fix(middleware): emit warning if `next` is called and nothing is returned (#7010)

* fix(middleware): emit warning if `next` is called and nothing is returned

* chore: add test case

* chore: changeset

* chore: restore code, ooops!

* chore: change logic

* change namespace

3 files changed, 7 insertions, 31 deletions

diff --git a/examples/middleware/src/env.d.ts b/examples/middleware/src/env.d.ts
index f2de6d45d..44f67965a 100644
--- a/examples/middleware/src/env.d.ts
+++ b/examples/middleware/src/env.d.ts
@@ -1,13 +1,9 @@
 /// <reference types="astro/client" />
-declare global {
-	namespace AstroMiddleware {
-		interface Locals {
-			user: {
-				name: string;
-				surname: string;
-			};
-		}
+declare namespace App {
+	interface Locals {
+		user: {
+			name: string;
+			surname: string;
+		};
 	}
 }
-
-export {};
diff --git a/examples/middleware/src/middleware.ts b/examples/middleware/src/middleware.ts
index 1c0bd855f..9871e9d01 100644
--- a/examples/middleware/src/middleware.ts
+++ b/examples/middleware/src/middleware.ts
@@ -63,9 +63,7 @@ const validation = defineMiddleware(async (context, next) => {
 			return context.redirect('/admin');
 		}
 	}
-	// we don't really care about awaiting the response in this case
-	next();
-	return;
+	return next();
 });
 
 export const onRequest = sequence(validation, minifier);
diff --git a/examples/middleware/src/pages/api/login.ts b/examples/middleware/src/pages/api/login.ts
deleted file mode 100644
index fa3f7b59b..000000000
--- a/examples/middleware/src/pages/api/login.ts
+++ /dev/null
@@ -1,18 +0,0 @@
-import { APIRoute } from 'astro';
-
-export const post: APIRoute = async ({ request }) => {
-	const data = await request.formData();
-	const username = data.get('username');
-	const password = data.get('password');
-	return new Response(
-		JSON.stringify({
-			username,
-			password,
-		}),
-		{
-			headers: {
-				'content-type': 'application/json',
-			},
-		}
-	);
-};