Where can one find a list of deprecated methods, APIs, etc, in order to upgrade from Rails 2.x to Rails 3?
How to disable colorize logging in ActiveRecord without Rails? Instead of keeping AR decoupled, independent ORM, it is now tightly bound to Rails framework.
Moving ActiveRecord::Base.colorize_logging to Rails::LogSubscriber.colorize_logging was just bad design and the wrong direction, wasn't was?
A good way of checking the specifics about an individual app would be to run the rails_upgrade plugin on it (you can find it at GitHub), it will output a list of deprecation notices and recommendations
Some useful info is also summarised in this blog post: http://www.simonecarletti.com/blog/2010/07/the-way-to-rails-3/
Additionally Railscasts has a bunch of movies on various changed aspects of the API. Go to Railscasts.com and browse the movies filed under the rails3 tag.
Another place to have deprecation's for active record is here (http://m.onkey.org/active-record-query-interface).
Reply if found useful.
The Rails 3 release notes have lots of good information:
Railties now deprecates:
ActionController:
ActiveRecord
ActionMailer
I found it to be a great value to buy http://www.railsupgradehandbook.com/
I don't think you'll find an exhaustive list of depreciations because it really depends on what version of rails you are upgrading from. For instance, Rails 2.3.9 (just released) added additional depreciations over the previous release.
The Rails Upgrade Handbook (as mentioned above) is a great tool and contains 12 pages of depreciation warnings and how to fix them. I don't think they'll be published here because you should just drop the $9 and download the pdf to get the list. The included tutorials and other information makes it well worth it. It was for me.
If you don't want to pay for good information then just run the rails_upgrade plugin for your specific application. More information on how the plugin is on the rails upgrade plugin github page.