Convert circular relationship into a has_one

Cycles in object graphs are best avoided so convert the creator
signature association to a has_one association using a boolean field
to indicate that it's a creator.

To prevent duplicate creator signatures we add a partial unique index
on the signature petition_id column with a `creator = 't'` condition.

app/controllers/admin/petition_details_controller.rb

@@ -21,7 +21,7 @@ def fetch_petition
   def petition_params
     params.require(:petition).permit(
       :action, :background, :additional_details,
-      :special_consideration, :creator_signature_attributes => [:name]
+      :special_consideration, :creator_attributes => [:name]
     )
   end
 end

app/controllers/petitions_controller.rb

@@ -56,7 +56,7 @@ def create
     assign_stage
     @stage_manager = Staged::PetitionCreator.manager(petition_params_for_create, request, params[:stage], params[:move])
     if @stage_manager.create_petition
-      @stage_manager.petition.creator_signature.store_constituency_id
+      @stage_manager.petition.creator.store_constituency_id
       send_email_to_gather_sponsors(@stage_manager.petition)
       redirect_to thank_you_petition_url(@stage_manager.petition)
     else
@@ -167,12 +167,12 @@ def petition_params_for_create
     params.
       require(:petition).
       permit(:action, :background, :additional_details, :duration,
-             creator_signature: [
+             creator: [
                :name, :email, :email_confirmation,
                :postcode, :location_code, :uk_citizenship
              ]).tap do |sanitized|
-               if sanitized['creator_signature'].present?
-                 sanitized['creator_signature_attributes'] = sanitized.delete('creator_signature')
+               if sanitized['creator'].present?
+                 sanitized['creator_attributes'] = sanitized.delete('creator')
                end
              end
   end

app/controllers/sponsors_controller.rb

@@ -5,7 +5,7 @@ class SponsorsController < SignaturesController
 
   before_action :redirect_to_petition_page_if_moderated, except: [:thank_you, :signed]
   before_action :redirect_to_moderation_info_page_if_sponsored, except: [:thank_you, :signed]
-  before_action :validate_creator_signature, only: [:new]
+  before_action :validate_creator, only: [:new]
 
   def verify
     if @signature.validated?
@@ -88,7 +88,7 @@ def redirect_to_moderation_info_page_if_sponsored
     end
   end
 
-  def validate_creator_signature
-    @petition.validate_creator_signature!
+  def validate_creator
+    @petition.validate_creator!
   end
 end

app/helpers/page_title_helper.rb

@@ -52,7 +52,7 @@ def options
           opts[:petition] = petition.action
 
           unless petition.is_a?(Archived::Petition)
-            opts[:creator] = petition.creator_signature.name
+            opts[:creator] = petition.creator.name
           end
         end
       end

app/helpers/petition_helper.rb

@@ -48,7 +48,7 @@ def render_petition_hidden_details(stage_manager, form)
       concat hidden_field_tag(:stage, stage_manager.stage)
       concat hidden_field_tag(:move, 'next')
       concat render('/petitions/create/petition_details_hidden', petition: stage_manager.stage_object, f: form) unless stage_manager.stage == 'petition'
-      if stage_manager.stage_object.creator_signature.present?
+      if stage_manager.stage_object.creator.present?
         concat render('/petitions/create/your_details_hidden', petition: stage_manager.stage_object, f: form) unless stage_manager.stage == 'creator'
         concat render('/petitions/create/email_hidden', petition: stage_manager.stage_object, f: form) unless ['creator', 'replay-email'].include? stage_manager.stage
       end

app/jobs/notify_creators_that_moderation_is_delayed_job.rb

@@ -3,7 +3,7 @@ class NotifyCreatorsThatModerationIsDelayedJob < ApplicationJob
 
   def perform(subject, body)
     petitions.find_each do |petition|
-      NotifyCreatorThatModerationIsDelayedJob.perform_later(petition.creator_signature, subject, body)
+      NotifyCreatorThatModerationIsDelayedJob.perform_later(petition.creator, subject, body)
     end
   end
 

app/jobs/notify_creators_that_parliament_is_dissolving_job.rb

@@ -3,7 +3,7 @@ class NotifyCreatorsThatParliamentIsDissolvingJob < ApplicationJob
 
   def perform
     petitions.find_each do |petition|
-      NotifyCreatorThatParliamentIsDissolvingJob.perform_later(petition.creator_signature)
+      NotifyCreatorThatParliamentIsDissolvingJob.perform_later(petition.creator)
     end
   end
 

app/jobs/notify_everyone_of_moderation_decision_job.rb

@@ -4,7 +4,7 @@ class NotifyEveryoneOfModerationDecisionJob < ApplicationJob
   end
 
   def perform(petition)
-    creator = petition.creator_signature
+    creator = petition.creator
     sponsors = petition.sponsors.validated
 
     if petition.published?

