[Bug 2012430] [NEW] <html lang="..."> attribute breaks dashes

Tue Mar 21 19:53:55 UTC 2023

Public bug reported:

The attached HTML file should be rendered as two lines of text, one with
dashes between the words and one with spaces. However, Firefox renders
the file with no dashes whatsoever. Instead of dashes, it shows double-
width spaces.

The HTML renders correctly if lang="de-x-formal" attribute is changed to
lang="de". Please note that de-x-formal is a valid language code, as
verified with http://schneegans.de/lv/ and it is found in the HTML
generated by MediaWiki when the language is set to de-formal.

I also noticed that the extra wide spaces Firefox incorrectly shows
instead of dashes are in the ori1Uni font while the regular letters are
in DejaVu Serif. With lang="de", everything is in DejaVu Serif,
including dashes which render correctly.

This problem does not occur with Chromium on Ubuntu, nor with Firefox on
Debian, nor Firefox on Windows.

Ubuntu version: Ubuntu 22.04.2 LTS
Firefox version: firefox 111.0-2 from snap

Thank you very much for looking into this.

** Affects: firefox (Ubuntu)
     Importance: Undecided
         Status: New

** Tags: html rendering

** Attachment added: "test.html"
   https://bugs.launchpad.net/bugs/2012430/+attachment/5656390/+files/test.html

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Title:
  <html lang="..."> attribute breaks dashes

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