1830527 - Tofu boxes are shown for some of the Brahmic group languages if font visibility is set to 1 or 2

Status: RESOLVED INVALID

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

Description

[Ciprian Georgiu, Desktop QA]

Found in

• Nighty 114.0a1

Affected versions

• Nightly 114.0a1

Tested platforms

• Affected platforms: macOS 13 and Ubuntu 20.04 x64, Windows 11 x64

Preconditions

• In about:config, set the preference "layout.css.font-visibility.private" to 1.

Steps to reproduce

1. Open a private window.
2. Navigate to Wikipedia and look for the following Brahmic languages: balinese, buhid, hanunoo, javanese, modi, new tai lue, sudanese, tagalog, tai le, bengali, kannada, Phags-pa, tamil supplement.

• you can use this spreadsheet (look at the affected websites from the Brahmic section) to find some sites where the issue can be reproduced

3. Observe the fonts.

Expected result

• The fonts should be properly displayed in Private Browsing.

Actual result

• During private browsing, the following languages are displaying tofu boxes:

Regression range

• This is not a regression.

Additional notes

• The tofu boxes are also displayed in private browsing when the preference "layout.css.font-visibility.private" is set to 2.
• The tofu boxes are not displayed in normal browsing or when "layout.css.font-visibility.private" is set to 3.

Comment 1

[Simona Badau, Desktop QA]

Tested on the latest Nightly 16.0a1 and the tofu boxes are no longer seen on macOS 13 and macOS 11.7.

The tofu boxes continue to be displayed in private browsing mode, whereas they are not present in normal browsing mode on Ubuntu 22.04 and Windows 11 for the specified fonts:
Ubuntu 22.04: balinese, buhid, javanese, modi, new tai lue, Sudanese, tagalog, tagbawna, Phags-pa, tamil supplement.
Windows 11: balinese, buhid, hanunoo, Sudanese, tagbawna

Comment 2

[Tom Ritter [:tjr] (OOTO until April)]

Tested with Balinese on Ubuntu 22.04 - so AFAICT this page is not specifying a font (except for 7 arabic characters), which for me makes it use DejaVu Sans. There's lots of Tofu none of it (at least the many spot-checks) specify a font.

Deja-Vu doesn't have these characters, so they're Tofu. I'm confused about why they would ever render for you. Can I ask another debugging question?

Could you test this again (Balinese on Ubuntu 22.04) and specify

1. If it still happens
2. Which table/row/column is an example of something that exhibits the behavior (works in normal, tofu in PBM)
3. Use Devtools Inspect on that character, and then go to the 'Fonts' section (it's the far right pane, under an arrow) and say what Font is Used to render it?
4. Confirm that this font is chosen by the browser and not the page by using the 'Computed' tab (same far right pane) and saying what is present (if anything) for font-family?

Comment 3

[Simona Badau, Desktop QA]

Attachment: Comparison with pref set to 1 vs 2.png

(In reply to Tom Ritter [:tjr] from comment #2)

Could you test this again (Balinese on Ubuntu 22.04) and specify

1. If it still happens

It happens when the preference layout.css.font-visibility.private is set to 1. Not happening when the preference is set to 2.

2. Which table/row/column is an example of something that exhibits the behavior (works in normal, tofu in PBM)

Please see the attached screenshot. Made a comparison screenshot with the behavior when the preference font-visibility-private is set to 1 vs 2.

3. Use Devtools Inspect on that character, and then go to the 'Fonts' section (it's the far right pane, under an arrow) and say what Font is Used to render it?

Tested with the pref layout.css.font-visibility.private set to 1 and these are the results:

• in normal browsing - Noto Serif Balinese
• in private browsing - DejaVu Sans

4. Confirm that this font is chosen by the browser and not the page by using the 'Computed' tab (same far right pane) and saying what is present (if anything) for font-family?

font-family: sans-serif

Comment 4

[Tom Ritter [:tjr] (OOTO until April)]

Okay, looking closer I can make an educated guess that the situation is the same for the following and rule out issues with

• Balinese
• Buhid
• Modi
• Sundanese
• Tagalog
• Tagbanwa
• Phags-pa
• Tamil

But the following confuse me:

• Javanese
• New Tai Lue

Can you confirm that for New Tai Lue - the characters that don't render with visibility=2 and don't render with visibility=1 are the ones in the New Tai Lue table? And not any others?

And Javanese has a lot of tables and the CSS is weird - could you also confirm that the difference only happens with visibility=1 and visibility=2 it shows normal?

Comment 5

[Tom Ritter [:tjr] (OOTO until April)]

Actually, the initial bug report says visibility=1 so I think it's safe to say working as intended even if I haven't identified the exact font.

Comment 6

[Simona Badau, Desktop QA]

(In reply to Tom Ritter [:tjr] from comment #4)

Can you confirm that for New Tai Lue - the characters that don't render with visibility=2 and don't render with visibility=1 are the ones in the New Tai Lue table? And not any others?

And Javanese has a lot of tables and the CSS is weird - could you also confirm that the difference only happens with visibility=1 and visibility=2 it shows normal?

I confirm that the characters for both New Tai Lue and Javanese are shown when visibility=2 and not shown (tofu boxes are displayed instead) only when visibility=1.