Possible to use ASM on other mods?

[Sqeegie]

I'm interested in making custom add-on mods for other mods which don't have APIs. However, I'm wondering if it's possible to use ASM, or Reflection for that matter, on other forge mods instead of vanilla MC code. From what I've read and picked up, the IClassTransformer interface is part of Mojang's launcher. Therefore, is technically separate from Forge/FML. So I'd assume that it'd therefore be possible to transform most classes that are loaded into the JVM, including Forge mods. That being said, I cannot find any examples of someone transforming a mod this way. I don't know if that's because of some copyright issue I'm unaware of, or because it's simply not possible to. I have a little experience transforming MC's code with ASM, however, I'm still quite new to the whole topic. So if someone could point me in the right direction, and if this concept is even possible, could supply me with some examples how it might differ from transforming MC's code (I'd assume you wouldn't be using FML's Loading Plugin), I'd be much obliged to you.

 

- Sqeegie

[Draco18s]

Can you?

Absolutely.

 

Should you?

Avoid ASM like the plague.

 

Better yet, avoid the plague like ASM.

[shadowfacts]

Jesus fucking christ no. This is a horrendously bad idea. Horrendously. This is incredibly dangerous and completely stupid. This is an even worse idea than using ASM on Minecraft code.

[jeffryfisher]

What you do depends on your situation and the foreign-mod:

 

If you are modding solely for yourself, running on your own machine(s), then anything goes.

 

If you are hosting a server for an invited group of friends, then first try reflection. If that doesn't work, then try to contact the foreign mod's developer(s) for source-code and support / collaboration. In extremis, you might try ASM, but back up everything first, and have your friends sign waivers.

 

If you're going to publish a mod at Curse, then forget about ASM, and carefully document any reflection that does anything more inside other mods besides reading protected/private data. Beware of dependencies. Either insist that users install them or else encapsulate features so that they side-step missing mods gracefully.

 

If I recall correctly, the postInit event is where you should detect other mods, possibly communicate with them, and decide what to do about the context in which your mod finds itself.