From 48b48e88ac30b5b7092d0e5f9e75565cf183e851 Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Fri, 11 Mar 2016 20:44:09 +0530
Subject: [PATCH 1/3] Add before_destroy :cancel to precent role destroy.Change
 Conference-Role association to have dependent: :destroy_all

---
 app/models/conference.rb | 3 ++-
 app/models/role.rb       | 9 ++++++++-
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/app/models/conference.rb b/app/models/conference.rb
index 6036a962..048da738 100644
--- a/app/models/conference.rb
+++ b/app/models/conference.rb
@@ -4,7 +4,8 @@ class Conference < ActiveRecord::Base
   require 'uri'
   serialize :events_per_week, Hash
   # Needed to call 'Conference.with_role' in /models/ability.rb
-  resourcify
+  # Dependent destroy will fail as roles#destroy will be cancelled,hence delete_all
+  resourcify :roles, dependent: :delete_all
 
   default_scope { order('start_date DESC') }
 
diff --git a/app/models/role.rb b/app/models/role.rb
index 07c5b29e..9673e700 100644
--- a/app/models/role.rb
+++ b/app/models/role.rb
@@ -1,10 +1,17 @@
 class Role < ActiveRecord::Base
   belongs_to :resource, polymorphic: true
   has_and_belongs_to_many :users, join_table: :users_roles
-
+  before_destroy :cancel
   scopify
 
   validates :name, presence: true
 
   validates :name, uniqueness: { scope: :resource }
+
+  private
+
+  # Needed to ensure that removing all user from role doesn't remove role.
+  def cancel
+    false
+  end
 end

From 3129c196faac7de0b7d01df232e859c7600cb692 Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Thu, 17 Mar 2016 00:53:50 +0530
Subject: [PATCH 2/3] Add rake task to re-add deleted roles from all
 conferences

---
 lib/tasks/roles.rake | 15 +++++++++++++++
 1 file changed, 15 insertions(+)
 create mode 100644 lib/tasks/roles.rake

diff --git a/lib/tasks/roles.rake b/lib/tasks/roles.rake
new file mode 100644
index 00000000..8c817db0
--- /dev/null
+++ b/lib/tasks/roles.rake
@@ -0,0 +1,15 @@
+namespace :roles do
+  desc 'Adds back deleted roles to all conferences'
+  task add: :environment do
+
+    Conference.all.each do |c|
+      Role.where(name: 'organizer', resource: c).first_or_create(description: 'For the organizers of the conference (who shall have full access)')
+      Role.where(name: 'cfp', resource: c).first_or_create(description: 'For the members of the CfP team')
+      Role.where(name: 'info_desk', resource: c).first_or_create(description: 'For the members of the Info Desk team')
+      Role.where(name: 'volunteers_coordinator', resource: c).first_or_create(description: 'For the people in charge of volunteers')
+    end
+
+    puts 'All done!'
+  end
+end
+

From 77649d73a6b2a5385a0bde13f156f276539f49cf Mon Sep 17 00:00:00 2001
From: Nishanth Vijayan <nishanththegr8@gmail.com>
Date: Thu, 24 Mar 2016 01:14:08 +0530
Subject: [PATCH 3/3] Add model test to verify role is not deleted on removing
 all of its users

---
 spec/models/role_spec.rb | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/spec/models/role_spec.rb b/spec/models/role_spec.rb
index 36cd9a6b..db2b04f9 100644
--- a/spec/models/role_spec.rb
+++ b/spec/models/role_spec.rb
@@ -5,10 +5,19 @@ describe Role do
   let!(:organizer_role) { Role.find_by(name: 'organizer', resource: conference) }
   let!(:cfp_role) { Role.find_by(name: 'cfp', resource: conference) }
   let!(:organizer) { create(:user, role_ids: organizer_role.id) }
+  let(:user) { create(:user) }
 
   it 'get_users' do
     expect(organizer_role.users).to include organizer
     expect(organizer_role.users.count).to eq 1
     expect(cfp_role.users).to eq []
   end
+
+  it 'does not delete role when last user of role is removed' do
+    user.add_role :cfp, conference
+    expect(cfp_role.users).to include user
+    user.remove_role :cfp, conference
+    expect(cfp_role.users).to eq []
+    expect(conference.roles.count).to eq 4
+  end
 end