Bug 1569943 - upgrading font version in a desktop session can affect rendering of text
Summary: upgrading font version in a desktop session can affect rendering of text
Keywords:
Status: ASSIGNED
Alias: None
Product: Fedora
Classification: Fedora
Component: firefox
Version: rawhide
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: ---
Assignee: Gecko Maintainer
QA Contact: Fedora Extras Quality Assurance
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2018-04-20 10:53 UTC by Jens Petersen
Modified: 2019-09-10 07:04 UTC (History)
16 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Type: Bug
Embargoed:


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System ID Private Priority Status Summary Last Updated
Mozilla Foundation 1580099 0 P3 UNCONFIRMED updating Linux system fonts causes text rendering corruption 2020-01-12 11:27:57 UTC

Description Jens Petersen 2018-04-20 10:53:11 UTC
Description of problem:
The Liberation 1 and 2 fonts may be binary incompatible
in the sense that upgrading a live desktop from Liberation 1 to 2
seemed to corrupt some characters for me in Firefox (with Ariel text in
Google Docs for the default unordered list mark symbols).

Version-Release number of selected component (if applicable):
liberation-fonts-2.00.1

Actual results:
'·' -> '>'
'⃝' -> '<'
for example

Expected results:
Not change of glyphs.

Additional info:
I suspect this might be due to caching of the old font's tables in memory.
It would be better if the tables were more compatible I suppose.

Comment 1 Jens Petersen 2018-04-23 08:42:40 UTC
This might be a issue with Firefox's fonts handling.

Comment 2 Nicolas Mailhot 2018-04-26 09:45:16 UTC
Yes, that's not specific to liberation at all, that's old and well-known broken fontconfig/harfbuzz integration in Firefox, it does not properly invalidate its font cache when fonts are updated. You have to close it to force it to parse the new font file metadata otherwise it seems to try reading glyphs as their location in the old font file even though the new font file has them moved somewhere else (with metadata that correctly indicates where this somewhere else is).

The bug should be reassigned

Comment 3 Pravin Satpute 2018-04-26 14:22:14 UTC
Thanks Nicolas for confirming. Being a font developer i often face this issue, specifically when FF is running and i update the font. For sometime all rendering gets broken

Comment 4 Jens Petersen 2018-07-17 08:33:57 UTC
I wonder if it could not be FreeType?

Comment 5 Akira TAGOH 2018-07-17 12:24:35 UTC
This isn't an issue in fontconfig even. this would rather be an application issue or rendering library where deal with file handles of fonts. fontconfig provides an API to let them know if fonts are being updated. they have a way to know that (but there are no way to know which one was updated...)
If they don't reopen a font when updating, the behavior may depends how they open it. that is likely to see such issue anyway.

Comment 6 Jan Kurik 2018-08-14 10:05:57 UTC
This bug appears to have been reported against 'rawhide' during the Fedora 29 development cycle.
Changing version to '29'.

Comment 7 Jens Petersen 2019-09-10 07:04:32 UTC
I reported this upstream in https://bugzilla.mozilla.org/show_bug.cgi?id=1580099


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