feat(webidl): add support for namespace attributes#4930
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Previously, namespace attributes in WebIDL were ignored by the binding generator. This change adds support for namespace attributes, generating proper getter bindings for them. Per the WebIDL spec, namespace attributes are always readonly, so only getter bindings are generated. The implementation uses static_method_of with a generated namespace type binding (e.g., JsNamespaceCSS) to enable proper property access on the namespace object. This enables APIs like the CSS Custom Highlight API which adds the `highlights` attribute to the `CSS` namespace. Includes an end-to-end test with a PI attribute on the math_test namespace. Fixes wasm-bindgen#4865
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logan-gatlin
approved these changes
Feb 5, 2026
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Summary
This PR adds support for WebIDL namespace attributes in
wasm-bindgen-webidl, which were previously ignored by the binding generator.AttributeNamespaceDatastruct and handling infirst_pass.rsNamespaceAttributeandNamespaceAttributeKindingenerator.rsNamespacestruct and code generation to include attributesappend_ns_attribute()method inlib.rs[Throws])Generated Output
For a WebIDL like:
namespace CSS { readonly attribute HighlightRegistry highlights; };The generated Rust code is:
Per the WebIDL spec, namespace attributes are always readonly, so only getter bindings are generated.
Fixes #4865