Make schedule and unschedule consistent

app/models/ci/build.rb

@@ -187,7 +187,7 @@ module Ci
 
       after_transition any => [:manual] do |build|
         build.run_after_commit do
-          build.schedule
+          build.schedule!
         end
       end
 
@@ -241,17 +241,17 @@ module Ci
     end
 
     def scheduled?
-      build.build_schedule.exist? 
+      build_schedule.present?
     end
 
-    def schedule
+    def schedule!
       return unless schedulable?
 
       create_build_schedule!(execute_at: execute_at)
     end
 
-    def unschedule
+    def unschedule!
-      build&.build_schedule&.delete
+      build_schedule.delete!
     end
 
     def execute_at

app/workers/ci/build_schedule_worker.rb

@@ -7,13 +7,10 @@ module Ci
 
     def perform(build_id)
       ::Ci::Build.preload(:build_schedule).find_by(id: build_id).try do |build|
-        break unless build.build_schedule.present?
+        break unless build.scheduled?
 
-        begin
+        build.unschedule!
-          Ci::PlayBuildService.new(build.project, build.user).execute(build)
+        Ci::PlayBuildService.new(build.project, build.user).execute(build)
-        ensure
-          build.unschedule
-        end
       end
     end
   end