1819025 - Zero-width joiners should not affect CSS white-space processing (collapsing/trimmng of space)

Status: RESOLVED FIXED

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

Description

[Jonathan Kew [:jfkthame]]

Spun off from bug 1817862 comment 3:

The presence of ZWJ (or ZWNJ) at the beginning or end of a word (e.g. as sometimes used to force joining forms of Arabic letters) should not have any effect on the CSS white-space processing of the surrounding spaces.

Testcase: https://codepen.io/jfkthame/pen/XWPNVPP

Here, the lines with 200c and 200d (ZWNJ and ZWJ) incorrectly show a leading space; and the first paragraph (with width:min-content) shows an unwanted leading space, a double space between "is" and "a", and excessive width of the frame.

Comment 1

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1819025 - Don't consider following join-controls when determining whether a space is collapsible. r=#layout-reviewers

Comment 2

[Jonathan Kew [:jfkthame]]

Attachment: Bug 1819025 - Add a couple of WPT reftests for joiners vs white-space processing. r=#layout-reviewers

These both fail with current mozilla-central, but pass once the patch here is applied.
They pass as expected in Safari.
Test 001 also passes in Chrome; 002 fails because of an apparent min-width calculation error
resulting in different wrapping.

Depends on D171061

Comment 3

[Pulsebot]

Pushed by [e-mail]:
https://hg.mozilla.org/integration/autoland/rev/fad4426b7b0b
Don't consider following join-controls when determining whether a space is collapsible. r=emilio
https://hg.mozilla.org/integration/autoland/rev/655b861eeef0
Add a couple of WPT reftests for joiners vs white-space processing. r=emilio

Comment 4

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Created web-platform-tests PR https://github.com/web-platform-tests/wpt/pull/38736 for changes under testing/web-platform/tests

Comment 5

[Marian-Vasile Laza]

https://hg.mozilla.org/mozilla-central/rev/fad4426b7b0b
https://hg.mozilla.org/mozilla-central/rev/655b861eeef0

Comment 6

[Web Platform Test Sync Bot [:wpt-sync] (Matrix: #interop:mozilla.org)]

Upstream PR merged by moz-wptsync-bot