Today after upgrading to mongoid 2.4.0 one spec started to fail, now #find throws BSON::InvalidObjectId instead of DocumentNotFound:

require 'bundler'
Bundler.require

Mongoid.configure do |config|
  config.master = Mongo::Connection.new.db("godfather")
end

class Foo
  include Mongoid::Document
end

begin
  Foo.find('1234')
rescue Mongoid::Errors::DocumentNotFound
  puts "Document not found."
  exit 0
end

exit -1

Running git bisect I've found that the following checkin introduced this problem:

1011f8d937ec8b0799564bec7c2c0fb8e42eca2b is the first bad commit
commit 1011f8d937ec8b0799564bec7c2c0fb8e42eca2b
Author: Durran Jordan <durran@gmail.com>
Date: Sat Dec 3 11:38:10 2011 +0100

Convert params to Model.find(id) to whatever the _id field type is defined as, no matter what the type. Closes MONGOID-1381.

Can you confirm this is a bug?

Thanks!