1859319 - Users are re-enrolled in a rollout after changing the feature configuration preference

Status: RESOLVED WONTFIX

(Firefox :: Nimbus Desktop Client, defect)

Description

[Carmen Tataru [:ctataru], Ecosystem QA]

Attachment: Screen Recording 2023-10-16 at 17.39.13.mov

[Affected versions]:

• Firefox Release, 116.0 (BUILD ID: 20230727152340)
• Firefox Release, 117.0, (BUILD ID: 20230824132758)
• Firefox Release, 118.0.2 (BUILD ID: 20231009140911)
• Firefox Beta 119.0b8 (BUILD ID: 20231011091528)
• Firefox Nightly 120.0a1 (BUILD ID: 20231002221644 )

[Affected Platforms]:

• MacOS 13.6
• Windows 11 x64

[Prerequisites]:

• Have the a rollout in preview state (e.g: https://stage.experimenter.nonprod.dataops.mozgcp.net/nimbus/feature-config-testing-for-racecachewithnetwork-treatment-a-rollout-copy/summary)
• Naturally enroll in the rollout.

[Steps to reproduce]:

1. Navigate to the “about:config” page.
2. Search for the pref changed by the rollout. (e.g: network.http.rcwn.enabled)
3. Change the pref to another value than set in the rollout.
4. Restart the browser.
5. Observe the results.

[Expected results]:

• The rollout is disabled and the user is not re-enrolled after the restart.

[Actual results]:

• The user is re-enrolled after the browser is restarted.

[Notes]:

• This issue might be related to this 1833248.
• This issue is not reproducible with Firefox 114.
• This issue is not reproducible with forced enrollment.
• Attached a screen recording of the current behavior.

Comment 1

[Beth Rennie [:beth] (she/her) - OOO until Sept 14]

This is intended behaviour. To prevent re-enrollment, either a) opt-out of the rollout on about:studies or b) the rollout targeting should check the box "Prevent enrollment if users have changed any prefs set by this experiment" which prevents enrollment if the user has changed these prefs.