firefox-ios VS profiler

Users are complaining that the latest Firefox for iOS update has removed the "Dark mode" option from the menu:[1]

> I suffer from Diabetic Retinopathy and hence photophobia. To me, this removal is an Accessability issue.

A forum moderator who's in touch with the developers said days ago that this is an experiment affecting half of the userbase:[2]

> The team is currently doing an experiment. Since March 15, 50% of users no longer see Night Mode switch from the hamburger menu. We're using this experiment to monitor and evaluate the impact of removing, so it'll be hugely valuable to hear your feedback around this feature. Thanks!

However, Mozilla's iOS team manager doesn't know about this huge experiment and think it is a bug:[3]

> Moving Focus into the Firefox repo so it can get more love and support. This happened last release and may be the culprit that broke dark mode. We're looking into this right now.

[1] https://github.com/mozilla-mobile/firefox-ios/issues/19365#issuecomment-2018447405

Yeah, Orion's support for Firefox extensions is a big red flag. These 2 issues on the Firefox-iOS tracker[0,1] around extensions and content blockers have long mentioned Orion, but there's no response from Mozilla.

[0]: https://github.com/mozilla-mobile/firefox-ios/issues/7374

[1]: https://github.com/mozilla-mobile/firefox-ios/issues/9155

If you keep being logged out, open this page and click on New issue.

Follow this bug report: Tabs reload when switching to another tab or app and screen remains blank in Firefox for iOS.

Please file an issue on Bugzilla (Android) or GitHub (iOS).

Please open this page and click on New issue to report bugs affecting Firefox for iOS.

If you have a GitHub account, subscribe to this issue: Extensions support on iOS.

https://github.com/mozilla-mobile/firefox-ios/commit/686d36402c6a956f460abafc8f1fe19a7887a2f3 landed in v38, so it looks like v37 was the last to support iOS 12.

When you use Reader View, Firefox parses the text of the webpage and loads it as a local page. It isn't supposed to show a red slash, though. Reader Mode shows a neutral icon (📄) on the desktop version. Please open this page and click on New Issue to report this to Mozilla, and then share the link with us.

Probably your best bet is to use the Firefox Profiler once it starts hogging the CPU to try to see what it's doing. I'd be happy to take a look at the result although I don't have a lot of experience at diagnosing performance problems; hopefully the profile will make it obvious what's going on.

I tried using the https://profiler.firefox.com/ and running with:

You can try to reproduce while taking a profile using the Firefox profiler, then share it in the #perf:mozilla.org room on Mozilla's Matrix instance.

Run a profiling session for ~30 sec when you notice something is running slower than you expect, see https://profiler.firefox.com/. Share results here if you want help interpreting them.

Next time, send a SIGABRT to the main process (kill -6 $(pidof firefox)) and use the resulting backtrace (you will find a link to the crash report in about:crashes) to file a bug. A performance profile could be useful, but you'll need to know first what to capture. This seems like a graphics issue, so try the Graphics preset. Share a link to your report.

https://profiler.firefox.com will be useful if you can capture and share it to developers.

If you can reproduce it in safe mode and a clean profile, capture a performance profile using the clean profile while trying to load a problematic webpage, don't remove any information from it, and share it here (although it's typically not easy for users to analyse them), or file a bug with it attached.

Next time, capture a performance profile using the Graphics preset, and kill the browser by entering kill -6 $(pidof firefox) in a shell. This will create a bug report (unless debian disables the crash reporter) that would indicate where Firefox is stuck at. You might need to use an official build to get useful results.