Auto enable React's new JSX transform on 17.x

.github/workflows/build_test_deploy.yml

@@ -96,8 +96,8 @@ jobs:
     steps:
       - run: exit 0
 
-  testWebpack5:
-    name: webpack 5 (Basic, Production, Acceptance)
+  testFutureDependencies:
+    name: React 17 + webpack 5 (Basic, Production, Acceptance)
     runs-on: ubuntu-latest
     env:
       NEXT_TELEMETRY_DISABLED: 1
@@ -108,6 +108,8 @@ jobs:
       - uses: actions/checkout@v2
       - run: git fetch --depth=1 origin +refs/tags/*:refs/tags/*
       - run: cat package.json | jq '.resolutions.webpack = "^5.0.0-beta.22"' > package.json.tmp && mv package.json.tmp package.json
+      - run: cat package.json | jq '.resolutions.react = "^17.0.0-rc.1"' > package.json.tmp && mv package.json.tmp package.json
+      - run: cat package.json | jq '.resolutions."react-dom" = "^17.0.0-rc.1"' > package.json.tmp && mv package.json.tmp package.json
       - run: yarn install --check-files
       - run: node run-tests.js test/integration/production/test/index.test.js
       - run: node run-tests.js test/integration/basic/test/index.test.js

package.json

@@ -37,9 +37,9 @@
   },
   "pre-commit": "lint-staged",
   "devDependencies": {
-    "@babel/plugin-proposal-object-rest-spread": "7.9.6",
-    "@babel/preset-flow": "7.9.0",
-    "@babel/preset-react": "7.9.4",
+    "@babel/plugin-proposal-object-rest-spread": "7.11.0",
+    "@babel/preset-flow": "7.10.4",
+    "@babel/preset-react": "7.10.4",
     "@fullhuman/postcss-purgecss": "1.3.0",
     "@mdx-js/loader": "0.18.0",
     "@types/cheerio": "0.22.16",
@@ -53,7 +53,7 @@
     "@zeit/next-sass": "1.0.2-canary.2",
     "@zeit/next-typescript": "1.1.2-canary.0",
     "abort-controller": "3.0.0",
-    "amphtml-validator": "1.0.30",
+    "amphtml-validator": "1.0.33",
     "async-sema": "3.0.1",
     "babel-core": "7.0.0-bridge.0",
     "babel-eslint": "10.0.3",

packages/next/build/babel/preset.ts

@@ -65,6 +65,9 @@ module.exports = (
   const supportsESM = api.caller(supportsStaticESM)
   const isServer = api.caller((caller: any) => !!caller && caller.isServer)
   const isModern = api.caller((caller: any) => !!caller && caller.isModern)
+  const hasJsxRuntime = Boolean(
+    api.caller((caller: any) => !!caller && caller.hasJsxRuntime)
+  )
 
   const isLaxModern =
     isModern ||
@@ -113,7 +116,7 @@ module.exports = (
           // This adds @babel/plugin-transform-react-jsx-source and
           // @babel/plugin-transform-react-jsx-self automatically in development
           development: isDevelopment || isTest,
-          pragma: '__jsx',
+          ...(hasJsxRuntime ? { runtime: 'automatic' } : { pragma: '__jsx' }),
           ...options['preset-react'],
         },
       ],
@@ -123,7 +126,7 @@ module.exports = (
       ],
     ],
     plugins: [
-      [
+      !hasJsxRuntime && [
         require('./plugins/jsx-pragma'),
         {
           // This produces the following injected import for modules containing JSX:
@@ -181,14 +184,10 @@ module.exports = (
       require('@babel/plugin-proposal-optional-chaining'),
       require('@babel/plugin-proposal-nullish-coalescing-operator'),
       isServer && require('@babel/plugin-syntax-bigint'),
-      [require('@babel/plugin-proposal-numeric-separator').default, false],
+      // Always compile numeric separator because the resulting number is
+      // smaller.
+      require('@babel/plugin-proposal-numeric-separator'),
       require('@babel/plugin-proposal-export-namespace-from'),
     ].filter(Boolean),
-    overrides: [
-      {
-        test: /\.tsx?$/,
-        plugins: [require('@babel/plugin-proposal-numeric-separator').default],
-      },
-    ],
   }
 }

