Debugging Vagrant with pry-byebug

What to do when running Vagrant with --debug flag is not enough? As Vagrant is nothing else than a Ruby program, you can use famous pry gem together with pry-byebug to debug it. The only thing you need to do to use pry from the Vagrant code base is to make sure it’s installed and available in the Vagrant environment. Continue reading

Safe code evaluation in Ruby with $SAFE

As you probably know, you can use eval() to evaluate Ruby code from Ruby. But evaluating things that come from the outside of the program like user inputs can be dangerous. Why they can be dangerous you ask? eval() evaluates anything as we would program it ourselves. Basically anything can happen. That’s why it’s best to avoid eval() for such inputs altogether. But we can evaluate Ruby in a safer manner too; with $SAFE. Continue reading

Running test/unit suites with Minitest

Sometimes it happens that you want to run an old test suite, but you don’t have a correct version of the testing framework available. That happens a lot in Fedora
since tooling around RPM supports only one version of each component and new rubies does not come with test/unit anymore. As we still need to run the tests, we have two options. Either go ahead and update the whole test suite to a new version or just use Ruby’s dynamic nature to actually run it. Let’s look how the latter can look like. Continue reading

What attributes RubyGems’ Marshal file really contain?

RubyGems started with a single marshaled file called Marshal.4.8.gz containing the array of every Gem::Specification object for every gem that has been uploaded to RubyGems directory. Since then we have new indexes for RubyGems to speed things up, but good old Marshal.4.8.gz is still around carrying important information about gems from Are you interested to know what is and what is not there and finally understand why gem specification rails -r does not give you the information on licensing even though it’s part of rails’ gemspec file? Continue reading