", read_len, MD5_SIZE);
-  return read_len == MD5_SIZE;
+  if (result.status != HttpReadStatus::OK) {
+    if (result.status == HttpReadStatus::TIMEOUT) {
+      ESP_LOGE(TAG, "Timeout reading MD5");
+    } else {
+      ESP_LOGE(TAG, "Error reading MD5: %d", result.error_code);
+    }
+    return false;
+  }
+  return true;
 }
 
 bool OtaHttpRequestComponent::validate_url_(const std::string &url) {

esphome/components/http_request/update/http_request_update.cpp

@@ -11,7 +11,12 @@ namespace http_request {
 
 // The update function runs in a task only on ESP32s.
 #ifdef USE_ESP32
-#define UPDATE_RETURN vTaskDelete(nullptr)  // Delete the current update task
+// vTaskDelete doesn't return, but clang-tidy doesn't know that
+#define UPDATE_RETURN \
+  do { \
+    vTaskDelete(nullptr); \
+    __builtin_unreachable(); \
+  } while (0)
 #else
 #define UPDATE_RETURN return
 #endif
@@ -70,19 +75,21 @@ void HttpRequestUpdate::update_task(void *params) {
     UPDATE_RETURN;
   }
 
-  size_t read_index = 0;
-  while (container->get_bytes_read() < container->content_length) {
-    int read_bytes = container->read(data + read_index, MAX_READ_SIZE);
-
-    yield();
-
-    if (read_bytes <= 0) {
-      // Network error or connection closed - break to avoid infinite loop
-      break;
+  auto read_result = http_read_fully(container.get(), data, container->content_length, MAX_READ_SIZE,
+                                     this_update->request_parent_->get_timeout());
+  if (read_result.status != HttpReadStatus::OK) {
+    if (read_result.status == HttpReadStatus::TIMEOUT) {
+      ESP_LOGE(TAG, "Timeout reading manifest");
+    } else {
+      ESP_LOGE(TAG, "Error reading manifest: %d", read_result.error_code);
     }
-
-    read_index += read_bytes;
+    // Defer to main loop to avoid race condition on component_state_ read-modify-write
+    this_update->defer([this_update]() { this_update->status_set_error(LOG_STR("Failed to read manifest")); });
+    allocator.deallocate(data, container->content_length);
+    container->end();
+    UPDATE_RETURN;
   }
+  size_t read_index = container->get_bytes_read();
 
   bool valid = false;
   {  // Ensures the response string falls out of scope and deallocates before the task ends

esphome/components/mqtt/mqtt_alarm_control_panel.cpp

@@ -119,8 +119,7 @@ bool MQTTAlarmControlPanelComponent::publish_state() {
     default:
       state_s = "unknown";
   }
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish(this->get_state_topic_to_(topic_buf), state_s);
+  return this->publish(this->get_state_topic_(), state_s);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_binary_sensor.cpp

@@ -52,9 +52,8 @@ bool MQTTBinarySensorComponent::publish_state(bool state) {
   if (this->binary_sensor_->is_status_binary_sensor())
     return true;
 
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
   const char *state_s = state ? "ON" : "OFF";
-  return this->publish(this->get_state_topic_to_(topic_buf), state_s);
+  return this->publish(this->get_state_topic_(), state_s);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_component.cpp

@@ -132,29 +132,17 @@ std::string MQTTComponent::get_command_topic_() const {
 }
 
 bool MQTTComponent::publish(const std::string &topic, const std::string &payload) {
-  return this->publish(topic.c_str(), payload.data(), payload.size());
+  return this->publish(topic, payload.data(), payload.size());
 }
 
 bool MQTTComponent::publish(const std::string &topic, const char *payload, size_t payload_length) {
-  return this->publish(topic.c_str(), payload, payload_length);
-}
-
-bool MQTTComponent::publish(const char *topic, const char *payload, size_t payload_length) {
-  if (topic[0] == '\0')
+  if (topic.empty())
     return false;
   return global_mqtt_client->publish(topic, payload, payload_length, this->qos_, this->retain_);
 }
 
-bool MQTTComponent::publish(const char *topic, const char *payload) {
-  return this->publish(topic, payload, strlen(payload));
-}
-
 bool MQTTComponent::publish_json(const std::string &topic, const json::json_build_t &f) {
-  return this->publish_json(topic.c_str(), f);
-}
-
-bool MQTTComponent::publish_json(const char *topic, const json::json_build_t &f) {
-  if (topic[0] == '\0')
+  if (topic.empty())
     return false;
   return global_mqtt_client->publish_json(topic, f, this->qos_, this->retain_);
 }

esphome/components/mqtt/mqtt_component.h

@@ -157,38 +157,6 @@ class MQTTComponent : public Component {
    */
   bool publish(const std::string &topic, const char *payload, size_t payload_length);
 
