Where can I find an actively developed lint tool for Ruby?

Question

Most of the code I write is in Ruby, and every once in a while, I make some typo which only gets caught after a while. This is irritating when I have my scripts running long tasks, and return to find I had a typo.

Is there an actively developed lint tool for Ruby that could help me overcome this? Would it be possible to use it across a system that works with a lot of source files, some of them loaded dynamically?

Take this snippet as an example:

a = 20 b = 30 puts c 

To win bounty, show me a tool that will detect the c variable as not created/undefined.

Answer 1

• ruby -c myfile.rb will check for correct Ruby syntax.
• Reek checks Ruby code for common code smells.
• Roodi checks Ruby code for common object-oriented design issues.
• Flog can warn you about unusually complex code.

[Plug] If your project is in a public Github repository, Caliper can run the latter three tools and others on your code every time you commit. (Disclaimer: I work on Caliper)

Answer 2

You could give Diamondback Ruby a try. It does a static typecheck of Ruby code, and will thus blame you for using an undefined variable.

While DRuby is an ongoing research project, it already works quite well for small, self-contained Ruby scripts. Currently, it is unable to analyze much of the Ruby standard library “out-of-the-box”. Currently they are working toward typing Ruby on Rails (see their most recent papers).