REGRESSION(253764@main): Disconnecting a subtree makes :lang pseudo class to never match

[rniwa]

06479a2

REGRESSION(253764@main): Disconnecting a subtree makes :lang pseudo class to never match
https://bugs.webkit.org/show_bug.cgi?id=244484

Reviewed by Antti Koivisto.

The bug was caused by removedFromAncestor always clearing the effective lang in ElementRareData
when the element itself doesn't have a lang content attribute specified. This is wrong; We need
to keep the effective lang when an ancestor of "this" element still has a lang content attribute.

This patch also fixes a bug in insertedIntoAncestor that the code to inherit the effective lang
from a parent node was not running when the subtree is not inside a document or a shadow root.
To this end, insertedIntoAncestor has been refactored to match the structure of removedFromAncestor.

Finally, this patch also removes the code in insertedIntoAncestor which was trying to clear
the effective lang when "this" element doesn't have a lang attribute. This is also clearly wrong
as any ancestor with a valid lang attribute should continue to apply the same effective lang.

* LayoutTests/fast/css/lang-pseudo-disconnected-expected.txt: Added.
* LayoutTests/fast/css/lang-pseudo-disconnected.html: Added.
* Source/WebCore/dom/Element.cpp:
(WebCore::Element::insertedIntoAncestor):
(WebCore::Element::removedFromAncestor):

Canonical link: https://commits.webkit.org/253915@main

225e389

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🛠 mac-AS-debug	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 api-mac	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk1
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2
	✅ 🛠 watch	✅ 🧪 mac-AS-debug-wk2
✅ 🛠 🧪 unsafe-merge	✅ 🛠 watch-sim	✅ 🧪 mac-wk2-stress

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 9892b9a)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	⏳ 🛠 mac-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	🧪 ios-wk2	✅ 🛠 mac-AS-debug	🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 api-mac	✅ 🧪 api-gtk
⏳ 🛠 🧪 jsc	✅ 🛠 tv	✅ 🧪 mac-wk1	⏳ 🛠 jsc-armv7
	✅ 🛠 tv-sim	🧪 mac-wk2	⏳ 🧪 jsc-armv7-tests
	✅ 🛠 watch	✅ 🧪 mac-AS-debug-wk2
	✅ 🛠 watch-sim	✅ 🧪 mac-wk2-stress

[webkit-early-warning-system]

EWS run on previous version of this PR (hash 4121e71)

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	⏳ 🛠 mac	⏳ 🛠 wpe	🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	⏳ 🛠 mac-debug	✅ 🛠 gtk	⏳ 🛠 wincairo
✅ 🧪 webkitperl	🧪 ios-wk2	⏳ 🛠 mac-AS-debug	🧪 gtk-wk2
	⏳ 🧪 api-ios	⏳ 🧪 api-mac	🧪 api-gtk
⏳ 🛠 🧪 jsc	⏳ 🛠 tv	⏳ 🧪 mac-wk1	⏳ 🛠 jsc-armv7
⏳ 🧪 services	⏳ 🛠 tv-sim	⏳ 🧪 mac-wk2	⏳ 🧪 jsc-armv7-tests
	⏳ 🛠 watch	⏳ 🧪 mac-AS-debug-wk2
	⏳ 🛠 watch-sim	⏳ 🧪 mac-wk2-stress

[webkit-early-warning-system]

225e389

Misc	iOS, tvOS & watchOS	macOS	Linux	Windows
✅ 🧪 style	✅ 🛠 ios	✅ 🛠 mac	✅ 🛠 wpe	✅ 🛠 🧪 win
✅ 🧪 bindings	✅ 🛠 ios-sim	✅ 🛠 mac-debug	✅ 🛠 gtk	✅ 🛠 wincairo
✅ 🧪 webkitperl	✅ 🧪 ios-wk2	✅ 🛠 mac-AS-debug	✅ 🧪 gtk-wk2
	✅ 🧪 api-ios	✅ 🧪 api-mac	✅ 🧪 api-gtk
	✅ 🛠 tv	✅ 🧪 mac-wk1
	✅ 🛠 tv-sim	✅ 🧪 mac-wk2
	✅ 🛠 watch	✅ 🧪 mac-AS-debug-wk2
✅ 🛠 🧪 unsafe-merge	✅ 🛠 watch-sim	✅ 🧪 mac-wk2-stress

[webkit-commit-queue]

Committed 253915@main (06479a2): https://commits.webkit.org/253915@main

Reviewed commits have been landed. Closing PR #3764 and removing active labels.