Bug 251657

Summary:	avoid creating ElementRareData when lang="" matches the effective document language
Product:	WebKit	Reporter:	Cameron McCormack (:heycam) <heycam>
Component:	DOM	Assignee:	Cameron McCormack (:heycam) <heycam>
Status:	RESOLVED FIXED
Severity:	Normal	CC:	commit-queue, darin, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified
Bug Depends on:	251932
Bug Blocks:

Description Cameron McCormack (:heycam) 2023-02-02 18:48:26 PST

On Wikipedia, there's a lang="" attribute on the <div> that contains the article content.  On the page I'm looking at, this lang="" matches the value on the document element.  Currently we'll create ElementRareData to store the effective language for the entire subtree, which for large articles can be several MB worth.  We can optimize this by detecting when the explicitly set lang="" matches the effective document language, and avoid the subtree traversal / restyle / ElementRareData creation.

Comment 1 Radar WebKit Bug Importer 2023-02-02 18:48:49 PST

<rdar://problem/104987630>

Comment 2 Cameron McCormack (:heycam) 2023-02-02 20:14:33 PST

Pull request: https://github.com/WebKit/WebKit/pull/9566

Comment 3 Cameron McCormack (:heycam) 2023-02-02 20:19:20 PST

Pull request: https://github.com/WebKit/WebKit/pull/9580

Comment 4 EWS 2023-02-06 19:16:33 PST

Committed 259931@main (8858f1de792a): <https://commits.webkit.org/259931@main>

Reviewed commits have been landed. Closing PR #9580 and removing active labels.

Comment 5 Darin Adler 2023-02-08 07:21:11 PST

Since this landed the !hasLanguageAttribute() assertion has been firing when running regression tests on bots:

https://ews-build.s3-us-west-2.amazonaws.com/macOS-AppleSilicon-Ventura-Debug-WK2-Tests-EWS/72c673b1-6062/css3/masking/mask-svg-no-fragmentId-tiled-crash-log.txt

https://ews-build.s3-us-west-2.amazonaws.com/macOS-AppleSilicon-Ventura-Debug-WK2-Tests-EWS/72c673b1-6062/fast/css/large-font-size-crash-crash-log.txt

https://ews-build.s3-us-west-2.amazonaws.com/macOS-AppleSilicon-Ventura-Debug-WK2-Tests-EWS/72c673b1-6062/imported/w3c/web-platform-tests/css/css-pseudo/first-letter-with-span-crash-log.txt

https://ews-build.s3-us-west-2.amazonaws.com/macOS-AppleSilicon-Ventura-Debug-WK2-Tests-EWS/72c673b1-6062/imported/w3c/web-platform-tests/css/selectors/invalidation/lang-pseudo-class-in-has-xhtml-crash-log.txt

Comment 6 WebKit Commit Bot 2023-02-08 10:06:21 PST

Re-opened since this is blocked by bug 251932

Comment 7 Ryan Haddad 2023-02-08 10:12:39 PST

Reverted in https://commits.webkit.org/260019@main due to the assertion failures.

Comment 8 Cameron McCormack (:heycam) 2023-02-08 12:07:07 PST

*** Bug 251904 has been marked as a duplicate of this bug. ***

Comment 9 Cameron McCormack (:heycam) 2023-02-08 12:55:27 PST

Pull request: https://github.com/WebKit/WebKit/pull/9833

Comment 10 EWS 2023-02-08 21:11:43 PST

Committed 260047@main (f31c6cd34376): <https://commits.webkit.org/260047@main>

Reviewed commits have been landed. Closing PR #9833 and removing active labels.