1690288 - [webcontent] Invalid resolving of the relative paths in CSS

Status: NEW

(Core :: DOM: CSS Object Model, defect)

Description

[Petru-Mugurel Lingurar [:petru]]

From github: https://github.com/mozilla-mobile/fenix/issues/16586.

Site with issue and any steps to reproduce

Minimal test case: https://znpd.pl/test-error.php
While loading site on Firefox Mobile, I'm getting two requests to the image:
https://znpd.pl/gfx/layout/logo.png
and
https://znpd.pl/static/gfx/layout/logo.png
where the latter one is correct.

See https://znpd.pl/static/css/test-error.css
linking to:
h1 { background: url("../gfx/layout/logo.png") no-repeat; }

Expected behavior

Browser should resolve paths in CSS file relative to the path of CSS file itself, not to the original document.

Actual behavior

Firefox first tries wrong path of the image defined in the CSS file.

Does toggling Tracking Protection fix the issue? (Press the shield icon in the toolbar while on the site to see toggle)

No,

Can you reproduce in Chrome (or other non-Mozilla browser)?

No, no error in Chrome, nor in Firefox Desktop.

Device information

• Android device: POCO F2 Pro
• Fenix version: 82.1.3

Change performed by the Move to Bugzilla add-on.

Comment 1

[Jonathan Kew [:jfkthame]]

Seems weird this would behave differently in Fenix than in desktop Firefox. If confirmed, it's a pretty serious error for us to be making. Any thoughts, Emilio?

Comment 2

[Emilio Cobos Álvarez [:emilio]]

Attachment: devtools network panel of the above url from Fenix nightly.

Can't seem to reproduce off-hand.

Comment 3

[Emilio Cobos Álvarez [:emilio]]

Couldn't repro on Firefox release either.

Comment 4

[Petru-Mugurel Lingurar [:petru]]

Thank you all for looking into this!
From the initial report I saw this as a browser issue but maybe the app accesses that resource, as kbrosnan said.
I am yet to confirm this on Fenix but we should probably investigate there more first.

Comment 5

[Jonathan Kew [:jfkthame]]

Seems unlikely this is a Core Gecko bug; marking as S4 for now pending further investigation (comment 4), but may well turn out to be invalid.