Steps to ensure Haml works:

1. In config/application.rb, be sure to add Haml as a template_engine.

config.generators do |g|
  g.template_engine :haml
end

2. Run haml –rails . to initialize Haml under Rails.

3. Rails 3 generators for Haml are at: http://github.com/pjb3/rails3-generators.

Passenger 2.2.9 is fully compatible with Rails 3. Though if you wish to take advantage of REE's optimizations you might want to delete config.ru file as detailed here: http://blog.phusion.nl/2010/01/08/phusion-passenger-2-2-9-released/.

Paperclip - http://github.com/thoughtbot/paperclip

seems to be working. i just did a very basic test though. Not using s3 or anything else custom.

Proof - http://github.com/lenary/photoist

EDIT: i haven't done the tests yet as i don't have an s3 instance to test with

To make exception_notification work, you've to create an initializer in config/initializers. Didn't actually test by receiving an email through Exception Notification, but log files show it is being called correctly.

Formtastic also requires an initializer:

# config/initializers/formtastic.rb
require 'formtastic'
ActionView::Base.send :include, Formtastic::SemanticFormHelper

I've tested simple and nested forms with no problems.

validation_reflection hooks into formtastic as expected. Just update the initializer:

# config/initializers/formtastic.rb
require 'formtastic'
ActionView::Base.send :include, Formtastic::SemanticFormHelper

require 'validation_reflection'

Authlogic's generators are failing (As expected from a 2.x generator syntax), so as nifty_generators.

RailsIndexes tests are passing, minor adaptations that will not affect users are required.

Searchlogic is not working with “undefined method `merge_joins' for class `Class' (NameError)”

The only thing Authlogic's generators do (at least as of the latest version) is make a user session model. I've added a quick-and-dirty authlogic:session generator to josevalim/indirect/paulberry's growing list of generators:

http://github.com/trydionel/rails3-generators

No clue if this lets Authlogic work properly though :)

OK, can everyone who has done something here please submit their names to the bugmash site at http://bugmash.com/submit

the judges think you're doing a pretty good job and are willing to accept these entries for the bugmash

Cucumber doesn't work, since you can't run the generator to get it started. I added it to the Gemfile and require'd it in environment.rb

The rails3 branch of factory_girl ( http://github.com/thoughtbot/factory_girl/commits/rails3 ) is working for me. We could use a few more people trying it out though before declaring it ready.

Paperclip works for me but only the rails3 branch (http://github.com/thoughtbot/paperclip/tree/rails3)

Having some issues with will_paginate. No luck as of yet.

thinking-sphinx ties in heavily to old ActiveRecord code and has some generator scripts that only work on Rails 2. Pat's aware and the community is looking into it.

Authlogic _seems_ to work OK if you don't care about generators.

Hm, rake rails:upgrade:check is telling me Paperclip has out-of-date generators. So it might work for existing code, but you'll be doing a lot of hand-hacking if you want to write new stuff :)

I wonder if activemessaging plugin have any issues reported with 3.0 ?