1658098 - Intermittent - Firefox fails to render spacing between words

Status: UNCONFIRMED

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

Description

[Daniel Morante]

Attachment: Screenshot_2020-08-08 firefox no spaces - Google Search.png

User Agent: Mozilla/5.0 (Windows NT 6.1; Win64; x64; rv:79.0) Gecko/20100101 Firefox/79.0

Steps to reproduce:

Update to Firefox 79

Actual results:

Websites sometimes fail to render spacing between words. (See screenshots).
Occurs intermittently from one moment to another, then resolves itself without any action.

Expected results:

Words should have spaces.

Comment 1

[Daniel Morante]

Attachment: Screenshot_2020-08-08 Wikipedia, the free encyclopedia.png

Comment 2

[Daniel Morante]

Attachment: Screenshot_2020-08-08 firefox no spaces - Google Search (with spaces).png

Same screen capture of Google after closing tab and reopening a few minutes later.

Comment 3

[Daniel Morante]

Attachment: Screenshot_2020-08-08 Wikipedia, the free encyclopedia(with spaces).png

Same screen capture of Wikipedia after closing tab and reopening a few minutes later.

Comment 4

[Alice0775 White]

Can you attach the contents of your about:support as a text file?

Comment 5

[Daniel Morante]

Attachment: firefox-79-about.support-2020-08-08-05-14.txt

Comment 6

[Daniel Holbert [:dholbert]]

Thanks! Could you let us know what version of Microsoft Windows you are running?

(Your about:support says OS: Windows_NT 6.1 7601 which according to https://en.wikipedia.org/wiki/List_of_Microsoft_Windows_versions would be some sort of Windows Server 2008 or 2010 or 2011, I think. It would be useful to know specifically which release you've got.)

(jfkthame: I wonder if this is perhaps an in-the-wild instance of bug 1392106 or something like it, where the missing character is the space character in this case.)

Comment 7

[Daniel Holbert [:dholbert]]

Oh actually -- reading further down that List_of_Microsoft_Windows_versions page, it looks like Windows_NT 6.1 7601 could also map to Windows 7 SP1.

That seems more likely to be what you're running. :) And that does make this feel suspiciously related to bug 1392106 and bug 1499459.

Comment 8

[Jonathan Kew [:jfkthame]]

Yes, this feels a lot like some version of bug 1392106, where a call to a DirectWrite API is intermittently failing.

Did this recently start happening on a system that previously was working reliably?

Comment 9

[Daniel Morante]

Yes to both your questions. This is a Windows 7 system and it has been running Firefox releases for several years up to this point.