[FF] vue3_migrate_performance_bar -- serve the performance bar on Vue 3

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Summary

Roll out the performance bar Vue 3 bundle currently behind the vue3_migrate_performance_bar feature flag.

• DRI: @mrincon
• Team Slack channel: #<slack-channel-of-dri-team>

Note

Process and guidance live in the docs — this issue is just the commands and a place to track the rollout. "Rolling out" means incrementally enabling the flag on GitLab.com to validate stability — it is not the same as releasing the feature, which happens when the flag is removed. Feature flag controls · Feature flag lifecycle

What could go wrong?

The flag selects which bundle Rails serves for the performance_bar entry: the Vue 2 build or the @vue/compat build of the same source. Both render the same UI. The performance bar only renders for users who have it enabled, so the blast radius is limited to those users. No data is written either way.

If the Vue 3 bundle fails, the bar does not render. Disable the flag to recover.

Rollout

Run all production /chatops in #production and cross-post the results to #<slack-channel-of-dri-team>. Background: incremental rollout process, feature actors.

Non-production

/chatops gitlab run feature set vue3_migrate_performance_bar 50 --actors --dev --pre --staging --staging-ref
/chatops gitlab run feature set vue3_migrate_performance_bar true --dev --pre --staging --staging-ref

Production — percentage rollout (wait ≥15 min between steps, watch dashboards):

/chatops gitlab run feature set vue3_migrate_performance_bar <percentage> --actors

Or target specific actors instead:

/chatops gitlab run feature set --project=gitlab-org/gitlab,gitlab-org/gitlab-foss vue3_migrate_performance_bar true
/chatops gitlab run feature set --group=gitlab-org,gitlab-com vue3_migrate_performance_bar true
/chatops gitlab run feature set --user=<gitlab-username-of-dri> vue3_migrate_performance_bar true

Before global rollout

Confirm the relevant gotchas before going to 100% — see enabling a feature for GitLab.com:

• Docs + version history updated
• Breaking changes announced, if any
• Change management issue opened, if required
• External API consumers handled with a fail-open mechanism, if applicable

Cleanup

Remove the flag once deemed stable — see cleaning up. Track it here, or open a follow-up Feature Flag Cleanup issue. Remove the flag and its YAML definition from the codebase, then:

/chatops gitlab run release check <merge-request-url> <milestone>
/chatops gitlab run feature delete vue3_migrate_performance_bar --dev --pre --staging --staging-ref --production

Rollback

/chatops gitlab run feature set vue3_migrate_performance_bar false                                         # production
/chatops gitlab run feature set vue3_migrate_performance_bar false --dev --pre --staging --staging-ref     # non-production
/chatops gitlab run feature delete vue3_migrate_performance_bar --dev --pre --staging --staging-ref --production  # remove entirely