🌸 Cherry pick request for 26484 into 26356 (cherry-picked)

[powerivq]

Cherry-pick request

Issue	PR	Production?	RC?	Release issue
#26484	#26479	YES	YES	#26356

Why does this issue meet the cherry-pick criteria?

This is a production-affecting bug.

Why is a RC cherry-pick not needed?

Not applicable.

Mini-postmortem

TODO: This postmortem will be written after the cherry-pick deployment and before this issue is closed. Delete this TODO when the postmortem is ready.

Summary

We are refactoring several interfaces out from resources service to a mutator service. amp-auto-lightbox uses the API from resources service and was not switched to the new one. It was not caught until on production, and console error log triggered the alarm.

Users affected	Impact
all users using amp-auto-lightbox on prod	partial loss of functionality of amp-auto-lightbox

Root Causes

1. amp-auto-lightbox uses element.getResources to obtain the service object, and the type checker is not able to find the type reference of that method. The type checker therefore failed to check whether the method call exists.

2. There is insufficient traffic for this single extension on canary that would have triggered an alarm.

Action Items

Action Item	Type	Owner	PR #
#26750	Prevent	@choumx	#<PR_NUMBER>

Lessons Learned

Things that went well

• The refactoring itself was splitted into phases, so that the final switch-over PR was not large and easy to be reverted.

Things that went wrong

• Traffic on canary is not large enough for relatively infrequent code paths.

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/cc @ampproject/wg-approvers @ampproject/cherry-pick-approvers

[powerivq]

/cc @gmajoulet

[cramforce]

Prod rolled back already right?

Is there a second cherry-pick coming? I thought that was the case.

[gmajoulet]

The other cherry-pick is here: #26477

Both should be cherry-picked into prod before it is rollforwarded

[cramforce]

Approved

[gmajoulet]

We decided to not cherry-pick production and skip this week's production release.
Canary has been patched, is available as of a few minutes ago, and will be pushed to production next Tuesday.

Reassigning to @powerivq for the mini post mortem.

[erwinmombay]

closing this issue