From 34345b86fa6ca0252c8029a14bc8f7a1e5859499 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Fri, 20 Mar 2026 18:36:07 -1000
Subject: [PATCH] [core] Reduce automation call chain stack depth
MIME-Version: 1.0
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Force-inline the Trigger→Automation→ActionList forwarding chain
and override play_complex() in leaf action classes to skip the
virtual play() dispatch, reducing the button→lambda call stack
from 8 frames to ~4.
---
 esphome/core/automation.h      |  6 +++---
 esphome/core/base_automation.h | 15 +++++++++++++++
 2 files changed, 18 insertions(+), 3 deletions(-)

diff --git a/esphome/core/automation.h b/esphome/core/automation.h
index 7934fdbec97..4bc4bdf71e0 100644
--- a/esphome/core/automation.h
+++ b/esphome/core/automation.h
@@ -322,7 +322,7 @@ 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) {
+  __attribute__((always_inline)) void trigger(const Ts &...x) {
     if (this->automation_parent_ == nullptr)
       return;
     this->automation_parent_->trigger(x...);
@@ -429,7 +429,7 @@ template<typename... Ts> class ActionList {
       this->add_action(action);
     }
   }
-  void play(const Ts &...x) {
+  __attribute__((always_inline)) void play(const Ts &...x) {
     if (this->actions_begin_ != nullptr)
       this->actions_begin_->play_complex(x...);
   }
@@ -473,7 +473,7 @@ template<typename... Ts> class Automation {
 
   void stop() { this->actions_.stop(); }
 
-  void trigger(const Ts &...x) { this->actions_.play(x...); }
+  __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 985f26e7116..6690c7d236e 100644
--- a/esphome/core/base_automation.h
+++ b/esphome/core/base_automation.h
@@ -217,6 +217,11 @@ template<typename... Ts> class LambdaAction : public Action<Ts...> {
  public:
   explicit LambdaAction(std::function<void(Ts...)> &&f) : f_(std::move(f)) {}
 
+  void play_complex(const Ts &...x) override {
+    this->num_running_++;
+    this->f_(x...);
+    this->play_next_(x...);
+  }
   void play(const Ts &...x) override { this->f_(x...); }
 
  protected:
@@ -230,6 +235,11 @@ template<typename... Ts> class StatelessLambdaAction : public Action<Ts...> {
  public:
   explicit StatelessLambdaAction(void (*f)(Ts...)) : f_(f) {}
 
+  void play_complex(const Ts &...x) override {
+    this->num_running_++;
+    this->f_(x...);
+    this->play_next_(x...);
+  }
   void play(const Ts &...x) override { this->f_(x...); }
 
  protected:
@@ -243,6 +253,11 @@ template<typename... Ts> class ContinuationAction : public Action<Ts...> {
  public:
   explicit ContinuationAction(Action<Ts...> *parent) : parent_(parent) {}
 
+  void play_complex(const Ts &...x) override {
+    this->num_running_++;
+    this->parent_->play_next_(x...);
+    this->play_next_(x...);
+  }
   void play(const Ts &...x) override { this->parent_->play_next_(x...); }
 
  protected: