Rails - migrating from 3.0 to 3.1 - ruby-on-rails-3

Question

I wanted to help out a open source project by migrating from 3 to 3.1
But I have never had to migrate a large project before so I am looking for some advise ?
this is the project - https://github.com/locomotivecms/engine
Thanks, Alex

Answer 1

here it is an "almost working" locomotivecms code, migrated on rails 3.1:
https://github.com/lgs/engine/tree/rails-3.1
... it is not ready for pull request,
infact it miss to replace /images/ whith /assets/ in all the relative path ...,
anyway it start and stay up (despite many "DEPRECATION WARNING"), on rails 3.1 server:
lsoave#ubuntu:~/rails/github/engine$ rails s
DEPRECATION WARNING: config.generators in Rails::Railtie is deprecated. Please use config.app_generators instead. (called from <top (required)> at /home/lsoave/rails/github/engine/config/application.rb:9)
DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/lsoave/rails/github/engine/config/application.rb:9)
DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/lsoave/rails/github/engine/config/application.rb:9)
=> Booting WEBrick
=> Rails 3.1.0.rc4 application starting in development on http://0.0.0.0:3000
=> Call with -d to detach
=> Ctrl-C to shutdown server
[2011-06-22 01:54:34] INFO WEBrick 1.3.1
[2011-06-22 01:54:34] INFO ruby 1.9.2 (2010-12-25) [i686-linux]
[2011-06-22 01:54:34] INFO WEBrick::HTTPServer#start: pid=2948 port=3000
Rails console works fine as well :
lsoave#ubuntu:~/rails/github/engine$ rails c
DEPRECATION WARNING: config.generators in Rails::Railtie is deprecated. Please use config.app_generators instead. (called from <top (required)> at /home/lsoave/rails/github/engine/config/application.rb:9)
DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/lsoave/rails/github/engine/config/application.rb:9)
DEPRECATION WARNING: class_inheritable_attribute is deprecated, please use class_attribute method instead. Notice their behavior are slightly different, so refer to class_attribute documentation first. (called from <top (required)> at /home/lsoave/rails/github/engine/config/application.rb:9)
Loading development environment (Rails 3.1.0.rc4)
ruby-1.9.2-p136 :001 >
This is the guide I followed during my try :
http://davidjrice.co.uk/2011/05/25/how-to-upgrade-a-rails-application-to-version-3-1-0.html
UPDATE:
"Cannot modify SafeBuffer in place" error resolved
UPDATE jun 23 11:
resolved "ArgumentError (wrong number of arguments (4 for 3))" adding options param (the fourth) to set_session into lib/locomotive/session_store.rb b/lib/locomotive/session_store.rb
Thanks to Nicholas Hubbard previous answer.

Answer 2

Reposting from GitHub:
It looks like the new sessions in 3.1 require 4 params:
https://github.com/rails/rails/blob/master/actionpack/lib/action_dispatch/middleware/session/cookie_store.rb Line 61
def set_session(env, sid, session_data, options)
The store in locomotive only takes three:
https://github.com/lgs/engine/blob/rails-3.1/lib/locomotive/session_store.rb Line 31
def set_session(env, sid, session_data)
Looks like options are being passed also that we are not expecting.