🌸 Cherry-pick request for #30243 into #30147, #30086 (Complete)

[powerivq]

Cherry-pick request

Issue	PR	Beta / Experimental?	Stable?	LTS?	Release issue
#30243	#30174 #30235	YES	YES	YES	#30147 #30086

Why does this issue meet the cherry-pick criteria?

The regression broke two ad networks and all users using these two ad vendors do not get any ad at all.

Why is an LTS cherry-pick needed?

The change has flowed into LTS, and it is serious enough that should not stand there for longer.

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

Since 9/8 release, Kargo and Yield Pro ads have stopped working. It was caused by us enabling strict mode for JS (#29929), and the ads using the implicit this in the vendor configuration suddenly finding this to become undefined. Kargo reached out to us once they noticed their ad is no longer serving on AMP.

Impact

• All publishers using Kargo and Yield Pro are affected
• All the ads using these two ad vendors fail to load

Action Items

• Fixed the issue (Fix yield pro use of implicit this #30235)
• Determined that the vendors are in the best position to add test coverage, either on amp repo or on their own infra. wg-ads does not have subject-matter expertise on the specific network.

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

[cramforce]

Approved

[gmajoulet]

All done, assigning to @powerivq for a post mortem.

[rsimha]

[Cleaning up old CP issues] Can this be closed?

[Enriqe]

[Cleaning up old CP issues] Can this be closed?