app/jobs/stop_petitions_early_job.rb

@@ -26,9 +26,9 @@ def send_notification(petition)
     unless petition.special_consideration?
       case petition.state
       when Petition::VALIDATED_STATE
-        NotifyCreatorOfValidatedPetitionBeingStoppedJob.perform_later(petition.creator_signature)
+        NotifyCreatorOfValidatedPetitionBeingStoppedJob.perform_later(petition.creator)
       when Petition::SPONSORED_STATE
-        NotifyCreatorOfSponsoredPetitionBeingStoppedJob.perform_later(petition.creator_signature)
+        NotifyCreatorOfSponsoredPetitionBeingStoppedJob.perform_later(petition.creator)
       end
     end
   end

app/mailers/petition_mailer.rb

@@ -91,7 +91,7 @@ def notify_creator_of_validated_petition_being_stopped(signature)
   end
 
   def gather_sponsors_for_petition(petition)
-    @petition, @creator = petition, petition.creator_signature
+    @petition, @creator = petition, petition.creator
     mail to: @creator.email, subject: subject_for(:gather_sponsors_for_petition)
   end
 

app/mailers/sponsor_mailer.rb

@@ -5,7 +5,7 @@ def sponsor_signed_email_below_threshold(petition, sponsor)
 
     mail(
       subject: "#{@sponsor.name} supported your petition",
-      to: @petition.creator_signature.email
+      to: @petition.creator.email
     )
   end
 
@@ -15,7 +15,7 @@ def sponsor_signed_email_on_threshold(petition, sponsor)
 
     mail(
       subject: "We’re checking your petition",
-      to: @petition.creator_signature.email
+      to: @petition.creator.email
     )
   end
 

app/models/petition.rb

@@ -33,7 +33,6 @@ class Petition < ActiveRecord::Base
   has_perishable_token called: 'sponsor_token'
 
   before_save :update_debate_state, if: :scheduled_debate_date_changed?
-  after_create :set_petition_on_creator_signature
   after_create :update_last_petition_created_at
 
   extend Searchable(:action, :background, :additional_details)
@@ -65,8 +64,8 @@ class Petition < ActiveRecord::Base
   facet :overdue_in_moderation,        -> { overdue_in_moderation.by_most_recent_moderation_threshold_reached }
   facet :tagged_in_moderation,         -> { tagged_in_moderation.by_most_recent_moderation_threshold_reached }
 
-  belongs_to :creator_signature, class_name: 'Signature'
-  accepts_nested_attributes_for :creator_signature, update_only: true
+  has_one :creator, -> { where(creator: true) }, class_name: 'Signature'
+  accepts_nested_attributes_for :creator, update_only: true
 
   belongs_to :locked_by, class_name: 'AdminUser'
 
@@ -84,12 +83,12 @@ class Petition < ActiveRecord::Base
   has_many :invalidations
 
   include Staged::Validations::PetitionDetails
-  validates_presence_of :open_at, if: :open?
-  validates_presence_of :creator_signature, on: :create
-  validates_inclusion_of :state, in: STATES
+  validates :open_at, presence: true, if: :open?
+  validates :creator, presence: true
+  validates :state, inclusion: { in: STATES }
 
   with_options allow_nil: true, prefix: true do
-    delegate :name, :email, to: :creator_signature, prefix: :creator
+    delegate :name, :email, to: :creator
     delegate :code, :details, to: :rejection
     delegate :summary, :details, :created_at, :updated_at, to: :government_response
     delegate :date, :transcript_url, :video_url, :overview, to: :debate_outcome, prefix: :debate
@@ -309,7 +308,7 @@ def in_need_of_closing(time = Time.current)
     end
 
     def in_need_of_stopping(time = nil)
-      scope = preload(:creator_signature)
+      scope = preload(:creator)
       time ? scope.stoppable.created_after(time) : scope.stoppable
     end
 
@@ -589,9 +588,9 @@ def stop!(time = Time.current)
     end
   end
 
-  def validate_creator_signature!
+  def validate_creator!
     if pending?
-      creator_signature && creator_signature.validate! && reload
+      creator && creator.validate! && reload
     end
   end
 
