Merge branch 'fix-labels-permisssion-check' into 'master'

Fix 403 Access Denied error messages when accessing Labels section in a project

This would occur if the project's issues or merge requests features were disabled. The change in 9bcd36396b caused `can?(current_user, :read_merge_request, project)` to be false if the merge request feature were disabled, so `authorize_labels!` needs to be changed accordingly.

Closes #1813

See merge request !836

app/controllers/application_controller.rb

@@ -140,11 +140,6 @@ class ApplicationController < ActionController::Base
     return access_denied! unless can?(current_user, action, project)
   end
 
-  def authorize_labels!
-    # Labels should be accessible for issues and/or merge requests
-    authorize_read_issue! || authorize_read_merge_request!
-  end
-
   def access_denied!
     render "errors/access_denied", layout: "errors", status: 404
   end

app/controllers/projects/labels_controller.rb

@@ -1,7 +1,7 @@
 class Projects::LabelsController < Projects::ApplicationController
   before_action :module_enabled
   before_action :label, only: [:edit, :update, :destroy]
-  before_action :authorize_labels!
+  before_action :authorize_read_label!
   before_action :authorize_admin_labels!, except: [:index]
 
   respond_to :js, :html

app/models/ability.rb

@@ -138,6 +138,7 @@ class Ability
         :read_project,
         :read_wiki,
         :read_issue,
+        :read_label,
         :read_milestone,
         :read_project_snippet,
         :read_project_member,

spec/controllers/application_controller_spec.rb

@@ -30,4 +30,44 @@ describe ApplicationController do
       controller.send(:check_password_expiration)
     end
   end
+
+  describe 'check labels authorization' do
+    let(:project) { create(:project) }
+    let(:user) { create(:user) }
+    let(:controller) { ApplicationController.new }
+
+    before do
+      project.team << [user, :guest]
+      allow(controller).to receive(:current_user).and_return(user)
+      allow(controller).to receive(:project).and_return(project)
+    end
+
+    it 'should succeed if issues and MRs are enabled' do
+      project.issues_enabled = true
+      project.merge_requests_enabled = true
+      controller.send(:authorize_read_label!)
+      expect(response.status).to eq(200)
+    end
+
+    it 'should succeed if issues are enabled, MRs are disabled' do
+      project.issues_enabled = true
+      project.merge_requests_enabled = false
+      controller.send(:authorize_read_label!)
+      expect(response.status).to eq(200)
+    end
+
+    it 'should succeed if issues are disabled, MRs are enabled' do
+      project.issues_enabled = false
+      project.merge_requests_enabled = true
+      controller.send(:authorize_read_label!)
+      expect(response.status).to eq(200)
+    end
+
+    it 'should fail if issues and MRs are disabled' do
+      project.issues_enabled = false
+      project.merge_requests_enabled = false
+      expect(controller).to receive(:access_denied!)
+      controller.send(:authorize_read_label!)
+    end
+  end
 end