Exceedingly strange ruby '||=' and rspec doubles behavior

Question

Running the following rspec gem versions:

  * rspec (2.14.1)
  * rspec-core (2.14.7)
  * rspec-expectations (2.14.5)
  * rspec-mocks (2.14.6)
  * rspec-rails (2.14.1)

And octokit 2.7.1

Given the following in spec/support/octokit.rb:

# This support package contains modules for octokit mocking

module OctokitHelper
  def mock_pull_requests_for_org org
     mock_org_repos(org).map do |repo| 
      mock_pull_requests repo 
    end.flatten
  end
  def mock_org_repos org
    @@repos ||= [
      double('Sawyer::Resource', name: 'repo 1'),
      double('Sawyer::Resource', name: 'repo 2')
    ]
    Octokit.stub(:org_repos) { |org=org| @@repos }
    @@repos
  end
  def mock_pull_requests repo, gh_handle=nil
    @@pulls ||= [
      double('Sawyer::Resource', title: 'pr 1'),
      double('Sawyer::Resource', title: 'pr 2')
    ]
    Octokit.stub(:pull_requests) { |repo| @@pulls }
    @@pulls 
  end
end

RSpec.configure do |config|
  config.include OctokitHelper 
end

Whenever I attempt to call mock_org_repos the first time from a spec, @@repos.first.name is repo 1. The second time around, @@repos.first.name throws a really bizarre error:

  1) StudentsController GET #submissions renders pull requests template
     Failure/Error: get :submissions, student_id: 2
       Double "Sawyer::Resource" received unexpected message :name with (no args)

An example of my usage of mock_org_repos:

require 'spec_helper'

describe StudentsController do
  describe 'GET #submissions' do
    before do
      @user = FactoryGirl.create(:instructor)
      @user.stub(:is_instructor?) { true }
      @submissions = mock_pull_requests_for_org ENV['GA_ORG_NAME']
      controller.stub(:current_user) { @user }
      get :submissions, student_id: 2
    end
    it 'assigns @submissions' do
      assigns(:submissions).should == @submissions
    end
    it 'renders pull requests template' do
      response.should render_template 'submissions'
    end
  end
end

Answer 1

Many thanks to rsofaer whom had lent me his second pair of eyes to resolve this, I would like to point out the now very very obvious problem:

Methods stubbed on doubles are 'cleared' every time examples are run, when the stubs are referenced via class variables.

This is a very clear explanation of how RSpec works under the covers.

Answer 2

My guess is that one of the doubles you've created in mock_pull_requests with the same name is getting sent :name, but you can check that by making sure your doubles have unique names (i.e. the first argument to double).