[close #800] Don't add a default "worker" process if they don't have that task

CHANGELOG.md

@@ -1,5 +1,7 @@
 ## Master
 
+* Do not add the `jobs:work` command if an app does not have that rake task available (https:/heroku/heroku-buildpack-ruby/pull/810)
+
 ## v193 (9/14/2018)
 
 * Fix link (https:/heroku/heroku-buildpack-ruby/pull/811)

lib/language_pack/rails2.rb

@@ -48,11 +48,11 @@ def default_process_types
  "bundle exec thin start -e $RAILS_ENV -p $PORT" :
  "bundle exec ruby script/server -p $PORT"
 
- super.merge({
-  "web" => web_process,
-  "worker" => "bundle exec rake jobs:work",
-  "console" => "bundle exec script/console"
- })
+ process_types = super
+ process_types["web"] = web_process
+ process_types["worker"] = "bundle exec rake jobs:work" if rake.task("jobs:work").is_defined?
+ process_types["console"] = "bundle exec script/console"
+ process_types
  end
  end
 

spec/hatchet/rails5_spec.rb

@@ -3,13 +3,31 @@
 describe "Rails 5" do
  it "works" do
  Hatchet::Runner.new("rails5").deploy do |app, heroku|
- expect(app.run("rails -v")).to match("")
-
  # Test BUNDLE_DISABLE_VERSION_CHECK works
  expect(app.output).not_to include("The latest bundler is")
+
+ # Test worker task only appears if the app has that rake task
+ worker_task = worker_task_for_app(app)
+ expect(worker_task).to be_nil
+
+ run!(%Q{echo "task 'jobs:work' do ; end" >> Rakefile})
+ app.commit!
+
+ app.deploy do
+ worker_task = worker_task_for_app(app)
+ expect(worker_task["command"]).to eq("bundle exec rake jobs:work")
+ end
  end
  end
 
+ def worker_task_for_app(app)
+ app
+ .api_rate_limit.call
+ .formation
+ .list(app.name)
+ .detect { |h| h["type"] == "worker" }
+ end
+
  describe "active storage" do
  it "non-local storage warnings" do
  Hatchet::Runner.new("active_storage_non_local").deploy do |app, heroku|