-  /** Send a MQTT message (no heap allocation for topic).
-   *
-   * @param topic The topic as C string.
-   * @param payload The payload buffer.
-   * @param payload_length The length of the payload.
-   */
-  bool publish(const char *topic, const char *payload, size_t payload_length);
-
-  /** Send a MQTT message (no heap allocation for topic).
-   *
-   * @param topic The topic as StringRef (for use with get_state_topic_to_()).
-   * @param payload The payload buffer.
-   * @param payload_length The length of the payload.
-   */
-  bool publish(StringRef topic, const char *payload, size_t payload_length) {
-    return this->publish(topic.c_str(), payload, payload_length);
-  }
-
-  /** Send a MQTT message (no heap allocation for topic).
-   *
-   * @param topic The topic as C string.
-   * @param payload The null-terminated payload.
-   */
-  bool publish(const char *topic, const char *payload);
-
-  /** Send a MQTT message (no heap allocation for topic).
-   *
-   * @param topic The topic as StringRef (for use with get_state_topic_to_()).
-   * @param payload The null-terminated payload.
-   */
-  bool publish(StringRef topic, const char *payload) { return this->publish(topic.c_str(), payload); }
-
   /** Construct and send a JSON MQTT message.
    *
    * @param topic The topic.
@@ -196,20 +164,6 @@ class MQTTComponent : public Component {
    */
   bool publish_json(const std::string &topic, const json::json_build_t &f);
 
-  /** Construct and send a JSON MQTT message (no heap allocation for topic).
-   *
-   * @param topic The topic as C string.
-   * @param f The Json Message builder.
-   */
-  bool publish_json(const char *topic, const json::json_build_t &f);
-
-  /** Construct and send a JSON MQTT message (no heap allocation for topic).
-   *
-   * @param topic The topic as StringRef (for use with get_state_topic_to_()).
-   * @param f The Json Message builder.
-   */
-  bool publish_json(StringRef topic, const json::json_build_t &f) { return this->publish_json(topic.c_str(), f); }
-
   /** Subscribe to a MQTT topic.
    *
    * @param topic The topic. Wildcards are currently not supported.

esphome/components/mqtt/mqtt_cover.cpp

@@ -115,8 +115,7 @@ bool MQTTCoverComponent::publish_state() {
                         : this->cover_->position == COVER_OPEN                       ? "open"
                         : traits.get_supports_position()                             ? "open"
                                                                                      : "unknown";
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  if (!this->publish(this->get_state_topic_to_(topic_buf), state_s))
+  if (!this->publish(this->get_state_topic_(), state_s))
     success = false;
   return success;
 }

esphome/components/mqtt/mqtt_date.cpp

@@ -53,8 +53,7 @@ bool MQTTDateComponent::send_initial_state() {
   }
 }
 bool MQTTDateComponent::publish_state(uint16_t year, uint8_t month, uint8_t day) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish_json(this->get_state_topic_to_(topic_buf), [year, month, day](JsonObject root) {
+  return this->publish_json(this->get_state_topic_(), [year, month, day](JsonObject root) {
     // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
     root[ESPHOME_F("year")] = year;
     root[ESPHOME_F("month")] = month;

esphome/components/mqtt/mqtt_datetime.cpp

@@ -66,17 +66,15 @@ bool MQTTDateTimeComponent::send_initial_state() {
 }
 bool MQTTDateTimeComponent::publish_state(uint16_t year, uint8_t month, uint8_t day, uint8_t hour, uint8_t minute,
                                           uint8_t second) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish_json(this->get_state_topic_to_(topic_buf),
-                            [year, month, day, hour, minute, second](JsonObject root) {
-                              // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
-                              root[ESPHOME_F("year")] = year;
-                              root[ESPHOME_F("month")] = month;
-                              root[ESPHOME_F("day")] = day;
-                              root[ESPHOME_F("hour")] = hour;
-                              root[ESPHOME_F("minute")] = minute;
-                              root[ESPHOME_F("second")] = second;
-                            });
+  return this->publish_json(this->get_state_topic_(), [year, month, day, hour, minute, second](JsonObject root) {
+    // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
+    root[ESPHOME_F("year")] = year;
+    root[ESPHOME_F("month")] = month;
+    root[ESPHOME_F("day")] = day;
+    root[ESPHOME_F("hour")] = hour;
+    root[ESPHOME_F("minute")] = minute;
+    root[ESPHOME_F("second")] = second;
+  });
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_event.cpp

