#510989 upgrading ttf fonts make text in some programs unreadable

Package:
iceweasel
Source:
firefox-esr
Submitter:
Євгеній Мещеряков
Date:
2011-11-04 21:00:08 UTC
Severity:
normal
#510989#5
Date:
2009-01-06 14:07:11 UTC
From:
To:
After upgrading ttf-dejavu cyrillic text in iceweasel bacame unreadable (letters are still
Cyrillic, and readable, but words look like made with random password generator), that
was fixed after restarting iceweasel.

It can be bacause:
  1. Font was open by Iceweasel and during upgrade it was overwritten in-place
     (instead of creating temporary file and then moving it, iceweasel could use
     deleted file with old contents)
  2. Information about glyph offsets/numbers is cached somewhere (Iceweasel, freetype...),
     and is not updated after font upgrade. And then new file was opened and cached
     information was used to get glyphs from it.
  3. Fontconfig caches were overwritten in-place during upgrade.
  4. Iceweasel keeps font files open, but reads fontconfig caches time-to-time.

lsof shows that iceweasel keeps ttf files open, and I think dpkg does not overwrite files
in-place, so this is probably case 3. But I dont have time now to ivestigate further.

This bug probably not specific to ttf-dejavu/iceweasel/Cyrillic glyphs, and probably
can be reproduced with fonts that change significantly during upgrade.
#510989#10
Date:
2009-01-06 15:19:09 UTC
From:
To:
 It is seen with ttf-vlgothic and iceweasel, too.
 I saw that with only iceweasel, so it seems that is iceweasel
 (or gecko-based browser) issue.
#510989#15
Date:
2011-11-04 20:56:32 UTC
From:
To:
reassign 510989 iceweasel
thanks

This bug's history clearly shows that the bug certainly doesn't lie in
ttf-dejavu. Reassigning to iceweasel, though I'm not sure that it's at
fault directly.