1543746 - Stop reading all files in both $app/defaults/prefs/*.js *and* $app/defaults/preferences/*.js

Status: NEW

(Core :: Preferences: Backend, defect, P5)

Description

[:Gijs (he/him)]

AFAICT:

https://searchfox.org/mozilla-central/rev/69ace9da347adcc4a33c6fa3d8e074759b91068c/modules/libpref/Preferences.cpp#4393,4402,4405

indicates we always load both of these locations for Firefox.

We should stop doing that, there's no real need to have 2 of these, we should settle on one of the two. Mike, do you know which of these are used by enterprises, and how quickly we could switch to just 1 location?

Comment 1

[Mike Kaply [:mkaply]]

$gre/defaults/pref/*.js is the one used by enterprises.

But $app/defaults/preferences/*.js is the one used by any app that uses the -app parameter to point to an application.ini (which is still being used).

So I don't think you can safely remove either of these in general.

You could remove the second one for Firefox only.

Comment 2

[:Gijs (he/him)]

(In reply to Mike Kaply [:mkaply] from comment #1)

But $app/defaults/preferences/*.js is the one used by any app that uses the -app parameter to point to an application.ini (which is still being used).

With current versions of Firefox? Is this a distribution thing or a "custom app built on gecko now that xulrunner is gone" thing, or something else?

Comment 3

[Mike Kaply [:mkaply]]

With current versions of Firefox?

Yep. You can quickly build a kiosk or locked down Firefox or something similar with current Firefox.

Is this a distribution thing or a "custom app built on gecko now that xulrunner is gone" thing, or something else?

custom app built on gecko now that xulrunner is gone.

You can pretty much take a XUL Runner app and invoke it with -app.

Comment 4

[Mike Conley (:mconley) (:⚙️)]

So I suppose the potential for a win here is knowing whether or not we were invoked with --app, and if not, skipping that second piece of IO.

Comment 5

[:Gijs (he/him)]

This should be fairly straightforward... in theory.

Comment 6

[BugBot [:suhaib / :marco/ :calixte]]

The priority flag is not set for this bug.
:njn, could you have a look please?

For more information, please visit auto_nag documentation.

Comment 7

[Mike Hommey [:glandium]]

We don't actually ship anything in browser/defaults/preferences, so we're effectively not reading anything there. As a matter of fact, the browser/defaults directory doesn't even exist. Are you saying that you see the failed attempt of directory opening in profiles? If so... WTF windows?

Comment 8

[Mike Hommey [:glandium]]

If you really want to stop reading browser/default/preferences, we might as well go back to bug 1376994 comment 18, because one simple way to not try to read browser/default/preferences is to stop making Firefox a pseudo-xulrunner application. But the questions in bug 1376994 need answering.

Comment 9

[Emma Malysz]

Attachment: Bug 1543746, skip IO for defaults/preferences/*.js if not invoked using app flag