Ruby 2.0/ Rails 4.0.0beta upgrade fails on push to heroku

Question

Brain dump because mine is fried with googling and slamming my head on the computer. Any help or clues would be GREATLY appreciated!

I manage my gems via rvm.

$ ruby -v
ruby 2.0.0p0 (2013-02-24 revision 39474) [x86_64-darwin12.2.0]

$ rails -v
Rails 4.0.0.beta1

Then when I want to create a brand new app from scratch

$ rails new brand_new_app
 create  
  create  README.rdoc
  ...
Your bundle is complete! Use `bundle show [gemname]` to see where a bundled gem is installed.

$ cd brand_new_app

Then I initialize a git repo, add the app I just created. I then create a heroku instance

brand_new_app $ heroku create
    Git remote heroku added

Then I try and deploy to heroku but it fails on the active support gem.

brand_new_app $ git push heroku master
    Counting objects: 62, done.
    Delta compression using up to 4 threads.
    Compressing objects: 100% (50/50), done.
    Writing objects: 100% (62/62), 20.54 KiB, done.
    Total 62 (delta 2), reused 0 (delta 0)

    -----> Ruby/Rails app detected
    -----> Installing dependencies using Bundler version 1.3.2
   Running: bundle install --without development:test --path vendor/bundle --binstubs vendor/bundle/bin --deployment
   Fetching gem metadata from https://rubygems.org/.........
   Fetching gem metadata from https://rubygems.org/..
   Installing rake (10.0.3)
   Installing i18n (0.6.4)
   Installing minitest (4.6.2)
   Installing multi_json (1.6.1)
   Installing atomic (1.0.1)
   Installing thread_safe (0.1.0)
   Installing tzinfo (0.3.37)
   Installing activesupport (4.0.0.beta1)
   Gem::InstallError: activesupport requires Ruby version >= 1.9.3.
   An error occurred while installing activesupport (4.0.0.beta1), and Bundler
   cannot continue.
   Make sure that `gem install activesupport -v '4.0.0.beta1'` succeeds before
   bundling.
     !
     !     Failed to install gems via Bundler.
     !
     !     Heroku push rejected, failed to compile Ruby/rails app

I have imploded rvm (idk why, mainly bc I was frustrated) and I have checked every place possible. I created the rails app without any special settings, it is just a normal install. If anyone has any hints that could lead me to the right direction, please send them my way! I appreciate you reading this far!

Answer 1

You should put a ruby line in your Gemfile like is explained in the heroku documentation.

Just add the line ruby "2.0.0" beneath source "https://rubygems.org" in your Gemfile.

https://blog.heroku.com/archives/2012/11/5/ruby-2-preview-on-heroku

I have tried this, and this works for heroku. Apparently Rails 4 is not compatible with different ruby versions. This is kind of odd, since they say here that:

Ruby 2.0 is the preferred Ruby to use with Rails 4.0.

http://weblog.rubyonrails.org/2013/2/25/Rails-4-0-beta1/

Apparently preferred, means required.

Hope this helps