Remove Dangling Recurring Tasks

lib/solid_queue/configuration.rb

@@ -208,7 +208,7 @@ def dispatchers
       def schedulers
         return [] if skip_recurring_tasks?
 
-        if recurring_tasks.any? || dynamic_recurring_tasks_enabled?
+        if recurring_tasks.any? || dynamic_recurring_tasks_enabled? || static_recurring_tasks_exist?
           [ Process.new(:scheduler, { recurring_tasks: recurring_tasks, **scheduler_options.with_defaults(SCHEDULER_DEFAULTS) }) ]
         else
           []
@@ -233,6 +233,10 @@ def dynamic_recurring_tasks_enabled?
         scheduler_options.fetch(:dynamic_tasks_enabled, SCHEDULER_DEFAULTS[:dynamic_tasks_enabled])
       end
 
+      def static_recurring_tasks_exist?
+        RecurringTask.static.exists?
+      end
+
       def recurring_tasks
         @recurring_tasks ||= recurring_tasks_config.map do |id, options|
           RecurringTask.from_configuration(id, **options.merge(static: true)) if options&.has_key?(:schedule)

test/unit/scheduler_test.rb

@@ -68,6 +68,29 @@ class SchedulerTest < ActiveSupport::TestCase
     scheduler.stop
   end
 
+  test "removes recurring tasks no longer present in the configuration" do
+    previous_scheduler = SolidQueue::Scheduler.new(
+      recurring_tasks: { removed_task: { class: "AddToBufferJob", schedule: "every hour" } }
+    ).tap(&:start)
+
+    wait_for_registered_processes(1, timeout: 1.second)
+    wait_for { SolidQueue::RecurringTask.exists?(key: "removed_task") }
+
+    previous_scheduler.stop
+
+    configuration = SolidQueue::Configuration.new(
+      recurring_schedule_file: config_file_path(:empty_configuration),
+      scheduler: { dynamic_tasks_enabled: false }
+    )
+
+    scheduler = configuration.configured_processes.find { |process| process.kind == :scheduler }.instantiate.tap(&:start)
+
+    wait_for_registered_processes(1, timeout: 1.second)
+    wait_for { !SolidQueue::RecurringTask.exists?(key: "removed_task") }
+  ensure
+    scheduler.stop
+  end
+
   test "run more than one instance of the scheduler with recurring tasks" do
     recurring_tasks = { example_task: { class: "AddToBufferJob", schedule: "every second", args: 42 } }
     schedulers = 2.times.collect do