rbs prototype rb can have duplicated declarations

[pocke]

Problem

rbs prototype rb command may generate duplicated declarations.
For example:

a.rb

class A
  def foo() end
end

class A
  class B
    def bar() end
  end
end

$ rbs prototype rb c.rb
class A
  def foo: () -> untyped
end

class A
end

class A::B
  def bar: () -> untyped
end

In this case, class A is duplicated.

And it easily causes in the real applications.

Solution

Now I avoid the problem with the following code.
full version: https://gist.github.com/pocke/a3faa4b87416c3d899e626f9197f2174#file-steep-rake-L13-L33

decls = Ruby::Signature::Parser.parse_signature(sig_base_path.read)
decl_map = {}
decls.each do |decl|
  if d = decl_map[decl.name]
    # TODO: Is it right for decl is not a class / module?
    c = Ruby::Signature::AST::Declarations::Class
    m = Ruby::Signature::AST::Declarations::Module
    next unless d.is_a?(c) || d.is_a?(m)
    next unless decl.is_a?(c) || decl.is_a?(m)

    d.members.concat decl.members
    if d.is_a?(c) && decl.is_a?(c)
      decl_map[decl.name] = c.new(name: d.name, type_params: d.type_params, super_class: d.super_class || decl.super_class, members: d.members, annotations: d.annotations, location: d.location, comment: d.comment)
    end
  else
    decl_map[decl.name] = decl
  end
end

But I think rbs command should provide a solution(s) for the problem.

So, I think it is better if rbs prototype rb command displays deduped declarations.

And we can implement rbs dedupe sub-command as an alternative. The sub-command may be useful for RBS files that are generated by other programs. But I'm not sure the sub-command is actually necessary.

By the way, I guess rbs prototype rbi also has the same issue.

How about the ideas? I'd like to implement them if they are acceptable.

[soutaro]

It's a good point. However, I don't think deduping declarations makes much sense. The tool is for prototyping and none of these fixes will completely solve the problem.

My suggestion is the simplest workaround: to stop generating declarations for empty classes/modules.

[pocke]

I'll close this issue because RBS became to accept duplicate class declaretions.