wrong constant name Virtus::Coercion::String (NameError)

[solnic]

it's me again :)

An exception occurred running /Users/solnic/.rvm/gems/rbx-head@virtus/bin/mutate
    wrong constant name Virtus::Coercion::String (NameError)

Backtrace:
  Rubinius::Type.coerce_to_constant_name at kernel/common/type.rb:109
               Module(Class)#const_set at kernel/common/module.rb:445
                      Class#initialize at kernel/common/class18.rb:12
             Rubinius.open_class_under at kernel/delta/rubinius18.rb:13
                   Rubinius.open_class at kernel/delta/rubinius.rb:26
                     Object#__script__ at lib/virtus/coercion/string.rb:1
        { } in Mutant::Mutator#mutate at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /../lib/mutant/mutator.rb:27
                            Array#each at kernel/bootstrap/array.rb:68
               Mutant::Mutator#mutate at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /../lib/mutant/mutator.rb:20
                 { } in Mutant.mutate at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /../lib/mutant.rb:25
                            Array#each at kernel/bootstrap/array.rb:68
                        Mutant.mutate at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /../lib/mutant.rb:24
        Mutant::Runners::RSpec#mutate at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /../lib/mutant/runners/rspec.rb:29
           Mutant::Runners::RSpec.run at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /../lib/mutant/runners/rspec.rb:11
                           Mutant.run at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /../lib/mutant.rb:20
                    Object#__script__ at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bundler/gems/mutant-68dd0a44a6b4/exe
                                         /mutate:6
                   Kernel(Object)#load at kernel/common/kernel.rb:577
                    Object#__script__ at /Users/solnic/.rvm/gems/rbx-head@virtus
                                         /bin/mutate:19
      Rubinius::CodeLoader#load_script at kernel/delta/codeloader.rb:67
      Rubinius::CodeLoader.load_script at kernel/delta/codeloader.rb:109
               Rubinius::Loader#script at kernel/loader.rb:632
                 Rubinius::Loader#main at kernel/loader.rb:836

[dkubb]

Looking at the stacktrace, just before the exception is thrown Module#const_set is called, then Rubinius::Type.coerce_to_constant_name is called and passed (presumably) whatever was passed into const_set.

Now, based on the error message it looks like the string "Virtus::Coercion::String" was passed in to const_set, which is obviously incorrect. A constant cannot contain colons.

So I'm guessing that wherever the class/module is being set it needs to split up the string and create a "chain" of modules, first "Virtus", then inside that "Coercion", then inside that "String. It would probably have to be smart about using a class or module as appropriate, and setting the correct superclass if applicable. (just a guess)

I think that place may be Mutant::Mutator#class_ast but I'm not 100% familiar with the internals of the mutator atm.

@txus does that sound right?

[txus]

Makes sense. You're running that on Virtus right? Could you paste me the bin/mutate ... command you used so that I can reproduce it? I'm not sure about the place where this is happening but Mutant::Mutator#class_ast sounds like a good place to start looking, I'll find out.

[dkubb]

In my case I ran it against another project of mine, but I had to do some tweaking to get it to work under rspec 2.

At the moment I'm using RSpec 1 in the master branch, but I'll create an rspec2 branch to make it easier to repro.

[dkubb]

Here are steps to repro: (I would assume any rbx would repro this, but I was using rbx-head)

rvm rbx-head
git clone git://github.com/dkubb/ice_nine.git
cd ice_nine
git checkout rspec2
gem install bundler && bundle
bundle exec mutate "IceNine::Freezer::Object.deep_freeze" spec/unit/ice_nine/freezer/object/class_methods/deep_freeze_spec.rb

EDIT: the exception I see is wrong constant name IceNine::Freezer::Object (NameError) and the backtrace is:

  Rubinius::Type.coerce_to_constant_name at kernel/common/type.rb:118
               Module(Class)#const_set at kernel/common/module.rb:446
                      Class#initialize at kernel/common/class18.rb:11
             Rubinius.open_class_under at kernel/delta/rubinius18.rb:13
                   Rubinius.open_class at kernel/delta/rubinius.rb:26
                     Object#__script__ at lib/ice_nine/freezer/object.rb:1
        { } in Mutant::Mutator#mutate at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/../lib/mutant/mutator.rb:27
                            Array#each at kernel/bootstrap/array.rb:68
               Mutant::Mutator#mutate at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/../lib/mutant/mutator.rb:20
                 { } in Mutant.mutate at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/../lib/mutant.rb:25
                            Array#each at kernel/bootstrap/array.rb:68
                        Mutant.mutate at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/../lib/mutant.rb:24
        Mutant::Runners::RSpec#mutate at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/../lib/mutant/runners/rspec.rb:29
           Mutant::Runners::RSpec.run at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/../lib/mutant/runners/rspec.rb:11
                           Mutant.run at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/../lib/mutant.rb:20
                    Object#__script__ at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/gems/mutant-0.1.1
                                         /exe/mutate:6
                   Kernel(Object)#load at kernel/common/kernel.rb:576
                    Object#__script__ at /Users/dkubb/.rvm/gems
                                         /rbx-head@ice_nine/bin/mutate:19
      Rubinius::CodeLoader#load_script at kernel/delta/codeloader.rb:67
      Rubinius::CodeLoader.load_script at kernel/delta/codeloader.rb:109
               Rubinius::Loader#script at kernel/loader.rb:632
                 Rubinius::Loader#main at kernel/loader.rb:836

[dkubb]

Ok, I started to poke around with this. I tried a few hacky attempts to get the AST for a class (or module) and I wasn't satisfied with any of them. I found it a bit hard to even tell if I was on the right track since the docs for this part of Rubinius are pretty sparse.

I'll give it a try again later this week, but I wanted to report that I tried for a couple of hours and didn't make any forward progress on this.