RDoc plugin output nothing with RDoc 6.5.0

[ybiquitous]

Hi. I find the RBS RDoc plugin outputs nothing with RDoc 6.5.0. Please look at the following sections for details.

Reproduction steps

1. Save the following content in a file named test.rb:

#!/usr/bin/env ruby
require 'bundler/inline'

rdoc_version, = ARGV
abort "Usage: #{$0} <rdoc_version>" unless rdoc_version

gemfile(true) do
  source 'https://rubygems.org'
  gem 'rdoc', rdoc_version
  gem 'rbs', '3.1.0'
end

rbs_file = 'user.rbs'
File.write rbs_file, <<~RBS
class User
  def name: -> String
end
RBS

require 'rdoc/rdoc'
RDoc::RDoc.new.document [rbs_file]

2. Run the following commands:

$ ./test.rb '>=6.5.0'
Fetching gem metadata from https://rubygems.org/.........
Resolving dependencies...
Using stringio 3.0.6
Using rbs 3.1.0
Using bundler 2.4.13
Using psych 5.1.0
Using rdoc 6.5.0
Parsing sources...
100% [ 1/ 1]  user.rbs

Generating Darkfish format into /Users/koba/tmp/rbs-rdoc/doc...

  Files:      1

  Classes:    0 (0 undocumented)
  Modules:    0 (0 undocumented)
  Constants:  0 (0 undocumented)
  Attributes: 0 (0 undocumented)
  Methods:    0 (0 undocumented)

  Total:      0 (0 undocumented)
    0.00% documented

  Elapsed: 0.1s

$ ./test.rb '<6.5.0'
Fetching gem metadata from https://rubygems.org/.........
Resolving dependencies...
Using bundler 2.4.13
Using rbs 3.1.0
Using stringio 3.0.6
Using psych 5.1.0
Using rdoc 6.4.0
Parsing sources...
100% [ 1/ 1]  user.rbs

Generating Darkfish format into /Users/masafumi.koba/tmp/rbs-rdoc/doc...

  Files:      1

  Classes:    1 (1 undocumented)
  Modules:    0 (0 undocumented)
  Constants:  0 (0 undocumented)
  Attributes: 0 (0 undocumented)
  Methods:    1 (1 undocumented)

  Total:      2 (2 undocumented)
    0.00% documented

  Elapsed: 0.1s

Using RDoc 6.5.0 ('>=6.5.0') outputs no classes, while using RDoc 6.4.0 (<6.5.0) outputs 1 class.

Suggestion

I think the cause is the following code:

rbs/lib/rdoc/discover.rb

Line 4 in 97187e9

gem 'rdoc', '~> 6.4.0'

This code can raise Gem::LoadError with the message:

Gem::LoadError: can't activate rdoc (~> 6.4.0), already activated rdoc-6.5.0. Make sure all dependencies are added to Gemfile.

Note that the message above is actually discarded here:

rbs/lib/rdoc/discover.rb

Lines 16 to 17 in 97187e9

	rescue Gem::LoadError
	# Error :sad:

So, I think we could fix the bug to allow newer RDoc versions like this:

-gem 'rdoc', '~> 6.4.0' 
+gem 'rdoc', '>= 6.4.0' 

But PR #1169 has pinned the RDoc version as 6.4.0 for some reason (I'm not sure why). 🤔

[ybiquitous]

Thank you for the quick fix! 😄