1669749 - Fix edge-cases with the FissionAutostart experiment pref integration

Status: VERIFIED FIXED

(Core :: DOM: Content Processes, task, P2)

Comment 1

[Nika Layzell [:nika] (ooo, ni? for response)]

Attachment: Bug 1669749 - Fix edge-cases with fission experiment pref integration,

This should fix some of the issues discovered by QA during their review of the
fission experiment's preference behaviour.

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/27ce8bcc3808
Fix edge-cases with fission experiment pref integration, r=kmag

Comment 4

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/27ce8bcc3808

Comment 5

[Maria Heres, inactive, contact Ecosystem QA]

The issues seem to have been fixed. The fission.experiment.enrollmentStatus and fission.experiment.startupEnrollmentStatus preferences now exist with the default value 0 even before enrolling in the experiment.

If the user unenrolls by enabling fission.autostart as described in Bug 1669703 the fission.experiment.enrollmentStatus and fission.experiment.startupEnrollmentStatus will remain on 2 until a restart, when they will become 3.
If the user changes the fission.autostart preference after enrollment + restart, the fission.experiment.enrollmentStatus and fission.experiment.startupEnrollmentStatus preferences will instantly change to 3.

Unenrolling by turning Fission off or on from Nightly Experiments will also correctly change the preferences to 3 ("instantly", as the entry requires restart at state change).

If the user unenrolls as described in Bug 1669536 the fission.experiment.enrollmentStatus and fission.experiment.startupEnrollmentStatus preferences will instantly change to 0 and the fission.autostart preference will remain on the experiment value until a restart, after which it will be false.

This was tested using Firefox Nightly 83.0a1 (Build ID: 20201009041754 and 20201008210150) on Windows 10 x64, macOS 10.15 and Windows 7.

Can :neha or :cpterson please confirm that the fact that some pref changes only occur after restart is the desired behavior?

Comment 6

[Chris Peterson [:cpeterson]]

(In reply to Maria Heres, :mheres, Ecosystem QA from comment #5)

If the user unenrolls by enabling fission.autostart as described in Bug 1669703 the fission.experiment.enrollmentStatus and fission.experiment.startupEnrollmentStatus will remain on 2 until a restart, when they will become 3.
If the user changes the fission.autostart preference after enrollment + restart, the fission.experiment.enrollmentStatus and fission.experiment.startupEnrollmentStatus preferences will instantly change to 3.

I think this is OK. IIUC, the Normandy code that checks whether any of the prefs related to the experiment (including fission.autostart) runs at startup. So the actual unenrollment will run after restart like you see.

If the user unenrolls as described in Bug 1669536 the fission.experiment.enrollmentStatus and fission.experiment.startupEnrollmentStatus preferences will instantly change to 0 and the fission.autostart preference will remain on the experiment value until a restart, after which it will be false.

Can :neha or :cpterson please confirm that the fact that some pref changes only occur after restart is the desired behavior?

As long as the fission.autostart, fission.experiment.enrollmentStatus, and fission.experiment.startupEnrollmentStatus prefs have the expected values after restart, I think we're good.

Comment 7

[Maria Heres, inactive, contact Ecosystem QA]

I am marking this issue as verified fixed based on the two previous comments.