[Feature Suggestion] Add "Undo Save/Load" on the menu, when save states are available

[capitaineflam25]

Overwriting the current save state by mistake can sometimes be very frustrating when playing.
A file based undo feature could help solving that, like the one on RetroArch.

Let's say you're playing SMB on the NES core, and current save slot is 1.

Before saving, SMB_1.ss can be renamed to SMB_1_prev.ss
If "Undo Save State" is pressed, SMB_1_prev.ss is then renamed to SMB_1.ss

Before restoring a state, current state can be saved to SMB_1_undo.ss
If "Undo Load State" is pressed, SMB_1_undo.ss can be loaded.

[sorgelig]

There are different ways to use save state to avoid frustration. For example you can use one slot for long-term savestate while other slot for temporary save state till you achieve required state and then save to long-term slot.

[capitaineflam25]

Thanks for the suggestion.

That's the kind of thing i'm actually doing to avoid overwriting by mistake my best save state.
It requires a bit of practice to master the technique 😁

[birdybro]

To handle this for me, since I'm error prone as well, in the PSX core I turn on the auto increment slot option to keep a backlog of previous save states in the previous slots. Might be a simple solution to add this option to the other cores that have savestates to standardize that experience. This could probably be done fairly easily.

[sorgelig]

this is good option too.

[capitaineflam25]

This is an interesting alternative 👍

It doesn't handle the following case :
You have made a save state at the beginning of a level, you succeed to the next one and want to make a new save, and by mistake you do a "Load"
The "undo load" can save you in that situation.

(Those mistakes seem stupid 🤪, but it may happen when you have mapped load/save to buttons on your controllers)

But i admit that the auto increment solution will allow you to restart from your previous save, which could be nice.

[birdybro]

Yeah, pretty much every emulator has instant save/load of savestates via hotkeys or controller button combinations, so this problem is not really endemic to MiSTer alone. I am looking at updating savestate_ui on the existing cores that use it to mirror the PSX core. It's fairly simple to do to make it match current PSX behavior --> MiSTer-devel/WonderSwan_MiSTer@main...birdybro:WonderSwan_MiSTer:autoinc-slot (I still have to fix one thing with this though, not done yet)