Add get_config_version_hash() and make hash functions constexpr

Add Application::get_config_version_hash() as a constexpr that returns
fnv1a_hash_extend(config_hash, ESPHOME_VERSION).

Make get_config_hash(), get_build_time(), fnv1a_hash(), and
fnv1a_hash_extend() constexpr inline functions.

Replace open-coded fnv1a_hash_extend(config_hash, ESPHOME_VERSION)
calls with get_config_version_hash() in sensor and wifi components.

Remove now-unnecessary version.h includes from component files.

esphome/components/sen5x/sen5x.cpp

@@ -3,7 +3,6 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include "esphome/core/version.h"
 #include <cinttypes>
 
 namespace esphome {
@@ -159,8 +158,7 @@ void SEN5XComponent::setup() {
         // Hash with config hash, version, and serial number
         // This ensures the baseline storage is cleared after OTA
         // Serial numbers are unique to each sensor, so multiple sensors can be used without conflict
-        uint32_t hash = fnv1a_hash_extend(App.get_config_hash(), ESPHOME_VERSION);
-        hash = fnv1a_hash_extend(hash, std::to_string(combined_serial));
+        uint32_t hash = fnv1a_hash_extend(App.get_config_version_hash(), std::to_string(combined_serial));
         this->pref_ = global_preferences->make_preference<Sen5xBaselines>(hash, true);
 
         if (this->pref_.load(&this->voc_baselines_storage_)) {

esphome/components/sgp30/sgp30.cpp

@@ -3,7 +3,6 @@
 #include "esphome/core/hal.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include "esphome/core/version.h"
 
 #include <cinttypes>
 
@@ -76,8 +75,7 @@ void SGP30Component::setup() {
   // Hash with config hash, version, and serial number
   // This ensures the baseline storage is cleared after OTA
   // Serial numbers are unique to each sensor, so multiple sensors can be used without conflict
-  uint32_t hash = fnv1a_hash_extend(App.get_config_hash(), ESPHOME_VERSION);
-  hash = fnv1a_hash_extend(hash, std::to_string(this->serial_number_));
+  uint32_t hash = fnv1a_hash_extend(App.get_config_version_hash(), std::to_string(this->serial_number_));
   this->pref_ = global_preferences->make_preference<SGP30Baselines>(hash, true);
 
   if (this->store_baseline_ && this->pref_.load(&this->baselines_storage_)) {

esphome/components/sgp4x/sgp4x.cpp

@@ -2,7 +2,6 @@
 #include "esphome/core/application.h"
 #include "esphome/core/log.h"
 #include "esphome/core/hal.h"
-#include "esphome/core/version.h"
 #include <cinttypes>
 
 namespace esphome {
@@ -61,8 +60,7 @@ void SGP4xComponent::setup() {
     // Hash with config hash, version, and serial number
     // This ensures the baseline storage is cleared after OTA
     // Serial numbers are unique to each sensor, so multiple sensors can be used without conflict
-    uint32_t hash = fnv1a_hash_extend(App.get_config_hash(), ESPHOME_VERSION);
-    hash = fnv1a_hash_extend(hash, std::to_string(this->serial_number_));
+    uint32_t hash = fnv1a_hash_extend(App.get_config_version_hash(), std::to_string(this->serial_number_));
     this->pref_ = global_preferences->make_preference<SGP4xBaselines>(hash, true);
 
     if (this->pref_.load(&this->voc_baselines_storage_)) {

esphome/components/wifi/wifi_component.cpp

@@ -28,7 +28,6 @@
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
 #include "esphome/core/util.h"
-#include "esphome/core/version.h"
 
 #ifdef USE_CAPTIVE_PORTAL
 #include "esphome/components/captive_portal/captive_portal.h"
@@ -376,7 +375,7 @@ void WiFiComponent::start() {
                 get_mac_address_pretty_into_buffer(mac_s));
   this->last_connected_ = millis();
 
