[select] Store options in flash to reduce RAM usage

esphome/components/api/api.proto

@@ -1143,7 +1143,7 @@ message ListEntitiesSelectResponse {
   reserved 4; // Deprecated: was string unique_id
 
   string icon = 5 [(field_ifdef) = "USE_ENTITY_ICON"];
-  repeated string options = 6 [(container_pointer) = "std::vector"];
+  repeated string options = 6 [(container_pointer_no_template) = "FixedVector<const char *>"];
   bool disabled_by_default = 7;
   EntityCategory entity_category = 8;
   uint32 device_id = 9 [(field_ifdef) = "USE_DEVICES"];

esphome/components/api/api_pb2.cpp

@@ -1475,8 +1475,8 @@ void ListEntitiesSelectResponse::encode(ProtoWriteBuffer buffer) const {
 #ifdef USE_ENTITY_ICON
   buffer.encode_string(5, this->icon_ref_);
 #endif
-  for (const auto &it : *this->options) {
-    buffer.encode_string(6, it, true);
+  for (const char *it : *this->options) {
+    buffer.encode_string(6, it, strlen(it), true);
   }
   buffer.encode_bool(7, this->disabled_by_default);
   buffer.encode_uint32(8, static_cast<uint32_t>(this->entity_category));
@@ -1492,8 +1492,8 @@ void ListEntitiesSelectResponse::calculate_size(ProtoSize &size) const {
   size.add_length(1, this->icon_ref_.size());
 #endif
   if (!this->options->empty()) {
-    for (const auto &it : *this->options) {
-      size.add_length_force(1, it.size());
+    for (const char *it : *this->options) {
+      size.add_length_force(1, strlen(it));
     }
   }
   size.add_bool(1, this->disabled_by_default);

esphome/components/api/api_pb2.h

@@ -1534,7 +1534,7 @@ class ListEntitiesSelectResponse final : public InfoResponseProtoMessage {
 #ifdef HAS_PROTO_MESSAGE_DUMP
   const char *message_name() const override { return "list_entities_select_response"; }
 #endif
-  const std::vector<std::string> *options{};
+  const FixedVector<const char *> *options{};
   void encode(ProtoWriteBuffer buffer) const override;
   void calculate_size(ProtoSize &size) const override;
 #ifdef HAS_PROTO_MESSAGE_DUMP

esphome/components/copy/select/copy_select.cpp

@@ -9,7 +9,8 @@ static const char *const TAG = "copy.select";
 void CopySelect::setup() {
   source_->add_on_state_callback([this](const std::string &value, size_t index) { this->publish_state(value); });
 
-  traits.set_options(source_->traits.get_options());
+  const auto &source_options = source_->traits.get_options();
+  traits.set_options({source_options.begin(), source_options.end()});
 
   if (source_->has_state())
     this->publish_state(source_->state);

esphome/components/lvgl/lvgl_esphome.h

@@ -358,7 +358,7 @@ class LvSelectable : public LvCompound {
   virtual void set_selected_index(size_t index, lv_anim_enable_t anim) = 0;
   void set_selected_text(const std::string &text, lv_anim_enable_t anim);
   std::string get_selected_text();
-  std::vector<std::string> get_options() { return this->options_; }
+  const std::vector<std::string> &get_options() { return this->options_; }
   void set_options(std::vector<std::string> options);
 
  protected:

esphome/components/lvgl/select/lvgl_select.h

@@ -53,7 +53,17 @@ class LVGLSelect : public select::Select, public Component {
     this->widget_->set_selected_text(value, this->anim_);
     this->publish();
   }
-  void set_options_() { this->traits.set_options(this->widget_->get_options()); }
+  void set_options_() {
+    // Widget uses std::vector<std::string>, SelectTraits uses FixedVector<const char*>
+    // Convert by extracting c_str() pointers
+    const auto &opts = this->widget_->get_options();
+    std::vector<const char *> opt_ptrs;
+    opt_ptrs.reserve(opts.size());
+    for (const auto &opt : opts) {
+      opt_ptrs.push_back(opt.c_str());
+    }
+    this->traits.set_options({opt_ptrs.begin(), opt_ptrs.end()});
+  }
 
