[esphome OTA] Allow compilation on host platform (#11655)

Co-authored-by: J. Nick Koston <nick@koston.org>
Co-authored-by: J. Nick Koston <nick@home-assistant.io>

esphome/components/esphome/ota/ota_esphome.cpp

@@ -387,14 +387,14 @@ bool ESPHomeOTAComponent::readall_(uint8_t *buf, size_t len) {
   while (len - at > 0) {
     uint32_t now = millis();
     if (now - start > OTA_SOCKET_TIMEOUT_DATA) {
-      ESP_LOGW(TAG, "Timeout reading %d bytes", len);
+      ESP_LOGW(TAG, "Timeout reading %zu bytes", len);
       return false;
     }
 
     ssize_t read = this->client_->read(buf + at, len - at);
     if (read == -1) {
       if (!this->would_block_(errno)) {
-        ESP_LOGW(TAG, "Read err %d bytes, errno %d", len, errno);
+        ESP_LOGW(TAG, "Read err %zu bytes, errno %d", len, errno);
         return false;
       }
     } else if (read == 0) {
@@ -414,14 +414,14 @@ bool ESPHomeOTAComponent::writeall_(const uint8_t *buf, size_t len) {
   while (len - at > 0) {
     uint32_t now = millis();
     if (now - start > OTA_SOCKET_TIMEOUT_DATA) {
-      ESP_LOGW(TAG, "Timeout writing %d bytes", len);
+      ESP_LOGW(TAG, "Timeout writing %zu bytes", len);
       return false;
     }
 
     ssize_t written = this->client_->write(buf + at, len - at);
     if (written == -1) {
       if (!this->would_block_(errno)) {
-        ESP_LOGW(TAG, "Write err %d bytes, errno %d", len, errno);
+        ESP_LOGW(TAG, "Write err %zu bytes, errno %d", len, errno);
         return false;
       }
     } else {

esphome/components/ota/__init__.py

@@ -1,3 +1,5 @@
+import logging
+
 from esphome import automation
 import esphome.codegen as cg
 from esphome.config_helpers import filter_source_files_from_platform
@@ -27,6 +29,8 @@ CONF_ON_PROGRESS = "on_progress"
 CONF_ON_STATE_CHANGE = "on_state_change"
 
 
+_LOGGER = logging.getLogger(__name__)
+
 ota_ns = cg.esphome_ns.namespace("ota")
 OTAComponent = ota_ns.class_("OTAComponent", cg.Component)
 OTAState = ota_ns.enum("OTAState")
@@ -45,6 +49,10 @@ def _ota_final_validate(config):
         raise cv.Invalid(
             f"At least one platform must be specified for '{CONF_OTA}'; add '{CONF_PLATFORM}: {CONF_ESPHOME}' for original OTA functionality"
         )
+    if CORE.is_host:
+        _LOGGER.warning(
+            "OTA not available for platform 'host'. OTA functionality disabled."
+        )
 
 
 FINAL_VALIDATE_SCHEMA = _ota_final_validate

esphome/components/ota/ota_backend_host.cpp

@@ -0,0 +1,24 @@
+#ifdef USE_HOST
+#include "ota_backend_host.h"
+
+#include "esphome/core/defines.h"
+
+namespace esphome::ota {
+
+// Stub implementation - OTA is not supported on host platform.
+// All methods return error codes to allow compilation of configs with OTA triggers.
+
+std::unique_ptr<ota::OTABackend> make_ota_backend() { return make_unique<ota::HostOTABackend>(); }
+
+OTAResponseTypes HostOTABackend::begin(size_t image_size) { return OTA_RESPONSE_ERROR_UPDATE_PREPARE; }
+
+void HostOTABackend::set_update_md5(const char *expected_md5) {}
+
+OTAResponseTypes HostOTABackend::write(uint8_t *data, size_t len) { return OTA_RESPONSE_ERROR_WRITING_FLASH; }
+
+OTAResponseTypes HostOTABackend::end() { return OTA_RESPONSE_ERROR_UPDATE_END; }
+
+void HostOTABackend::abort() {}
+
+}  // namespace esphome::ota
+#endif

esphome/components/ota/ota_backend_host.h

@@ -0,0 +1,21 @@
+#pragma once
+#ifdef USE_HOST
+#include "ota_backend.h"
+
+namespace esphome::ota {
+
+/// Stub OTA backend for host platform - allows compilation but does not implement OTA.
+/// All operations return error codes immediately. This enables configurations with
+/// OTA triggers to compile for host platform during development.
+class HostOTABackend : public OTABackend {
+ public:
+  OTAResponseTypes begin(size_t image_size) override;
+  void set_update_md5(const char *md5) override;
+  OTAResponseTypes write(uint8_t *data, size_t len) override;
+  OTAResponseTypes end() override;
+  void abort() override;
+  bool supports_compression() override { return false; }
+};
+
+}  // namespace esphome::ota
+#endif

tests/components/ota/test.host.yaml

@@ -0,0 +1,4 @@
+<<: !include common.yaml
+
+#host platform does not support wifi / network is automatically included
+wifi: !remove