@@ -722,11 +721,6 @@ def closing_early_for_dissolution?(dissolution_at = Parliament.dissolution_at)
     open_at && dissolution_at ? deadline > dissolution_at : false
   end
 
-  # need this callback since the relationship is circular
-  def set_petition_on_creator_signature
-    creator_signature.update_attribute(:petition_id, id)
-  end
-
   def cache_key(*timestamp_names)
     case
     when new_record?

app/models/signature.rb

@@ -234,10 +234,6 @@ def sanitized_name
     name.to_s.parameterize
   end
 
-  def creator?
-    petition.creator_signature == self
-  end
-
   def pending?
     state == PENDING_STATE
   end
@@ -272,7 +268,7 @@ def validate!(now = Time.current)
     retry_lock do
       if pending?
         update_signature_counts = true
-        petition.validate_creator_signature! unless creator?
+        petition.validate_creator! unless creator?
 
         update_columns(
           number:       petition.signature_count + 1,

app/models/staged/base/creator_signature.rb

@@ -10,7 +10,7 @@ def initialize(petition)
 
       delegate :id, :to_param, :model_name, :to_key, :name,
                :email, :email?, :uk_citizenship, :postcode,
-               :location_code, :constituency, to: :creator_signature
+               :location_code, :constituency, to: :creator
 
       def validation_context
         :create
@@ -20,11 +20,11 @@ def validation_context
 
       attr_reader :petition
 
-      def creator_signature
-        if petition.creator_signature.nil?
-          petition.build_creator_signature(location_code: 'GB')
+      def creator
+        if petition.creator.nil?
+          petition.build_creator(location_code: 'GB')
         end
-        petition.creator_signature
+        petition.creator
       end
     end
   end

app/models/staged/base/petition.rb

@@ -11,7 +11,7 @@ def initialize(petition)
 
       delegate :id, :to_param, :model_name, :to_key,
                :action, :background, :additional_details,
-               :duration, :creator_signature, to: :petition
+               :duration, :creator, to: :petition
     end
   end
 end

app/models/staged/petition_creator.rb

@@ -47,9 +47,9 @@ def stage_manager
       end
 
       def sanitize!
-        if petition.creator_signature
-          petition.creator_signature.email.strip! unless petition.creator_signature.email.blank?
-          petition.creator_signature.ip_address = @request.remote_ip
+        if petition.creator
+          petition.creator.email.strip! unless petition.creator.email.blank?
+          petition.creator.ip_address = @request.remote_ip
         end
         petition.action.strip! unless petition.action.blank?
       end

app/models/staged/petition_creator/has_creator_signature.rb

@@ -4,20 +4,20 @@ module HasCreatorSignature
       extend ActiveSupport::Concern
 
       included do
-        validate :creator_signature_valid?
+        validate :creator_valid?
 
-        def creator_signature
-          @_creator_signature ||= self.class::CreatorSignature.new(petition)
+        def creator
+          @_creator ||= self.class::CreatorSignature.new(petition)
         end
 
         private
 
-        def creator_signature_valid?
-          if creator_signature.valid?
+        def creator_valid?
+          if creator.valid?
             true
           else
-            creator_signature.errors.each do |attribute, message|
-              attribute = "creator_signature.#{attribute}"
+            creator.errors.each do |attribute, message|
+              attribute = "creator.#{attribute}"
               errors[attribute] << message
               errors[attribute].uniq!
             end

app/views/admin/petition_details/show.html.erb

@@ -31,10 +31,10 @@
         <%= f.text_area :additional_details, tabindex: increment, rows: 7, class: 'form-control', disabled: @petition.editing_disabled? %>
       <% end %>
 
-      <%= form_row for: [f.object, :creator_signature_name] do %>
-        <%= f.fields_for :creator_signature do |c| %>
+      <%= form_row for: [f.object, :creator_name] do %>
+        <%= f.fields_for :creator do |c| %>
           <%= c.label :name, "Creator", class: 'form-label' %>
-          <%= error_messages_for_field @petition.creator_signature, :name %>
+          <%= error_messages_for_field @petition.creator, :name %>
           <%= c.text_field :name, tabindex: increment, rows: 8, class: 'form-control', disabled: @petition.editing_disabled? %>
         <% end %>
       <% end %>
@@ -59,4 +59,4 @@
 
