Revert "feat: make enableUndici: true default and remove `node-fetc…

…h` (vercel#49061)"

This reverts commit e6acd40.

packages/next-swc/crates/next-core/js/src/polyfill/app-polyfills.ts

@@ -2,3 +2,4 @@ import 'next/dist/server/node-polyfill-fetch'
 import 'next/dist/server/node-polyfill-web-streams'
 import 'next/dist/server/node-polyfill-headers'
 import './async-local-storage'
+;(globalThis as any).__NEXT_USE_UNDICI = true

packages/next/src/build/index.ts

@@ -1263,6 +1263,7 @@ export default async function build(
               configFileName,
               runtimeEnvConfig,
               httpAgentOptions: config.httpAgentOptions,
+              enableUndici: config.experimental.enableUndici,
               locales: config.i18n?.locales,
               defaultLocale: config.i18n?.defaultLocale,
               nextConfigOutput: config.output,
@@ -1422,7 +1423,6 @@ export default async function build(
                   if (pageType === 'app' || !isReservedPage(page)) {
                     try {
                       let edgeInfo: any
-
                       if (isEdgeRuntime(pageRuntime)) {
                         if (pageType === 'app') {
                           edgeRuntimeAppCount++

packages/next/src/build/utils.ts

@@ -1327,6 +1327,7 @@ export async function isPageStatic({
   configFileName,
   runtimeEnvConfig,
   httpAgentOptions,
+  enableUndici,
   locales,
   defaultLocale,
   parentId,
@@ -1344,6 +1345,7 @@ export async function isPageStatic({
   configFileName: string
   runtimeEnvConfig: any
   httpAgentOptions: NextConfigComplete['httpAgentOptions']
+  enableUndici?: NextConfigComplete['experimental']['enableUndici']
   locales?: string[]
   defaultLocale?: string
   parentId?: any
@@ -1376,6 +1378,7 @@ export async function isPageStatic({
       require('../shared/lib/runtime-config').setConfig(runtimeEnvConfig)
       setHttpClientAndAgentOptions({
         httpAgentOptions,
+        experimental: { enableUndici },
       })
 
       let componentsResult: LoadComponentsReturnType

packages/next/src/cli/next-info.ts

@@ -4,9 +4,7 @@ import childProcess from 'child_process'
 
 import chalk from 'next/dist/compiled/chalk'
 import arg from 'next/dist/compiled/arg/index.js'
-const { fetch } = require('next/dist/compiled/undici') as {
-  fetch: typeof global.fetch
-}
+import fetch from 'next/dist/compiled/node-fetch'
 import { printAndExit } from '../server/lib/utils'
 import { CliCommand } from '../lib/commands'
 import isError from '../lib/is-error'

packages/next/src/export/index.ts

@@ -725,6 +725,7 @@ export default async function exportApp(
             parentSpanId: pageExportSpan.id,
             httpAgentOptions: nextConfig.httpAgentOptions,
             serverComponents: options.hasAppDir,
+            enableUndici: nextConfig.experimental.enableUndici,
             debugOutput: options.debugOutput,
             isrMemoryCacheSize: nextConfig.experimental.isrMemoryCacheSize,
             fetchCache: nextConfig.experimental.appDir,

packages/next/src/export/worker.ts

@@ -80,6 +80,7 @@ interface ExportPageInput {
   parentSpanId: any
   httpAgentOptions: NextConfigComplete['httpAgentOptions']
   serverComponents?: boolean
+  enableUndici: NextConfigComplete['experimental']['enableUndici']
   debugOutput?: boolean
   isrMemoryCacheSize?: NextConfigComplete['experimental']['isrMemoryCacheSize']
   fetchCache?: boolean
@@ -137,6 +138,7 @@ export default async function exportPage({
   disableOptimizedLoading,
   httpAgentOptions,
   serverComponents,
+  enableUndici,
   debugOutput,
   isrMemoryCacheSize,
   fetchCache,
@@ -145,6 +147,7 @@ export default async function exportPage({
 }: ExportPageInput): Promise<ExportPageResults> {
   setHttpClientAndAgentOptions({
     httpAgentOptions,
+    experimental: { enableUndici },
   })
   const exportPageSpan = trace('export-page-worker', parentSpanId)
 

packages/next/src/lib/download-wasm-swc.ts

@@ -3,12 +3,7 @@ import fs from 'fs'
 import path from 'path'
 import * as Log from '../build/output/log'
 import tar from 'next/dist/compiled/tar'
-const { fetch } = require('next/dist/compiled/undici') as {
-  fetch: typeof global.fetch
-}
-const { WritableStream } = require('node:stream/web') as {
-  WritableStream: typeof global.WritableStream
-}
+import fetch from 'next/dist/compiled/node-fetch'
 import { fileExists } from './file-exists'
 import { getRegistry } from './helpers/get-registry'
 
