1958486 - [Experiment][Desktop] Cannot enroll in the experiment and trigger the toast notification if a “Required experiment” targeting is set

Status: VERIFIED FIXED

(Firefox :: Messaging System, defect, P1)

Description

[Valentin Bandac [:vbandac], Ecosystem QA]

[Affected versions]:

• Firefox Release 137.0 - BuildID: 20250327043313

[Affected Platforms]:

• Windows 10 x64
• Windows 11

[Prerequisites]:

• Have a Firefox Release 137.0 build with en-* locale installed.
• Have the "browser.search.region" pref set on US, CA or RO region.

[Steps to reproduce]:

1. Open the browser from the prerequisites and make sure that the profile is enrolled in the Long term holdback 2025H1 Growth Desktop - Delivery branch.
2. Close the browser and add the user.js file in the profile directory.
3. Open and close the browser again.
4. Navigate to the "C:\Users\username\AppData\Roaming\Mozilla\Firefox\Background Tasks Profiles" location and delete all the folders.
5. Change the system date to be 1h in the future.
6. Open PowerShell and run the following command (make sure that the path to the Firefox folder is correct):
   & "C:\Program Files\Mozilla Firefox\firefox.exe" --attach-console --backgroundtask backgroundupdate --preview --reset-storage --debug | clip

[Expected result]:

• The toast notification is displayed.

[Actual result]:

• The toast notification is NOT displayed.

[Notes]:

• This issue is NOT reproducible if the “Required Experiments” section is empty - the toast notification is triggered if the Required experiment is removed.

Comment 1

[Mimi Jung]

Confirmed over Slack that the H1 Growth Holdback branch was not supposed to be added back to the required experiments. Experiment has been updated to exclude any required experiments, could you please verify the fix? Thank you!

Comment 2

[Valentin Bandac [:vbandac], Ecosystem QA]

Thank you for the quick reply!
We have verified this issue on Firefox Release 137.0 (BuildID: 20250327043313), on Windows 10 x64 and Windows 11.
We can confirm that enrollment happens accordingly and the toast notification is triggered after the experiment’s recipe was updated.

Comment 3

[Mimi Jung]

Thanks for verifying! I think we can close this bug then if that sounds good to you.

Comment 4

[Valentin Bandac [:vbandac], Ecosystem QA]

Based on Comment 2 and Comment 3, I am marking this issue as Fixed - Verified.