Fix application error when Project#last_activity_at is nil

app/models/project.rb

@@ -689,7 +689,7 @@ class Project < ActiveRecord::Base
   end
 
   def last_activity_date
-    last_activity_at || updated_at
+    last_repository_updated_at || last_activity_at || updated_at
   end
 
   def project_id

app/views/shared/projects/_project.html.haml

@@ -7,7 +7,7 @@
 - show_last_commit_as_description = false unless local_assigns[:show_last_commit_as_description] == true && project.commit
 - css_class += " no-description" if project.description.blank? && !show_last_commit_as_description
 - cache_key = project_list_cache_key(project)
-- updated_tooltip = time_ago_with_tooltip(project.last_activity_at)
+- updated_tooltip = time_ago_with_tooltip(project.last_activity_date)
 
 %li.project-row{ class: css_class }
   = cache(cache_key) do

spec/features/dashboard/projects_spec.rb

@@ -15,13 +15,25 @@ RSpec.describe 'Dashboard Projects', feature: true do
     expect(page).to have_content('awesome stuff')
   end
 
-  it 'shows the last_activity_at attribute as the update date' do
-    now = Time.now
-    project.update_column(:last_activity_at, now)
+  context 'when last_repository_updated_at, last_activity_at and update_at are present' do
+    it 'shows the last_repository_updated_at attribute as the update date' do
+      project.update_attributes!(last_repository_updated_at: Time.now, last_activity_at: 1.hour.ago)
 
       visit dashboard_projects_path
 
-    expect(page).to have_xpath("//time[@datetime='#{now.getutc.iso8601}']")
+      expect(page).to have_xpath("//time[@datetime='#{project.last_repository_updated_at.getutc.iso8601}']")
+    end
+  end
+
+  context 'when last_repository_updated_at and last_activity_at are missing' do
+    it 'shows the updated_at attribute as the update date' do
+      project.update_attributes!(last_repository_updated_at: nil, last_activity_at: nil)
+      project.touch
+
+      visit dashboard_projects_path
+
+      expect(page).to have_xpath("//time[@datetime='#{project.updated_at.getutc.iso8601}']")
+    end
   end
 
   context 'when on Starred projects tab' do