RVM .ruby-gemset file does not switch gemsets

Question

Why doesn't rvm switch to @project_gemset when I cd into my project's directory? The gemset name in my .ruby-gemset file matches the name listed from rvm gemset list.

> cd project
> ls -A
.ruby-gemset
> cat .ruby-gemset
project_gemset
> rvm gemset list

gemsets for ruby-1.9.3-p392 (found in /Users/david/.rvm/gems/ruby-1.9.3-p392)
=> (default)
   global
   project_gemset

Answer 1

It seems you must have both a valid .ruby-version file and a .ruby-gemset file in order for rvm to make the switch.

I was hoping it would switch gemsets and use the default ruby version, since the gemset is one of the existing gemsets for my default ruby. But that's not how it works.