Add setting flag to run string setting change callbacks on config load

src/settings.cpp

@@ -662,6 +662,10 @@ void StringSettingDesc::ParseValue(const IniItem *item, void *object) const
 {
 	std::string str = (item == nullptr) ? this->def : item->value.value_or("");
 	this->MakeValueValid(str);
+	if (this->flags & SF_RUN_CALLBACKS_ON_PARSE) {
+		if (this->pre_check != nullptr && !this->pre_check(str)) str = this->def;
+		if (this->post_callback != nullptr) this->post_callback(str);
+	}
 	this->Write(object, str);
 }
 

src/settings_internal.h

@@ -31,6 +31,7 @@ enum SettingFlag : uint32 {
 	SF_ENUM                    = 1 << 14, ///< the setting can take one of the values given by an array of struct SettingDescEnumEntry
 	SF_NO_NEWGAME              = 1 << 15, ///< the setting does not apply and is not shown in a new game context
 	SF_DEC1SCALE               = 1 << 16, ///< also display a float representation of the scale of a decimal1 scale parameter
+	SF_RUN_CALLBACKS_ON_PARSE  = 1 << 17, ///< run callbacks when parsing from config file
 };
 DECLARE_ENUM_AS_BIT_SET(SettingFlag)