Crashes in Content Processes starting in Firefox 111

[tomrittervg]

Users of Nightly 111 may have started experiencing content process crashes in the past 2 days. Once 111 goes to Beta/Release, users on Beta or Release may start experiencing incorrect behavior.

This is because I landed 1811294 which will cause content process crashes when dynamically named string preferences (i.e. preferences that aren't specified in prefs.js or StaticPrefList) are accessed in the content process. I'm here because we just got crash reports for one user accessing userChrome.searchSelectionShortcut.keycode which I know is a userchrome thing.

There are preferences that affect the crashing behavior referenced in that bug. As before, Mozilla's policy is that userschrome stuff is not supported, so we're not going to go out of our way to make things work* and we don't recommend you disable security settings. But at the same time we appreciate all of our users and as one hacker to another(s) - I wanted to give you a head's up.

* well actually, we've been going really far out of our way for a while, but there are limits

I also left this comment at xiaoxiaoflood/firefox-scripts#241 which is where I frequently post updates for userchrome stuff.

[aminomancer]

Thanks for reporting! I can probably just have these scripts request the pref values from the parent process.

[aminomancer]

kinda looks like if I prefixed all the custom prefs with ui., they wouldn't get blocklisted in the first place. curious what you think about that?

[tomrittervg]

Yeah, either approach would work