Ensure "shutdown?" behavior is consistent between J Ruby and C Ruby

lib/good_job/scheduler.rb

@@ -71,9 +71,11 @@ def initialize(performer, max_threads: nil, max_cache: nil, warm_cache_on_initia
     # @return [Boolean, nil]
     delegate :running?, to: :executor, allow_nil: true
 
-    # Tests whether the scheduler is shutdown.
+    # Tests whether the scheduler is shutdown and no tasks are running.
     # @return [Boolean, nil]
-    delegate :shutdown?, to: :executor, allow_nil: true
+    def shutdown?
+      @executor.nil? || (executor.shutdown? && !executor.shuttingdown?)
+    end
 
     # Shut down the scheduler.
     # This stops all threads in the thread pool.
@@ -85,7 +87,7 @@ def initialize(performer, max_threads: nil, max_cache: nil, warm_cache_on_initia
     #   * A positive number will wait that many seconds before stopping any remaining active tasks.
     # @return [void]
     def shutdown(timeout: -1)
-      return if executor.nil? || executor.shutdown?
+      return if executor.nil? || (executor.shutdown? && !executor.shuttingdown?)
 
       instrument("scheduler_shutdown_start", { timeout: timeout })
       instrument("scheduler_shutdown", { timeout: timeout }) do
@@ -100,6 +102,7 @@ def shutdown(timeout: -1)
           unless executor.wait_for_termination(executor_wait)
             instrument("scheduler_shutdown_kill", { active_job_ids: @performer.performing_active_job_ids.to_a })
             executor.kill
+            executor.wait_for_termination
           end
         end
       end

lib/good_job/shared_executor.rb

@@ -21,12 +21,10 @@ def running?
       @executor&.running?
     end
 
+    # Tests whether the scheduler is shutdown and no tasks are running.
+    # @return [Boolean, nil]
     def shutdown?
-      if @executor
-        @executor.shutdown?
-      else
-        true
-      end
+      @executor.nil? || (@executor.shutdown? && !@executor.shuttingdown?)
     end
 
     # Shut down the SharedExecutor.
@@ -38,13 +36,16 @@ def shutdown?
     #   * A positive number will wait that many seconds before stopping any remaining active threads.
     # @return [void]
     def shutdown(timeout: -1)
-      return if @executor.nil? || @executor.shutdown?
+      return if @executor.nil? || (@executor.shutdown? && !@executor.shuttingdown?)
 
       @executor.shutdown if @executor.running?
 
       if @executor.shuttingdown? && timeout # rubocop:disable Style/GuardClause
         executor_wait = timeout.negative? ? nil : timeout
-        @executor.kill unless @executor.wait_for_termination(executor_wait)
+        unless @executor.wait_for_termination(executor_wait)
+          @executor.kill
+          @executor.wait_for_termination
+        end
       end
     end