@@ -44,8 +44,7 @@ void MQTTEventComponent::dump_config() {
 }
 
 bool MQTTEventComponent::publish_event_(const std::string &event_type) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish_json(this->get_state_topic_to_(topic_buf), [event_type](JsonObject root) {
+  return this->publish_json(this->get_state_topic_(), [event_type](JsonObject root) {
     // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
     root[MQTT_EVENT_TYPE] = event_type;
   });

esphome/components/mqtt/mqtt_fan.cpp

@@ -158,10 +158,9 @@ void MQTTFanComponent::send_discovery(JsonObject root, mqtt::SendDiscoveryConfig
   }
 }
 bool MQTTFanComponent::publish_state() {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
   const char *state_s = this->state_->state ? "ON" : "OFF";
   ESP_LOGD(TAG, "'%s' Sending state %s.", this->state_->get_name().c_str(), state_s);
-  this->publish(this->get_state_topic_to_(topic_buf), state_s);
+  this->publish(this->get_state_topic_(), state_s);
   bool failed = false;
   if (this->state_->get_traits().supports_direction()) {
     bool success = this->publish(this->get_direction_state_topic(),

esphome/components/mqtt/mqtt_light.cpp

@@ -34,8 +34,7 @@ void MQTTJSONLightComponent::on_light_remote_values_update() {
 MQTTJSONLightComponent::MQTTJSONLightComponent(LightState *state) : state_(state) {}
 
 bool MQTTJSONLightComponent::publish_state_() {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish_json(this->get_state_topic_to_(topic_buf), [this](JsonObject root) {
+  return this->publish_json(this->get_state_topic_(), [this](JsonObject root) {
     // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
     LightJSONSchema::dump_json(*this->state_, root);
   });

esphome/components/mqtt/mqtt_lock.cpp

@@ -47,14 +47,13 @@ void MQTTLockComponent::send_discovery(JsonObject root, mqtt::SendDiscoveryConfi
 bool MQTTLockComponent::send_initial_state() { return this->publish_state(); }
 
 bool MQTTLockComponent::publish_state() {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
 #ifdef USE_STORE_LOG_STR_IN_FLASH
   char buf[LOCK_STATE_STR_SIZE];
   strncpy_P(buf, (PGM_P) lock_state_to_string(this->lock_->state), sizeof(buf) - 1);
   buf[sizeof(buf) - 1] = '\0';
-  return this->publish(this->get_state_topic_to_(topic_buf), buf);
+  return this->publish(this->get_state_topic_(), buf);
 #else
-  return this->publish(this->get_state_topic_to_(topic_buf), LOG_STR_ARG(lock_state_to_string(this->lock_->state)));
+  return this->publish(this->get_state_topic_(), LOG_STR_ARG(lock_state_to_string(this->lock_->state)));
 #endif
 }
 

esphome/components/mqtt/mqtt_number.cpp

@@ -74,10 +74,9 @@ bool MQTTNumberComponent::send_initial_state() {
   }
 }
 bool MQTTNumberComponent::publish_state(float value) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
   char buffer[64];
-  size_t len = buf_append_printf(buffer, sizeof(buffer), 0, "%f", value);
-  return this->publish(this->get_state_topic_to_(topic_buf), buffer, len);
+  buf_append_printf(buffer, sizeof(buffer), 0, "%f", value);
+  return this->publish(this->get_state_topic_(), buffer);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_select.cpp

@@ -50,8 +50,7 @@ bool MQTTSelectComponent::send_initial_state() {
   }
 }
 bool MQTTSelectComponent::publish_state(const std::string &value) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish(this->get_state_topic_to_(topic_buf), value.data(), value.size());
+  return this->publish(this->get_state_topic_(), value);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_sensor.cpp

@@ -79,13 +79,12 @@ bool MQTTSensorComponent::send_initial_state() {
   }
 }
 bool MQTTSensorComponent::publish_state(float value) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
   if (mqtt::global_mqtt_client->is_publish_nan_as_none() && std::isnan(value))
-    return this->publish(this->get_state_topic_to_(topic_buf), "None", 4);
+    return this->publish(this->get_state_topic_(), "None", 4);
   int8_t accuracy = this->sensor_->get_accuracy_decimals();
   char buf[VALUE_ACCURACY_MAX_LEN];
   size_t len = value_accuracy_to_buf(buf, value, accuracy);
-  return this->publish(this->get_state_topic_to_(topic_buf), buf, len);
+  return this->publish(this->get_state_topic_(), buf, len);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_switch.cpp

@@ -52,9 +52,8 @@ void MQTTSwitchComponent::send_discovery(JsonObject root, mqtt::SendDiscoveryCon
 bool MQTTSwitchComponent::send_initial_state() { return this->publish_state(this->switch_->state); }
 
 bool MQTTSwitchComponent::publish_state(bool state) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
   const char *state_s = state ? "ON" : "OFF";
-  return this->publish(this->get_state_topic_to_(topic_buf), state_s);
+  return this->publish(this->get_state_topic_(), state_s);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_text.cpp