@@ -102,24 +97,17 @@ export async function downloadWasmSwc(
     const registry = getRegistry()
 
     await fetch(`${registry}${pkgName}/-/${tarFileName}`).then((res) => {
-      const { ok, body } = res
-      if (!ok) {
+      if (!res.ok) {
         throw new Error(`request failed with status ${res.status}`)
       }
-      if (!body) {
-        throw new Error('request failed with empty body')
-      }
       const cacheWriteStream = fs.createWriteStream(tempFile)
-      return body.pipeTo(
-        new WritableStream({
-          write(chunk) {
-            cacheWriteStream.write(chunk)
-          },
-          close() {
-            cacheWriteStream.close()
-          },
-        })
-      )
+
+      return new Promise<void>((resolve, reject) => {
+        res.body
+          .pipe(cacheWriteStream)
+          .on('error', (err) => reject(err))
+          .on('finish', () => resolve())
+      }).finally(() => cacheWriteStream.close())
     })
     await fs.promises.rename(tempFile, path.join(cacheDirectory, tarFileName))
   }

packages/next/src/server/config-schema.ts

@@ -420,6 +420,9 @@ const configSchema = {
           },
           type: 'array',
         },
+        enableUndici: {
+          type: 'boolean',
+        },
         workerThreads: {
           type: 'boolean',
         },

packages/next/src/server/config-shared.ts

@@ -217,6 +217,7 @@ export interface ExperimentalConfig {
    * [webpack/webpack#ModuleNotoundError.js#L13-L42](https://github.com/webpack/webpack/blob/2a0536cf510768111a3a6dceeb14cb79b9f59273/lib/ModuleNotFoundError.js#L13-L42)
    */
   fallbackNodePolyfills?: false
+  enableUndici?: boolean
   sri?: {
     algorithm?: SubresourceIntegrityAlgorithm
   }
@@ -702,6 +703,7 @@ export const defaultConfig: NextConfig = {
     disablePostcssPresetEnv: undefined,
     amp: undefined,
     urlImports: undefined,
+    enableUndici: false,
     adjustFontFallbacks: false,
     adjustFontFallbacksWithSizeAdjust: false,
     turbo: undefined,

packages/next/src/server/config.ts

@@ -19,11 +19,17 @@ import {
 import { loadWebpackHook } from './config-utils'
 import { ImageConfig, imageConfigDefault } from '../shared/lib/image-config'
 import { loadEnvConfig, updateInitialEnv } from '@next/env'
+import { gte as semverGte } from 'next/dist/compiled/semver'
 import { flushAndExit } from '../telemetry/flush-and-exit'
 import { findRootDir } from '../lib/find-root'
 
 export { DomainLocale, NextConfig, normalizeConfig } from './config-shared'
 
+const NODE_16_VERSION = '16.8.0'
+const NODE_18_VERSION = '18.0.0'
+const isAboveNodejs16 = semverGte(process.version, NODE_16_VERSION)
+const isAboveNodejs18 = semverGte(process.version, NODE_18_VERSION)
+
 const experimentalWarning = execOnce(
   (configFileName: string, features: string[]) => {
     const s = features.length > 1 ? 's' : ''
@@ -43,9 +49,26 @@ const experimentalWarning = execOnce(
   }
 )
 
-export function setHttpClientAndAgentOptions(config: {
-  httpAgentOptions?: NextConfig['httpAgentOptions']
-}) {
+export function setHttpClientAndAgentOptions(
+  config: {
+    httpAgentOptions?: NextConfig['httpAgentOptions']
+    experimental?: {
+      enableUndici?: boolean
+    }
+  },
+  silent = false
+) {
+  if (isAboveNodejs16) {
+    // Node.js 18 has undici built-in.
+    if (config.experimental?.enableUndici && !isAboveNodejs18) {
+      // When appDir is enabled undici is the default because of Response.clone() issues in node-fetch
+      ;(globalThis as any).__NEXT_USE_UNDICI = config.experimental?.enableUndici
+    }
+  } else if (config.experimental?.enableUndici && !silent) {
+    Log.warn(
+      `\`enableUndici\` option requires Node.js v${NODE_16_VERSION} or greater. Falling back to \`node-fetch\``
+    )
+  }
   if ((globalThis as any).__NEXT_HTTP_AGENT) {
     // We only need to assign once because we want
     // to reuse the same agent for all requests.
@@ -263,6 +286,10 @@ function assignDefaults(
     )
   }
 
+  if (result.experimental?.appDir) {
+    result.experimental.enableUndici = true
+  }
+
   if (result.basePath !== '') {
     if (result.basePath === '/') {
       throw new Error(
@@ -485,7 +512,7 @@ function assignDefaults(
     result.output = undefined
   }
 
