fix: middleware redirect not always bailing out of routing (#386)

.changeset/seven-socks-roll.md

@@ -0,0 +1,5 @@
+---
+'@cloudflare/next-on-pages': patch
+---
+
+Fix middleware redirects not always bailing out of the routing stages.

packages/next-on-pages/templates/_worker.js/routes-matcher.ts

@@ -453,8 +453,10 @@ export class RoutesMatcher {
 		// Call and process the middleware if this is a middleware route.
 		const success = await this.runRouteMiddleware(route.middlewarePath);
 		if (!success) return 'error';
-		// If the middleware set a response body, we are done.
-		if (this.body !== undefined) return 'done';
+		// If the middleware set a response body or resulted in a redirect, we are done.
+		if (this.body !== undefined || this.headers.middlewareLocation) {
+			return 'done';
+		}
 
 		// Update final headers with the ones from this route.
 		this.applyRouteHeaders(route, srcMatch, captureGroupKeys);

packages/next-on-pages/tests/templates/requestTestData/middleware.ts

@@ -27,6 +27,14 @@ const rawVercelConfig: VercelConfig = {
 			middlewareRawSrc: ['/:nextData(_next/data/[^/]{1,})?/api/:path*(.json)?'],
 			override: true,
 		},
+		{
+			src: '^/((?!.+\\.rsc).+?)(?:/)?$',
+			has: [{ type: 'header', key: 'rsc' }],
+			dest: '/$1.rsc',
+			headers: { vary: 'RSC, Next-Router-State-Tree, Next-Router-Prefetch' },
+			continue: true,
+			override: true,
+		},
 		{ handle: 'resource' },
 		{ src: '/.*', status: 404 },
 		{ handle: 'hit' },
@@ -109,6 +117,18 @@ export const testSet: TestSet = {
 				},
 			},
 		},
+		{
+			name: 'middleware route returns redirect when a later matching config rule would be an override',
+			paths: ['/api/hello?redirect'],
+			headers: { rsc: '1' },
+			expected: {
+				status: 307,
+				data: '',
+				headers: {
+					location: 'http://localhost/somewhere-else',
+				},
+			},
+		},
 		{
 			name: 'middleware route applies rewrite for `NextResponse.rewrite()`',
 			paths: ['/api/hello?rewrite'],