2076607 - font.name-list.emoji=Noto Color Emoji ignores 18.0 emojis unless explicitly declared in the CSS

Status: UNCONFIRMED

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

Description

[ulomalopn63]

Attachment: Visual example of what I'm trying to say.

User Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:157.0) Gecko/20100101 Firefox/157.0

Steps to reproduce

1. Downloaded the latest version of Noto Color Emoji from GitHub and installed it
2. I set font.name-list.emoji to Noto Color Emoji, Segoe UI Emoji, Twemoji Mozilla
3. Added some emojis in about:blank for testing: <div style="font-size:64px;font-family:Noto Color Emoji;">🫪 🫫</div>

Actual results

Cracking Face emoji (🫫) didn't appear by default among the rest of the 18.0 emojis, I had to set font-family to Noto Color Emoji explicitly.

Expected results

18.0 emojis should appear by default without explicitly set the font name via CSS.

Comment 1

[Jonathan Kew [:jfkthame]]

I suspect the reason is that we don't yet have support for the new Unicode 18 codepoints -- e.g. we don't know which codepoints have the Emoji property, so don't apply emoji-specific font selection behavior to them.

Checking the ICU-TC Home Page, it looks like there isn't a new release for Unicode 18 yet. When one becomes available and is vendored into Firefox, we should check whether that resolves this issue.

Comment 2

[Jonathan Kew [:jfkthame]]

Marking as S3 for now (though it may be that when bug 2078280 is resolved, it will simply solve this).