automatic fix unexpectedly modifying the file

[fabiopelosin]

I'm shaping up some specs files and I have disabled all the cops which where detecting an infraction:

$ rubocop spec/specification_spec.rb
Inspecting 1 file
.

1 file inspected, no offences detected

I would then expect that the automatic fix would not modify the file, instead it does:

$ rubocop spec/specification_spec.rb -a
Inspecting 1 file
E

Offenses:

spec/specification_spec.rb:98:34: W: ambiguous first argument; parenthesize arguments or add whitespace to the right
        end.message.should.match /Invalid string representation/
                                 ^
spec/specification_spec.rb:235:31: E: unexpected token tLCURLY
          s.subspec 'Subspec' { |sp| }
                              ^
spec/specification_spec.rb:404:34: W: ambiguous first argument; parenthesize arguments or add whitespace to the right
        end.message.should.match /No podspec exists/
                                 ^
spec/specification_spec.rb:412:34: W: ambiguous first argument; parenthesize arguments or add whitespace to the right
        end.message.should.match /Unsupported specification format/
                                 ^
spec/specification_spec.rb:439:31: E: unexpected token tLCURLY
          s.subspec 'Subspec' { |sp| }
                              ^
spec/specification_spec.rb:443:34: W: ambiguous first argument; parenthesize arguments or add whitespace to the right
        end.message.should.match /can be set only for root specs/
                                 ^
spec/specification_spec.rb:451:1: E: unexpected token $end

1 file inspected, 7 offences detected

An example of the diff:

         @spec = Spec.new do |s|
           s.name = "Pod"
           s.version = "1.0"
-          s.subspec 'Subspec' do |sp| end
+          s.subspec 'Subspec' { |sp| }
         end
         @subspec = @spec.subspecs.first
       end

I understand that this is not elegant Ruby and that the original file should be changed, but still is valid Ruby and rubocop should not break it (hence why I'm reporting the issue).

[bbatsov]

Yep, we'll fix this. @jonas054 has been fixing all sorts of similar problems lately. Unfortunately auto-correction is not easy by a long shot. :-)

[fabiopelosin]

Unfortunately auto-correction is not easy by a long shot. :-)

I guess it... but it is such an amazing feature!

[fabiopelosin]

Thanks!