Fixing the nokogiri built against libxml warning

Just installed Mountain Lion 10.8 fresh on my Mac Mini with a new SSD. As I get my rails environment up and running I ran into this common problem:

WARNING: Nokogiri was built against LibXML version 2.9.0, but has dynamically loaded 2.7.8

I had installed nokogiri with bundler. Unfortunately I don’t know which of these things quite resolved my issue, but this is what I did:

gem uninstall nokogiri
brew update
brew uninstall libxml2
brew install libxml2 --with-xml2-config
bundle exec gem pristine nokogiri

After all this, the warning was gone. I wish I knew which of these was extraneous, if any, but I guess I’ll find out next time assuming this common problem doesn’t get smoothed out upstream.