Reconstruct active formatting elements when <math> or <svg> start#724
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simonwuelker merged 1 commit intoservo:mainfrom Jan 25, 2026
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As per 13.2.6.4.7 The "in body" insertion mode: A start tag whose tag name is "math" [Reconstruct the active formatting elements](https://html.spec.whatwg.org/multipage/parsing.html#reconstruct-the-active-formatting-elements), if any. [Adjust MathML attributes](https://html.spec.whatwg.org/multipage/parsing.html#adjust-mathml-attributes) for the token. (This fixes the case of MathML attributes that are not all lowercase.) [Adjust foreign attributes](https://html.spec.whatwg.org/multipage/parsing.html#adjust-foreign-attributes) for the token. (This fixes the use of namespaced attributes, in particular XLink.) [Insert a foreign element](https://html.spec.whatwg.org/multipage/parsing.html#insert-a-foreign-element) for the token, with [MathML namespace](https://infra.spec.whatwg.org/#mathml-namespace) and false. If the token has its *[self-closing flag](https://html.spec.whatwg.org/multipage/parsing.html#self-closing-flag)* set, pop the [current node](https://html.spec.whatwg.org/multipage/parsing.html#current-node) off the [stack of open elements](https://html.spec.whatwg.org/multipage/parsing.html#stack-of-open-elements) and [acknowledge the token's *self-closing flag*](https://html.spec.whatwg.org/multipage/parsing.html#acknowledge-self-closing-flag). A start tag whose tag name is "svg" [Reconstruct the active formatting elements](https://html.spec.whatwg.org/multipage/parsing.html#reconstruct-the-active-formatting-elements), if any. [Adjust SVG attributes](https://html.spec.whatwg.org/multipage/parsing.html#adjust-svg-attributes) for the token. (This fixes the case of SVG attributes that are not all lowercase.) [Adjust foreign attributes](https://html.spec.whatwg.org/multipage/parsing.html#adjust-foreign-attributes) for the token. (This fixes the use of namespaced attributes, in particular XLink in SVG.) [Insert a foreign element](https://html.spec.whatwg.org/multipage/parsing.html#insert-a-foreign-element) for the token, with [SVG namespace](https://infra.spec.whatwg.org/#svg-namespace) and false. If the token has its *[self-closing flag](https://html.spec.whatwg.org/multipage/parsing.html#self-closing-flag)* set, pop the [current node](https://html.spec.whatwg.org/multipage/parsing.html#current-node) off the [stack of open elements](https://html.spec.whatwg.org/multipage/parsing.html#stack-of-open-elements) and [acknowledge the token's *self-closing flag*](https://html.spec.whatwg.org/multipage/parsing.html#acknowledge-self-closing-flag).
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There might be more coming, let me know if you're interested in them or not!
We absolutely are, thank you!
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Resolves #27 - the vendored html5ever has been replaced with a git dependency on servo/html5ever main branch. Key changes: - Remove vendor/html5ever directory entirely - Update Cargo.toml to use git deps for html5ever, markup5ever, tendril - Fix test that incorrectly expected body to NOT receive attributes from stray <body> tags (the spec says to merge them, and browsers do too) The upstream html5ever now includes the math/svg active formatting elements reconstruction fix (servo/html5ever#724), which makes it match browser behavior for cases like <li><u><li><svg>. Investigation notes: - The original patch to avoid merging body attrs was incorrect - HTML5 spec section 13.2.6.4.7 explicitly says to add missing attrs - Browser fuzzing confirmed Chrome adds attrs from stray body tags - The vendored html5ever had no other hotmeal-specific patches needed
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As per 13.2.6.4.7 The "in body" insertion mode.
Found via fuzzing in https://github.com/bearcove/hotmeal (one of the fuzz targets compare DOM trees as parsed by Blink and html5ever).
There might be more coming, let me know if you're interested in them or not!