fix: ensure logic blocks keep consistent namespacing (#14817)

* fix: ensure logic blocks keep consitent namespacing

* lint

* add test

* handle `<title>` ambiguity the same as `<a>`

* update changeset

---------

Co-authored-by: Rich Harris <rich.harris@vercel.com>

.changeset/real-onions-confess.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: inherit correct namespace for `<title>` elements

packages/svelte/src/compiler/phases/2-analyze/visitors/RegularElement.js

@@ -90,8 +90,11 @@ export function RegularElement(node, context) {
 		if (is_svg(node.name)) {
 			return true;
 		}
-		if (node.name === 'a') {
+
-			for (let i = context.path.length - 1; i >= 0; i--) {
+		if (node.name === 'a' || node.name === 'title') {
+			let i = context.path.length;
+
+			while (i--) {
 				const ancestor = context.path[i];
 				if (ancestor.type === 'RegularElement') {
 					return ancestor.metadata.svg;

packages/svelte/tests/runtime-runes/samples/svg-namespace-if-block-3/_config.js

@@ -0,0 +1,11 @@
+import { test, ok } from '../../test';
+
+export default test({
+	html: `<svg><title>potato</title></svg>`,
+	test({ assert, target }) {
+		const title = target.querySelector('title');
+		ok(title);
+
+		assert.equal(title.namespaceURI, 'http://www.w3.org/2000/svg');
+	}
+});

packages/svelte/tests/runtime-runes/samples/svg-namespace-if-block-3/main.svelte

@@ -0,0 +1,5 @@
+<svg>
+	{#if true}
+		<title>potato</title>
+	{/if}
+</svg>