Issues dropped from Epics without any action

Summary

Root Cause: !73007 (merged), which was intended to remove invalid epic/issue relationships, inadvertently removed valid relationships including issues from a subgroup of the epic's group. This was because the migration only checked base_and_ancestors for determining if a relationship was valid. It also needs to check base_and_descendents

We've received several reports of Epics not showing their associated issues. The issues in question also don't show the epic, despite system notes indicating the relationship has been added and not removed.

Slack threads (internal):

What is the current bug behavior?

Some epics and their issues don't show the relationship, despite the system notes indicating that it should exist. Example: gitlab-com&1655 (closed)

The epic relationship is not visible in the Epic page issue list, nor in the sidebar for the issues.

What is the expected correct behavior?

Issues added to epics should show their parent epic. Epics should show their child issues.

Customer Reports (GitLab Internal)

Proposed fix

Restore the inadvertently removed relationships via the system notes, which remain in tact.

Edited Dec 15, 2021 by Jake Lear