fix: store from props hoist wrong param (#11367)

Fixes #11355

---------

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

.changeset/tiny-moose-kiss.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+fix: ensure store from props is hoisted correctly

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

@@ -456,27 +456,30 @@ function get_hoistable_params(node, context) {
 
 	/** @type {import('estree').Identifier[]} */
 	const params = [];
-	let added_props = false;
 
 	/**
-	 * we only want to push if it's not already present to avoid name clashing
+	 * We only want to push if it's not already present to avoid name clashing
 	 * @param {import('estree').Identifier} id
 	 */
-	function safe_push(id) {
+	function push_unique(id) {
 		if (!params.find((param) => param.name === id.name)) {
 			params.push(id);
 		}
 	}
 
 	for (const [reference] of scope.references) {
-		const binding = scope.get(reference);
+		let binding = scope.get(reference);
 
 		if (binding !== null && !scope.declarations.has(reference) && binding.initial !== node) {
 			if (binding.kind === 'store_sub') {
 				// We need both the subscription for getting the value and the store for updating
-				safe_push(b.id(binding.node.name.slice(1)));
+				push_unique(b.id(binding.node.name));
-				safe_push(b.id(binding.node.name));
+				binding = /** @type {import('#compiler').Binding} */ (
-			} else if (
+					scope.get(binding.node.name.slice(1))
+				);
+			}
+
+			if (
 				// If it's a destructured derived binding, then we can extract the derived signal reference and use that.
 				binding.expression !== null &&
 				typeof binding.expression !== 'function' &&
@@ -486,7 +489,7 @@ function get_hoistable_params(node, context) {
 				binding.expression.object.callee.name === '$.get' &&
 				binding.expression.object.arguments[0].type === 'Identifier'
 			) {
-				safe_push(b.id(binding.expression.object.arguments[0].name));
+				push_unique(b.id(binding.expression.object.arguments[0].name));
 			} else if (
 				// If we are referencing a simple $$props value, then we need to reference the object property instead
 				(binding.kind === 'prop' || binding.kind === 'bindable_prop') &&
@@ -494,14 +497,10 @@ function get_hoistable_params(node, context) {
 				binding.initial === null &&
 				!context.state.analysis.accessors
 			) {
-				// Handle $$props.something use-cases
+				push_unique(b.id('$$props'));
-				if (!added_props) {
-					added_props = true;
-					safe_push(b.id('$$props'));
-				}
 			} else {
 				// create a copy to remove start/end tags which would mess up source maps
-				safe_push(b.id(binding.node.name));
+				push_unique(b.id(binding.node.name));
 			}
 		}
 	}

packages/svelte/tests/runtime-runes/samples/store-from-props-hoisting/_config.js

@@ -0,0 +1,18 @@
+import { test } from '../../test';
+
+export default test({
+	compileOptions: {
+		dev: true
+	},
+	async test({ assert, target }) {
+		const button = target.querySelector('button');
+		await button?.click();
+
+		assert.htmlEqual(
+			target.innerHTML,
+			`
+			<button>1</button>
+		`
+		);
+	}
+});

packages/svelte/tests/runtime-runes/samples/store-from-props-hoisting/child.svelte

@@ -0,0 +1,8 @@
+<script>
+	const { attrs } = $props();
+	function increment() {
+		$attrs.count++;
+	}
+</script>
+
+<button onclick={increment}>{$attrs.count}</button>

packages/svelte/tests/runtime-runes/samples/store-from-props-hoisting/main.svelte

@@ -0,0 +1,7 @@
+<script>
+	import { writable } from "svelte/store";
+	import Child from "./child.svelte";
+	const attrs = writable({ count: 0 });
+</script>
+
+<Child {attrs} />