   LvSelectable *widget_;
   lv_anim_enable_t anim_;

esphome/components/select/select.cpp

@@ -1,5 +1,6 @@
 #include "select.h"
 #include "esphome/core/log.h"
+#include <cstring>
 
 namespace esphome {
 namespace select {
@@ -35,7 +36,7 @@ size_t Select::size() const {
 optional<size_t> Select::index_of(const std::string &option) const {
   const auto &options = traits.get_options();
   for (size_t i = 0; i < options.size(); i++) {
-    if (options[i] == option) {
+    if (strcmp(options[i], option.c_str()) == 0) {
       return i;
     }
   }
@@ -53,7 +54,7 @@ optional<size_t> Select::active_index() const {
 optional<std::string> Select::at(size_t index) const {
   if (this->has_index(index)) {
     const auto &options = traits.get_options();
-    return options.at(index);
+    return std::string(options.at(index));
   } else {
     return {};
   }

esphome/components/select/select_traits.cpp

@@ -3,9 +3,9 @@
 namespace esphome {
 namespace select {
 
-void SelectTraits::set_options(std::vector<std::string> options) { this->options_ = std::move(options); }
+void SelectTraits::set_options(std::initializer_list<const char *> options) { this->options_ = options; }
 
-const std::vector<std::string> &SelectTraits::get_options() const { return this->options_; }
+const FixedVector<const char *> &SelectTraits::get_options() const { return this->options_; }
 
 }  // namespace select
 }  // namespace esphome

esphome/components/select/select_traits.h

@@ -1,18 +1,18 @@
 #pragma once
 
-#include <vector>
-#include <string>
+#include "esphome/core/helpers.h"
+#include <initializer_list>
 
 namespace esphome {
 namespace select {
 
 class SelectTraits {
  public:
-  void set_options(std::vector<std::string> options);
-  const std::vector<std::string> &get_options() const;
+  void set_options(std::initializer_list<const char *> options);
+  const FixedVector<const char *> &get_options() const;
 
  protected:
-  std::vector<std::string> options_;
+  FixedVector<const char *> options_;
 };
 
 }  // namespace select

esphome/components/template/select/template_select.cpp

@@ -22,7 +22,7 @@ void TemplateSelect::setup() {
       ESP_LOGD(TAG, "State from initial (could not load stored index): %s", value.c_str());
     } else if (!this->has_index(index)) {
       value = this->initial_option_;
-      ESP_LOGD(TAG, "State from initial (restored index %d out of bounds): %s", index, value.c_str());
+      ESP_LOGD(TAG, "State from initial (restored index %zu out of bounds): %s", index, value.c_str());
     } else {
       value = this->at(index).value();
       ESP_LOGD(TAG, "State from restore: %s", value.c_str());

esphome/core/helpers.h

@@ -304,6 +304,11 @@ template<typename T> class FixedVector {
     return data_[size_ - 1];
   }
 
+  /// Access first element (no bounds checking - matches std::vector behavior)
+  /// Caller must ensure vector is not empty (size() > 0)
+  T &front() { return data_[0]; }
+  const T &front() const { return data_[0]; }
+
   /// Access last element (no bounds checking - matches std::vector behavior)
   /// Caller must ensure vector is not empty (size() > 0)
   T &back() { return data_[size_ - 1]; }
@@ -317,6 +322,11 @@ template<typename T> class FixedVector {
   T &operator[](size_t i) { return data_[i]; }
   const T &operator[](size_t i) const { return data_[i]; }
 
+  /// Access element with bounds checking (matches std::vector behavior)
+  /// Caller must ensure index is valid (i < size())
+  T &at(size_t i) { return data_[i]; }
+  const T &at(size_t i) const { return data_[i]; }
+
   // Iterator support for range-based for loops
   T *begin() { return data_; }
   T *end() { return data_ + size_; }

script/api_protobuf/api_protobuf.py

@@ -1533,6 +1533,11 @@ class RepeatedTypeInfo(TypeInfo):
     def encode_content(self) -> str:
         if self._use_pointer:
             # For pointer fields, just dereference (pointer should never be null in our use case)
+            # Special handling for const char* elements (when container_no_template contains "const char")
+            if "const char" in self._container_no_template:
+                o = f"for (const char *it : *this->{self.field_name}) {{\n"
+                o += f"  buffer.{self._ti.encode_func}({self.number}, it, strlen(it), true);\n"
+            else:
                 o = f"for (const auto &it : *this->{self.field_name}) {{\n"
                 if isinstance(self._ti, EnumType):
                     o += f"  buffer.{self._ti.encode_func}({self.number}, static_cast<uint32_t>(it), true);\n"
@@ -1588,6 +1593,11 @@ class RepeatedTypeInfo(TypeInfo):
             o += f"  size.add_precalculated_size({size_expr} * {bytes_per_element});\n"
         else:
             # Other types need the actual value
+            # Special handling for const char* elements
+            if self._use_pointer and "const char" in self._container_no_template:
+                o += f"  for (const char *it : {container_ref}) {{\n"
+                o += "    size.add_length_force(1, strlen(it));\n"
+            else:
                 auto_ref = "" if self._ti_is_bool else "&"
                 o += f"  for (const auto {auto_ref}it : {container_ref}) {{\n"
                 o += f"    {self._ti.get_size_calculation('it', True)}\n"