I just got a new laptop which means re-installing everything. This included Rails and I ended up with 2.3.8. Most of my projects use 2.3.5. I figured no big deal since various Rails versions have always played together in the past. I installed 2.3.5 with gem install rails -v=2.3.5 and figured all would be well.
I would be wrong in that assumption.
Instead of just working anytime I try to run a 2.3.5 app (most of my apps at the moment). I get this:
Missing the Rails 2.3.5 gem. Please `gem install -v=2.3.5 rails`, update your RAILS_GEM_VERSION setting in config/environment.rb for the Rails version you do have installed, or comment out RAILS_GEM_VERSION to use the latest version installed.
So my next step was to uninstall 2.3.8. I still get the error. I uninstalled and then reinstalled Rails and things seem to be working.
Heroku has the answer: .
This is why it’s usually a good idea to wait a little while after a Rails update. I have to keep reminding myself of that.