Level Backup don't use ChangedSinceBackup flag.

[rdebath]

The flag ChangedSinceBackup is ignored because it is set when a block is placed and never cleared.
The AutoSave server task will do a backup with a 1 in 15 chance each time that a map save is triggered by a block change within the last save period (backup-time). With the default setup, if a level is changed every 5 minutes for 75 minutes a backup will be triggered.

I would not expect this semi-random method is what it was supposed to do.

Perhaps the backup is supposed to be done 15 backup-time periods after the first change (plus when the map is unloaded)?
It is very unclear because the counter used is on the task not the level.

[UnknownShadow200]

That quirky logic for auto backup has been there since MCForge, and even all the way back to MCLawl/MCZall.

Probably should be changed into using separate autosave-interval and autobackup-interval config options though

---

I accidentally removed resetting of ChangedSinceBackup to unchanged around 5 years with the commit 50c2140

[rdebath]

This seems to be working nicely; doesn't backup on exit-level but does stop main getting perpetually saved by Snakes and Zombies.

From f3a9fe4d016fb02e0b3fa0cdf4ef7252f864eea0 Mon Sep 17 00:00:00 2001
From: Robert de Bath <[email protected]>
Date: Fri, 23 Jun 2023 11:20:04 +0100
Subject: [PATCH] Use ChangedSinceBackup to allow and disallow backups

---
 MCGalaxy/Levels/Level.cs             | 2 ++
 MCGalaxy/Server/Tasks/ServerTasks.cs | 4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/MCGalaxy/Levels/Level.cs b/MCGalaxy/Levels/Level.cs
index 2902c6921..e4b76b577 100644
--- a/MCGalaxy/Levels/Level.cs
+++ b/MCGalaxy/Levels/Level.cs
@@ -301,7 +301,9 @@ namespace MCGalaxy
             if (ChangedSinceBackup || force) {
                 if (backup.Length == 0) backup = LevelInfo.NextBackup(name);
 
+                ChangedSinceBackup = false;
                 if (!LevelActions.Backup(name, backup)) {
+                    ChangedSinceBackup = true;
                     Logger.Log(LogType.Warning, "FAILED TO INCREMENTAL BACKUP :" + name);
                     return null;
                 }
diff --git a/MCGalaxy/Server/Tasks/ServerTasks.cs b/MCGalaxy/Server/Tasks/ServerTasks.cs
index 0f29e73ce..c7f72b97f 100644
--- a/MCGalaxy/Server/Tasks/ServerTasks.cs
+++ b/MCGalaxy/Server/Tasks/ServerTasks.cs
@@ -130,7 +130,9 @@ namespace MCGalaxy.Tasks {
             
             foreach (Level lvl in levels) {
                 try {
-                    if (!lvl.Changed || !lvl.SaveChanges) continue;
+                    if (!lvl.SaveChanges) continue;
+                    if ((count != 0 || !lvl.ChangedSinceBackup) && !lvl.Changed)
+                        continue;
 
                     lvl.Save();
                     if (count == 0)  {