We originally were expecting to re-use the current preference - browser.search.cohort.

However, in discussions with the Normandy team, the general recommendation is that experiments set preferences on the default branch (this has several advantages).

Given that the cohort pref was set by the old search service and has been set in many cases by the responses from ABSearch, I think re-using the same preference would be difficult, because of the user-set values.

Therefore I'd like to do a quick swap to browser.search.experiment and update the configuration to use experiment rather than cohort.

Looking to get this onto beta so we have it all in place from 78 onwards.

We don't currently use the cohort value in modern configuration, so this should be fine to switch.

https://hg.mozilla.org/mozilla-central/rev/1dfd09bbff34

Comment on attachment 9154324 [details]
Bug 1643468 - Use a different pref for search engine configuration experiments. r?daleharvey!

Beta/Release Uplift Approval Request

• User impact if declined: No user impact, but if we run experiments whilst using the new modern search engine configuration, then those experiments won't run properly.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: QA are testing this as part of the modern search engine configuration validation.
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Covered by automated tests, only affects experiments.
• String changes made/needed: none

Comment on attachment 9154324 [details]
Bug 1643468 - Use a different pref for search engine configuration experiments. r?daleharvey!

approved for 78.0b5

https://hg.mozilla.org/releases/mozilla-beta/rev/fa707c4fb00b

I verified this issue using Fx 78.0b9 and Fx 79.0a1 on macOS and Windows 10 x64.