CLDC-1315: Model deletion cascade and foreign key constraints (#765)

* failed rebase, copied onto new branch

* lint

* fix migration file and lint

* fix migration - remove duplication

* fix migration - remove duplicate foreign key

* fix migration - remove duplication

* lint

* migration fix

* fix migration and lint

* keep foreign key for managing organisations

app/models/organisation.rb

@@ -1,10 +1,10 @@
 class Organisation < ApplicationRecord
-  has_many :users
-  has_many :owned_case_logs, class_name: "CaseLog", foreign_key: "owning_organisation_id"
+  has_many :users, dependent: :delete_all
+  has_many :owned_case_logs, class_name: "CaseLog", foreign_key: "owning_organisation_id", dependent: :delete_all
   has_many :managed_case_logs, class_name: "CaseLog", foreign_key: "managing_organisation_id"
   has_many :data_protection_confirmations
   has_many :organisation_rent_periods
-  has_many :owned_schemes, class_name: "Scheme", foreign_key: "owning_organisation_id"
+  has_many :owned_schemes, class_name: "Scheme", foreign_key: "owning_organisation_id", dependent: :delete_all
   has_many :managed_schemes, class_name: "Scheme", foreign_key: "managing_organisation_id"
 
   scope :search_by_name, ->(name) { where("name ILIKE ?", "%#{name}%") }

app/models/scheme.rb

@@ -1,8 +1,8 @@
 class Scheme < ApplicationRecord
   belongs_to :owning_organisation, class_name: "Organisation"
   belongs_to :managing_organisation, optional: true, class_name: "Organisation"
-  has_many :locations
-  has_many :case_logs
+  has_many :locations, dependent: :delete_all
+  has_many :case_logs, dependent: :delete_all
 
   has_paper_trail
 

app/models/user.rb

@@ -6,7 +6,7 @@ class User < ApplicationRecord
          :trackable, :lockable, :two_factor_authenticatable, :confirmable, :timeoutable
 
   belongs_to :organisation
-  has_many :owned_case_logs, through: :organisation
+  has_many :owned_case_logs, through: :organisation, dependent: :delete_all
   has_many :managed_case_logs, through: :organisation
 
   validate :validate_email

db/migrate/20220720214646_add_delete_cascade_from_orgs_down.rb

@@ -0,0 +1,6 @@
+class AddDeleteCascadeFromOrgsDown < ActiveRecord::Migration[7.0]
+  def change
+    remove_foreign_key :schemes, :organisations, column: "owning_organisation_id"
+    add_foreign_key :schemes, :organisations, column: "owning_organisation_id", on_delete: :cascade
+  end
+end

db/migrate/20220722133738_add_delete_caselogs_users.rb

@@ -0,0 +1,6 @@
+class AddDeleteCaselogsUsers < ActiveRecord::Migration[7.0]
+  def change
+    add_foreign_key :case_logs, :organisations, column: "owning_organisation_id", on_delete: :cascade
+    add_foreign_key :users, :organisations, on_delete: :cascade
+  end
+end

db/schema.rb

@@ -380,8 +380,9 @@ ActiveRecord::Schema[7.0].define(version: 2022_08_02_125711) do
   end
 
   add_foreign_key "case_logs", "locations"
+  add_foreign_key "case_logs", "organisations", column: "owning_organisation_id", on_delete: :cascade
   add_foreign_key "case_logs", "schemes"
   add_foreign_key "locations", "schemes"
-  add_foreign_key "schemes", "organisations", column: "managing_organisation_id"
-  add_foreign_key "schemes", "organisations", column: "owning_organisation_id"
+  add_foreign_key "schemes", "organisations", column: "owning_organisation_id", on_delete: :cascade
+  add_foreign_key "users", "organisations", on_delete: :cascade
 end

spec/features/organisation_spec.rb

@@ -218,6 +218,39 @@ RSpec.describe "User Features" do
               end
             end
           end
+
+          describe "delete cascade" do
+            context "when the organisation is deleted" do
+              let!(:organisation) { FactoryBot.create(:organisation) }
+              let!(:user) { FactoryBot.create(:user, :support, last_sign_in_at: Time.zone.now, organisation:) }
+              let!(:scheme_to_delete) { FactoryBot.create(:scheme, owning_organisation: user.organisation) }
+              let!(:log_to_delete) { FactoryBot.create(:case_log, owning_organisation: user.organisation) }
+
+              context "when organisation is deleted" do
+                it "child relationships ie logs, schemes and users are deleted too - application" do
+                  organisation.destroy!
+                  expect { organisation.reload }.to raise_error(ActiveRecord::RecordNotFound)
+                  expect { CaseLog.find(log_to_delete.id) }.to raise_error(ActiveRecord::RecordNotFound)
+                  expect { Scheme.find(scheme_to_delete.id) }.to raise_error(ActiveRecord::RecordNotFound)
+                  expect { User.find(user.id) }.to raise_error(ActiveRecord::RecordNotFound)
+                end
+
+                context "when the organisation is deleted" do
+                  let!(:organisation) { FactoryBot.create(:organisation) }
+                  let!(:user) { FactoryBot.create(:user, :support, last_sign_in_at: Time.zone.now, organisation:) }
+                  let!(:scheme_to_delete) { FactoryBot.create(:scheme, owning_organisation: user.organisation) }
+                  let!(:log_to_delete) { FactoryBot.create(:case_log, :in_progress, needstype: 1, owning_organisation: user.organisation) }
+
+                  it "child relationships ie logs, schemes and users are deleted too - database" do
+                    ActiveRecord::Base.connection.exec_query("DELETE FROM organisations WHERE id = #{organisation.id};")
+                    expect { CaseLog.find(log_to_delete.id) }.to raise_error(ActiveRecord::RecordNotFound)
+                    expect { Scheme.find(scheme_to_delete.id) }.to raise_error(ActiveRecord::RecordNotFound)
+                    expect { User.find(user.id) }.to raise_error(ActiveRecord::RecordNotFound)
+                  end
+                end
+              end
+            end
+          end
         end
       end
     end