Tapioca::Dsl::Compilers::ActiveJob creates an invalid RBI for generic job classes

[AndrewSwerlick]

Given classes like this

class Operation
  abstract!

  sig { abstract.void }
  def save!; end
end

class OperationJob < Active::Job
    extend T::Sig
    extend T::Generic
    abstract!
    OperationType = type_member { { upper: Operations::Model } }

    sig { returns(OperationType) }
    attr_reader :operation

    sig { abstract.returns(T::Class[OperationType]) }
    def operation_type; end

    def perform(**args)
      @operation = operation_type.new(**args)
      @operation.save!
    end
end

The compiler produces output like this

class. OperationJob
  class << self
    sig do
      params(
        args: T.untyped,
        block: T.nilable(T.proc.params(job: OperationJob).void)
      ).returns(T.any(OperationJob, FalseClass))
    end
    def perform_later(**args, &block); end

    sig { params(args: T.untyped).returns(T.untyped) }
    def perform_now(**args); end
  end
end

This fails type checking with the error Malformed type declaration. Generic class without type arguments.

Locally we worked around this by monkey patching the compiler to skip generics by calling

def decorate
  return if constant.is_a?(T::Generic)

  # continue with existing code
end

Should this change be upstreamed? If so I'm happy to submit a PR

[KaanOzkan]

You shouldn't need to skip generics, I think we can generate a generic type in the method signature instead, OperationJob[T.untyped]. Assuming T.untyped will be okay with any given upper/lower bound.

Also instead of the is_a? it'll be better to do T::Generic === constant to cover for the possibility of being overwritten.

[st0012]

This looks similar to Shopify/job-iteration#550
A fix similar Shopify/job-iteration#556 to should address the problem.