packages/next/build/webpack-config.ts

@@ -3,6 +3,7 @@ import ReactRefreshWebpackPlugin from '@next/react-refresh-utils/ReactRefreshWeb
 import crypto from 'crypto'
 import { readFileSync } from 'fs'
 import chalk from 'next/dist/compiled/chalk'
+import semver from 'next/dist/compiled/semver'
 import TerserPlugin from 'next/dist/compiled/terser-webpack-plugin'
 import path from 'path'
 import webpack from 'webpack'
@@ -14,6 +15,8 @@ import {
   PAGES_DIR_ALIAS,
 } from '../lib/constants'
 import { fileExists } from '../lib/file-exists'
+import { getPackageVersion } from '../lib/get-package-version'
+import { Rewrite } from '../lib/load-custom-routes'
 import { resolveRequest } from '../lib/resolve-request'
 import { getTypeScriptConfiguration } from '../lib/typescript/getTypeScriptConfiguration'
 import {
@@ -54,7 +57,7 @@ import WebpackConformancePlugin, {
   ReactSyncScriptsConformanceCheck,
 } from './webpack/plugins/webpack-conformance-plugin'
 import { WellKnownErrorsPlugin } from './webpack/plugins/wellknown-errors-plugin'
-import { Rewrite } from '../lib/load-custom-routes'
+
 type ExcludesFalse = <T>(x: T | false) => x is T
 
 const isWebpack5 = parseInt(webpack.version!) === 5
@@ -226,7 +229,13 @@ export default async function getBaseWebpackConfig(
     }
   }
 
-  const hasReactRefresh = dev && !isServer
+  const reactVersion = await getPackageVersion({ cwd: dir, name: 'react' })
+  const hasReactRefresh: boolean = dev && !isServer
+  const hasJsxRuntime: boolean =
+    Boolean(reactVersion) &&
+    // 17.0.0-rc.0 had a breaking change not compatible with Next.js, but was
+    // fixed in rc.1.
+    semver.gte(reactVersion!, '17.0.0-rc.1')
 
   const distDir = path.join(dir, config.distDir)
   const defaultLoaders = {
@@ -243,6 +252,7 @@ export default async function getBaseWebpackConfig(
         hasModern: !!config.experimental.modern,
         development: dev,
         hasReactRefresh,
+        hasJsxRuntime,
       },
     },
     // Backwards compat

packages/next/build/webpack/loaders/next-babel-loader.js

@@ -3,9 +3,9 @@ import hash from 'next/dist/compiled/string-hash'
 import { basename, join } from 'path'
 import * as Log from '../../output/log'
 
-// increment 'm' to invalidate cache
+// increment 'n' to invalidate cache
 // eslint-disable-next-line no-useless-concat
-const cacheKey = 'babel-cache-' + 'm' + '-'
+const cacheKey = 'babel-cache-' + 'n' + '-'
 const nextBabelPreset = require('../../babel/preset')
 
 const getModernOptions = (babelOptions = {}) => {
@@ -61,6 +61,7 @@ module.exports = babelLoader.custom((babel) => {
         babelPresetPlugins: opts.babelPresetPlugins,
         development: opts.development,
         hasReactRefresh: opts.hasReactRefresh,
+        hasJsxRuntime: opts.hasJsxRuntime,
       }
       const filename = join(opts.cwd, 'noop.js')
       const loader = Object.assign(
@@ -76,6 +77,7 @@ module.exports = babelLoader.custom((babel) => {
                 '-new-polyfills' +
                 (opts.development ? '-development' : '-production') +
                 (opts.hasReactRefresh ? '-react-refresh' : '') +
+                (opts.hasJsxRuntime ? '-jsx-runtime' : '') +
                 JSON.stringify(
                   babel.loadPartialConfig({
                     filename,
@@ -99,6 +101,7 @@ module.exports = babelLoader.custom((babel) => {
       delete loader.babelPresetPlugins
       delete loader.development
       delete loader.hasReactRefresh
+      delete loader.hasJsxRuntime
       return { loader, custom }
     },
     config(
@@ -113,6 +116,7 @@ module.exports = babelLoader.custom((babel) => {
           babelPresetPlugins,
           development,
           hasReactRefresh,
+          hasJsxRuntime,
         },
       }
     ) {
@@ -136,6 +140,7 @@ module.exports = babelLoader.custom((babel) => {
       options.caller.isServer = isServer
       options.caller.isModern = isModern
       options.caller.isDev = development
+      options.caller.hasJsxRuntime = hasJsxRuntime
 
