Open Bug 1428233 Opened 3 years ago Updated 2 years ago

user.js does not override about:config in some cases


(Core :: Preferences: Backend, defect)

Not set




(Reporter: emceeaich, Unassigned)



Filed on behalf of

> The optional user.js file, if one exists, will override any modified preferences. 

At best, it will over-ride ** SOME ** modifications of preferences.  As to the driving reason for inquiry, locking down involuntary plug-in installations, and involuntary including trying to completely disable 'telemetry' 'phone home' of data [anonimyzed or not], it does ** NOT ** work and stay unaltered

I encountered also UN-asked for changes at:

// set (historical mode):

browser.tabs.remote.autostart = false
browser.tabs.remote.autostart.2 = false

// ... above silently set itself true again  2017 08 29
//      52.2.0 (64-bit) ESR
//      Centos 7, 2017 09 update is: 52.3.0 (64-bit)

contrary to my user.js settings

also "e10s" would invisibly revert 'lockouts' I set in user.js

[herrold@centos-7 firefox]$ grep "e10" *
x-tunnel-ICP-fail.txt: [e10s] Tabs crash on loading large sites.
> // ... above silently set itself true again  2017 08 29

Maybe because of the e10s rollout system addon?
Mike, have you heard of this?
Flags: needinfo?(mozilla)
Product: Firefox → Toolkit
I have not, but user.js has never been a guaranteed mechanism. It would be worth a quick glance to see why these aren't overridden.
Flags: needinfo?(mozilla)
Emma Humphries, Bugmaster [:emceeaich] (UTC-8)

Filed on behalf of

can you modify settings, to assign this to me as reporter?  If so, I so request that change
Flags: needinfo?(ehumphries)
I don't have a way to do this, but asking if this can be done through other means.
I have inquired, but it is not possible to change who filed the bug.
Flags: needinfo?(ehumphries)
Thinking about this more, all user.js can do is set values that can be overridden by other values. So if any thing sets the value (like e10s) it will override the value from user.js.

Your only option is to lock these values which can't be done with user.js (yet - bug 440908). If you're need is to lock preferences, you should look into AutoConfig.
Component: Preferences → Preferences: Backend
Product: Toolkit → Core
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