-  setHttpClientAndAgentOptions(result || defaultConfig)
+  setHttpClientAndAgentOptions(result || defaultConfig, silent)
 
   if (result.i18n) {
     const { i18n } = result
@@ -832,6 +859,6 @@ export default async function loadConfig(
     silent
   ) as NextConfigComplete
   completeConfig.configFileName = configFileName
-  setHttpClientAndAgentOptions(completeConfig)
+  setHttpClientAndAgentOptions(completeConfig, silent)
   return completeConfig
 }

packages/next/src/server/dev/next-dev-server.ts

@@ -1650,6 +1650,7 @@ export default class DevServer extends Server {
         publicRuntimeConfig,
         serverRuntimeConfig,
         httpAgentOptions,
+        experimental: { enableUndici },
       } = this.nextConfig
       const { locales, defaultLocale } = this.nextConfig.i18n || {}
       const staticPathsWorker = this.getStaticPathsWorker()
@@ -1664,6 +1665,7 @@ export default class DevServer extends Server {
             serverRuntimeConfig,
           },
           httpAgentOptions,
+          enableUndici,
           locales,
           defaultLocale,
           originalAppPath,

packages/next/src/server/dev/static-paths-worker.ts

@@ -26,6 +26,7 @@ export async function loadStaticPaths({
   pathname,
   config,
   httpAgentOptions,
+  enableUndici,
   locales,
   defaultLocale,
   isAppPath,
@@ -40,6 +41,7 @@ export async function loadStaticPaths({
   pathname: string
   config: RuntimeConfig
   httpAgentOptions: NextConfigComplete['httpAgentOptions']
+  enableUndici: NextConfigComplete['enableUndici']
   locales?: string[]
   defaultLocale?: string
   isAppPath?: boolean
@@ -58,6 +60,7 @@ export async function loadStaticPaths({
   require('../../shared/lib/runtime-config').setConfig(config)
   setHttpClientAndAgentOptions({
     httpAgentOptions,
+    experimental: { enableUndici },
   })
 
   const components = await loadComponents({

packages/next/src/server/node-polyfill-fetch.ts

@@ -3,7 +3,9 @@
 
 if (typeof fetch === 'undefined' && typeof globalThis.fetch === 'undefined') {
   function getFetchImpl() {
-    return require('next/dist/compiled/undici')
+    return (global as any).__NEXT_USE_UNDICI
+      ? require('next/dist/compiled/undici')
+      : require('next/dist/compiled/node-fetch')
   }
 
   function getRequestImpl() {
@@ -20,19 +22,30 @@ if (typeof fetch === 'undefined' && typeof globalThis.fetch === 'undefined') {
   globalThis.fetch = (...args: any[]) => {
     const fetchImpl = getFetchImpl()
 
-    // Undici does not support the `keepAlive` option,
-    // instead we have to pass a custom dispatcher
-    if (
-      !(global as any).__NEXT_HTTP_AGENT_OPTIONS?.keepAlive &&
-      !(global as any).__NEXT_UNDICI_AGENT_SET
-    ) {
-      ;(global as any).__NEXT_UNDICI_AGENT_SET = true
-      fetchImpl.setGlobalDispatcher(new fetchImpl.Agent({ pipelining: 0 }))
-      console.warn(
-        'Warning - Configuring `keepAlive: false` is deprecated. Use `{ headers: { connection: "close" } }` instead.'
-      )
+    if ((global as any).__NEXT_USE_UNDICI) {
+      // Undici does not support the `keepAlive` option,
+      // instead we have to pass a custom dispatcher
+      if (
+        !(global as any).__NEXT_HTTP_AGENT_OPTIONS?.keepAlive &&
+        !(global as any).__NEXT_UNDICI_AGENT_SET
+      ) {
+        ;(global as any).__NEXT_UNDICI_AGENT_SET = true
+        fetchImpl.setGlobalDispatcher(new fetchImpl.Agent({ pipelining: 0 }))
+      }
+      return fetchImpl.fetch(...args)
+    }
+    const agent = ({ protocol }: any) =>
+      protocol === 'http:'
+        ? (global as any).__NEXT_HTTP_AGENT
+        : (global as any).__NEXT_HTTPS_AGENT
+
+    if (!args[1]) {
+      args[1] = { agent }
+    } else if (!args[1].agent) {
+      args[1].agent = agent
     }
-    return fetchImpl.fetch(...args)
+
+    return fetchImpl(...args)
   }
 
   Object.defineProperties(global, {

packages/next/src/telemetry/post-payload.ts

@@ -1,20 +1,15 @@
 import retry from 'next/dist/compiled/async-retry'
-const { fetch } = require('next/dist/compiled/undici') as {
-  fetch: typeof global.fetch
-}
+import fetch from 'next/dist/compiled/node-fetch'
 
 export function _postPayload(endpoint: string, body: object, signal?: any) {
-  if (!signal && 'timeout' in AbortSignal) {
-    // @ts-expect-error Needs @types/node@16.14.0 or newer
-    signal = AbortSignal.timeout(5000)
-  }
   return (
     retry(
       () =>
         fetch(endpoint, {
           method: 'POST',
           body: JSON.stringify(body),
           headers: { 'content-type': 'application/json' },
+          timeout: 5000,
           signal,
         }).then((res) => {
           if (!res.ok) {

packages/next/taskfile-swc.js

@@ -70,8 +70,8 @@ module.exports = function (task) {
         },
         env: {
           targets: {
-            // Follows version defined in packages/next/package.json#engine
-            // Currently a few minors behind due to babel class transpiling
+            // Should match version defined in packages/next/package.json#engine
+            // Should also match NODE_16_VERSION in packages/next/src/server/config.ts
             node: '16.8.0',
           },
         },