如何在不使用Bundler的情况下通过CLI使用特定的ruby gem版本

Question

I have two rails projects on my box, one that is using rails 3.0 and as such Bundler handles all it's dependencies.. and the other is a rails 2.3.5 that doesn't use bundler.

I'm getting this error when running rake:

ERROR: 'rake/rdoctask' is obsolete and no longer supported. Use 'rdoc/task' 
(available in RDoc 2.4.2+) instead.

doing a bit of research it turns out that I have two options

• edit the rake file to require rdoc/task rather than rake/rdoctask
• upgrade my rake gem to version >=10

if I run gem list | grep rake gem list | grep rake I get rake (10.1.1, 10.1.0, 0.8.7) , so naturally I have multiple versions of the same gem installed.. my question is how do i ask my rails 2.3.5 project to always use the 0.8.7 version of the gem?

Answer 1

In environment.rb

Rails::Initializer.run do |config|
  #other code
  config.gem "rake", :version => "0.8.7"
end

Should work I think