From f278250740330b6b4e990ae19b0bc91d846ec924 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@koston.org>
Date: Mon, 2 Mar 2026 06:57:59 -1000
Subject: [PATCH] [core] Deduplicate ControllerRegistry notify dispatch loop
 (#14394)

---
 esphome/core/controller_registry.cpp | 21 +++++++++++++--------
 esphome/core/controller_registry.h   | 15 +++++++++++++++
 2 files changed, 28 insertions(+), 8 deletions(-)

diff --git a/esphome/core/controller_registry.cpp b/esphome/core/controller_registry.cpp
index 13b505e8e9..255efa86ba 100644
--- a/esphome/core/controller_registry.cpp
+++ b/esphome/core/controller_registry.cpp
@@ -10,21 +10,26 @@ StaticVector<Controller *, CONTROLLER_REGISTRY_MAX> ControllerRegistry::controll
 
 void ControllerRegistry::register_controller(Controller *controller) { controllers.push_back(controller); }
 
+void ControllerRegistry::notify(void *obj, DispatchFunc dispatch) {
+  for (auto *controller : controllers) {
+    dispatch(controller, obj);
+  }
+}
+
 // Macro for standard registry notification dispatch - calls on_<entity_name>_update()
+// Each wrapper passes a small trampoline lambda that calls the correct virtual method.
+// NOLINTBEGIN(bugprone-macro-parentheses)
 #define CONTROLLER_REGISTRY_NOTIFY(entity_type, entity_name) \
-  void ControllerRegistry::notify_##entity_name##_update(entity_type *obj) { /* NOLINT(bugprone-macro-parentheses) */ \
-    for (auto *controller : controllers) { \
-      controller->on_##entity_name##_update(obj); \
-    } \
+  void ControllerRegistry::notify_##entity_name##_update(entity_type *obj) { \
+    notify(obj, [](Controller *c, void *o) { c->on_##entity_name##_update(static_cast<entity_type *>(o)); }); \
   }
 
 // Macro for entities where controller method has no "_update" suffix (Event, Update)
 #define CONTROLLER_REGISTRY_NOTIFY_NO_UPDATE_SUFFIX(entity_type, entity_name) \
-  void ControllerRegistry::notify_##entity_name(entity_type *obj) { /* NOLINT(bugprone-macro-parentheses) */ \
-    for (auto *controller : controllers) { \
-      controller->on_##entity_name(obj); \
-    } \
+  void ControllerRegistry::notify_##entity_name(entity_type *obj) { \
+    notify(obj, [](Controller *c, void *o) { c->on_##entity_name(static_cast<entity_type *>(o)); }); \
   }
+// NOLINTEND(bugprone-macro-parentheses)
 
 #ifdef USE_BINARY_SENSOR
 CONTROLLER_REGISTRY_NOTIFY(binary_sensor::BinarySensor, binary_sensor)
diff --git a/esphome/core/controller_registry.h b/esphome/core/controller_registry.h
index d6452d8827..15e3b4ba83 100644
--- a/esphome/core/controller_registry.h
+++ b/esphome/core/controller_registry.h
@@ -247,6 +247,21 @@ class ControllerRegistry {
 #endif
 
  protected:
+  /** Type-erased dispatch function pointer.
+   *
+   * Each notify method passes a small trampoline that calls the
+   * correct virtual method on Controller. The shared notify() loop
+   * iterates controllers once, calling the trampoline for each.
+   */
+  using DispatchFunc = void (*)(Controller *, void *);
+
+  /** Shared dispatch loop - iterates controllers and calls dispatch for each.
+   *
+   * Marked noinline to ensure only one copy of the loop exists in flash,
+   * rather than being duplicated into each notify_*_update wrapper.
+   */
+  static void __attribute__((noinline)) notify(void *obj, DispatchFunc dispatch);
+
   static StaticVector<Controller *, CONTROLLER_REGISTRY_MAX> controllers;
 };