I’ve used rvm to install ruby 1.9.3-p0. Unfortunately, after installing, I get these errors:

yo:~ $ gem install rails
/Users/maryh/.rvm/rubies/ruby-1.9.3-p0/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>':
It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your ruby.

This did absolutely nothing and it’s still annoying as heck.

To fix this, because it’s annoying, I’ve tried this:

yo:~ $sudo port install libyaml
yo:~ $ rvm install ruby-1.9.3-p0 --with-libyaml=/opt/local
yo:~ $ gem install psych

That fixed things. Though, the –with-libyaml bit was ignored, so I could have dropped it and gotten the same result.

BUG! Just found that there’s a bug between ruby 1.9.3 and passenger 3.0.9. The error I was getting is discussed here. The solution is to go back to ruby 1.9.2 for now.