Workflow not opening in editor stuck on Loading Dialog Box Spinning Icon - Support and Troubleshooting

Workflow not opening in editor stuck on Loading Dialog Box Spinning Icon Description  Having issues with recently moved workflow from dev to test or prod environment. The customer would see a spinning loading dialog box when he would try to open the workflow from the workflow editor

We see the following in the system logs:

Child processor failed: java.lang.RuntimeException: java.lang.NullPointerException: com.glideapp.workflow.ui.WorkflowDiagramProcessor.process(WorkflowDiagramProcessor.java:141) com.glide.processors.xmlhttp.internal.XMLHttpRequestExecutor.process(XMLHttpRequestExecutor.java:110) com.glide.processors.xmlhttp.internal.XMLHttpRequestExecutor.process(XMLHttpRequestExecutor.java:76) com.glide.processors.xmlhttp.AJAXXMLHttpAggregator.process(AJAXXMLHttpAggregator.java:70) com.glide.processors.XMLHttpProcessor.processJavaAJAX(XMLHttpProcessor.java:151) com.glide.processors.XMLHttpProcessor.process(XMLHttpProcessor.java:104) com.glide.processors.AProcessor.runProcessor(AProcessor.java:483) com.glide.processors.AProcessor.processTransaction(AProcessor.java:205) com.glide.processors.ProcessorRegistry.process0(ProcessorRegistry.java:178) com.glide.processors.ProcessorRegistry.process(ProcessorRegistry.java:167) com.glide.ui.GlideServletTransaction.process(GlideServletTransaction.java:31) com.glide.sys.Transaction.run(Transaction.java:2038) java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) java.lang.Thread.run(Thread.java:748) Cause workflow does not contain custom activity definition [wf_element_activity] record is missing custom activity definition was not brought over in an Update Set Resolution A script to identify which custom activity definition(s) are missing run in /sys.scripts.do the output will be the sys_id of the missing custom activity you will then need to go into the other environments (dev, test, etc), search in table [wf_element_activity] export & import XML file into the affected environment

var nodes = new GlideAggregate('wf_activity'); nodes.addAggregate('COUNT', 'activity_definition'); nodes.addQuery('workflow_version.published', 'true'); nodes.query(); while(nodes.next()) { var def = new GlideRecord('wf_element_definition'); if(!def.get(nodes.getValue('activity_definition'))) gs.print('wf_element_definition ' + nodes.getValue('activity_definition') + ' is missing from this system'); }

Additional Information In hindsight, the custom activity update and workflow update should be captured in Update Set(s) and moved over to the target source