Ignore unindexed projects that have no repository

Changelog: changed
EE: true

ee/lib/tasks/gitlab/elastic.rake

@@ -160,7 +160,15 @@ namespace :gitlab do
 
     desc "GitLab | Elasticsearch | Display which projects are not indexed"
     task projects_not_indexed: :environment do
-      not_indexed = Project.where.not(id: IndexStatus.select(:project_id).distinct)
+      not_indexed = []
+
+      Project.where.not(id: IndexStatus.select(:project_id).distinct).each_batch do |batch|
+        batch.each do |project|
+          next if !project.repository_exists? || project.empty_repo?
+
+          not_indexed << project
+        end
+      end
 
       if not_indexed.count == 0
         puts 'All projects are currently indexed'.color(:green)
@@ -271,9 +279,7 @@ namespace :gitlab do
               projects[1..500]
             end
 
-      arr.each do |p|
-        puts "Project '#{p.full_path}' (ID: #{p.id}) isn't indexed.".color(:red)
-      end
+      arr.each { |p| puts "Project '#{p.full_path}' (ID: #{p.id}) isn't indexed.".color(:red) }
 
       puts "#{arr.count} out of #{projects.count} non-indexed projects shown."
     end

ee/spec/tasks/gitlab/elastic_rake_spec.rb

@@ -348,4 +348,37 @@ RSpec.describe 'gitlab:elastic namespace rake tasks', :elastic, :silence_stdout
       end
     end
   end
+
+  describe 'projects_not_indexed' do
+    subject { run_rake_task('gitlab:elastic:projects_not_indexed') }
+
+    let_it_be(:project) { create(:project, :repository) }
+
+    context 'no projects are indexed' do
+      it 'displays non-indexed projects' do
+        expected = <<~END
+          Project '#{project.full_path}' (ID: #{project.id}) isn't indexed.
+          1 out of 1 non-indexed projects shown.
+        END
+
+        expect { subject }.to output(expected).to_stdout
+      end
+    end
+
+    context 'all projects are indexed' do
+      before do
+        IndexStatus.create!(project: project, indexed_at: Time.current, last_commit: 'foo')
+      end
+
+      it 'displays that all projects are indexed' do
+        expect { subject }.to output(/All projects are currently indexed/).to_stdout
+      end
+
+      it 'does not include projects without repositories' do
+        create(:project)
+
+        expect { subject }.to output(/All projects are currently indexed/).to_stdout
+      end
+    end
+  end
 end