DJ setup_lifecycle for < 4.1 (simply patch around Worker.lifecycle)

src/main/ruby/delayed/jruby_worker.rb

@@ -12,16 +12,29 @@ class JRubyWorker < Worker
     require 'delayed/sleep_calculator'
     include SleepCalculator
 
-    require 'delayed/sync_lifecycle'
-    # @patch make sure concurrent worker threads do not cause multiple initializations
-    Worker.extend SyncLifecycle if Delayed.const_defined? :Lifecycle
-
     # @override to return the same as Delayed::Worker.lifecycle (uses class instance state)
     def self.lifecycle; Worker.lifecycle end
 
-    # @override since `initialize` does: `self.class.setup_lifecycle`
+    # @override since `initialize` (DJ 4.1) does: `self.class.setup_lifecycle`
     def self.setup_lifecycle; Worker.setup_lifecycle end
 
+    unless defined? Worker.setup_lifecycle
+      # adapt DJ 3.0/4.0 :
+      # def self.lifecycle
+      #   @lifecycle ||= Delayed::Lifecycle.new
+      # end
+      def Worker.lifecycle
+        @lifecycle ||= setup_lifecycle
+      end
+      def Worker.setup_lifecycle
+        @lifecycle = Delayed::Lifecycle.new
+      end
+    end
+
+    require 'delayed/sync_lifecycle'
+    # @patch make sure concurrent worker threads do not cause multiple initializations
+    Worker.extend SyncLifecycle if Delayed.const_defined? :Lifecycle
+
     THREAD_LOCAL_ACCESSORS = [
       :min_priority, :max_priority, :sleep_delay, :read_ahead, :queues, :exit_on_complete
     ]

src/main/ruby/delayed/sync_lifecycle.rb

@@ -18,6 +18,7 @@ def setup_lifecycle_sync
           #@lifecycle = Delayed::Lifecycle.new
           #lifecycle = @lifecycle
         end
+        @lifecycle # make sure returns lifecycle (for DJ < 4.1 compat layer)
       end
     end
 

src/test/ruby/delayed/plugin_test.rb

@@ -9,12 +9,16 @@ def self.startup
     end
 
     def self.load_plugin!
+      load_plugin_like!
+      require 'delayed_cron_job' # order is important - backend needs to be loaded
+      # gem: spec.add_dependency "delayed_job", ">= 4.1"
+    end
+
+    def self.load_plugin_like!
       require 'active_record'
       require 'active_record/connection_adapters/jdbcsqlite3_adapter'
 
       require 'delayed_job_active_record' # DJ 3.0+
-
-      require 'delayed_cron_job' # order is important - backend needs to be loaded
     end
 
     setup do
@@ -23,12 +27,12 @@ def self.load_plugin!
     end
 
     test "only one lifecycle instance is created" do
-      self.class.load_plugin!
+      self.class.load_plugin_like!
 
       lifecycle = Delayed::Lifecycle.new
       Delayed::Lifecycle.expects(:new).returns(lifecycle).once
       begin
-        Delayed::Worker.reset # @lifecycle = nil
+        reset_worker
         threads = start_threads(3) do
           l1 = Delayed::JRubyWorker.lifecycle
           l2 = Delayed::Worker.lifecycle
@@ -42,12 +46,12 @@ def self.load_plugin!
 
 
     test "setup lifecycle does guard for lifecycle creation" do
-      self.class.load_plugin!
+      self.class.load_plugin_like!
 
       lifecycle = Delayed::Lifecycle.new
       Delayed::Lifecycle.expects(:new).returns(lifecycle).once
       begin
-        Delayed::Worker.reset # @lifecycle = nil
+        reset_worker
         threads = start_threads(5) do
           Delayed::JRubyWorker.new
           sleep 0.1
@@ -61,13 +65,15 @@ def self.load_plugin!
 
     context "with backend" do
 
+      @@plugin = nil
+
       def self.startup
         require 'active_record'
         require 'active_record/connection_adapters/jdbcsqlite3_adapter'
         load 'delayed/active_record_schema_cron.rb'
         Delayed::Job.reset_column_information
 
-        load_plugin!
+        @@plugin = begin; load_plugin!; rescue Exception => ex; ex end
       end
 
       setup do
@@ -93,6 +99,8 @@ def perform
       end
 
       test "works (integration)" do
+        omit "#{@@plugin.inspect}" if @@plugin.is_a?(Exception) # 'plugin not supported on DJ < 4.1'
+
         worker = Delayed::JRubyWorker.new({ :sleep_delay => 0.10 })
         start = Time.now
         Delayed::Job.enqueue job = CronJob.new(:boo), cron: '0-59/1 * * * *'
@@ -134,5 +142,11 @@ def start_threads(count)
       threads
     end
 
+    def reset_worker
+      # Worker.reset only does `@lifecycle = nil` on DJ 4.1
+      Delayed::Worker.instance_variable_set :@lifecycle, nil
+      Delayed::Worker.reset
+    end
+
   end
 end