Unknown property 'project' while trying to use extraMappings about mixingradle HOT 1 CLOSED

I can say that this is affecting a mixed bag of people working on SpongeCommon now with Gradle 5.6.2

Relevant stack trace and relevant script that fails (granted, we're using kotlin-dsl, but this property intermittently fails).

This is the setup:
MixinGradle 0.7-SNAPSHOT
Gradle 5.6.4
ForgeGradle 3.0.184

The awkward aspect of all of this is that this was failing for me locally, until I did some quasi clean and break and somehow my workspace is functioning, but @Zidane and some others at Sponge aren't able to get the same workspace working anymore.

@Mumfrey if you're up for it, I'd be more than happy at updating the extension to using Gradle's properties api introduced in 4.3 (and an example written in a build script with a task)

from mixingradle.