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Ignoring diffs

A powerful feature in the Happo review process is the ability to permanently ignore a diff.

Permanently ignoring a diff Ignoring a diff in a Happo report.

Ignoring a diff will instruct Happo to ignore that specific diff now and in the future. It should be used with caution as it might hide issues that should be caught.

Examples of where it is okay to permanently ignore:

  • ✅ When there's a subtle diff that you can't attribute to the changes made.
  • ✅ When there are flaky rendering-related issues not caused by your code

Examples of where you should avoid using the permanently ignore feature:

  • ❌ You've made a UI update causing diffs (simply accept the report instead).
  • ❌ You're having spurious diffs where some images/fonts won't load (reach out to us instead — this might be a bug)

Global effect​

Ignored diffs apply to all future and past Happo reports. This can lead to some confusion when your Happo build status (in e.g. GitHub) shows a number of diffs, but the Happo report page shows fewer diffs (or even none). Build statuses aren't updated when you ignore a diff, you still need to manually approve or reject.