Hi folks, Gradle 5 is migrating to Groovy 2.5 (yay!). However, we discovered several regressions (in @CompileStatic, in covariant return type checking, ...) that may make the migration painful. One of them is unexpected for our users: the @Immutable AST transformation changed the runtime checks, so a class compiled with 2.4 running on 2.5 would suddenly fail. An example of such a problem has been reported at https://github.com/ajoberstar/grgit/issues/237
Our partners at Netflix already mentioned they had to fork several plugins to accommodate the problem. While the new checks are legit, the fact that it's an AST xform (happening at compile time) and that the additional check happens at runtime can be surprising. I'm not sure if we need to change this, but having an incompatibility may be annoying.
