Adding the possibility to load/unload plugins at runtime

[StevenKrahforst]

For what that can be useful?

• Ingame Mod Manager/Browser for downloading/installing plugins while game is running
• Auto Updater before the game has been started (requires some more work cause the assemblies get locked when they are loaded)

Idea:

• Static methods like LoadFile(path) or LoadFromStream(stream) or LoadFrom(byteArray) like Assembly.LoadFile(path)
• Helper functions in order the mod can add compatibility when loaded manual
• For unloading I have no idea yet, probably something with the Garbage Collecter after the plugin has been disabled

[nike4613]

Unloading is not possible.

In a .NET Framework-adjacent environment like Unity Mono, the only way to do unloading is to load what you need into a separate AppDomain and then unload that domain. Unfortunately, in order to communicate between these domains, the runtime provides remoting proxies, and those are only generated for types which are MarshalByRefObject derived. Otherwise, the object is serialized in one domain then deserialized in the other. This would have unacceptable performance overhead, but even ignoring that, Unity would not behave, and at best you'd be unable to reliably create Unity object. At worst, you'd see hard-crashes.

It would be possible to just load a new copy of a given mot into memory, but that comes with its own set of problems. It would also require that the mod properly clean itself up when it is disabled, which the vast majority of mods simply do not do.

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All that being said, the two uses you specified do not need unloading; they would just require a game restart. Both of them are, in fact, already possible with the functionality that BSIPA provides. BSIPA used to even have the updater built in, and a mod manager like plugin has existed (though not been published, in large part because of my own laziness) for years in the form of https://github.com/nike4613/BSIPA-ModList-BeatSaber. I believe that ModList does actually work at present, though I have not tested it myself.

[StevenKrahforst]

Yeah makes sense