1493194 - Fallback web font file is requested before the first web font in a font-family stack has finished loading

Status: RESOLVED DUPLICATE of bug 1422530

(Core :: Layout: Text and Fonts, defect)

Description

[Zach Leatherman]

Attachment: fallback-stack-reduced.html

User Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:62.0) Gecko/20100101 Firefox/62.0
Build ID: 20180830143136

Steps to reproduce:

Opened `fallback-stack-reduced.html`


Actual results:

Both the LatoSubset and Lato web fonts were loaded in parallel and requested simultaneously.


Expected results:

Per the spec, the Font Matching Algorithm Steps 3–5 occur for LatoSubset and a single font should be downloaded. Then Step 6 is reached after LatoSubset is downloaded and Steps 3–5 should be repeated for Lato.

https://www.w3.org/TR/css-fonts-3/#font-matching-algorithm

They are downloaded sequentially (not in parallel) in both Chrome and Safari.

Comment 1

[Mike Taylor [:miketaylr]]

Thanks for the report Zach!

Jonathan, do you know if this is a known bug?

Comment 2

[Jonathan Kew [:jfkthame]]

I don't recall an existing report that matches this; it does sound like the behavior is not as expected, though, if I'm understanding right.

Zach, do you have a test site we can look at where this problem occurs? Just loading the attached testcase isn't a good example, because the font files aren't found at all on bugzilla.mozilla.org.

Comment 3

[Zach Leatherman]

Ah yes, of course sorry.

The test with working font files is hosted here: https://www.zachleat.com/web-fonts/demos/fallback-stack-reduced.html

Comment 4

[Jonathan Kew [:jfkthame]]

Attachment: web console showing network requests for the fonts

Loading the testcase in Nightly (64.0a1), the two font files appear to be loaded in sequence, as expected.

Could you try with Nightly (https://www.mozilla.org/en-US/firefox/channel/desktop/#nightly) and see if you still experience the problem? It seems possible the underlying issue has already been fixed.

Comment 5

[Jonathan Kew [:jfkthame]]

Aha -- I believe this is the same issue as bug 1422530, which was fixed for Firefox 63.