From 653f4accbd3393fdaed072b936a39d908cf9d20a Mon Sep 17 00:00:00 2001
From: Paolo Ricciuti <ricciutipaolo@gmail.com>
Date: Mon, 11 Nov 2024 10:28:56 +0100
Subject: [PATCH] fix: migration script messing with attributes (#14260)

---
 .changeset/afraid-donuts-whisper.md               |  5 +++++
 packages/svelte/src/compiler/migrate/index.js     |  2 +-
 .../slot-dont-mess-with-attributes/input.svelte   |  5 +++++
 .../slot-dont-mess-with-attributes/output.svelte  | 15 +++++++++++++++
 4 files changed, 26 insertions(+), 1 deletion(-)
 create mode 100644 .changeset/afraid-donuts-whisper.md
 create mode 100644 packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/input.svelte
 create mode 100644 packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/output.svelte

diff --git a/.changeset/afraid-donuts-whisper.md b/.changeset/afraid-donuts-whisper.md
new file mode 100644
index 0000000000..df9eea40ad
--- /dev/null
+++ b/.changeset/afraid-donuts-whisper.md
@@ -0,0 +1,5 @@
+---
+'svelte': patch
+---
+
+fix: migration script messing with attributes
diff --git a/packages/svelte/src/compiler/migrate/index.js b/packages/svelte/src/compiler/migrate/index.js
index 8c2429b1c9..080babdfb7 100644
--- a/packages/svelte/src/compiler/migrate/index.js
+++ b/packages/svelte/src/compiler/migrate/index.js
@@ -1309,7 +1309,7 @@ const template = {
 						parent.type === 'RegularElement' ||
 						parent.type === 'SvelteElement' ||
 						parent.type === 'SvelteFragment') &&
-					parent.attributes.some((attr) => (attr.type = 'LetDirective'))
+					parent.attributes.some((attr) => attr.type === 'LetDirective')
 			)
 		) {
 			aliased_slot_name = `${name}_render`;
diff --git a/packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/input.svelte b/packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/input.svelte
new file mode 100644
index 0000000000..53f38e0332
--- /dev/null
+++ b/packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/input.svelte
@@ -0,0 +1,5 @@
+<MyComponent
+  variant="outlined"
+>
+  <slot />
+</MyComponent>
diff --git a/packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/output.svelte b/packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/output.svelte
new file mode 100644
index 0000000000..39a6ff7957
--- /dev/null
+++ b/packages/svelte/tests/migrate/samples/slot-dont-mess-with-attributes/output.svelte
@@ -0,0 +1,15 @@
+<script>
+  /**
+   * @typedef {Object} Props
+   * @property {import('svelte').Snippet} [children]
+   */
+
+  /** @type {Props} */
+  let { children } = $props();
+</script>
+
+<MyComponent
+  variant="outlined"
+>
+  {@render children?.()}
+</MyComponent>
\ No newline at end of file