Confirmation dialog when overwriting a different world save

[Zaflis]

The problem is that people, me included just now, sometimes overwrite a playthrough A save with playthrough B. You are left with hopes that autosaves still have a trace left or all will be lost. If you just now played the world for an hour, chances are big that no autosaves exist anymore of the other playthrough. Why do we have only 3 autosaves?

So how do we fix this? Wouldn't it be convenient if every save had a unique number that no other save has, game would read the header of the old file and compare it to currently ongoing game's number. If they don't match, you'd get something like: "WARNING! You are attempting to overwrite a save that seems different! Are you sure?".

Now... It's complicated. I don't believe saves have that number, and even if you compare just seeds, 2 saves can have same one. If you are willing to add such number, everything would get simple. Now you would have to compare multiple things to know if it's unique, and even then you aren't 100% sure. There are clues:
- Exchange string includes seed and worldgen settings. The primary condition. People can still play with same one to see if they can do better, or just do it differently.
- If time played on the save is significantly different, say 10h vs 50h. What is a good margin you ask... How long sessions players do inbetween manual saves at longest? Shall we say noone will play 40 hours straight without saving? The question could then be different, indicating the time difference alone.
- If you still haven't found any differences between saves, compare production or pollution graphs at certain time intervals. Do they match at all?

[Koub]

You might want to have a look at these topics :
viewtopic.php?f=6&t=51306
viewtopic.php?f=6&t=61025
viewtopic.php?f=6&t=50342
viewtopic.php?f=6&t=12733
viewtopic.php?f=6&t=21363
viewtopic.php?f=6&t=17121
(Also, there are links in my post on the first thread I have linked, also relevant).

[HellhoundIndustries]

TL;DR

When a user tries to save over an existing file that belongs to a different world, Factorio should display a warning message and ask for confirmation.

What?

When an existing file is selected in the save menu and the player presses Save, Factorio would first read the file's metadata and check if it matches the world currently being played. (E.g. by either comparing the mapgen seed, giving every world a unique ID on creation, or simply checking if the file you're writing to is the same one you loaded.)

If there's a mismatch, a dialog box would appear with a message like " This save file is for a different world. Are you sure you want to overwrite 'my-important-factory'?" The player would then be able to either confirm and overwrite the save, or cancel before any damage is done.

IMO it's important that the warning doesn't appear if the player tries to save over the same world/file they loaded, otherwise it's likely to be dismissed without being read.

Why?

Well, long story short, today I found out I accidentally overwrote my singleplayer save (with weeks of progress) by absent-mindedly hitting Save in a multiplayer server. Luckily, I still had a recent autosave for it, so I was able to recover it. But this sort of scenario is still very easy to get in by mistake, and in most circumstances the player won't have autosaves of the world they just lost. Adding a simple mechanism to prevent accidental data loss would save players a lot of pain and frustration.

[Koub]

[Koub] Merged into an older thread with the same suggestion.