From bfa446a28ea27d3ee5bfc9d104036fd233ec4f40 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 20 Mar 2026 18:59:45 -1000
Subject: [PATCH] [core] Switch to always_inline only, drop play_complex
 overrides

The play_complex overrides cost flash per template instantiation
across every automation. The always_inline on the forwarding chain
(Trigger::trigger, Automation::trigger, ActionList::play) is a
fixed cost that collapses 3 frames into 1.
---
 esphome/core/automation.h      | 12 +++++++++---
 esphome/core/base_automation.h | 21 ---------------------
 2 files changed, 9 insertions(+), 24 deletions(-)

diff --git a/esphome/core/automation.h b/esphome/core/automation.h
index 7934fdbec9..954565aca0 100644
--- a/esphome/core/automation.h
+++ b/esphome/core/automation.h
@@ -322,7 +322,9 @@ template<typename... Ts> class Automation;
 template<typename... Ts> class Trigger {
  public:
   /// Inform the parent automation that the event has triggered.
-  void trigger(const Ts &...x) {
+  // Force-inline: collapses the Trigger→Automation→ActionList forwarding
+  // chain into a single frame, reducing automation call stack depth.
+  __attribute__((always_inline)) void trigger(const Ts &...x) {
     if (this->automation_parent_ == nullptr)
       return;
     this->automation_parent_->trigger(x...);
@@ -429,7 +431,9 @@ template<typename... Ts> class ActionList {
       this->add_action(action);
     }
   }
-  void play(const Ts &...x) {
+  // Force-inline: part of the Trigger→Automation→ActionList forwarding
+  // chain collapsed to reduce automation call stack depth.
+  __attribute__((always_inline)) void play(const Ts &...x) {
     if (this->actions_begin_ != nullptr)
       this->actions_begin_->play_complex(x...);
   }
@@ -473,7 +477,9 @@ template<typename... Ts> class Automation {
 
   void stop() { this->actions_.stop(); }
 
-  void trigger(const Ts &...x) { this->actions_.play(x...); }
+  // Force-inline: part of the Trigger→Automation→ActionList forwarding
+  // chain collapsed to reduce automation call stack depth.
+  __attribute__((always_inline)) void trigger(const Ts &...x) { this->actions_.play(x...); }
 
   bool is_running() { return this->actions_.is_running(); }
 
diff --git a/esphome/core/base_automation.h b/esphome/core/base_automation.h
index b809c56f1a..985f26e711 100644
--- a/esphome/core/base_automation.h
+++ b/esphome/core/base_automation.h
@@ -217,13 +217,6 @@ template<typename... Ts> class LambdaAction : public Action<Ts...> {
  public:
   explicit LambdaAction(std::function<void(Ts...)> &&f) : f_(std::move(f)) {}
 
-  // Override play_complex to call play() non-virtually (qualified call),
-  // eliminating one virtual dispatch frame from the call stack.
-  void play_complex(const Ts &...x) override {
-    this->num_running_++;
-    LambdaAction::play(x...);
-    this->play_next_(x...);
-  }
   void play(const Ts &...x) override { this->f_(x...); }
 
  protected:
@@ -237,13 +230,6 @@ template<typename... Ts> class StatelessLambdaAction : public Action<Ts...> {
  public:
   explicit StatelessLambdaAction(void (*f)(Ts...)) : f_(f) {}
 
-  // Override play_complex to call play() non-virtually (qualified call),
-  // eliminating one virtual dispatch frame from the call stack.
-  void play_complex(const Ts &...x) override {
-    this->num_running_++;
-    StatelessLambdaAction::play(x...);
-    this->play_next_(x...);
-  }
   void play(const Ts &...x) override { this->f_(x...); }
 
  protected:
@@ -257,13 +243,6 @@ template<typename... Ts> class ContinuationAction : public Action<Ts...> {
  public:
   explicit ContinuationAction(Action<Ts...> *parent) : parent_(parent) {}
 
-  // Override play_complex to call play() non-virtually (qualified call),
-  // eliminating one virtual dispatch frame from the call stack.
-  void play_complex(const Ts &...x) override {
-    this->num_running_++;
-    ContinuationAction::play(x...);
-    this->play_next_(x...);
-  }
   void play(const Ts &...x) override { this->parent_->play_next_(x...); }
 
  protected: