2.5.59.3 causes older versions to crash when viewing cooling settings

[Alohacajun]

Fix: Delete %AppData%/SuperSlicer/ui_layout

Bug description
If you run 2.5.59.3 and switch back to an older version (ie 2.5.59.2), opening Filament > Cooling will cause it to crash.

Expected behavior
A clear and concise description of what you expected to happen.

To Reproduce
Steps to reproduce the behavior:

1. Run 2.5.59.3, then close.
2. Run 2.5.59.2
3. Open Filament tab
4. Open cooling options
5. Crash

Desktop (please complete the following information):

• OS: Windows
• Version 2.5.59.3 / 2.5.59.2

Additional context
This might happen because all my versions share the same AppData config folder.
Is this related to the "Rework of fan speed control by extrusion type." in 59.3?

[legend069]

Yes this is most likely due to the fan speeds rework.

Not sure why it would crash though, unless it's unhappy with extra variables in the config.

It might be because of overhangs_fan_speed
And overhang_perimeter_fan_speed ?

[Alohacajun]

Would it be viable to have alpha/beta/RC builds use their own AppData directory? They do this in the PS repo as seen here.

[Darkmann12]

I have also run into this :)

[legend069]

@supermerill
would it be worth while reverting the variables that were changed back to original?
or adjusting code so any old variable names are still loaded from the config but get assigned to the new variable names?
ie overhang_perimeter_fan_speed = overhangs_fan_speed

also #3991

[supermerill]

The issue comes from the ui layout.
The layout used is the last one, but with an old version, there can be empty lines, where the settings doesn't exists yet.
And currently, there is a bug with a crash when there is an empty line.
I fixed it, and next version will have the patch.
I'll patch the 2.5 and future 2.7
For the 2.4, I'm not sure it's that useful, tell me.

as said @Alohacajun, the easiest way to manually fix the issue: before using an old version, delete the ui_layout directory from your configuration directory.
The way the ui layout is updated is really subpar, i'll work a bit on that right now to avoid future problems with it.