Don’t sweat it. I’m still digging myself.Maybe the problem is in the way wire_gen tries to detect the version of wire. Its got this little snippet of code:

@memoized_property
  def _wire_compiler_version(self):
    wire_compiler = self.tool_targets(self.context, 'wire_compiler')[0]
    wire_compiler_jar = wire_compiler.jar_dependencies[0]
    wire_compiler_version = wire_compiler_jar.rev
    return Revision.lenient(wire_compiler_version)