Auction Config Passed Macro Replacements Not Working with Some 3P Configurations

[thegreatfatzby]

Seeing a tricky issue where the macro replacement via the deprecatedReplaceInUrn does work, but the same replacement does not work if done via the auctionConfig.deprecatedRenderURLReplacements. I see this in Stable (which I'm typing this on Version 130.0.6723.70 (Official Build) (arm64)) as well as dev (on other laptop but I believe it was in the 132's).

Test "System"

I have a little toy set up that allows you to see the replacement work (or not) with values you input, the navigator.deprecatedReplaceInUrn one is here and the auctionConfig.deprecatedRenderURLReplacements is here. Both will set up a simple IG that is guaranteed to win a simple auction, and then the query param is sent to the creative rendering server which spits back what it sees as a way of easily knowing that the param was swapped and sent to the server. You can of course just inspect the elements if you like.

Results

The chrome flag that causes/uncauses the issue is #tpc-phase-out-facilitated-testing, so basically (I assume) related to the 3PC state of the browser.

I see the following behavior (for both of the Control2 options my test seems to have some bug I'll need to work on later) Enabled: Not working via auctionConfig Enabled Control 1: No Enabled LabelOnly: No Enabled Treatment: No Enabled Control2: test issue Enabled Force Control1: No Enabled Force LabelOnly: No Enabled Force Treatment: No Enabled Force Control2: test issue Disabled: works fine

[JacobGo]

Looks like you also ran into https://github.com/WICG/turtledove/issues/286#issuecomment-2120319985.

[MattMenke2]

The comments in #286 say it rolled out to stable at 100% back in May, so seem unlikely to be relevant.

[JacobGo]

@MattMenke2 from what I understand, Chrome has held back the feature on labeled traffic despite otherwise landing 100% stable, see corresponding logic.