1532168 - Proxy PAC script should not support file:// protocol

Status: UNCONFIRMED

(Core :: Networking: Proxy, defect, P3)

Description

[meet.again.someday]

User Agent: Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/72.0.3626.119 Safari/537.36

Steps to reproduce:

Set proxy script in the system configurations pointing to a PAC file using file://

Actual results:

The browser loads the PAC file and interprets it correctly.

Expected results:

Ignore the PAC file and not supporting loading PAC script via file:// from the system settings.

Lets me explain more.
This bug report is weird to you as it was weird to me.
This bug originates from the Chromium development team.

They said that setting system PAC script via file:// isn't a valid proxy setting. It is arguably a bug that applications such as Chrome and Firefox interpreted the file:// there.

From here exactly:
https://bugs.chromium.org/p/chromium/issues/detail?id=839566

So they removed the support for file:// and plan on creating Chromium only solution to support loading PAC script from local file.
This makes Firefox the only major browser that supports loading PAC via file:// in the system setting.

Now it is truly pointless to set file:// PAC there because it will be exclusively for Firefox alone. No other browsers respect the same setting.
Might as well move the setting into the browser instead of relying on system settings, like what Chrome just did.

I too really like the feature and think that It was a Microsoft&Safari bug.
There will be some uproar if Mozilla does it too, but I guess it is the way forward.

That particular OS feature never intends to support PAC setting this way.

Comment 1

[Matthias Versen [:Matti]]

There are compatibility problems if Firefox is the only browser to support that "feature" and that means that it's no reason to remove that feature.

Why should that "feature" get removed ?

Comment 2

[meet.again.someday]

No, sorry I did not address it well enough.
The main focus is not about getting the feature "removed", but about providing PAC file configuration internally, in case the file is on local storage.
I agreed that the subject might set the wrong implication.

Comment 3

[Kershaw Chang [:kershaw]]

P3 for now.

We can consider how to implement this when the sandboxing for socket process is done.

Comment 4

[BMO Automation]

Moving bug to Core/Networking: Proxy.