Question

I’m on windows, and have updated from ruby 1.8.x to 1.9.x, and am now getting error popups that complain ruby-mssomethingrt.1.8.x.dll is missing.

I would like to find out which gems have native extensions, so I can uninstall them and force a rebuild of the native extensions locally during installation again, to make the error go away.

Answer 1

A good start would be to look at the gem specification for each gem and see if it has the extensions field set. That should leave you with a short-list of gems to re-install. They don’t necessarily all use native extensions, but if you look at the corresponding extconf.rb files, this should be pretty easy to find out.

Update: Here is a short ruby script to list those gems:

require 'rubygems'

Gem.source_index.each do |gem|
  spec =  Gem.source_index.specification(gem[0])
  ext = spec.extensions
  puts "#{gem[0]} has extensions: #{ext}" unless ext.empty?
end