Make language of a node consider lang attribute on SVG elements. #9882

dbaron · 2023-10-25T14:27:52Z

The rules for finding the language of a node were made somewhat more formal in 11dc4c7 (PR #9796, fixing #3699). Both before and after that change they considered the lang attribute in the XML namespace, and the lang attribute in no namespace on HTML elements. However, the SVG spec at https://www.w3.org/TR/2018/CR-SVG2-20181004/struct.html#LangSpaceAttrs has very similar wording to the HTML spec prior to that edit, and also defined a lang attribute on SVG elements.

This updates the language of a node algorithm in HTML to consider SVG elements as well, since implementing it as written (without this change) breaks the lang attribute in SVG.

At least two implementers are interested (and none opposed):
- Chromium
- Gecko (already implements)
Tests are written and can be reviewed and commented upon at:
- https://wpt.fyi/results/svg/text/reftests/lang-attribute.svg (failing on some engines, haven't investigated why)
- https://wpt.fyi/results/svg/text/reftests/lang-attribute-dynamic.svg (implementing the spec as currently written broke this test, which is what made me notice this issue!)
- Implement updated HTML language inheritance rules. web-platform-tests/wpt#42732
Implementation bugs are filed:
- Chromium: https://crbug.com/1490711 and https://crrev.com/c/4974775
- Gecko: already implements exactly this behavior (plus support in the XUL namespace), see nsIContent::GetLang and nsIContent::SupportsLangAttr
- WebKit: https://bugs.webkit.org/show_bug.cgi?id=263655
MDN issue is filed: probably https://developer.mozilla.org/en-US/docs/Web/HTML/Global_attributes/lang and https://developer.mozilla.org/en-US/docs/Web/SVG/Attribute/lang are sufficient and no issue needs to be filed
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The rules for finding the language of a node were made somewhat more formal in 11dc4c7 (PR whatwg#9796, fixing whatwg#3699). Both before and after that change they considered the lang attribute in the XML namespace, and the lang attribute in no namespace on HTML elements. However, the SVG spec at https://www.w3.org/TR/2018/CR-SVG2-20181004/struct.html#LangSpaceAttrs has very similar wording to the HTML spec prior to that edit, and also defined a lang attribute on SVG elements. This updates the language of a node algorithm in HTML to consider SVG elements as well, since implementing it as written (without this change) breaks the lang attribute in SVG.

This makes two changes to match the HTML spec: * only honor the unnamespaced lang attribute on HTML and SVG elements * have <slot> elements in a shadow tree inherit language from the shadow host Note that an update to the HTML specification regarding the SVG elements case is proposed in whatwg/html#9882, but https://www.w3.org/TR/SVG/struct.html#LangAttribute already defines it. These changes match the related changes to the dir attribute, but use a separate feature flag as a killswitch, since they are separable. Fixed: 1490711 Bug: 576815 Change-Id: I6462181e6d4433aa1dcc9a2c42e5c12754830e52

annevk · 2023-10-25T15:40:51Z

What about MathML?

cc @bkardell

dbaron · 2023-10-25T16:34:18Z

I did check https://www.w3.org/TR/MathML/chapter2.html#fund.globatt before posting this, and it explicitly says to use xml:lang.

(Also, Gecko's code explicitly allows the unnamespaced lang attribute for HTML, SVG, and XUL elements.)

annevk · 2023-10-25T17:22:25Z

Thanks, https://w3c.github.io/mathml-core/ doesn't seem to say anything about this either. Might be best to stick with xml:lang there then.

This makes two changes to match the HTML spec: * only honor the unnamespaced lang attribute on HTML and SVG elements * have <slot> elements in a shadow tree inherit language from the shadow host Note that an update to the HTML specification regarding the SVG elements case is proposed in whatwg/html#9882, but https://www.w3.org/TR/SVG/struct.html#LangAttribute already defines it. These changes match the related changes to the dir attribute, but use a separate feature flag as a killswitch, since they are separable. Fixed: 1490711 Bug: 576815 Change-Id: I6462181e6d4433aa1dcc9a2c42e5c12754830e52 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4974775 Commit-Queue: Di Zhang <dizhangg@chromium.org> Commit-Queue: David Baron <dbaron@chromium.org> Reviewed-by: Di Zhang <dizhangg@chromium.org> Cr-Commit-Position: refs/heads/main@{#1215017}

…nce rules., a=testonly Automatic update from web-platform-tests Implement updated HTML language inheritance rules. This makes two changes to match the HTML spec: * only honor the unnamespaced lang attribute on HTML and SVG elements * have <slot> elements in a shadow tree inherit language from the shadow host Note that an update to the HTML specification regarding the SVG elements case is proposed in whatwg/html#9882, but https://www.w3.org/TR/SVG/struct.html#LangAttribute already defines it. These changes match the related changes to the dir attribute, but use a separate feature flag as a killswitch, since they are separable. Fixed: 1490711 Bug: 576815 Change-Id: I6462181e6d4433aa1dcc9a2c42e5c12754830e52 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4974775 Commit-Queue: Di Zhang <dizhangg@chromium.org> Commit-Queue: David Baron <dbaron@chromium.org> Reviewed-by: Di Zhang <dizhangg@chromium.org> Cr-Commit-Position: refs/heads/main@{#1215017} -- wpt-commits: 6148c29da568184fae4184f739ecccaafd651af6 wpt-pr: 42732

…nce rules., a=testonly Automatic update from web-platform-tests Implement updated HTML language inheritance rules. This makes two changes to match the HTML spec: * only honor the unnamespaced lang attribute on HTML and SVG elements * have <slot> elements in a shadow tree inherit language from the shadow host Note that an update to the HTML specification regarding the SVG elements case is proposed in whatwg/html#9882, but https://www.w3.org/TR/SVG/struct.html#LangAttribute already defines it. These changes match the related changes to the dir attribute, but use a separate feature flag as a killswitch, since they are separable. Fixed: 1490711 Bug: 576815 Change-Id: I6462181e6d4433aa1dcc9a2c42e5c12754830e52 Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/4974775 Commit-Queue: Di Zhang <dizhanggchromium.org> Commit-Queue: David Baron <dbaronchromium.org> Reviewed-by: Di Zhang <dizhanggchromium.org> Cr-Commit-Position: refs/heads/main{#1215017} -- wpt-commits: 6148c29da568184fae4184f739ecccaafd651af6 wpt-pr: 42732 UltraBlame original commit: 6425b442dc96bbae14adf5799ce58ea64fcfd493

dbaron requested a review from annevk October 25, 2023 14:35

chromium-wpt-export-bot mentioned this pull request Oct 25, 2023

Implement updated HTML language inheritance rules. web-platform-tests/wpt#42732

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annevk approved these changes Oct 25, 2023

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Remove extra period while in the area

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domenic merged commit aec6260 into whatwg:main Oct 26, 2023
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Make language of a node consider lang attribute on SVG elements. #9882

Make language of a node consider lang attribute on SVG elements. #9882

dbaron commented Oct 25, 2023 •

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annevk commented Oct 25, 2023

dbaron commented Oct 25, 2023

annevk commented Oct 25, 2023

Make language of a node consider lang attribute on SVG elements. #9882

Make language of a node consider lang attribute on SVG elements. #9882

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