@@ -53,8 +53,7 @@ bool MQTTTextComponent::send_initial_state() {
   }
 }
 bool MQTTTextComponent::publish_state(const std::string &value) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish(this->get_state_topic_to_(topic_buf), value.data(), value.size());
+  return this->publish(this->get_state_topic_(), value);
 }
 
 }  // namespace esphome::mqtt

esphome/components/mqtt/mqtt_text_sensor.cpp

@@ -31,10 +31,7 @@ void MQTTTextSensor::dump_config() {
   LOG_MQTT_COMPONENT(true, false);
 }
 
-bool MQTTTextSensor::publish_state(const std::string &value) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish(this->get_state_topic_to_(topic_buf), value.data(), value.size());
-}
+bool MQTTTextSensor::publish_state(const std::string &value) { return this->publish(this->get_state_topic_(), value); }
 bool MQTTTextSensor::send_initial_state() {
   if (this->sensor_->has_state()) {
     return this->publish_state(this->sensor_->state);

esphome/components/mqtt/mqtt_time.cpp

@@ -53,8 +53,7 @@ bool MQTTTimeComponent::send_initial_state() {
   }
 }
 bool MQTTTimeComponent::publish_state(uint8_t hour, uint8_t minute, uint8_t second) {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish_json(this->get_state_topic_to_(topic_buf), [hour, minute, second](JsonObject root) {
+  return this->publish_json(this->get_state_topic_(), [hour, minute, second](JsonObject root) {
     // NOLINTNEXTLINE(clang-analyzer-cplusplus.NewDeleteLeaks) false positive with ArduinoJson
     root[ESPHOME_F("hour")] = hour;
     root[ESPHOME_F("minute")] = minute;

esphome/components/mqtt/mqtt_update.cpp

@@ -28,8 +28,7 @@ void MQTTUpdateComponent::setup() {
 }
 
 bool MQTTUpdateComponent::publish_state() {
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  return this->publish_json(this->get_state_topic_to_(topic_buf), [this](JsonObject root) {
+  return this->publish_json(this->get_state_topic_(), [this](JsonObject root) {
     root[ESPHOME_F("installed_version")] = this->update_->update_info.current_version;
     root[ESPHOME_F("latest_version")] = this->update_->update_info.latest_version;
     root[ESPHOME_F("title")] = this->update_->update_info.title;

esphome/components/mqtt/mqtt_valve.cpp

@@ -84,8 +84,7 @@ bool MQTTValveComponent::publish_state() {
                         : this->valve_->position == VALVE_OPEN                       ? "open"
                         : traits.get_supports_position()                             ? "open"
                                                                                      : "unknown";
-  char topic_buf[MQTT_DEFAULT_TOPIC_MAX_LEN];
-  if (!this->publish(this->get_state_topic_to_(topic_buf), state_s))
+  if (!this->publish(this->get_state_topic_(), state_s))
     success = false;
   return success;
 }

esphome/core/helpers.h

@@ -655,9 +655,11 @@ inline uint32_t fnv1_hash_object_id(const char *str, size_t len) {
 }
 
 /// snprintf-like function returning std::string of maximum length \p len (excluding null terminator).
+/// @warning Allocates heap memory. Use snprintf() with a stack buffer instead.
 std::string __attribute__((format(printf, 1, 3))) str_snprintf(const char *fmt, size_t len, ...);
 
 /// sprintf-like function returning std::string.
+/// @warning Allocates heap memory. Use snprintf() with a stack buffer instead.
 std::string __attribute__((format(printf, 1, 2))) str_sprintf(const char *fmt, ...);
 
 #ifdef USE_ESP8266

script/ci-custom.py

@@ -692,6 +692,8 @@ HEAP_ALLOCATING_HELPERS = {
     "str_truncate": "removal (function is unused)",
     "str_upper_case": "removal (function is unused)",
     "str_snake_case": "removal (function is unused)",
+    "str_sprintf": "snprintf() with a stack buffer",
+    "str_snprintf": "snprintf() with a stack buffer",
 }
 
 
@@ -710,7 +712,9 @@ HEAP_ALLOCATING_HELPERS = {
     r"str_sanitize(?!_)|"
     r"str_truncate|"
     r"str_upper_case|"
-    r"str_snake_case"
+    r"str_snake_case|"
+    r"str_sprintf|"
+    r"str_snprintf"
     r")\s*\(" + CPP_RE_EOL,
     include=cpp_include,
     exclude=[