fix: infer `svg` namespace correctly (#10027)

Add recursive check for logic blocks, ignore things such as ConstTags and Comments
closes #10025

---------

Co-authored-by: Simon Holthausen <simon.holthausen@vercel.com>

.changeset/dull-roses-relate.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: infer `svg` namespace correctly

packages/svelte/src/compiler/phases/3-transform/utils.js

@@ -211,23 +211,67 @@ export function infer_namespace(namespace, parent, nodes, path) {
 			parent_node.type === 'SvelteFragment' ||
 			parent_node.type === 'SnippetBlock')
 	) {
-		// Heuristic: Keep current namespace, unless we find a regular element,
-		// in which case we always want html, or we only find svg nodes,
-		// in which case we assume svg.
-		let only_svg = true;
-		for (const node of nodes) {
-			if (node.type === 'RegularElement') {
-				if (!node.metadata.svg) {
-					namespace = 'html';
-					only_svg = false;
-					break;
-				}
-			} else if (node.type !== 'Text' || node.data.trim() !== '') {
-				only_svg = false;
-			}
+		const new_namespace = check_nodes_for_namespace(nodes, 'keep');
+		if (new_namespace !== 'keep' && new_namespace !== 'maybe_html') {
+			namespace = new_namespace;
 		}
-		if (only_svg) {
-			namespace = 'svg';
+	}
+
+	return namespace;
+}
+
+/**
+ * Heuristic: Keep current namespace, unless we find a regular element,
+ * in which case we always want html, or we only find svg nodes,
+ * in which case we assume svg.
+ * @param {import('#compiler').SvelteNode[]} nodes
+ * @param {import('#compiler').Namespace | 'keep' | 'maybe_html'} namespace
+ */
+function check_nodes_for_namespace(nodes, namespace) {
+	for (const node of nodes) {
+		if (node.type === 'RegularElement') {
+			if (!node.metadata.svg) {
+				namespace = 'html';
+				break;
+			} else if (namespace === 'keep') {
+				namespace = 'svg';
+			}
+		} else if (
+			(node.type === 'Text' && node.data.trim() !== '') ||
+			node.type === 'HtmlTag' ||
+			node.type === 'RenderTag'
+		) {
+			namespace = 'maybe_html';
+		} else if (node.type === 'EachBlock') {
+			namespace = check_nodes_for_namespace(node.body.nodes, namespace);
+			if (namespace === 'html') break;
+			if (node.fallback) {
+				namespace = check_nodes_for_namespace(node.fallback.nodes, namespace);
+				if (namespace === 'html') break;
+			}
+		} else if (node.type === 'IfBlock') {
+			namespace = check_nodes_for_namespace(node.consequent.nodes, namespace);
+			if (namespace === 'html') break;
+			if (node.alternate) {
+				namespace = check_nodes_for_namespace(node.alternate.nodes, namespace);
+				if (namespace === 'html') break;
+			}
+		} else if (node.type === 'AwaitBlock') {
+			if (node.pending) {
+				namespace = check_nodes_for_namespace(node.pending.nodes, namespace);
+				if (namespace === 'html') break;
+			}
+			if (node.then) {
+				namespace = check_nodes_for_namespace(node.then.nodes, namespace);
+				if (namespace === 'html') break;
+			}
+			if (node.catch) {
+				namespace = check_nodes_for_namespace(node.catch.nodes, namespace);
+				if (namespace === 'html') break;
+			}
+		} else if (node.type === 'KeyBlock') {
+			namespace = check_nodes_for_namespace(node.fragment.nodes, namespace);
+			if (namespace === 'html') break;
 		}
 	}
 

packages/svelte/tests/runtime-runes/samples/destructure-async-assignments/main.svelte

@@ -34,6 +34,10 @@
         return Promise.resolve([24, 25]);
     }
 
+    const some = {
+        fn: () => {}
+    }
+
     const update = async () => {
         [a, b] = [1, await Promise.resolve(2)];
         ({ c = await Promise.resolve(3), d } = { d: 4 });
@@ -49,7 +53,7 @@
         [l = obj[await Promise.resolve("prop")] + 1] = [];
         [m] = [`${1}${await Promise.resolve("3")}`];
         [n] = [-(await Promise.resolve(-14))];
-        [o] = [(console.log(15), await Promise.resolve(15))];
+        [o] = [(some.fn(), await Promise.resolve(15))];
         ({ anotherprop: p = await Promise.resolve(16) } = obj);
         let val1, val2;
         ({ val1 = (async function (x) { return await x; })(Promise.resolve(18)), r = await val1 }

packages/svelte/tests/runtime-runes/samples/svg-namespace-infer/Wrapper.svelte

@@ -0,0 +1,13 @@
+<text x="0" y=14>outside</text>
+
+{#if true}
+  <text x="0" y="26">true</text>
+{:else}
+  <text x="0" y="26">false</text>
+{/if}
+
+{#each  Array(3).fill(0) as item, idx}
+  <text x={idx * 10} y={42}>{idx}</text>
+{/each}
+
+<!-- comment should not set infer html namespace -->

packages/svelte/tests/runtime-runes/samples/svg-namespace-infer/_config.js

@@ -0,0 +1,26 @@
+import { test, ok } from '../../test';
+
+export default test({
+	html: `
+	<svg>
+		<text x="0" y="14">outside</text>
+		<text x="0" y="26">true</text>
+		<text x="0" y="42">0</text>
+		<text x="10" y="42">1</text>
+		<text x="20" y="42">2</text>
+	</svg>
+`,
+	test({ assert, target }) {
+		const svg = target.querySelector('svg');
+		ok(svg);
+
+		assert.equal(svg.namespaceURI, 'http://www.w3.org/2000/svg');
+
+		const text_elements = target.querySelectorAll('text');
+
+		assert.equal(text_elements.length, 5);
+
+		for (const { namespaceURI } of text_elements)
+			assert.equal(namespaceURI, 'http://www.w3.org/2000/svg');
+	}
+});

packages/svelte/tests/runtime-runes/samples/svg-namespace-infer/main.svelte

@@ -0,0 +1,7 @@
+<script>
+  import Wrapper from "./Wrapper.svelte";
+</script>
+
+<svg>
+  <Wrapper />
+</svg>