trying to run rails_upgrade plugin and getting a fork() error:

I am 开发者_运维百科investigating whether I should upgrade from rails 2.3.5 to rails 3, so installed the upgrade plugin and ran it:

rake rails:upgrade:check

Got an error:

** Invoke rails:upgrade:check (first_time)
** Execute rails:upgrade:check
rake aborted!
fork() function is unimplemented on this machine

I just had the same problem. You need to install the win32-open3 gem (gem install win32-open3) and then edit this file in your webapp:

vendor\plugins\rails_upgrade\lib\application_checker.rb

and change:

require 'open3'

to:

require 'win32/open3'