Frequenty occurring error during migration - IllegalArgumentException: DIRECTED transition with ID [x] should have at-least 1 source

Issue Summary

We came across an error which is causing failure during migration and has impacted multiple customers while using JCMA and C2C Beta tool. The error would look like this -

ERROR ABC project-import We couldn't import Workflow 'Workflow Name'. Reason: IllegalArgumentException: DIRECTED transition with ID [xxx] should have at-least 1 source. This caused xxxx other items to fail.

On digging further, we could see that a transition with this ID is present in the XML export of the workflow (steps to export - https://support.atlassian.com/jira-cloud-administration/docs/import-and-export-issue-workflows/) but the same transition is no where seen on the workflow UI (neither text nor diagram form).

This happens for both

• Server to cloud 
• Cloud to Cloud migration

Steps to Reproduce

No fixed way to replicate since this happens for both C2C Beta as well as Server to cloud JCMA migration.

Expected Results

Migration should complete successfully or there should be a way to prevent these workflow corruptions.

Actual Results

Error - 

IllegalArgumentException: DIRECTED transition with ID [2] should have at-least 1 source  

Workaround

Important - Take backup before any change on Database level 

Server to Cloud -
Identify the impacted workflow and request user to share XML for the workflow => Get the exact error message from from JCMA error logs or c2c logs => Get the ID => Trace the impacted Transition => Either ask the user to create a fresh workflow without using copy operation OR remove that code piece from XML and import it to create fresh workflow = > Make changes in the project settings and attach the correct one.

Cloud to Cloud - 

Since importing an XML to create a workflow in cloud is not a simple process, we may have to request the customer to manually create a workflow with same transition and replace it in existing project OR run an update command in the database to replace the current XML.

• To do so, edit the XML of current workflow and remove the corrupt transition 
• Look for impacted workflow in jiraworkflows table

• update jiraworkflows set descriptor = 'CORRECT XML' where id = 'XXXX' returning *; 

  for the concerned workflow