F15 comes with Rails 3

[geofft]

Our Rails autoinstaller doesn't work any more, since it assumes Rails 2 command lines.

Rails 2 sites don't work any more.

[ezyang]

A vanilla autoinstalled Rails website seems to work fine.

[ezyang]

Never mind, I'm wrong. Essentially everything breaks.

[ezyang]

First problem: we appear to be pegging the Rails version in our autoinstaller, so it chokes when the gem is not available:

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.

[ezyang]

Bumping the version then results in:

/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:53:in `gem_original_require': no such file to load -- initializer (LoadError)
	from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:53:in `require'
	from ./../config/boot.rb:55:in `load_initializer'
	from ./../config/boot.rb:38:in `run'
	from ./../config/boot.rb:11:in `boot!'
	from ./../config/boot.rb:110
	from ./../config/environment.rb:11:in `require'
	from ./../config/environment.rb:11
	from dispatch.fcgi:21:in `require'
	from dispatch.fcgi:21

[ezyang]

Based on ​http://omgbloglol.com/post/353978923/the-path-to-rails-3-approaching-the-upgrade I think the problem is that boot.rb is wrong.

[ezyang]

Swapping out boot.rb for latest version gives:

./../config/environment.rb:13: uninitialized constant Rails (NameError)
	from dispatch.fcgi:21:in `require'
	from dispatch.fcgi:21

We're definitely not supposed to overwrite environment.rb on upgrade.

[ezyang]

Automated upgrades are a lost cause. Investigating if we can make Rails 2 and Rails 3 coexist.

[ezyang]

Installing the old gem triggers this bug:

​http://stackoverflow.com/questions/5176782/uninitialized-constant-activesupportdependenciesmutex-nameerror

Fortunately the require 'thread' workaround works. It would be nice to update Rails to the latest version, which doesn't have this bug, but most autoinstalls are pegged to a specific version. We need an autoupgrade.