Issue Summary

Subs-task, stories, and epics become orphans after performing an S2C migration and doing a C2C afterward.

Steps to Reproduce

1. Create a Migration plan from a server instance to a cloud with a project that has sub-task
2. Do a C2C migration using the project that came from the server.
3. Observe that all sub-task become orphans in the Cloud Destination.

Expected Results

All items to keep their parent and link relationship after doing C2C migration.

Actual Results

The issue is that the parent relationship for a subtask is currently being dual-written to two locations, the "issuelink" table (the old method) and the "issue_parent_association" table (the new method).

When performing an S2C migration the app only writes this relationship into the new table, but when we perform a cloud-to-cloud migration it is reading data from the old table. That's why data that's being created on the cloud instance directly (and still being dual written) is migrated correctly, but data that was migrated from the server (and isn't dual written) fails the C2C migration.

Workaround

Do the migration from Server to the Destination cloud Directly.