Upgrading your models:
- Get rid of all validates_xxx_of with appropriate validates
- Get rid of all def validate ... end methods with custom validator
- Find out all occurrences of :conditions, :limit, :order and use new active record methods instead
- Replace all named_scope with scope
- Make sure your acts_as_xxxx plugins are all updated to use Ruby on Rails 3. I had troubles with Authlogic as it shows Based.named_scope is DEPRICATED. Still looking for a solution.
- Ruby 1.9.2 doesn't work with soap42 wsdl driver. Haven't found a solution yet as it keeps reporting an error regarding "XML processor module" missing.
Upgrading your controllers:
- Find out all occurrences of find method and replace with where.
- Find out all calls to Mailer that looks like deliver_xxx and make it xxx.deliver
Upgrading your views:
- All erb blocks must start with a has to be changed to . Do the same for all such erb blocks with a do.
- All link_to_remote or remote_form_for or other remote form helpers need to be changed to their non-remote counterparts with a param :remote => true.
Upgrading your mailers:
- body method is gone, instead of the hashed params to this method, just define instance variables.
- All xxx.text.html.erb now becomes xxx.html.erb in the mailer views.
Upgrading the config files:
- The best way is to crate a new rails app and then copy the config folder into yours.
- Look at the initializers and clean up any required initializers.
- Make sure you have autoload_paths setup to include the lib folder. It is not included by default, so your code from the lib folder won't be accessible.
- Look at deprecation warning and you will see lots of config.action_controller.* need to changed to config.*
- All plugin/lib/rails/tasks/*.rake needs to be copied in to plugin/lib/tasks/*.rake
- Make sure your plugins don't use named_scope, if you find any, replace with scope.
- Whatever applies to your models should also be applied to your plugins that act on models.
- Check you have updated shoulda, rspec or whatever lib you use.
- Update test codes according to your new lib.
Upgrading IDE to use RVM:
- Your IDE is not smart enough to use RVM. However use this to get TextMate ready.