I understand that ConventionMapping isn’t a public feature, but it definitely a widely used and stable feature of Gradle. Is there some magic annotation or some marker interface to have the project.extensions.create call to the add the IConventionMapping interface? I can see that it’s still _Decorated and hence being byte-code altered, I just understand why it’s no longer IConventionAware.
Essentially I just learned the lesson of @NonExtensible. Since I was extending a @NonExtensible, my extension doesn’t get Convention Mapping magic. The change in 1.8 is that the previous equivalent class CopySpecImpl did not have this annotation. Thanks for your help.