[fix] prerendered endpoint callable from non-prerendered server load (#8453)

Fixes #8341

Author: dummdidumm

.changeset/angry-ways-divide.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+[fix] prerendered endpoint callable from non-prerendered server load

packages/kit/src/runtime/server/data/index.js

@@ -31,6 +31,8 @@ export async function render_data(
 		});
 	}
 
+	state.initiator = route;
+
 	try {
 		const node_ids = [...route.page.layouts, route.page.leaf];
 		const invalidated = invalidated_data_nodes ?? node_ids.map(() => true);

packages/kit/test/apps/basics/src/routes/prerendering/prerendered-endpoint/api/+server.js

@@ -0,0 +1,7 @@
+import { json } from '@sveltejs/kit';
+
+export const prerender = true;
+
+export function GET() {
+	return json({ message: 'Im prerendered and called from a non-prerendered +page.server.js' });
+}

packages/kit/test/apps/basics/src/routes/prerendering/prerendered-endpoint/page/+page.server.js

@@ -0,0 +1,6 @@
+/** @type {import('./$types').PageServerLoad} */
+export async function load({ fetch }) {
+	const res = await fetch('/prerendering/prerendered-endpoint/api');
+	const json = await res.json();
+	return json;
+}

packages/kit/test/apps/basics/src/routes/prerendering/prerendered-endpoint/page/+page.svelte

@@ -0,0 +1,5 @@
+<script>
+	export let data;
+</script>
+
+<h1>{data.message}</h1>

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

@@ -941,6 +941,23 @@ test.describe('Load', () => {
 
 		expect(await page.textContent('h1')).toBe('true');
 	});
+
+	test('Prerendered +server.js called from a non-prerendered +page.server.js works', async ({
+		page,
+		app,
+		javaScriptEnabled
+	}) => {
+		if (javaScriptEnabled) {
+			await page.goto('/');
+			await app.goto('/prerendering/prerendered-endpoint/page');
+		} else {
+			await page.goto('/prerendering/prerendered-endpoint/page');
+		}
+
+		expect(await page.textContent('h1')).toBe(
+			'Im prerendered and called from a non-prerendered +page.server.js'
+		);
+	});
 });
 
 test.describe('Nested layouts', () => {