2026-02-02: Inline comments on MRs cannot be hidden or expanded

Inline comments on MRs cannot be hidden or expanded (Severity 3)

Problem: Collapsing and expanding inline comment threads is broken for merge requests.

Impact: All users have been unable to collapse or expand inline comment threads in merge requests. The issue is highly visible but has a minor workflow impact, with a workaround available.

Causes: A recent refactor of the diff_row.vue component caused the problem. Testing confirmed that collapsing inline comments fails after this change and works before it.

Response strategy: A status page update was published. A workaround was provided: users can use the 'Show all comments' or 'Hide all comments' button at the top of the merge request. We prepared a fix and it has now been merged; deployment to production has completed.

This ticket was created to track INC-7002, by incident.io 🔥