From 7c259d2f6426c835c98cc6fbe27b8ebe07f609af Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Thu, 26 Mar 2026 15:39:29 -1000
Subject: [PATCH] Simplify save_state_ compat path, move CopyFan preset copy to
 setup()

- save_state_(): split into two clear branches instead of conditional
  FanTraits construction trick
- CopyFan: copy source preset modes once in setup() instead of on
  every get_traits() call
---
 esphome/components/copy/fan/copy_fan.cpp | 10 +++++++--
 esphome/components/fan/fan.cpp           | 26 ++++++++++++++++--------
 2 files changed, 25 insertions(+), 11 deletions(-)

diff --git a/esphome/components/copy/fan/copy_fan.cpp b/esphome/components/copy/fan/copy_fan.cpp
index e7d01827aa..bdaa35c467 100644
--- a/esphome/components/copy/fan/copy_fan.cpp
+++ b/esphome/components/copy/fan/copy_fan.cpp
@@ -7,6 +7,12 @@ namespace copy {
 static const char *const TAG = "copy.fan";
 
 void CopyFan::setup() {
+  // Copy preset modes once from source fan — stored on Fan base class
+  auto source_traits = source_->get_traits();
+  if (source_traits.supports_preset_modes()) {
+    this->set_supported_preset_modes(source_traits.supported_preset_modes());
+  }
+
   source_->add_on_state_callback([this]() {
     this->copy_state_from_source_();
     this->publish_state();
@@ -39,8 +45,8 @@ fan::FanTraits CopyFan::get_traits() {
   traits.set_speed(base.supports_speed());
   traits.set_supported_speed_count(base.supported_speed_count());
   traits.set_direction(base.supports_direction());
-  // Preset modes are wired from source fan's storage via get_traits()
-  this->set_supported_preset_modes(base.supported_preset_modes());
+  // Preset modes are set once in setup() and wired via wire_preset_modes_()
+  this->wire_preset_modes_(traits);
   return traits;
 }
 
diff --git a/esphome/components/fan/fan.cpp b/esphome/components/fan/fan.cpp
index fb9654da5b..563c0eff13 100644
--- a/esphome/components/fan/fan.cpp
+++ b/esphome/components/fan/fan.cpp
@@ -297,15 +297,23 @@ void Fan::save_state_() {
   state.preset_mode = FanRestoreState::NO_PRESET;
 
   if (this->has_preset_mode()) {
-    // Use Fan-owned vector, or fall back to traits for deprecated path.
-    // Keep traits alive so the reference to compat_preset_modes_ doesn't dangle.
-    auto traits = this->supported_preset_modes_ ? FanTraits() : this->get_traits();
-    const auto &preset_modes =
-        this->supported_preset_modes_ ? *this->supported_preset_modes_ : traits.supported_preset_modes();
-    for (size_t i = 0; i < preset_modes.size(); i++) {
-      if (preset_modes[i] == this->preset_mode_) {
-        state.preset_mode = i;
-        break;
+    if (this->supported_preset_modes_) {
+      // New path: search Fan-owned vector directly
+      for (size_t i = 0; i < this->supported_preset_modes_->size(); i++) {
+        if ((*this->supported_preset_modes_)[i] == this->preset_mode_) {
+          state.preset_mode = i;
+          break;
+        }
+      }
+    } else {
+      // Compat: fall back to traits for deprecated path. Remove in 2026.11.0.
+      auto traits = this->get_traits();
+      const auto &preset_modes = traits.supported_preset_modes();
+      for (size_t i = 0; i < preset_modes.size(); i++) {
+        if (preset_modes[i] == this->preset_mode_) {
+          state.preset_mode = i;
+          break;
+        }
       }
     }
   }