From 901cfc9f15561500c6d78b5060266d648f118270 Mon Sep 17 00:00:00 2001
From: Dominic Gannaway <trueadm@users.noreply.github.com>
Date: Tue, 9 Jan 2024 10:54:29 +0000
Subject: [PATCH] fix: improve ssr template literal generation (#10127)

---
 .changeset/wicked-hairs-cheer.md                         | 5 +++++
 .../phases/3-transform/server/transform-server.js        | 2 +-
 .../runtime-runes/samples/attribute-parts/_config.js     | 6 ++++++
 .../runtime-runes/samples/attribute-parts/main.svelte    | 9 +++++++++
 4 files changed, 21 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/wicked-hairs-cheer.md
 create mode 100644 packages/svelte/tests/runtime-runes/samples/attribute-parts/_config.js
 create mode 100644 packages/svelte/tests/runtime-runes/samples/attribute-parts/main.svelte

diff --git a/.changeset/wicked-hairs-cheer.md b/.changeset/wicked-hairs-cheer.md
new file mode 100644
index 0000000000..532d81260b
--- /dev/null
+++ b/.changeset/wicked-hairs-cheer.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: improve ssr template literal generation
diff --git a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
index f00091a20b..5cb479b91a 100644
--- a/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
+++ b/packages/svelte/src/compiler/phases/3-transform/server/transform-server.js
@@ -705,7 +705,7 @@ function serialize_attribute_value(
 					/** @type {import('estree').Expression} */ (context.visit(node.expression))
 				)
 			);
-			if (i === attribute_value.length) {
+			if (i === attribute_value.length || attribute_value[i]?.type !== 'Text') {
 				quasis.push(b.quasi('', true));
 			}
 		}
diff --git a/packages/svelte/tests/runtime-runes/samples/attribute-parts/_config.js b/packages/svelte/tests/runtime-runes/samples/attribute-parts/_config.js
new file mode 100644
index 0000000000..dabe420686
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/attribute-parts/_config.js
@@ -0,0 +1,6 @@
+import { flushSync } from 'svelte';
+import { test } from '../../test';
+
+export default test({
+	html: `<div class="123"></div><img src="12 hello, world 13">`
+});
diff --git a/packages/svelte/tests/runtime-runes/samples/attribute-parts/main.svelte b/packages/svelte/tests/runtime-runes/samples/attribute-parts/main.svelte
new file mode 100644
index 0000000000..3bbd04cb7a
--- /dev/null
+++ b/packages/svelte/tests/runtime-runes/samples/attribute-parts/main.svelte
@@ -0,0 +1,9 @@
+<script>
+	let a = 1;
+	let b = 2;
+	let c = 3;
+</script>
+
+<div class="{a}{b}{c}" />
+
+<img src="{a}{b} hello, world {a}{c}" />