[template] Conditionally compile select set_trigger

Only allocate the set_trigger when set_action is configured.
This saves ~20-24 bytes of heap per template select that doesn't
use set_action.

esphome/components/template/select/__init__.py

@@ -87,6 +87,7 @@ async def to_code(config):
             cg.add(var.set_restore_value(True))
 
     if CONF_SET_ACTION in config:
+        cg.add_define("USE_TEMPLATE_SELECT_SET_TRIGGER")
         await automation.build_automation(
             var.get_set_trigger(), [(cg.StringRef, "x")], config[CONF_SET_ACTION]
         )

esphome/components/template/select/template_select.cpp

@@ -41,7 +41,9 @@ void TemplateSelect::update() {
 }
 
 void TemplateSelect::control(size_t index) {
+#ifdef USE_TEMPLATE_SELECT_SET_TRIGGER
   this->set_trigger_->trigger(StringRef(this->option_at(index)));
+#endif
 
   if (this->optimistic_)
     this->publish_state(index);

esphome/components/template/select/template_select.h

@@ -18,7 +18,9 @@ class TemplateSelect final : public select::Select, public PollingComponent {
   void dump_config() override;
   float get_setup_priority() const override { return setup_priority::HARDWARE; }
 
+#ifdef USE_TEMPLATE_SELECT_SET_TRIGGER
   Trigger<StringRef> *get_set_trigger() const { return this->set_trigger_; }
+#endif
   void set_optimistic(bool optimistic) { this->optimistic_ = optimistic; }
   void set_initial_option_index(size_t initial_option_index) { this->initial_option_index_ = initial_option_index; }
   void set_restore_value(bool restore_value) { this->restore_value_ = restore_value; }
@@ -28,7 +30,9 @@ class TemplateSelect final : public select::Select, public PollingComponent {
   bool optimistic_ = false;
   size_t initial_option_index_{0};
   bool restore_value_ = false;
+#ifdef USE_TEMPLATE_SELECT_SET_TRIGGER
   Trigger<StringRef> *set_trigger_ = new Trigger<StringRef>();
+#endif
   TemplateLambda<std::string> f_;
 
   ESPPreferenceObject pref_;

tests/components/template/common-base.yaml

@@ -296,6 +296,16 @@ select:
           // Migration guide: Store in std::string
           std::string stored_option(id(template_select).current_option());
           ESP_LOGI("test", "Stored: %s", stored_option.c_str());
+  - platform: template
+    id: template_select_with_action
+    name: "Template select with action"
+    options:
+      - option_a
+      - option_b
+    set_action:
+      - logger.log:
+          format: "Selected: %s"
+          args: ["x.c_str()"]
 
 lock:
   - platform: template