From 8ebbb3c7bccfba4f509456b5b4f5b81ccf13d65c Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sat, 1 Nov 2025 23:35:20 +0100
Subject: [PATCH 1/2] fix: preserve symbols when creating derived rest
 properties (#17096)

fixes #17094
---
 .changeset/sixty-comics-bow.md                     |  5 +++++
 packages/svelte/src/internal/client/runtime.js     | 14 ++++++++++----
 .../derived-rest-includes-symbol/_config.js        |  5 +++++
 .../derived-rest-includes-symbol/main.svelte       |  8 ++++++++
 4 files changed, 28 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/sixty-comics-bow.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte

diff --git a/.changeset/sixty-comics-bow.md b/.changeset/sixty-comics-bow.md
new file mode 100644
index 0000000000..2463e52430
--- /dev/null
+++ b/.changeset/sixty-comics-bow.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: preserve symbols when creating derived rest properties
diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 2197f34d16..6485d21ec2 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -763,12 +763,12 @@ export function set_signal_status(signal, status) {
 }
 
 /**
- * @param {Record<string, unknown>} obj
- * @param {string[]} keys
- * @returns {Record<string, unknown>}
+ * @param {Record<string | symbol, unknown>} obj
+ * @param {Array<string | symbol>} keys
+ * @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;
 }
 
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js
new file mode 100644
index 0000000000..eec60928a2
--- /dev/null
+++ b/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>`
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte b/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte
new file mode 100644
index 0000000000..ee161696e1
--- /dev/null
+++ b/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>

From b7625fd42c067b7cd03fea9589ef45349f9dedbe Mon Sep 17 00:00:00 2001
From: 7nik <kifiranet@gmail.com>
Date: Sun, 2 Nov 2025 11:40:32 +0200
Subject: [PATCH 2/2] fix: do not spread non-enumerable symbols (#17097)

---
 packages/svelte/src/internal/client/runtime.js           | 2 +-
 .../samples/derived-rest-includes-symbol/_config.js      | 2 +-
 .../samples/derived-rest-includes-symbol/main.svelte     | 9 ++++++---
 3 files changed, 8 insertions(+), 5 deletions(-)

diff --git a/packages/svelte/src/internal/client/runtime.js b/packages/svelte/src/internal/client/runtime.js
index 6485d21ec2..76531d3320 100644
--- a/packages/svelte/src/internal/client/runtime.js
+++ b/packages/svelte/src/internal/client/runtime.js
@@ -778,7 +778,7 @@ export function exclude_from_object(obj, keys) {
 	}
 
 	for (var symbol of Object.getOwnPropertySymbols(obj)) {
-		if (!keys.includes(symbol)) {
+		if (Object.propertyIsEnumerable.call(obj, symbol) && !keys.includes(symbol)) {
 			result[symbol] = obj[symbol];
 		}
 	}
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js b/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js
index eec60928a2..d0633983d2 100644
--- a/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js
+++ b/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/_config.js
@@ -1,5 +1,5 @@
 import { test } from '../../test';
 
 export default test({
-	html: `<p>42</p>`
+	html: `<p>true false</p>`
 });
diff --git a/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte b/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte
index ee161696e1..2454e98ab7 100644
--- a/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte
+++ b/packages/svelte/tests/runtime-runes/samples/derived-rest-includes-symbol/main.svelte
@@ -1,8 +1,11 @@
 <script>
-	const symbol = Symbol();
+	const symbol1 = Symbol();
+	const symbol2 = Symbol();
+
+	let a = { [symbol1]: 42 };
+	Object.defineProperty(a, symbol2, { enumerable: false, value: "nope" })
 
-	let a = { [symbol]: 42 };
 	let { ...b } = $derived(a);
 </script>
 
-<p>{b[symbol]}</p>
+<p>{symbol1 in b} {symbol2 in b}</p>