1852788 - Enable fdlibm Math by default in Nightly and Early Beta

Status: RESOLVED FIXED

(Core :: Privacy: Anti-Tracking, enhancement)

Description

[Tom Ritter [:tjr]]

To fully realize the benefits of our AudioContext Work we want to enable the fdlibm Math Functions in FPP (privacy.fingerprintingProtection). This can be done manually by setting privacy.fingerprintingProtection.overrides to +JSMathFdlibm - we want to add it to the default set of options.

Because this change is very subtle, I am concerned that we will not be able to tease out any issues or compatibility concerns prior to shipping using our normal mechanism, which would be to enable in Nightly in PBM and perform a release experiment (also in PBM).

Therefore, I would like to enable it by default, in normal and PBM, in Early Beta and Nightly for at least a cycle before shipping it. I'd like to then leave it on for another couple cycles to more bake time.

The reason we have not shipped this by default before is performance concerns, this previous intent to imeplement discusses that.

Comment 1

[Tom Ritter [:tjr]]

Attachment: Bug 1852788: Enable fdlibm math for Early Beta and Nightly r?timhuang

Comment 2

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/a0b54360ac30
Enable fdlibm math for Early Beta and Nightly r=timhuang

Comment 3

[Narcis Beleuzu [:NarcisB]]

https://hg.mozilla.org/mozilla-central/rev/a0b54360ac30

Comment 4

[Jan de Mooij [:jandem]]

Do we have a bug on file for reverting this in the future? To help minimize (perf) differences between Nightly and release.

Comment 5

[Tom Ritter [:tjr]]

I've added a reminder to the bug

Comment 6

[Dianna Smith [:diannaS]]

:tjr is this something we want to mention in the fx120 nightly notes?

Comment 7

[Tom Ritter [:tjr]]

I don't think so... This isn't user-visible at all, it could possibly cause a regression if a website was fingerprinting Firefox using the math numbers (which I have seen before) - but I'm not sure if putting it in the release notes would indicate to someone it might be the culprit vs them just filing a bug (which is what I hope they do.)

Comment 8

[Thorin [:thorin]]

which I have seen before

for reference see Bug 1784111 and Bug 1784309, which is a sad state of affairs where overzealous anti-fraud/FPing scripts assume gecko will never update libraries and we have to ship an intervention

Comment 9

[BugBot [:suhaib / :marco/ :calixte]]

5 months ago, tjr placed a reminder on the bug using the whiteboard tag [reminder-pref 2024-03-05] .

tjr, please refer to the original comment to better understand the reason for the reminder.

Comment 10

[Tom Ritter [:tjr]]

Filed Bug 1887682 to follow up on this