1850672 - Standard fonts list doesn't contain the localized name

Status: VERIFIED FIXED

(Core :: Privacy: Anti-Tracking, defect, P2)

Description

[6k64x4ma]

Attachment: test.html

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:109.0) Gecko/20100101 Firefox/118.0

Steps to reproduce:

1. Load the attached file in the private window on Windows.

Actual results:

• Serif font is used for second div because the localized name is not recognized by font visibility restrictions.

Expected results:

• The Latin name and the localized name should be treated equally.

Comment 1

[Tim Huang[:timhuang]]

Jonathan, is there a way for the font visibility check to match the localized font name with the font name in the list?

Comment 2

[Takanori MATSUURA]

This bug is seen by more users with the fix for bug 1846224.
For example, if a JA user with ETP set to Strict sets font.name.sans-serif.ja to "BIZ UDPゴシック" through about:preferences, which is the localized font name for the "BIZ UDPGothic" font, "BIZ UDPゴシック" will not match and will use Meiryo font which is set to font.name-list.sans-serif.en for fallback.

Comment 3

[Jonathan Kew [:jfkthame]]

(In reply to Tim Huang[:timhuang] from comment #1)

Jonathan, is there a way for the font visibility check to match the localized font name with the font name in the list?

Yeah, I think we should make it so that the same visibility level is used for all localized names of a font family. This looks reasonably straightforward to implement.

Comment 4

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1850672 - Standard platform font-visibility level should be applied to localized names of the family. r=#layout-reviewers

Comment 5

[Takanori MATSUURA]

[Tracking Requested - why for this release]:

• Significant visual regression occurs on web pages that use localized font names in the font-fmily CSS property.
• Significant visual regression occurs on web pages when localized font names and strict ETP are set at about:preference.

Comment 6

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/5befb31b3c12
Standard platform font-visibility level should be applied to localized names of the family. r=emilio

Comment 7

[Tom Schuster]

Doesn't this also affect 118? Bug 1849903 landed in that version.

Comment 8

[Tom Schuster]

[Tracking Requested - why for this release]:

Comment 9

[Cosmin Sabou [:CosminS]]

https://hg.mozilla.org/mozilla-central/rev/5befb31b3c12

Comment 10

[Jonathan Kew [:jfkthame]]

Comment on attachment 9353736 [details]
Bug 1850672 - Standard platform font-visibility level should be applied to localized names of the family. r=#layout-reviewers

Beta/Release Uplift Approval Request

• User impact if declined: Potential for wrong fonts used in private-browsing windows due to anti-fingerprinting setting - primarily affecting CJK content.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: No
• Needs manual test from QE?: Yes
• If yes, steps to reproduce: STR in comment 0
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Minor change during font-list initialization, to ensure all (localized) names of a font are classed as equivalent for lookup
• String changes made/needed:
• Is Android affected?: No

Comment 11

[BugBot [:suhaib / :marco/ :calixte]]

Set release status flags based on info from the regressing bug 1849903

Comment 12

[Dianna Smith [:diannaS]]

Comment on attachment 9353736 [details]
Bug 1850672 - Standard platform font-visibility level should be applied to localized names of the family. r=#layout-reviewers

Approved for 119.0b3

Comment 13

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-beta/rev/7c80e4b76539

Comment 14

[Giorgia Nichita, Release Desktop QA]

Reproduced this issue on an affected Nightly build from 2023-08-30, on Win 10.
Verified as fixed on latest nightly 120.0a1 (20230928215127) and Firefox 119.0b3 (treeherder build 20230927183607) on Win 10, Ubuntu 20.04 and macOS 10.15.

Comment 15

[Pascal Chevrel:pascalc]

Jonathan, is this a good candidate for uplifting in our planned dot release? Thanks

Comment 16

[Jonathan Kew [:jfkthame]]

I don't have a strong opinion one way or the other. On the one hand, I believe the patch has minimal risk, and it will improve the experience for affected users/sites; but on the other hand the "breakage" is cosmetic (wrong/less-desirable font being used) rather than drastic (content unusable).

I guess Japanese & Chinese users might appreciate it being uplifted; they're probably the main communities affected (though by no means all users, as it's only relevant when anti-fingerprinting settings are made stricter, as in private browsing).

Comment 17

[Jonathan Kew [:jfkthame]]

Comment on attachment 9353736 [details]
Bug 1850672 - Standard platform font-visibility level should be applied to localized names of the family. r=#layout-reviewers

Beta/Release Uplift Approval Request

• User impact if declined: Some users (especially CJK) may get wrong/undesired fonts when strict anti-fingerprinting is in force.
• Is this code covered by automated tests?: Yes
• Has the fix been verified in Nightly?: Yes
• Needs manual test from QE?: No
• If yes, steps to reproduce:
• List of other uplifts needed: None
• Risk to taking this patch: Low
• Why is the change risky/not risky? (and alternatives if risky): Patch just changes visibility annotations on localized font names; otherwise, no functional changes.
• String changes made/needed:
• Is Android affected?: No

Comment 19

[Pascal Chevrel:pascalc]

Comment on attachment 9353736 [details]
Bug 1850672 - Standard platform font-visibility level should be applied to localized names of the family. r=#layout-reviewers

Approved for our next 118 dot release, thanks.

Comment 20

[Pulsebot]

https://hg.mozilla.org/releases/mozilla-release/rev/ddc5b92516d4

Comment 21

[Pascal Chevrel:pascalc]

https://hg.mozilla.org/releases/mozilla-release/rev/ddc5b92516d4

Comment 22

[Giorgia Nichita, Release Desktop QA]

Verified as fixed on Firefox 118.0.2 (20231009140911) on Windows 10, Ubuntu 20.04 and macOS 10.15.