fix: don't write temporary remote function bundle to disk (#14161)

* fix: don't write temporary remote function bundle to disk

* add test

* cleanup ts

* Apply suggestion from @eltigerchino

---------

Co-authored-by: Chew Tee Ming <[email protected]>
Co-authored-by: Tee Ming <[email protected]>

Author: KTibow

.changeset/witty-kids-fail.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: avoid writing remote function bundle to disk when treeshaking prerendered queries

packages/kit/src/exports/vite/build/build_remote.js

@@ -102,9 +102,10 @@ export async function treeshake_prerendered_remotes(out, manifest_data, metadata
 		input[prefix + remote.hash] = remote_file;
 	}
 
-	const bundle = await vite.build({
+	const bundle = /** @type {import('vite').Rollup.RollupOutput} */ (await vite.build({
 		configFile: false,
 		build: {
+			write: false,
 			ssr: true,
 			rollupOptions: {
 				external: (id) => {
@@ -114,11 +115,10 @@ export async function treeshake_prerendered_remotes(out, manifest_data, metadata
 				input
 			}
 		}
-	});
+	}));
 
-	// @ts-expect-error TypeScript doesn't know what type `bundle` is
 	for (const chunk of bundle.output) {
-		if (chunk.name.startsWith(prefix)) {
+		if (chunk.type === 'chunk' && chunk.name.startsWith(prefix)) {
 			fs.writeFileSync(`${dir}/${chunk.fileName.slice(prefix.length)}`, chunk.code);
 		}
 	}

packages/kit/test/apps/basics/test/server.test.js

@@ -768,3 +768,10 @@ test.describe('$app/environment', () => {
 		expect(code).not.toContain('browser');
 	});
 });
+
+test.describe('remote functions', () => {
+	test("doesn't write bundle to disk when treeshaking prerendered remote functions", () => {
+		test.skip(!!process.env.DEV, 'skip when in dev mode');
+		expect(fs.existsSync(path.join(root, 'dist'))).toBe(false);
+	});
+});