1541831 - No lazy loading with range on unicode-range

Status: RESOLVED INVALID

(Core :: CSS Parsing and Computation, defect)

Description

[Martin Trigaux]

Attachment: bad.html

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:66.0) Gecko/20100101 Firefox/66.0

Steps to reproduce:

Load[1] the bad.html example attached that contains:

• DOM with Latin alphabet only
• CSS with 2 font-face to load a custom font

The two font-face are taking advantage of the unicode-range property to be used only for characters in the unicode code range U+0600 to U+06FF (Arabic alphabet).

The first unicode-range is defined with wildcard in the format U+06??.
The second unicode-range is defined with range in the format U+0600–06FF.

Actual results:

See in the Network tab the requests :

• a request is made to load 'font-with-codepoint-range.ttf' (bad)
• 'font-with-wildcard.ttf' is not loaded (good)

Expected results:

According to the MDN page, the font files should NOT be loaded as no characters match the unicode-range definitions in any of the two font-face.
https://developer.mozilla.org/en-US/docs/Web/CSS/@font-face/unicode-range

Both font-face should have the same behaviour and skip the font when not needed.

[1] to properly reproduce, the file must not be open directly but accessed via HTTP, through a server, otherwise, no request are logged in the Network tab.
For instance, on a system with python installed, use "python -m http.server" to have a quick local server

Comment 1

[Emilio Cobos Álvarez (:emilio)]

I think this is invalid, the second rule doesn't have a valid unicode-range descriptor. You can verify it with:

document.styleSheets[0].cssRules[1].cssText

In the console (which doesn't show the unicode range, because it didn't parse).

Also, if you enable the devtools CSS errors:

Unknown descriptor ‘+0600–06FF’ in @font-face rule. Skipped to next declaration.

The reason for that is that you're using the wrong hyphen character. If I change the descriptor to be unicode-range: U+0600-06FF; then the issue goes away.

Let me know if that's not the case and I'm happy to look into it further.

Thanks for the report :)

Comment 2

[Martin Trigaux]

Damn, I feel stupid. Copy-paste from wikipedia which uses the "En Dash".
Thank you for the fast reply.