🌸 Cherry-pick request for #36197 into 2109272305000

[samouri]

Issue (P0 Bug)

ampproject/error-reporting#106

Pull Request(s)

#36197

Release Tracker(s)

#36186

Channels

Beta / Experimental

Formats

Websites, Stories

Justification

The bug causes an error to be thrown for all pages that emit layout-shift events before Performance service has fully initialized. AFAICT this shouldn't actually break UX of the page, and will only create noise. Judging by volume on Nightly, the amount of noise is incredibly high.

Therefore this is worth fixing in Beta, where the bar is lower for CPs

Verification Steps

New unit test + the stacktrace in the error make it clear that it should be fixed.

Summary

No response

Impact

Noise in error logs on Beta channel.

Action Items

N/A, all taken within the fix PR.

Notifications

/cc @ampproject/release-on-duty @ampproject/wg-approvers @ampproject/cherry-pick-approvers

[gmajoulet]

Would we have a drop in layout-shift events volume unless we CP?

[kristoferbaxter]

Approved. Thanks!

[samouri]

Would we have a drop in layout-shift events volume unless we CP?

Still digging through the code now. I'm not sure if it will affect volume, but a side effect in the error path would be a reduced CLS ticked under cls-1. I do believe the OG PR will affect volume though (#36147)

[rsimha]

Judging by volume on Nightly, the amount of noise is incredibly high.
Therefore this is worth fixing in Beta, where the bar is lower for CPs

I'm convinced by these two statements. Approved.