Error when processing controller action

[vleonty]

I have one controller action that is throwing an error during processing. I am using ruby 2.1.2 and Brakeman 3.1.1. There are around 20+ controllers with a fair number of actions that all process without issue. A report is generated but brakeman exits in error.

I ran it in debug mode and got this call stack in the middle of the processing output:

Rendering backbone/index (["BackboneController#index"])
Error when processing backbone/index: Error when processing backbone/index: Error when processing backbone/index: undefined method `empty?' for nil:NilClass
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/processors/base_processor.rb:80:in `block in process_dstr'
(eval):3:in `map!'
(eval):3:in `map!'
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/processors/base_processor.rb:75:in `process_dstr'
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/ruby_parser/bm_sexp_processor.rb:75:in `block in process'
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/ruby_parser/bm_sexp_processor.rb:112:in `in_context'
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/ruby_parser/bm_sexp_processor.rb:71:in `process'
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/processors/template_processor.rb:24:in `process'
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/processors/base_processor.rb:79:in `block in process_dstr'

Then at the end of the run and following "Indexing call sites..":

Indexing call sites...        
/Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/ruby_parser/bm_sexp_processor.rb:69:in `process': Type should be a Symbol, not: [nil, nil] in {nil=>nil} (RuntimeError)
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/processors/lib/find_all_calls.rb:22:in `process_source'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/tracker.rb:182:in `block in index_call_sites'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/tracker.rb:110:in `block in each_template'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/tracker.rb:109:in `each'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/tracker.rb:109:in `each_template'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/tracker.rb:181:in `index_call_sites'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/scanner.rb:305:in `index_call_sites'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman/scanner.rb:65:in `process'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman.rb:327:in `scan'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/lib/brakeman.rb:62:in `run'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/gems/brakeman-3.1.1/bin/brakeman:78:in `<top (required)>'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/bin/brakeman:23:in `load'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/bin/brakeman:23:in `<main>'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/bin/ruby_executable_hooks:15:in `eval'
    from /Users/Me/.rvm/gems/ruby-2.1.2-v@myapp/bin/ruby_executable_hooks:15:in `<main>'

I can't quite figure out why the index action in this controller class is a problem. When I delete the action outright and then do a Brakeman run, it completes without any issue. Running 'ruby -c' and 'ruby_parse' run without any issue on this controller file.

[presidentbeef]

Sorry you having trouble.

The debug messages are not very clear, but it's not the controller action that's causing an issue, it's the backbone/index view. What kind of template is it?

[vleonty]

Sorry, I understand that the debug messages may not be that clear and lack some degree of context. I thought it might be a reasonable starting point, and it is as much as I have to go on at this point.

It is a haml template.

[presidentbeef]

Oops I didn't mean to blame you for the unclear errors. Those are my fault :)

Unfortunately I can't replicate this issue without knowing the contents of the view. Is there any way you can either share the code or narrow it down to a sample that still causes the error?

[vleonty]

No problem. I did some experimentation with the problem template and determined that it did not like an embedded comment that was under a javascript tag, I distilled it down to:

%body
    :javascript
        $(function() {
            #{
                # Ticket #9999
                # my variable needs to be number 4
             }
             var myVar = 4;
        });

[presidentbeef]

Perfect, I can reproduce the issue.

[presidentbeef]

Should be fixed with #750