Check org name uniqueness

app/controllers/organisations_controller.rb

@@ -155,6 +155,7 @@ class OrganisationsController < ApplicationController
         end
         redirect_to details_organisation_path(@organisation)
       else
+        @used_rent_periods = @organisation.lettings_logs.pluck(:period).uniq.compact.map(&:to_s)
         @rent_periods = helpers.rent_periods_with_checked_attr(checked_periods: selected_rent_periods)
         render :edit, status: :unprocessable_entity
       end

app/models/organisation.rb

@@ -58,6 +58,7 @@ class Organisation < ApplicationRecord
   alias_method :la?, :LA?
 
   validates :name, presence: { message: I18n.t("validations.organisation.name_missing") }
+  validates :name, uniqueness: { case_sensitive: false, message: I18n.t("validations.organisation.name_not_unique") }
   validates :provider_type, presence: { message: I18n.t("validations.organisation.provider_type_missing") }
 
   def self.find_by_id_on_multiple_fields(id)

config/locales/en.yml

@@ -235,6 +235,7 @@ en:
     organisation:
       data_sharing_agreement_not_signed: "Your organisation must accept the Data Sharing Agreement before you can create any logs."
       name_missing: "Enter the name of the organisation."
+      name_not_unique: "An organisation with this name already exists. Enter a name that hasn’t been used."
       provider_type_missing: "Select the organisation type."
       stock_owner:
         blank: "You must choose a stock owner."

db/migrate/20241125153349_add_unique_index_to_org_name.rb

@@ -0,0 +1,5 @@
+class AddUniqueIndexToOrgName < ActiveRecord::Migration[7.0]
+  def change
+    add_index :organisations, :name, unique: true
+  end
+end

db/schema.rb

@@ -546,6 +546,7 @@ ActiveRecord::Schema[7.0].define(version: 2024_12_04_100518) do
     t.datetime "discarded_at"
     t.datetime "schemes_deduplicated_at"
     t.index ["absorbing_organisation_id"], name: "index_organisations_on_absorbing_organisation_id"
+    t.index ["name"], name: "index_organisations_on_name", unique: true
     t.index ["old_visible_id"], name: "index_organisations_on_old_visible_id", unique: true
   end
 

spec/models/organisation_spec.rb

@@ -19,6 +19,12 @@ RSpec.describe Organisation, type: :model do
         .to raise_error(ActiveRecord::RecordInvalid, "Validation failed: Provider type #{I18n.t('validations.organisation.provider_type_missing')}")
     end
 
+    it "validates uniqueness of name" do
+      org = build(:organisation, name: organisation.name.downcase)
+      org.valid?
+      expect(org.errors[:name]).to include(I18n.t("validations.organisation.name_not_unique"))
+    end
+
     context "with parent/child associations", :aggregate_failures do
       let!(:child_organisation) { create(:organisation, name: "MHCLG Child") }
       let!(:grandchild_organisation) { create(:organisation, name: "MHCLG Grandchild") }