Fixes #3787 - UploadCacheCleanupJob does not execute.

app/jobs/upload_cache_cleanup_job.rb

@@ -3,6 +3,7 @@
 class UploadCacheCleanupJob < ApplicationJob
   def perform
     taskbar_form_ids = Taskbar.with_form_id.filter_map(&:persisted_form_id)
+    return if store_object_id.blank?
 
     Store.where(store_object_id: store_object_id).where('created_at < ?', 1.month.ago).where.not(o_id: taskbar_form_ids).find_each do |store|
       Store.remove_item(store.id)
@@ -12,6 +13,6 @@ class UploadCacheCleanupJob < ApplicationJob
   private
 
   def store_object_id
-    Store::Object.lookup(name: 'UploadCache').id
+    Store::Object.lookup(name: 'UploadCache')&.id
   end
 end

db/migrate/20211005110047_issue3787_fix_job.rb

@@ -0,0 +1,11 @@
+# Copyright (C) 2012-2021 Zammad Foundation, http://zammad-foundation.org/
+
+class Issue3787FixJob < ActiveRecord::Migration[6.0]
+  def change
+
+    # return if it's a new setup
+    return if !Setting.exists?(name: 'system_init_done')
+
+    Scheduler.find_by(name: 'Delete old upload cache entries.').update(error_message: nil, status: nil, active: true)
+  end
+end

spec/jobs/upload_cache_cleanup_job_spec.rb

@@ -3,45 +3,53 @@
 require 'rails_helper'
 
 RSpec.describe UploadCacheCleanupJob, type: :job do
-  let(:upload_cache) { UploadCache.new(1337) }
+  context 'when upload cache exists' do
+    let(:upload_cache) { UploadCache.new(1337) }
 
-  before do
-    UserInfo.current_user_id = 1
+    before do
+      UserInfo.current_user_id = 1
 
-    upload_cache.add(
-      data:        'current example',
-      filename:    'current.txt',
-      preferences: {
-        'Content-Type' => 'text/plain',
-      },
-    )
-
-    travel_to 1.month.ago
-
-    # create one taskbar and related upload cache entry, which should not be deleted
-    create(:taskbar, state: { form_id: 9999 })
-    UploadCache.new(9999).add(
-      data:        'Some Example with related Taskbar',
-      filename:    'another_example_with_taskbar.txt',
-      preferences: {
-        'Content-Type' => 'text/plain',
-      }
-    )
-
-    3.times do
       upload_cache.add(
-        data:        'hello world',
-        filename:    'some.txt',
+        data:        'current example',
+        filename:    'current.txt',
         preferences: {
           'Content-Type' => 'text/plain',
         },
       )
+
+      travel_to 1.month.ago
+
+      # create one taskbar and related upload cache entry, which should not be deleted
+      create(:taskbar, state: { form_id: 9999 })
+      UploadCache.new(9999).add(
+        data:        'Some Example with related Taskbar',
+        filename:    'another_example_with_taskbar.txt',
+        preferences: {
+          'Content-Type' => 'text/plain',
+        }
+      )
+
+      3.times do
+        upload_cache.add(
+          data:        'hello world',
+          filename:    'some.txt',
+          preferences: {
+            'Content-Type' => 'text/plain',
+          },
+        )
+      end
+
+      travel_back
     end
 
-    travel_back
+    it 'cleanup the store items which are expired with job' do
+      expect { described_class.perform_now }.to change(Store, :count).by(-3)
+    end
   end
 
-  it 'cleanup the store items which are expired with job' do
-    expect { described_class.perform_now }.to change(Store, :count).by(-3)
+  context 'when upload cache does not exist' do
+    it 'does not crash' do
+      expect { described_class.perform_now }.not_to raise_error
+    end
   end
 end