Rollout auto_merge_on_merge_status_change feature flag

Summary

This issue is to roll out the feature on production, behind the auto_merge_on_merge_status_change feature flag.

Introduced in: !217382 (merged)

Owners

• Slack channel: #g_code_review
• DRI: @marc_shaw

Expectations

What are we expecting to happen?

When enabled, MRs with auto merge enabled will trigger AutoMergeProcessWorker when merge status changes to can_be_merged.

What can go wrong?

• Unexpected auto merges
• Increased worker load
• Error rate increases

Rollout Steps

Non-production

• Deploy at 50%: /chatops run feature set auto_merge_on_merge_status_change 50 --actors --dev --pre --staging --staging-ref
• Enable globally: /chatops run feature set auto_merge_on_merge_status_change true --dev --pre --staging --staging-ref

Production

• Enable for gitlab-org: /chatops run feature set --project=gitlab-org/gitlab auto_merge_on_merge_status_change true
• Incrementally roll out globally
• Create cleanup MR to remove flag

Rollback

/chatops run feature set auto_merge_on_merge_status_change false