Ignoring GEM because its extensions are not built

Question

On both my work and home computers, I recently upgraded Ruby to 2.3.1, using ruby-install. I use chruby as my Ruby switcher.

I started seei

Answer 1

I came across this exact issue today - getting warnings like this for gems that weren't even installed!

... Well, it turns out the gems were installed - for a different ruby than the one I had set active with chruby (2.2.3 vs 2.3.1).

Switching to all the different rubies and running gem pristine --all on all of them solved the problem.