Service validation for project and type uniqueness

This validation prevents duplicated services of the
same type in the same project. The validation can
only run on create because it is possible that the
database holds invalid data. If this is the case,
updating a service would fail.

app/models/service.rb

@@ -34,6 +34,7 @@ class Service < ApplicationRecord
 
   validates :project_id, presence: true, unless: -> { template? || instance? }
   validates :project_id, absence: true, if: -> { template? || instance? }
+  validates :type, uniqueness: { scope: :project_id }, unless: -> { template? || instance? }, on: :create
   validates :type, presence: true
   validates :template, uniqueness: { scope: :type }, if: -> { template? }
   validates :instance, uniqueness: { scope: :type }, if: -> { instance? }

changelogs/unreleased/207385-service-project-type-uniqueness-validation.yml

+---
+title: Validate uniqueness of project_id and type when a new project service is created
+merge_request: 26308
+author:
+type: fixed

spec/fixtures/lib/gitlab/import_export/complex/project.json

@@ -7312,7 +7312,7 @@
       "tag_push_events": true,
       "note_events": true,
       "job_events": true,
-      "type": "AssemblaService",
+      "type": "AsanaService",
       "category": "common",
       "default": false,
       "wiki_page_events": true

spec/fixtures/lib/gitlab/import_export/light/project.json

@@ -125,7 +125,7 @@
     },
     {
       "id": 101,
-      "title": "JetBrains TeamCity CI",
+      "title": "Jira",
       "project_id": 5,
       "created_at": "2016-06-14T15:01:51.315Z",
       "updated_at": "2016-06-14T15:01:51.315Z",
@@ -139,7 +139,7 @@
       "tag_push_events": true,
       "note_events": true,
       "job_events": true,
-      "type": "TeamcityService",
+      "type": "JiraService",
       "category": "ci",
       "default": false,
       "wiki_page_events": true

spec/models/service_spec.rb

@@ -56,6 +56,14 @@ describe Service do
         expect(build(:service, :instance)).to be_invalid
       end
     end
+
+    it 'validates uniqueness of type and project_id on create' do
+      project = create(:project)
+
+      expect(create(:service, project: project, type: 'Service')).to be_valid
+      expect(build(:service, project: project, type: 'Service').valid?(:create)).to eq(false)
+      expect(build(:service, project: project, type: 'Service').valid?(:update)).to eq(true)
+    end
   end
 
   describe 'Scopes' do