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

.changeset/large-seahorses-reply.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Call `next()` without return anything should work, with a warning

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 {};

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);

examples/middleware/src/pages/api/login.ts

@@ -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',
-			},
-		}
-	);
-};

packages/astro/src/core/middleware/callMiddleware.ts

@@ -46,9 +46,11 @@ export async function callMiddleware<R>(
 	});
 
 	let nextCalled = false;
+	let responseFunctionPromise: Promise<R> | undefined = undefined;
 	const next: MiddlewareNext<R> = async () => {
 		nextCalled = true;
-		return await responseFunction();
+		responseFunctionPromise = responseFunction();
+		return responseFunctionPromise;
 	};
 
 	let middlewarePromise = onRequest(apiContext, next);
@@ -74,8 +76,11 @@ export async function callMiddleware<R>(
 				/**
 				 * Here we handle the case where `next` was called and returned nothing.
 				 */
-				const responseResult = await responseFunction();
-				return responseResult;
+				if (responseFunctionPromise) {
+					return responseFunctionPromise;
+				} else {
+					throw new AstroError(AstroErrorData.MiddlewareNotAResponse);
+				}
 			}
 		} else if (typeof value === 'undefined') {
 			/**

packages/astro/test/fixtures/middleware-dev/src/middleware.js

@@ -34,7 +34,7 @@ const third = defineMiddleware(async (context, next) => {
 	} else if (context.request.url.includes('/does-nothing')) {
 		return undefined;
 	}
-	next();
+	return next();
 });
 
 export const onRequest = sequence(first, second, third);

packages/astro/test/fixtures/middleware-tailwind/astro.config.mjs

@@ -0,0 +1,11 @@
+import { defineConfig } from 'astro/config';
+import tailwind from '@astrojs/tailwind';
+
+
+// https://astro.build/config
+export default defineConfig({
+	integrations: [tailwind()],
+	experimental: {
+		middleware: true,
+	}
+});

packages/astro/test/fixtures/middleware-tailwind/package.json

@@ -0,0 +1,9 @@
+{
+  "name": "@test/middleware-tailwind",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "astro": "workspace:*",
+    "@astrojs/tailwind": "workspace:*"
+  }
+}

packages/astro/test/fixtures/middleware-tailwind/src/middleware.js

@@ -0,0 +1,3 @@
+export const onRequest = (_, next) => {
+	next();
+}

packages/astro/test/fixtures/middleware-tailwind/src/pages/index.astro

@@ -0,0 +1,7 @@
+<h1 class="text-blue-500 text-2xl font-bold">Hello world</h1>
+
+<style>
+    p {
+        color: red;
+    }
+</style>

packages/astro/test/middleware.test.js

@@ -77,8 +77,6 @@ describe('Middleware in DEV mode', () => {
 describe('Middleware in PROD mode, SSG', () => {
 	/** @type {import('./test-utils').Fixture} */
 	let fixture;
-	/** @type {import('./test-utils').PreviewServer} */
-	let previewServer;
 
 	before(async () => {
 		fixture = await loadFixture({
@@ -200,3 +198,25 @@ describe('Middleware API in PROD mode, SSR', () => {
 		expect($('title').html()).to.not.equal('MiddlewareNoDataReturned');
 	});
 });
+
+describe('Middleware with tailwind', () => {
+	/** @type {import('./test-utils').Fixture} */
+	let fixture;
+
+	before(async () => {
+		fixture = await loadFixture({
+			root: './fixtures/middleware-tailwind/',
+		});
+		await fixture.build();
+	});
+
+	it('should correctly emit the tailwind CSS file', async () => {
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerio.load(html);
+		const bundledCSSHREF = $('link[rel=stylesheet][href^=/_astro/]').attr('href');
+		const bundledCSS = (await fixture.readFile(bundledCSSHREF.replace(/^\/?/, '/')))
+			.replace(/\s/g, '')
+			.replace('/n', '');
+		expect(bundledCSS.includes('--tw-content')).to.be.true;
+	});
+});

pnpm-lock.yaml

@@ -2771,6 +2771,15 @@ importers:
         specifier: workspace:*
         version: link:../../..
 
+  packages/astro/test/fixtures/middleware-tailwind:
+    dependencies:
+      '@astrojs/tailwind':
+        specifier: workspace:*
+        version: link:../../../../integrations/tailwind
+      astro:
+        specifier: workspace:*
+        version: link:../../..
+
   packages/astro/test/fixtures/multiple-renderers:
     dependencies:
       '@test/astro-renderer-one':