Fix user archival (#434)

* Fix user archival

* Fix method call on nil

* Fix null error

* Fix validation

* Fix user nil

* Fix lint again

* Disable lint on line

app/jobs/user_archive_job.rb

@@ -33,7 +33,18 @@ def migrate_keep_entities(user)
       key = entity_key(entity)
       records = entity.where({ key => user })
 
-      records.each { |r| r.update({ key => global_archive_user }) && r.versions.destroy_all }
+      migrate_keep_entity_records(key, records)
+    end
+  end
+
+  def migrate_keep_entity_records(key, records)
+    records.each do |r|
+      unless r.update({ key => global_archive_user })
+        raise ActiveRecord::RecordInvalid.new(r),
+              "Failed to update #{r.class} record (ID: #{r.id})"
+      end
+
+      r.versions.destroy_all
     end
   end
 

app/models/form/response.rb

@@ -8,7 +8,7 @@ class Response < ApplicationRecord
     has_many :closed_question_answers, dependent: :destroy
     has_many :closed_questions, through: :closed_question_answers, source: :question
 
-    validates :user, uniqueness: { scope: :form }
+    validates :user, uniqueness: { scope: :form, unless: -> { user_id == 0 } } # rubocop:disable Style/NumericPredicate
     validate :form_allows_responses?
 
     after_create :update_completed_status!

spec/models/form/response_spec.rb

@@ -28,6 +28,22 @@
       it { expect(another_response).not_to be_valid }
     end
 
+    context 'when the user is archived' do
+      let(:archived_user) { create(:user, id: 0) }
+      let(:another_response) do
+        build(:response, form: form, user: archived_user)
+      end
+      let(:form) { create(:form) }
+
+      before do
+        create(:response, form: form, user: archived_user)
+      end
+
+      it 'allows multiple responses' do
+        expect(another_response).to be_valid
+      end
+    end
+
     context 'when form is not published' do
       before do
         response.form.update(respond_from: 2.days.ago, respond_until: Date.yesterday)