Webkit doesn't automatically right-align Adlam

[r12a]

Adlam text displayed in a block element with dir set to auto should be automatically right-aligned, unless the base direction is set to LTR, like this:

The GAP

In WebKit the text appears as follows:

This is a serious issue, and indicates that first-strong heuristics are not being applied. Note that this was not an issue for N'Ko, Arabic, Hebrew, Thaana, or Syriac text.

Tests & results

Interactive test, Text in languages that use RTL scripts will be automatically aligned with the right side of their container when dir is set to auto

• Gecko: ✅ Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:96.0) Gecko/20100101 Firefox/96.0
• Blink: ✅ Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/97.0.4692.71 Safari/537.36
• Webkit: ✅ Adlam used to be broken, but is now fixed (see the bug report). Browser: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/605.1.15 (KHTML, like Gecko) Version/15.2 Safari/605.1.15

Action taken

Webkit

Outcomes

This was fixed in WebKit, so it now works as expected for all 3 major browser engines.

Priority

Priority initially set to basic because this was a serious issue for Adlam users, but now set to OK.

[r12a]

The first comment in this issue contains text that will automatically appear in one or more gap-analysis documents as a subsection with the same title as this issue. Any edits made to that comment will be immediately available in the document. Proposals for changes or discussion of the content can be made in comments below this point.

Relevant gap analysis documents include:
Adlam

[xfq]

Browser bug raised: https://bugs.webkit.org/show_bug.cgi?id=220885