From fa3078ce9f5eda408340a78c6d275f3e0b2437dc Mon Sep 17 00:00:00 2001
From: Emanuele Stoppa <my.burning@gmail.com>
Date: Tue, 19 Dec 2023 08:28:04 +0000
Subject: [PATCH] fix: handle middleware loading error (#9458)

* fix: handle middleware loading error

* remove the try/catch

* rethrow error

* Update packages/astro/src/core/middleware/loadMiddleware.ts

Co-authored-by: Arsh <69170106+lilnasy@users.noreply.github.com>

---------

Co-authored-by: Arsh <69170106+lilnasy@users.noreply.github.com>
---
 .changeset/selfish-rings-occur.md             |  5 +++++
 packages/astro/src/core/errors/errors-data.ts | 20 +++++++++++++++++++
 .../src/core/middleware/loadMiddleware.ts     | 10 ++++++----
 3 files changed, 31 insertions(+), 4 deletions(-)
 create mode 100644 .changeset/selfish-rings-occur.md

diff --git a/.changeset/selfish-rings-occur.md b/.changeset/selfish-rings-occur.md
new file mode 100644
index 000000000000..e5722bb95f23
--- /dev/null
+++ b/.changeset/selfish-rings-occur.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Correctly handle the error in case the middleware throws a runtime error
diff --git a/packages/astro/src/core/errors/errors-data.ts b/packages/astro/src/core/errors/errors-data.ts
index 047bb533721c..691162d595af 100644
--- a/packages/astro/src/core/errors/errors-data.ts
+++ b/packages/astro/src/core/errors/errors-data.ts
@@ -780,6 +780,26 @@ export const LocalsNotAnObject = {
 	hint: 'If you tried to remove some information from the `locals` object, try to use `delete` or set the property to `undefined`.',
 } satisfies ErrorData;
 
+/**
+ * @docs
+ * @description
+ * Thrown in development mode when middleware throws an error while attempting to loading it.
+ *
+ * For example:
+ * ```ts
+ * import {defineMiddleware} from "astro:middleware";
+ * throw new Error("Error thrown while loading the middleware.")
+ * export const onRequest = defineMiddleware(() => {
+ *   return "string"
+ * });
+ * ```
+ */
+export const MiddlewareCantBeLoaded = {
+	name: 'MiddlewareCantBeLoaded',
+	title: "Can't load the middleware.",
+	message: 'The middleware thrown an error while Astro was trying to loading it.',
+} satisfies ErrorData;
+
 /**
  * @docs
  * @see
diff --git a/packages/astro/src/core/middleware/loadMiddleware.ts b/packages/astro/src/core/middleware/loadMiddleware.ts
index 4f524ee52756..135f7fbc479e 100644
--- a/packages/astro/src/core/middleware/loadMiddleware.ts
+++ b/packages/astro/src/core/middleware/loadMiddleware.ts
@@ -1,5 +1,7 @@
 import type { ModuleLoader } from '../module-loader/index.js';
 import { MIDDLEWARE_MODULE_ID } from './vite-plugin.js';
+import { MiddlewareCantBeLoaded } from '../errors/errors-data.js';
+import { AstroError } from '../errors/index.js';
 
 /**
  * It accepts a module loader and the astro settings, and it attempts to load the middlewares defined in the configuration.
@@ -8,9 +10,9 @@ import { MIDDLEWARE_MODULE_ID } from './vite-plugin.js';
  */
 export async function loadMiddleware(moduleLoader: ModuleLoader) {
 	try {
-		const module = await moduleLoader.import(MIDDLEWARE_MODULE_ID);
-		return module;
-	} catch {
-		return void 0;
+		return await moduleLoader.import(MIDDLEWARE_MODULE_ID);
+	} catch (error: any) {
+		const astroError = new AstroError(MiddlewareCantBeLoaded, undefined, { cause: error });
+		throw astroError;
 	}
 }