From 00a85182fa13bb6734f97cd6c35b09ef6ab2d5df Mon Sep 17 00:00:00 2001
From: Rich Harris <rich.harris@vercel.com>
Date: Sun, 18 Aug 2024 13:03:47 -0400
Subject: [PATCH] fix: add `?? ` to memoized function calls in strings

---
 .../phases/3-transform/client/visitors/shared/utils.js    | 8 +++++++-
 .../samples/text-multiple-call-expression-null/_config.js | 5 +++++
 .../text-multiple-call-expression-null/main.svelte        | 5 +++++
 3 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/main.svelte

diff --git a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
index bd43075e6f..b7ec27f6e3 100644
--- a/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
+++ b/packages/svelte/src/compiler/phases/3-transform/client/visitors/shared/utils.js
@@ -59,7 +59,13 @@ export function build_template_literal(values, visit, state) {
 						id,
 						create_derived(
 							state,
-							b.thunk(/** @type {Expression} */ (visit(node.expression, state)))
+							b.thunk(
+								b.logical(
+									'??',
+									/** @type {Expression} */ (visit(node.expression, state)),
+									b.literal('')
+								)
+							)
 						)
 					)
 				);
diff --git a/packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/_config.js b/packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/_config.js
new file mode 100644
index 0000000000..a357effda4
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/_config.js
@@ -0,0 +1,5 @@
+import { test } from '../../test';
+
+export default test({
+	html: '<span></span>'
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/main.svelte b/packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/main.svelte
new file mode 100644
index 0000000000..e691630ad5
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/text-multiple-call-expression-null/main.svelte
@@ -0,0 +1,5 @@
+<script lang="ts">
+	const identity = (x: any) => x;
+</script>
+
+<span>{identity(null)}{identity(undefined)}</span>