fix(web): dynamic() honors xmlns when creating a tag-name element (#3386)

[ryansolid]

Closes #3386 (part 2; part 1 landed in #3396).

Problem

The compiler resolves a tag's namespace from its parent at build time. The dynamic() runtime path creates the element before it has a parent, so it can only infer from the tag name — and a tag that exists in both HTML and SVG (a, script, style, title) was always created as HTML. <svg><Link href=…/></svg> with Link = dynamic(() => "a") produced an HTML anchor inside the SVG tree. @yak/solid carries an ambiguousSvgTags set to route around this.

Fix

The instance says which namespace it means with the attribute compiled JSX already uses for exactly this purpose:

const Link = dynamic(() => "a");
<svg><Link xmlns="http://www.w3.org/2000/svg" href="/x">…</Link></svg>

xmlns joins is as an attribute of the element that also decides how the node is created: read once, untracked, at creation (the DOM can't re-namespace a node), then applied through spread() as an ordinary attribute. That keeps a client-rendered element byte-for-byte the same as its own SSR output: the server already serializes xmlns (as compiled SSR does for <a xmlns>), the parser keeps it, and hydration claims the parser-namespaced node — so the server is untouched and hydration was never affected. Without xmlns inference from the tag name still applies.

Deliberately not inferring from the mount parent: there is no parent at creation time, and any deferred scheme (create-then-reparent, a context) would tax every dynamic() instance to fix four tags.

Types

dynamic() returns Component<DynamicComponentProps<T>>, which adds xmlns?: string for tag-name targets only. (The ambiguous tags' IntrinsicElements types are the HTML attribute sets, which don't include xmlns; SVG/MathML attribute sets already do.)

Tests

• test/dynamic-namespace.spec.tsx: namespaceURI with/without xmlns inside <svg> and <math>; unambiguous tags still inferred; xmlns overrides inference in both directions; <Dynamic> parity; read-once (a later value updates the attribute, never recreates the node).
• test/server/dynamic-xmlns.spec.tsx: server output equals compiled <a xmlns> output.
• Parity-harness scenario dynamic-xmlns-svg-link: SSR → hydrate a dynamic() <a xmlns> inside <svg>, adopt-all, stable identity through an update.
• Also pins ref arrays through a spread into a dynamic() tag — the shape Kobalte's solid2 branch works around with a TODO at rc.3 — as working on next.

All three @solidjs/web suites green (778 / 895 / 181).

[changeset-bot]

🦋 Changeset detected

Latest commit: 919b2ab

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 11 packages

Name	Type
@solidjs/web	Patch
@solidjs/h	Patch
@solidjs/babel-plugin	Patch
@solidjs/element	Patch
@solidjs/html	Patch
test-integration	Patch
@solidjs/compiler	Patch
@solidjs/diagnostics	Patch
@solidjs/signals	Patch
solid-js	Patch
@solidjs/universal	Patch

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[codspeed]

Merging this PR will not alter performance

✅ 160 untouched benchmarks

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_{Comparing fix/dynamic-xmlns (919b2ab) with next (efcaeba)}

[coveralls]

Coverage Report for CI Build 34901829164

Coverage remained the same at 71.842%

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• Coverage remained the same as the base build.
• Patch coverage: No coverable lines changed in this PR.
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Relevant Lines:	1007
Covered Lines:	772
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💛 - Coveralls

[ryansolid]

Narrowed the xmlns typing in 919b2ab. The previous commit put it on ElementAttributes, which made every HTML tag accept it; it now lives on SVGAttributes/MathMLAttributes (as before) plus a small AmbiguousNamespaceAttributes mixin on the four tags that exist in both HTML and SVG — AnchorHTMLAttributes, ScriptHTMLAttributes, StyleHTMLAttributes, and a new TitleHTMLAttributes (title was previously bare HTMLAttributes). Those are the only tags where the attribute changes what gets created, in both the compiler and dynamic(); <div xmlns> is rejected again.

Verified locally: @solidjs/web test-types clean, @solidjs/h types build, both xmlns specs pass. Changeset wording updated to match.

— Claude via Cursor