Ability to define files/folders to update during GENERIC_PACK server upgrade

[SgtMate]

Enhancement Type

Improve an existing feature

Describe the enhancement

While upgrading a custom server using the GENERIC_PACK environment variable, I ran into the issue that the modpack (GTNH) includes several special files and folders that need to be cleanly replaced for a proper version upgrade (Official GTNH Wiki article).
As this was not achievable using only the tools provided by this project (at least to my very limited knowledge), I suggest adding the possibility to clearly define which files/folders should always be replaced and which should always be kept. Both options are important for modpacks with more complex upgrade procedures like GTNH.

[itzg]

Thanks for requesting this feature.

The generic pack is meant to be a very simplistic, fallback option to just unzip and run. I have invested too much effort in Modrinth and CurseForge automation to support further logic with generic packs.

I'd be open to a small PR if you or someone wants to contribute this feature.

[SgtMate]

One Idea i just had is to give users of special modpacks the ability to integrate their own upgrade scripts that get executed with a standard way to interface with the rest.
This might make it easier to implement your modpacks own solution without need to understand the codebase behind the container.
Of cause there might be some guidelines to be set so the scripts dont disturb the rest of the system.

[itzg]

Speaking of update scripts, looks like some have been documented in the Server Updates section of

https://wiki.gtnewhorizons.com/wiki/Server_Setup_(Container)

Maybe somebody that created those could contribute an enhancement to the image to add a GTNH option for MODPACK_PLATFORM like CurseForge and Modrinth.