From 85889143c739bf5fdaff6fb71a901c87b79cc942 Mon Sep 17 00:00:00 2001
From: Jonathan G Rennison <j.g.rennison@gmail.com>
Date: Wed, 15 Feb 2023 21:13:07 +0000
Subject: [PATCH] Add mode to AutoRestoreBackup to not change backed up value

---
 src/core/backup_type.hpp | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/src/core/backup_type.hpp b/src/core/backup_type.hpp
index 23beedefb4..cce6ddb8d1 100644
--- a/src/core/backup_type.hpp
+++ b/src/core/backup_type.hpp
@@ -144,6 +144,8 @@ private:
 	const int line;
 };
 
+struct AutoRestoreBackupNoNewValueTag {};
+
 /**
  * Class to backup a specific variable and restore it upon destruction of this object to prevent
  * stack values going out of scope before resetting the global to its original value. Contrary to
@@ -157,6 +159,13 @@ struct AutoRestoreBackup {
 	 * the whole goal and reason for existing of this object.
 	 */
 
+	/**
+	 * Backup variable.
+	 * @param original Variable to backup.
+	 * @param tag Tag to indicate that the variable's value should not be changed.
+	 */
+	AutoRestoreBackup(T &original, AutoRestoreBackupNoNewValueTag tag) : original(original), original_value(original) {}
+
 	/**
 	 * Backup variable and switch to new value.
 	 * @param original Variable to backup.