       const emitWarning = this.emitWarning.bind(this)
       Object.defineProperty(options.caller, 'onWarning', {

packages/next/package.json

@@ -59,24 +59,24 @@
   },
   "dependencies": {
     "@ampproject/toolbox-optimizer": "2.6.0",
-    "@babel/code-frame": "7.8.3",
+    "@babel/code-frame": "7.10.4",
     "@babel/core": "7.7.7",
-    "@babel/plugin-proposal-class-properties": "7.8.3",
+    "@babel/plugin-proposal-class-properties": "7.10.4",
     "@babel/plugin-proposal-export-namespace-from": "7.10.4",
-    "@babel/plugin-proposal-nullish-coalescing-operator": "7.8.3",
-    "@babel/plugin-proposal-numeric-separator": "7.8.3",
-    "@babel/plugin-proposal-object-rest-spread": "7.9.6",
-    "@babel/plugin-proposal-optional-chaining": "7.9.0",
+    "@babel/plugin-proposal-nullish-coalescing-operator": "7.10.4",
+    "@babel/plugin-proposal-numeric-separator": "7.10.4",
+    "@babel/plugin-proposal-object-rest-spread": "7.11.0",
+    "@babel/plugin-proposal-optional-chaining": "7.11.0",
     "@babel/plugin-syntax-bigint": "7.8.3",
     "@babel/plugin-syntax-dynamic-import": "7.8.3",
-    "@babel/plugin-transform-modules-commonjs": "7.9.6",
-    "@babel/plugin-transform-runtime": "7.9.6",
-    "@babel/preset-env": "7.9.6",
-    "@babel/preset-modules": "0.1.3",
-    "@babel/preset-react": "7.9.4",
-    "@babel/preset-typescript": "7.9.0",
-    "@babel/runtime": "7.9.6",
-    "@babel/types": "7.9.6",
+    "@babel/plugin-transform-modules-commonjs": "7.10.4",
+    "@babel/plugin-transform-runtime": "7.11.5",
+    "@babel/preset-env": "7.11.5",
+    "@babel/preset-modules": "0.1.4",
+    "@babel/preset-react": "7.10.4",
+    "@babel/preset-typescript": "7.10.4",
+    "@babel/runtime": "7.11.2",
+    "@babel/types": "7.11.5",
     "@next/react-dev-overlay": "9.5.3-canary.25",
     "@next/react-refresh-utils": "9.5.3-canary.25",
     "ast-types": "0.13.2",
@@ -160,7 +160,7 @@
     "@types/text-table": "0.2.1",
     "@types/webpack-sources": "0.1.5",
     "@zeit/ncc": "0.22.0",
-    "amphtml-validator": "1.0.31",
+    "amphtml-validator": "1.0.33",
     "arg": "4.1.0",
     "async-retry": "1.2.3",
     "async-sema": "3.0.0",
@@ -169,7 +169,7 @@
     "cache-loader": "4.1.0",
     "chalk": "2.4.2",
     "ci-info": "watson/ci-info#f43f6a1cefff47fb361c88cf4b943fdbcaafe540",
-    "comment-json": "3.0.2",
+    "comment-json": "3.0.3",
     "compression": "1.7.4",
     "conf": "5.0.0",
     "content-type": "1.0.4",

