Where can I find the version numbers of gems with the Ruby version it is compatible with?

Question

The question says it all.

For example, I have a server with ruby 1.8.6 installed. And when I try sudo gem install roo, it gives an error nokogiri requires Ruby version >= 1.8.7. So, I want to install an older version of roo which is compatible with Ruby 1.8.6. But I dont know where to search. I know of RubyForge but it also does not say about the compatible versions of Ruby.

Answer 1

The brute force approach would be to get a git clone, search for where it specifies what Ruby version it's after, and use git blame or even the git pickaxe to determine the last version that didn't have that requirement.