From 15a8518b91b80a8e578fd3378c59f808677c9a53 Mon Sep 17 00:00:00 2001
From: Dominic Gannaway <trueadm@users.noreply.github.com>
Date: Thu, 4 Jul 2024 15:20:21 +0100
Subject: [PATCH] fix: ensure each blocks properly handle $state.frozen objects
 in prod (#12305)

* fix: ensure each blocks properly handle $state.frozen objects in prod

* fix: ensure each blocks properly handle $state.frozen objects in prod
---
 .changeset/long-carrots-sneeze.md             |  5 +++++
 .../src/internal/client/dom/blocks/each.js    |  9 +++++++--
 .../samples/each-updates-frozen/_config.js    | 19 +++++++++++++++++++
 .../samples/each-updates-frozen/main.svelte   | 16 ++++++++++++++++
 4 files changed, 47 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/long-carrots-sneeze.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/each-updates-frozen/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/each-updates-frozen/main.svelte

diff --git a/.changeset/long-carrots-sneeze.md b/.changeset/long-carrots-sneeze.md
new file mode 100644
index 0000000000..90a66121e4
--- /dev/null
+++ b/.changeset/long-carrots-sneeze.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: ensure each blocks properly handle $state.frozen objects in prod
diff --git a/packages/svelte/src/internal/client/dom/blocks/each.js b/packages/svelte/src/internal/client/dom/blocks/each.js
index e6146b2f23..2e274d1b03 100644
--- a/packages/svelte/src/internal/client/dom/blocks/each.js
+++ b/packages/svelte/src/internal/client/dom/blocks/each.js
@@ -28,7 +28,7 @@ import {
 } from '../../reactivity/effects.js';
 import { source, mutable_source, set } from '../../reactivity/sources.js';
 import { is_array, is_frozen } from '../../utils.js';
-import { INERT, STATE_SYMBOL } from '../../constants.js';
+import { INERT, STATE_FROZEN_SYMBOL, STATE_SYMBOL } from '../../constants.js';
 import { queue_micro_task } from '../task.js';
 import { current_effect } from '../../runtime.js';
 
@@ -137,7 +137,12 @@ export function each(anchor, flags, get_collection, get_key, render_fn, fallback
 		// If we are working with an array that isn't proxied or frozen, then remove strict equality and ensure the items
 		// are treated as reactive, so they get wrapped in a signal.
 		var flags = state.flags;
-		if ((flags & EACH_IS_STRICT_EQUALS) !== 0 && !is_frozen(array) && !(STATE_SYMBOL in array)) {
+		if (
+			(flags & EACH_IS_STRICT_EQUALS) !== 0 &&
+			!is_frozen(array) &&
+			!(STATE_FROZEN_SYMBOL in array) &&
+			!(STATE_SYMBOL in array)
+		) {
 			flags ^= EACH_IS_STRICT_EQUALS;
 
 			// Additionally if we're in an keyed each block, we'll need ensure the items are all wrapped in signals.
diff --git a/packages/svelte/tests/runtime-runes/samples/each-updates-frozen/_config.js b/packages/svelte/tests/runtime-runes/samples/each-updates-frozen/_config.js
new file mode 100644
index 0000000000..42e0796d91
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/each-updates-frozen/_config.js
@@ -0,0 +1,19 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	// TODO: need to force DEV to be false for runtime somehow
+	async test({ assert, target, logs }) {
+		const [btn1] = target.querySelectorAll('button');
+
+		assert.equal(logs.length, 3);
+
+		logs.length = 0;
+
+		flushSync(() => {
+			btn1.click();
+		});
+
+		assert.equal(logs.length, 1);
+	}
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/each-updates-frozen/main.svelte b/packages/svelte/tests/runtime-runes/samples/each-updates-frozen/main.svelte
new file mode 100644
index 0000000000..8aabde46cf
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/each-updates-frozen/main.svelte
@@ -0,0 +1,16 @@
+<script>
+  let frozen_items = $state.frozen([
+		{id: 0, text: 'a'},
+		{id: 1, text: 'b'},
+		{id: 2, text: 'c'}
+	])
+</script>
+
+{#each frozen_items as item (item.id)}
+	{console.log(item.text)}
+  {item.text}
+{/each}
+
+<button onclick={() => {
+	frozen_items = [...frozen_items, {id: 3, text: 'd'}]
+}}></button>