Any time I try to load a world with this mod in the mods folder, it gets to "Loading Textures" and then crashes and gives the crash message "Error: lava.lang.IllegalArgumentException: Can't find attribute combatroll:count" with the exit code 255. I am using Forge 1.20.1 with the latest version of the mod that is available on Forge 1.20.1.

Had the same issue.
Here's my crash log: https://gist.github.com/TenKotowsky/b78f1b7894e3656357b609ebb9f5a8ee

Thank you for reporting. I'll investigate.

What is the in-game usecase to reproduce this crash?

What is the in-game usecase to reproduce this crash?

For me, if I remember correctly, it crashed at start when I tried to join the world. I didn't even start playing, it just crashed instantly as soon as the world loaded

Launching the game and entering the world does not produce a crash for me, this is most likely a conflict with some other mod.
In order to fix the issue, I need to know which specific mod causes this.

Ok I think I have found the issue, it seems to be Pufferfish's Skills and based on the previous reply it seems to be affecting fabric as well. I think this might be something to do with the custom attributes added with pufferfish skills that might be casuing the game to abrupptly crash as they are immediatley loaded up on world join/enter.

Heres logs, keep in mind I got a pretty big mod list:

latest.log
crash-2023-07-31_18.52.33-client.txt

Will also report this issue on Pufferfishe's Skills Github

i actually had the same issue, but i'm running the 1.19 version of the mod on quilt.

here's my crash report (and it comes with a modlist) https://pastebin.com/bphrNhZr

It looks like the third party mod in question is referencing a combat roll attribute at an incorrect time (before its registration).
This cannot be fixed by Combat Roll.

Closing the issue due to being non-actionable.
Feel free to reopen in when a hint of (specific) technical shortcoming of Combat Roll arises.

Anyone who wants something similar to "pufferfish's skills" use this mod instead "Passive Skill Tree"
https://www.curseforge.com/minecraft/mc-mods/passive-skill-tree