mruby-proc-ext: #parameters mistakes keyword "splat" for a block parameter

[ntl]

Hello, thanks so much for MRuby!

I'm currently investigating some behavior in Proc#parameters (from mrbgems/mruby-proc-ext), and believe I may have spotted a bug (or else I am unaware of the expected behavior). Here is a file that reproduces my issue (I put it in a test project under e.g. mrblib/bug_example.rb):

class BugExample
  def all_method(reqp, optp=nil, *restp, keyreqp:, keyp: nil, **keyrestp, &blockp)
    Invocation::Binding.get
  end
end

example = BugExample.new

puts example.method(:all_method).parameters.inspect

When I run the above code, with mruby-proc-ext (and mruby-io, for #puts), I see the following output:

[[:req, :reqp], [:opt, :optp], [:rest, :restp], [:block, :keyrestp]]

This indicates that the **keyrestp parameter has been interpreted as a block parameter. I'm not sure how keyword arguments are handled internally by MRuby, but I believe the expected output is this:

[[:req, :reqp], [:opt, :optp], [:rest, :restp], [:keyreq, :keyreqp], [:key, :keyp], [:keyrest, :keyrestp], [:block, :blockp]]

I'm not sure how mruby-proc-ext is supposed to work with keyword arguments. I have discovered that the keyword arguments appear to be placed in the stack after the block argument (and mrb->c->ci->argc does not indicate their presence; only ci_nregs in src/vm.c, line 405).

I am very new to MRuby, though, so I realize I may be in error here.

[matz]

It's fixed in the mruby3 branch.
Note that mruby's Proc#parameters does not distinguish required keyword arguments and optional keyword arguments.
It's a TODO.

[ntl]

Thanks so much!