fix: preserve symbols when creating derived rest properties (#17096)

fixes #17094

.changeset/sixty-comics-bow.md

@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve symbols when creating derived rest properties

packages/svelte/src/internal/client/runtime.js

@@ -763,12 +763,12 @@ export function set_signal_status(signal, status) {
 }
 
 /**
- * @param {Record<string, unknown>} obj
+ * @param {Record<string | symbol, unknown>} obj
- * @param {string[]} keys
+ * @param {Array<string | symbol>} keys
- * @returns {Record<string, unknown>}
+ * @returns {Record<string | symbol, unknown>}
  */
 export function exclude_from_object(obj, keys) {
-	/** @type {Record<string, unknown>} */
+	/** @type {Record<string | symbol, unknown>} */
 	var result = {};
 
 	for (var key in obj) {
@@ -777,6 +777,12 @@ export function exclude_from_object(obj, keys) {
 		}
 	}
 
+	for (var symbol of Object.getOwnPropertySymbols(obj)) {
+		if (!keys.includes(symbol)) {
+			result[symbol] = obj[symbol];
+		}
+	}
+
 	return result;
 }
 

packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js

@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: `<p>42</p>`
+});

packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte

@@ -0,0 +1,8 @@
+<script>
+	const symbol = Symbol();
+
+	let a = { [symbol]: 42 };
+	let { ...b } = $derived(a);
+</script>
+
+<p>{b[symbol]}</p>