JRuby-Lint

See how ready your Ruby code is to run on JRuby.

JRuby-Lint is a simple tool that allows you to check your project code and configuration for common gotchas and issues that might make it difficult to run your code on JRuby.

Usage

JRuby-Lint requires JRuby to run. So, install JRuby first if you already haven't, then gem install jruby-lint.

Then simply run jrlint in your project to receive a report of places in your project where you should investigate further.

Checks

Here is a list of the current checks implemented:

• Report usage of ObjectSpace.each_object and ObjectSpace._id2ref which are expensive and disabled by default
• Report usage of Thread.critical, which is discouraged in favor of a plain Mutex.
• Report known gems and libraries that use C extensions and try to provide known alternatives.
• Report usage of Kernel#fork (which does not work) and Kernel#exec (which does not replace the current process).
• Report usage of Timeout::timeout which, when used excessively tend to be slow and expensive because of native threads
• Report behavior difference when using system('ruby'), which launches the command in-process in a new copy of the interpreter for speed

Reports

JRuby-lint supports text and html reports. Run jrlint with the option --html to generate an html report with the results.

TODO

Here is a list of checks and options we'd like to implement:

• Add in check for `` to make sure not execing ruby ...
• Report on more threading and concurrency issues/antipatterns
  • arr.each {|x| arr.delete(x) }
• Try to detect IO/File resource usage without blocks
• Check .gemspec files for extensions and extconf.rb for #create_makefile and warn about compiliing C extensions
• Check whether Rails production.rb contains config.threadsafe!
• Detect ERB files and skip them, or...
• Detect ERB files and pre-process them to Ruby source with Erubis
• Detect Bundler gems that have a platforms qualifier and ignore "platforms :ruby"
• Change to use jruby-parser
• 1.8/1.9 parser support/configuration without having to run JRuby itself in the right mode
• Allow use of a comment marker to suppress individual checks

Further Down the Road

• Arbitrary method/AST search functionality
• Code rewriter: option to change code automatically where it's feasible
• Revive or build an isit.jruby.org site for tracking
• Make JRuby-Lint submit results to tracking site based on lint passes and/or test suite runs

License

JRuby-Lint is Copyright (c) 2007-2013 The JRuby project, and is released under a tri EPL/GPL/LGPL license. You can use it, redistribute it and/or modify it under the terms of the:

Eclipse Public License version 1.0 GNU General Public License version 2 GNU Lesser General Public License version 2.1

See the file LICENSE.txt in distribution for details.