Does heroku use rvm?

Question

Does heroku use rvm or rbenv?

I'm reading https://github.com/heroku/stack-images/blob/master/bin/cedar-14.sh

and there's no mention of rvm. Yet I know for a fact then when you do

git push heroku master

the apropriate ruby magically manifests itself in the remote heroku lxc container.

Answer 1

They have custom scripts for downloading and installing ruby. Or at least it looks like that from those scripts:

https://github.com/heroku/heroku-buildpack-ruby/blob/master/bin/support/download_ruby https://github.com/heroku/heroku-buildpack-ruby/blob/master/lib/language_pack/installers/heroku_ruby_installer.rb