fix: load env before prerender (#14219)

* fix: load env before prerender

* chore: changeset

* chore: add test

* chore: add comment in test file

Co-authored-by: Rich Harris <richard.a.harris@gmail.com>

* simplify

---------

Co-authored-by: Rich Harris <richard.a.harris@gmail.com>
Co-authored-by: Rich Harris <rich.harris@vercel.com>

Author: paoloricciuti

.changeset/wide-cobras-yell.md

@@ -0,0 +1,5 @@
+---
+'@sveltejs/kit': patch
+---
+
+fix: load env before prerender

packages/kit/src/core/postbuild/prerender.js

@@ -125,6 +125,12 @@ async function prerender({ hash, out, manifest_path, metadata, verbose, env }) {
 
 	installPolyfills();
 
+	const server = new Server(manifest);
+	await server.init({
+		env,
+		read: (file) => createReadableStream(`${config.outDir}/output/server/${file}`)
+	});
+
 	/** @type {Map<string, string>} */
 	const saved = new Map();
 
@@ -503,12 +509,6 @@ async function prerender({ hash, out, manifest_path, metadata, verbose, env }) {
 
 	log.info('Prerendering');
 
-	const server = new Server(manifest);
-	await server.init({
-		env,
-		read: (file) => createReadableStream(`${config.outDir}/output/server/${file}`)
-	});
-
 	for (const entry of config.prerender.entries) {
 		if (entry === '*') {
 			for (const [id, prerender] of prerender_map) {

packages/kit/test/apps/basics/src/routes/remote/accessing-env.remote.js

@@ -0,0 +1,8 @@
+import { env } from '$env/dynamic/private';
+import { env as public_env } from '$env/dynamic/public';
+
+if (!env.PRIVATE_DYNAMIC || !public_env.PUBLIC_DYNAMIC) {
+	// This checks that dynamic env vars are available when prerendering remote functions
+	// https://github.com/sveltejs/kit/pull/14219
+	throw new Error('Dynamic environment variables are not set up correctly');
+}