MappingProvider.getFieldMapping passes an invalid field discriptor to MappingProvider when using @Accessor

[modmuss50]

MappingProvider.getFieldMapping passes an invalid field discriptor to MappingProvider when using @Accessor

MappingProvider.getFieldMapping in some cases is passing an invalid MappingField.desc of

Lnet/minecraft/client/particle/ParticleManager$SimpleSpriteProvider;sprites:()Ljava/util/List;

The expected field desc should be:

Lnet/minecraft/client/particle/ParticleManager$SimpleSpriteProvider;sprites:Ljava/util/List;

Note the removal of the ()

A Possible Cause

After a bit of digging I believe this is happening here:

AnnotatedMixinElementHandlerAccessor.java#L297

It appears to be passing the accessor's method desc including the paramters, I believe it should just be the methods return value. My guess is this went untoiced with MCP as it does not handle the concept of field descriptors.

An Example

Note: All minecraft names are in yarn names

We can came across this issue with the following mixin.

The accessor is an innner interface to a parent mixin if that helps. I have tried with . and / package seperators to no avail, as well as removing the accessor target as its not needed here.

	@Mixin(targets = "net/minecraft/client/particle/ParticleManager$SimpleSpriteProvider")
	interface SimpleSpriteProviderAccessor {
		@Accessor("sprites")
		List<Sprite> getSprites();
	}

The target class (ParticleManager.SimpleSpriteProvider) looks something similar to this:

   @Environment(EnvType.CLIENT)
   class SimpleSpriteProvider implements SpriteProvider {
      private List<Sprite> sprites;

      public void setSprites(List<Sprite> sprites) {
         this.sprites = ImmutableList.copyOf(sprites);
      }
   }

Conclusion

fabric-mixin-compile-extensions could also strip the paremeters from the MappingField before looking up the obfuscated name.

Please dont hesisate to ask for more info if there is something I have missed. I am also in the sponge discord if thats easier.

[modmuss50]

I have applied a workaround succesfully here: MixinMappingProviderTiny.java.

Its just a simple change that removes any method params that turned up in the field desc

[Johni0702]

Same issue as the Invalid field descriptor section of #390 I believe.

[modmuss50]

Yes, you are correct.

That would have saved me a lot of time lol 👍