Ensure proxy rewrite does not hang on error

packages/next/next-server/server/next-server.ts

@@ -924,12 +924,29 @@ export default class Server {
               target,
               changeOrigin: true,
               ignorePath: true,
+              proxyTimeout: 30_000, // limit proxying to 30 seconds
             })
-            proxy.web(req, res)
 
-            proxy.on('error', (err: Error) => {
-              console.error(`Error occurred proxying ${target}`, err)
+            await new Promise((proxyResolve, proxyReject) => {
+              let finished = false
+
+              proxy.on('proxyReq', (proxyReq) => {
+                proxyReq.on('close', () => {
+                  if (!finished) {
+                    finished = true
+                    proxyResolve(true)
+                  }
+                })
+              })
+              proxy.on('error', (err) => {
+                if (!finished) {
+                  finished = true
+                  proxyReject(err)
+                }
+              })
+              proxy.web(req, res)
             })
+
             return {
               finished: true,
             }

test/integration/custom-routes/next.config.js

@@ -11,6 +11,10 @@ module.exports = {
               },
             ]
           : []),
+        {
+          source: '/to-nowhere',
+          destination: 'http://localhost:12233',
+        },
         {
           source: '/rewriting-to-auto-export',
           destination: '/auto-export/hello?rewrite=1',

test/integration/custom-routes/test/index.test.js

@@ -38,6 +38,14 @@ let appPort
 let app
 
 const runTests = (isDev = false) => {
+  it('should not hang when proxy rewrite fails', async () => {
+    const res = await fetchViaHTTP(appPort, '/to-nowhere', undefined, {
+      timeout: 5000,
+    })
+
+    expect(res.status).toBe(500)
+  })
+
   it('should parse params correctly for rewrite to auto-export dynamic page', async () => {
     const browser = await webdriver(appPort, '/rewriting-to-auto-export')
     const text = await browser.eval(() => document.documentElement.innerHTML)
@@ -1395,6 +1403,11 @@ const runTests = (isDev = false) => {
             },
           ],
           afterFiles: [
+            {
+              destination: 'http://localhost:12233',
+              regex: normalizeRegEx('^\\/to-nowhere$'),
+              source: '/to-nowhere',
+            },
             {
               destination: '/auto-export/hello?rewrite=1',
               regex: normalizeRegEx('^\\/rewriting-to-auto-export$'),