Comment 4 for bug 541951

(In reply to comment #2)
> Because I apparently inherited ownership of this code by default, I'm going to
> need some more summary here:
>
> * what is the motivation for this change?
> * where did lockPref use to work? In what new cases are we making it work?

lockPref is an exclusive feature of the autoconfig stuff right now. Autoconfig uses a single file, located in the application directory, and which name is given by the general.config.filename preference, with pseudo security featured by a general.config.obscure_value preference.

Autoconfig also allows to use javascript constructs, contrary to standard pref files that are limited to pref() and user_pref().

The problem we had in debian is that we need to lock some preferences, to avoid users to harm themselves with bad preferences. app.update.enable, for instance. The first solution was to use the general.config.filename/obscure_value pair to just do that. The problem is that this file being provided by the package, it is also overwritten on any package upgrade, which means admins needing to use autoconfig just can't.

I found it a convenient way to solve this by allowing standard preferences to lock preferences.

I'm pretty sure you can find some other uses to this feature.

> * I'm going to need tests. I think writing an xpcshell test for this shouldn't
> be too hard.

Can you still review the patch without the tests ?