From 8525439dc8b78ae55f36ec885321938a2b8e90c4 Mon Sep 17 00:00:00 2001
From: "J. Nick Koston" <nick@home-assistant.io>
Date: Mon, 16 Mar 2026 17:23:10 -1000
Subject: [PATCH] [debug] [bme680_bsec] Use fnv1_hash_extend to avoid temporary
 string allocations

Replace fnv1_hash(str1 + str2) with fnv1_hash_extend(fnv1_hash(str1), str2)
to avoid constructing temporary std::string objects just to compute a hash.
This eliminates the only callers of operator+(const char*, StringRef),
allowing the linker to drop 197 bytes of string concatenation code.
---
 esphome/components/bme680_bsec/bme680_bsec.cpp | 2 +-
 esphome/components/debug/debug_esp32.cpp       | 6 ++++--
 2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/esphome/components/bme680_bsec/bme680_bsec.cpp b/esphome/components/bme680_bsec/bme680_bsec.cpp
index 75efb6835a..bb0417b823 100644
--- a/esphome/components/bme680_bsec/bme680_bsec.cpp
+++ b/esphome/components/bme680_bsec/bme680_bsec.cpp
@@ -521,7 +521,7 @@ int BME680BSECComponent::reinit_bsec_lib_() {
 }
 
 void BME680BSECComponent::load_state_() {
-  uint32_t hash = fnv1_hash("bme680_bsec_state_" + this->device_id_);
+  uint32_t hash = fnv1_hash_extend(fnv1_hash("bme680_bsec_state_"), this->device_id_);
   this->bsec_state_ = global_preferences->make_preference<uint8_t[BSEC_MAX_STATE_BLOB_SIZE]>(hash, true);
 
   if (!this->bsec_state_.load(&this->bsec_state_data_)) {
diff --git a/esphome/components/debug/debug_esp32.cpp b/esphome/components/debug/debug_esp32.cpp
index aa379599c6..2e04090749 100644
--- a/esphome/components/debug/debug_esp32.cpp
+++ b/esphome/components/debug/debug_esp32.cpp
@@ -49,7 +49,8 @@ static const size_t REBOOT_MAX_LEN = 24;
 void DebugComponent::on_shutdown() {
   auto *component = App.get_current_component();
   char buffer[REBOOT_MAX_LEN]{};
-  auto pref = global_preferences->make_preference(REBOOT_MAX_LEN, fnv1_hash(REBOOT_KEY + App.get_name()));
+  auto pref = global_preferences->make_preference(REBOOT_MAX_LEN,
+                                                  fnv1_hash_extend(fnv1_hash(REBOOT_KEY), App.get_name().c_str()));
   if (component != nullptr) {
     strncpy(buffer, LOG_STR_ARG(component->get_component_log_str()), REBOOT_MAX_LEN - 1);
     buffer[REBOOT_MAX_LEN - 1] = '\0';
@@ -66,7 +67,8 @@ const char *DebugComponent::get_reset_reason_(std::span<char, RESET_REASON_BUFFE
   unsigned reason = esp_reset_reason();
   if (reason < sizeof(RESET_REASONS) / sizeof(RESET_REASONS[0])) {
     if (reason == ESP_RST_SW) {
-      auto pref = global_preferences->make_preference(REBOOT_MAX_LEN, fnv1_hash(REBOOT_KEY + App.get_name()));
+      auto pref = global_preferences->make_preference(REBOOT_MAX_LEN,
+                                                      fnv1_hash_extend(fnv1_hash(REBOOT_KEY), App.get_name().c_str()));
       char reboot_source[REBOOT_MAX_LEN]{};
       if (pref.load(&reboot_source)) {
         reboot_source[REBOOT_MAX_LEN - 1] = '\0';