109932 - pref locking on browser.startup.homepage broken

Status: RESOLVED DUPLICATE of bug 333049

(Core :: Preferences: Backend, defect)

Description

[Steve Meredith (gone)]

If I use

pref("browser.startup.homepage",
"chrome://navigator-region/locale/region.properties");

the value in the chrome file is used for my homepage. However, if I use


lockPref("browser.startup.homepage",
"chrome://navigator-region/locale/region.properties");

then chrome://navigator-region/locale/region.properties is used as my homepage.
It's not dereferenced.

Comment 1

[Samir Gehani]

-> prefs backend

Comment 2

[Brian Nesse (gone)]

Oddly enough this is basically a dupe of bug 109902 which has a lengthy
discussion of things pertaining to LocalizedUnicharPrefs. To save myself from
explaining this in 2 different bugs, adding the participants from that bug to
the cc list because this is relevant.

In a nutshell, LocalizedUnicharPrefs pull their defaults from a properties file.
You change the default value by changing the properties file, not by setting a
default preference value (which is what lockPref does).

LocalizedUnicharPrefs work differently from other prefs in that when they are
locked, they return a user value instead of a default value. This may or may not
be the indended functionality, but that is how it was implemented.

When a LocalizedUnicharPref is assigned a user value, the value is treated as a
direct URL. What you are doing (via lockPref) is supplying a "default" value
where one is not supposed to exist. Then, when you request the (non-existent)
user value (because the preference is locked), the prefs falls back to the
"default" value (which shouldn't exist) and returns it as a direct URL value
because that's how it "thinks" it's supposed to work.

Comment 3

[Alec Flett]

ack, that's not how that should be working. lockPref() should be setting a
locked flag so that when I call PREF_CopyCharPref or some other internal
routine, it automatically goes back to the default pref. Otherwise, this means I
can override locked prefs just by modifying my all.js or something.

So basically, no that was not the indented functionality...:)

Comment 4

[Brian Nesse (gone)]

Umm, well, lockPref does set a lock flag, which internally causes the functions
such as PREF_CopyCharPref to return the default value. But with
GetLocalizedUnicharPref there is no default value...

Comment 5

[Rodney Velasco]

*** Bug 110902 has been marked as a duplicate of this bug. ***

Comment 6

[Jeff Hooker]

removed jhooker from cc: list

Comment 7

[Mike Kaply [:mkaply]]

Sorry to dupe this forward, but the later bug has more info.