 </div>
 
-<%= render 'edit_lock' %>
+<%= render 'edit_lock' %>

app/views/admin/petitions/_petition_details.html.erb

@@ -9,8 +9,8 @@
 
 <dt>Creator</dt>
 <dd>
-  <%=  @petition.creator_signature.name %><br />
-  <%= auto_link(@petition.creator_signature.email) %>
+  <%=  @petition.creator.name %><br />
+  <%= auto_link(@petition.creator.email) %>
 </dd>
 
 <% if @petition.in_todo_list? %>

app/views/admin/petitions/index.html.erb

@@ -55,7 +55,7 @@
     <% @petitions.each do |petition| -%>
       <tr class="petition-list-petition petition-list-petition-state-<%= petition.state.dasherize %>">
         <td class="petition-list-petition-action"><%= link_to petition.action, admin_petition_path(petition) %></td>
-        <td class="petition-list-petition-creator"><%= mail_to petition.creator_signature.email, petition.creator_signature.name %></td>
+        <td class="petition-list-petition-creator"><%= mail_to petition.creator.email, petition.creator.name %></td>
         <td class="petition-list-petition-id"><%= petition.id %></td>
         <td><%= petition.state.humanize %></td>
         <td class="date"><%= date_format(petition.deadline) %></td>

app/views/petitions/_open_petition_show.html.erb

@@ -35,7 +35,7 @@
 
   <ul class="petition-meta">
     <li class="meta-created-by">
-      <span class="label">Created by</span> <%= petition.creator_signature.name %>
+      <span class="label">Created by</span> <%= petition.creator.name %>
     </li>
     <li class="meta-deadline">
       <% if petition.closing_early_for_dissolution? %>

app/views/petitions/create/_email_hidden.html.erb

@@ -1,3 +1,3 @@
-<%= f.fields_for :creator_signature, petition.creator_signature do |csf| %>
+<%= f.fields_for :creator, petition.creator do |csf| %>
   <%= csf.hidden_field :email %>
 <% end %>

app/views/petitions/create/_replay_email_ui.html.erb

@@ -2,7 +2,7 @@
 
 <h1 class="page-title">Make sure this is right</h1>
 
-<%= f.fields_for :creator_signature, petition.creator_signature do |csf| %>
+<%= f.fields_for :creator, petition.creator do |csf| %>
   <%= render 'petitions/create/signature_email', f: csf, signature: csf.object,  hide_label: true %>
 <% end %>
 

app/views/petitions/create/_your_details_hidden.html.erb

@@ -1,3 +1,3 @@
-<%= f.fields_for :creator_signature, petition.creator_signature do |csf| %>
+<%= f.fields_for :creator, petition.creator do |csf| %>
   <%= render 'petitions/create/signature_hidden', f: csf, signature: csf.object %>
 <% end %>

app/views/petitions/create/_your_details_ui.html.erb

@@ -5,7 +5,7 @@
 
 <%= render 'petitions/create/error_summary', f: f %>
 
-<%= f.fields_for :creator_signature, petition.creator_signature do |csf| %>
+<%= f.fields_for :creator, petition.creator do |csf| %>
   <%= render 'petitions/create/signature_form', :f => csf, :signature => csf.object, :context => 'create-petition' %>
 <% end %>
 

app/views/petitions/gathering_support.html.erb

@@ -1,5 +1,5 @@
 <h1>This petition is gathering support</h1>
 
-<p><%= @petition.creator_signature.name %>’s petition needs <%= Site.minimum_number_of_sponsors %> supporters before we will check that it meets the <%= link_to "petition standards", help_path(anchor: 'standards') %> and publish it.</p>
+<p><%= @petition.creator.name %>’s petition needs <%= Site.minimum_number_of_sponsors %> supporters before we will check that it meets the <%= link_to "petition standards", help_path(anchor: 'standards') %> and publish it.</p>
 
 <p>Please try again in a few days.</p>

app/views/petitions/moderation_info.html.erb

@@ -1,6 +1,6 @@
 <h1>We’re checking this petition</h1>
 
-<p><%= Site.minimum_number_of_sponsors %> people have already supported <%= @petition.creator_signature.name %>’s petition.</p>
+<p><%= Site.minimum_number_of_sponsors %> people have already supported <%= @petition.creator.name %>’s petition.</p>
 
 <p>We need to check it meets the <%= link_to "petition standards", help_path(anchor: 'standards') %> before we publish it.</p>