-  uint32_t hash = this->has_sta() ? fnv1a_hash_extend(App.get_config_hash(), ESPHOME_VERSION) : 88491487UL;
+  uint32_t hash = this->has_sta() ? App.get_config_version_hash() : 88491487UL;
 
   this->pref_ = global_preferences->make_preference<wifi::SavedWifiSettings>(hash, true);
 #ifdef USE_WIFI_FAST_CONNECT

esphome/core/application.cpp

@@ -719,10 +719,6 @@ void Application::wake_loop_threadsafe() {
 }
 #endif  // defined(USE_SOCKET_SELECT_SUPPORT) && defined(USE_WAKE_LOOP_THREADSAFE)
 
-uint32_t Application::get_config_hash() { return ESPHOME_CONFIG_HASH; }
-
-time_t Application::get_build_time() { return ESPHOME_BUILD_TIME; }
-
 void Application::get_build_time_string(std::span<char, BUILD_TIME_STR_SIZE> buffer) {
 #ifdef USE_ESP8266
   strncpy_P(buffer.data(), ESPHOME_BUILD_TIME_STR, buffer.size());

esphome/core/application.h

@@ -6,6 +6,7 @@
 #include <span>
 #include <string>
 #include <vector>
+#include "esphome/core/build_info_data.h"
 #include "esphome/core/component.h"
 #include "esphome/core/defines.h"
 #include "esphome/core/hal.h"
@@ -13,6 +14,7 @@
 #include "esphome/core/preferences.h"
 #include "esphome/core/scheduler.h"
 #include "esphome/core/string_ref.h"
+#include "esphome/core/version.h"
 
 #ifdef USE_DEVICES
 #include "esphome/core/device.h"
@@ -266,10 +268,13 @@ class Application {
   static constexpr size_t BUILD_TIME_STR_SIZE = 26;
 
   /// Get the config hash as a 32-bit integer
-  uint32_t get_config_hash();
+  constexpr uint32_t get_config_hash() { return ESPHOME_CONFIG_HASH; }
+
+  /// Get the config hash extended with ESPHome version
+  constexpr uint32_t get_config_version_hash() { return fnv1a_hash_extend(ESPHOME_CONFIG_HASH, ESPHOME_VERSION); }
 
   /// Get the build time as a Unix timestamp
-  time_t get_build_time();
+  constexpr time_t get_build_time() { return ESPHOME_BUILD_TIME; }
 
   /// Copy the build time string into the provided buffer
   /// Buffer must be BUILD_TIME_STR_SIZE bytes (compile-time enforced)

esphome/core/helpers.cpp

@@ -155,17 +155,6 @@ uint32_t fnv1_hash(const char *str) {
   return hash;
 }
 
-// FNV-1a hash - preferred for new code
-uint32_t fnv1a_hash_extend(uint32_t hash, const char *str) {
-  if (str) {
-    while (*str) {
-      hash ^= *str++;
-      hash *= FNV1_PRIME;
-    }
-  }
-  return hash;
-}
-
 float random_float() { return static_cast<float>(random_uint32()) / static_cast<float>(UINT32_MAX); }
 
 // Strings

esphome/core/helpers.h

@@ -388,12 +388,20 @@ constexpr uint32_t FNV1_OFFSET_BASIS = 2166136261UL;
 constexpr uint32_t FNV1_PRIME = 16777619UL;
 
 /// Extend a FNV-1a hash with additional string data.
-uint32_t fnv1a_hash_extend(uint32_t hash, const char *str);
+constexpr uint32_t fnv1a_hash_extend(uint32_t hash, const char *str) {
+  if (str) {
+    while (*str) {
+      hash ^= *str++;
+      hash *= FNV1_PRIME;
+    }
+  }
+  return hash;
+}
 inline uint32_t fnv1a_hash_extend(uint32_t hash, const std::string &str) {
   return fnv1a_hash_extend(hash, str.c_str());
 }
 /// Calculate a FNV-1a hash of \p str.
-inline uint32_t fnv1a_hash(const char *str) { return fnv1a_hash_extend(FNV1_OFFSET_BASIS, str); }
+constexpr uint32_t fnv1a_hash(const char *str) { return fnv1a_hash_extend(FNV1_OFFSET_BASIS, str); }
 inline uint32_t fnv1a_hash(const std::string &str) { return fnv1a_hash(str.c_str()); }
 
 /// Return a random 32-bit unsigned integer.