Store description changes65776-store-issue-mr-description-changes

Saves old and new description and associates with the system note

6 files changed, 84 insertions, 2 deletions

diff --git a/app/models/description_change.rb b/app/models/description_change.rb
new file mode 100644
index 00000000000..f860f80f884
--- /dev/null
+++ b/app/models/description_change.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class DescriptionChange < ApplicationRecord
+  belongs_to :system_note, class_name: 'Note'
+
+  validates :system_note, presence: true
+end
diff --git a/app/services/system_note_service.rb b/app/services/system_note_service.rb
index 1b48b20e28b..b7af1ae20a9 100644
--- a/app/services/system_note_service.rb
+++ b/app/services/system_note_service.rb
@@ -341,7 +341,15 @@ module SystemNoteService
   def change_description(noteable, project, author)
     body = 'changed the description'
 
-    create_note(NoteSummary.new(noteable, project, author, body, action: 'description'))
+    create_note(NoteSummary.new(noteable, project, author, body, action: 'description')).tap do |note|
+      next unless Feature.enabled?(:description_diffs)
+
+      DescriptionChange.create(
+        system_note_id: note.id,
+        old_description: noteable.description_before_last_save,
+        new_description: noteable.description
+      )
+    end
   end
 
   # Called when the confidentiality changes
diff --git a/db/migrate/20190905233225_create_description_changes.rb b/db/migrate/20190905233225_create_description_changes.rb
new file mode 100644
index 00000000000..dc30f64156a
--- /dev/null
+++ b/db/migrate/20190905233225_create_description_changes.rb
@@ -0,0 +1,15 @@
+# frozen_string_literal: true
+
+class CreateDescriptionChanges < ActiveRecord::Migration[5.2]
+  include Gitlab::Database::MigrationHelpers
+
+  DOWNTIME = false
+
+  def change
+    create_table :description_changes do |t|
+      t.references :system_note, index: true, foreign_key: { to_table: :notes }, null: false
+      t.text :old_description
+      t.text :new_description
+    end
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index 61f7787f192..34ee90a925d 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 2019_09_05_223900) do
+ActiveRecord::Schema.define(version: 2019_09_05_233225) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "pg_trgm"
@@ -1167,6 +1167,13 @@ ActiveRecord::Schema.define(version: 2019_09_05_223900) do
     t.index ["project_id", "status"], name: "index_deployments_on_project_id_and_status"
   end
 
+  create_table "description_changes", force: :cascade do |t|
+    t.bigint "system_note_id", null: false
+    t.text "old_description"
+    t.text "new_description"
+    t.index ["system_note_id"], name: "index_description_changes_on_system_note_id"
+  end
+
   create_table "design_management_designs", force: :cascade do |t|
     t.integer "project_id", null: false
     t.integer "issue_id", null: false
@@ -3827,6 +3834,7 @@ ActiveRecord::Schema.define(version: 2019_09_05_223900) do
   add_foreign_key "deploy_keys_projects", "projects", name: "fk_58a901ca7e", on_delete: :cascade
   add_foreign_key "deployments", "clusters", name: "fk_289bba3222", on_delete: :nullify
   add_foreign_key "deployments", "projects", name: "fk_b9a3851b82", on_delete: :cascade
+  add_foreign_key "description_changes", "notes", column: "system_note_id"
   add_foreign_key "design_management_designs", "issues", on_delete: :cascade
   add_foreign_key "design_management_designs", "projects", on_delete: :cascade
   add_foreign_key "design_management_designs_versions", "design_management_designs", column: "design_id", name: "fk_03c671965c", on_delete: :cascade
diff --git a/spec/models/description_change_spec.rb b/spec/models/description_change_spec.rb
new file mode 100644
index 00000000000..cde328d2956
--- /dev/null
+++ b/spec/models/description_change_spec.rb
@@ -0,0 +1,13 @@
+# frozen_string_literal: true
+
+require 'spec_helper'
+
+describe DescriptionChange do
+  describe 'associations' do
+    it { is_expected.to belong_to(:system_note) }
+  end
+
+  describe 'validations' do
+    it { is_expected.to validate_presence_of(:system_note) }
+  end
+end
diff --git a/spec/services/system_note_service_spec.rb b/spec/services/system_note_service_spec.rb
index 910fe3b50b7..c428db105c1 100644
--- a/spec/services/system_note_service_spec.rb
+++ b/spec/services/system_note_service_spec.rb
@@ -414,6 +414,37 @@ describe SystemNoteService do
       it 'sets the note text' do
         expect(subject.note).to eq('changed the description')
       end
+
+      context 'description diffs' do
+        before do
+          noteable.update(description: "New description")
+        end
+
+        context 'when feature is enabled' do
+          before do
+            stub_feature_flags(description_diffs: true)
+          end
+
+          it 'saves the description changes' do
+            subject
+
+            description_change = DescriptionChange.where(system_note_id: subject.id).first
+
+            expect(description_change.old_description).to eq(noteable.description_before_last_save)
+            expect(description_change.new_description).to eq(noteable.description)
+          end
+        end
+
+        context 'when feature is not enabled' do
+          before do
+            stub_feature_flags(description_diffs: false)
+          end
+
+          it 'does not save the description changes' do
+            expect { subject }.not_to change { DescriptionChange.count }
+          end
+        end
+      end
     end
   end