From 8de9dc61447fbad9d0984ffaa9434ce3f9655c16 Mon Sep 17 00:00:00 2001
From: Simon H <5968653+dummdidumm@users.noreply.github.com>
Date: Mon, 3 Jul 2023 22:50:23 +0200
Subject: [PATCH] fix: handle falsy srcset values (#8901)

fixes #8899
---
 .changeset/early-lizards-decide.md            | 5 +++++
 packages/svelte/src/runtime/internal/utils.js | 4 ++--
 packages/svelte/test/utils/utils.test.js      | 1 +
 3 files changed, 8 insertions(+), 2 deletions(-)
 create mode 100644 .changeset/early-lizards-decide.md

diff --git a/.changeset/early-lizards-decide.md b/.changeset/early-lizards-decide.md
new file mode 100644
index 0000000000..fbd2f8de0f
--- /dev/null
+++ b/.changeset/early-lizards-decide.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: handle falsy srcset values
diff --git a/packages/svelte/src/runtime/internal/utils.js b/packages/svelte/src/runtime/internal/utils.js
index 190c4534c6..ec39c0d9e4 100644
--- a/packages/svelte/src/runtime/internal/utils.js
+++ b/packages/svelte/src/runtime/internal/utils.js
@@ -90,12 +90,12 @@ function split_srcset(srcset) {
 
 /**
  * @param {HTMLSourceElement | HTMLImageElement} element_srcset
- * @param {string} srcset
+ * @param {string | undefined | null} srcset
  * @returns {boolean}
  */
 export function srcset_url_equal(element_srcset, srcset) {
 	const element_urls = split_srcset(element_srcset.srcset);
-	const urls = split_srcset(srcset);
+	const urls = split_srcset(srcset || '');
 
 	return (
 		urls.length === element_urls.length &&
diff --git a/packages/svelte/test/utils/utils.test.js b/packages/svelte/test/utils/utils.test.js
index 301361ea3d..2764f0098a 100644
--- a/packages/svelte/test/utils/utils.test.js
+++ b/packages/svelte/test/utils/utils.test.js
@@ -162,6 +162,7 @@ describe('utils', () => {
 		it('should return false if urls are different', () => {
 			assert.notOk(srcset_url_equal(create_element('a 1x'), 'b 1x'));
 			assert.notOk(srcset_url_equal(create_element('a 2x'), 'a 1x'));
+			assert.notOk(srcset_url_equal(create_element('a 2x'), null));
 		});
 	});
 });