packages/react-dev-overlay/package.json

@@ -16,7 +16,7 @@
     "build": "tsc -d -w -p tsconfig.json"
   },
   "dependencies": {
-    "@babel/code-frame": "7.8.3",
+    "@babel/code-frame": "7.10.4",
     "ally.js": "1.4.1",
     "anser": "1.4.9",
     "chalk": "4.0.0",

test/acceptance/ReactRefreshLogBox.test.js

@@ -238,6 +238,7 @@ test('render error not shown right after syntax error', async () => {
   await session.patch(
     'index.js',
     `
+      import * as React from 'react';
       class ClassDefault extends React.Component {
         render() {
           return <h1>Default Export</h1>;
@@ -576,6 +577,7 @@ test('boundaries', async () => {
     'index.js',
     `
       import FunctionDefault from './FunctionDefault.js'
+      import * as React from 'react'
       class ErrorBoundary extends React.Component {
         constructor() {
           super()

test/acceptance/helpers.js

@@ -38,6 +38,9 @@ export async function sandbox(
   })
   const browser = await webdriver(appPort, '/')
 
+  // Slow down tests a bit to ensure application is ready:
+  await new Promise((resolve) => setTimeout(resolve, 750))
+
   return [
     {
       sandboxDirectory,

test/integration/basic/test/dynamic.js

@@ -13,17 +13,17 @@ export default (context, render) => {
       it('should render dynamic import components', async () => {
         const $ = await get$('/dynamic/ssr')
         // Make sure the client side knows it has to wait for the bundle
-        expect($('body').html()).toContain(
-          '"dynamicIds":["./components/hello1.js"]'
+        expect(JSON.parse($('#__NEXT_DATA__').html()).dynamicIds).toContain(
+          './components/hello1.js'
         )
         expect($('body').text()).toMatch(/Hello World 1/)
       })
 
       it('should render dynamic import components using a function as first parameter', async () => {
         const $ = await get$('/dynamic/function')
         // Make sure the client side knows it has to wait for the bundle
-        expect($('body').html()).toContain(
-          '"dynamicIds":["./components/hello1.js"]'
+        expect(JSON.parse($('#__NEXT_DATA__').html()).dynamicIds).toContain(
+          './components/hello1.js'
         )
         expect($('body').text()).toMatch(/Hello World 1/)
       })

test/integration/basic/test/error-recovery.js

@@ -253,22 +253,9 @@ export default (context, renderViaHTTP) => {
             '__WEBPACK_DEFAULT_EXPORT__',
             'Unknown'
           )
-        ).toMatchInlineSnapshot(`
-          " 1 of 1 unhandled error
-          Server Error
-
-          Error: Objects are not valid as a React child (found: /search/). If you meant to render a collection of children, use an array instead.
-              in Unknown
-              in App
-              in Unknown
-              in Context.Provider
-              in Context.Provider
-              in Context.Provider
-              in Context.Provider
-              in AppContainer
-
-          This error happened while generating the page. Any console logs will be displayed in the terminal window."
-        `)
+        ).toMatch(
+          'Objects are not valid as a React child (found: /search/). If you meant to render a collection of children, use an array instead.'
+        )
 
         aboutPage.restore()
 

test/integration/numeric-sep/test/index.test.js

@@ -0,0 +1,22 @@
+/* eslint-env jest */
+
+import { nextBuild } from 'next-test-utils'
+import { join } from 'path'
+
+jest.setTimeout(1000 * 60 * 2)
+
+const appDir = join(__dirname, '../')
+
+describe('Numeric Separator Support', () => {
+  it('should successfully build for a JavaScript file', async () => {
+    const { code, stdout, stderr } = await nextBuild(appDir, [], {
+      stdout: true,
+      stderr: true,
+    })
+
+    expect(code).toBe(0)
+
+    expect(stdout).toContain('Compiled successfully')
+    expect(stderr).not.toContain('Failed to compile')
+  })
+})