fix: don't apply scoped CSS class to elements inside <svelte:head>

[sliang-code]

Problem

When a Svelte component contains both a svelte:head block and a <style> block, the compiler incorrectly injects a scoped CSS hash class (e.g. class="s-xxxx") onto elements inside svelte:head such as , , and <script>.
These elements are not styleable and should never receive a class attribute. This bloats the HTML and produces invalid/unexpected markup.

Example:

<svelte:head>
  <meta name="author" content="Re:Designed" />
  <link rel="author" href="https://example.com" />
</svelte:head>

<div class="credits">Hello</div>

<style>
  .credits { color: red; }
</style>

Before this fix, the rendered HTML would contain:

<meta name="author" content="Re:Designed" class="s-Oo-daCANuhh7">
<link rel="author" href="https://example.com" class="s-Oo-daCANuhh7">

Root Cause

In 2-analyze/index.js, all elements in analysis.elements were being marked as scoped = true regardless of whether they lived inside svelte:head. In 2-analyze/css/css-prune.js, CSS selectors were being matched against head elements for the same reason.

Fix

Two changes:

In analyze_component (2-analyze/index.js): before processing scoped elements, skip any element whose ancestor path includes a SvelteHead node by setting node.metadata.scoped = false.
In apply_selector (2-analyze/css/css-prune.js): early-return false for any element inside <svelte:head>, preventing CSS selector matching against head elements entirely.

Both changes use a shared helper is_inside_svelte_head() that walks node.metadata.path.

Tests Added

tests/runtime-browser/samples/head-elements-not-scoped/ — verifies that <meta>, <link>, and <script> inside <svelte:head> have no class attribute at runtime, even when a <style> block is present
tests/hydration/samples/head-css-no-class/ — verifies the same for hydration

[changeset-bot]

🦋 Changeset detected

Latest commit: 4914802

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

This PR includes changesets to release 1 package

Name	Type
svelte	Patch

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[pkg-svelte-dev]

Install the latest version of svelte from 4914802:

pnpm add https://pkg.svelte.dev/svelte/c/4914802a52e1152f339d172258824518c4154791

Open in pkg.svelte.dev: https://pkg.svelte.dev/repos/svelte/pr/18160

Note

This PR is from a fork. A maintainer must approve approve each commit before it can be built and installed.

[dummdidumm]

thank you!