Allow @next plugins to be loaded without experimental flag

packages/next/build/plugins/collect-plugins.ts

@@ -23,7 +23,6 @@ export const VALID_MIDDLEWARE = [
   'on-init-server',
   'on-error-client',
   'on-error-server',
-  'babel-preset-build',
 ]
 
 type ENV_OPTIONS = { [name: string]: string }

packages/next/build/webpack-config.ts

@@ -204,24 +204,15 @@ export default async function getBaseWebpackConfig(
 ): Promise<webpack.Configuration> {
   const productionBrowserSourceMaps =
     config.experimental.productionBrowserSourceMaps && !isServer
-  let plugins: PluginMetaData[] = []
-  let babelPresetPlugins: { dir: string; config: any }[] = []
+  let plugins: PluginMetaData[] = await collectPlugins(
+    dir,
+    config.env,
+    config.plugins
+  )
 
   const hasRewrites = rewrites.length > 0 || dev
 
-  if (config.experimental.plugins) {
-    plugins = await collectPlugins(dir, config.env, config.plugins)
-    pluginLoaderOptions.plugins = plugins
-
-    for (const plugin of plugins) {
-      if (plugin.middleware.includes('babel-preset-build')) {
-        babelPresetPlugins.push({
-          dir: plugin.directory,
-          config: plugin.config,
-        })
-      }
-    }
-  }
+  pluginLoaderOptions.plugins = plugins
 
   const reactVersion = await getPackageVersion({ cwd: dir, name: 'react' })
   const hasReactRefresh: boolean = dev && !isServer
@@ -242,7 +233,6 @@ export default async function getBaseWebpackConfig(
         cwd: dir,
         // Webpack 5 has a built-in loader cache
         cache: !isWebpack5,
-        babelPresetPlugins,
         development: dev,
         hasReactRefresh,
         hasJsxRuntime,
@@ -259,9 +249,8 @@ export default async function getBaseWebpackConfig(
     /next[\\/]dist[\\/]client/,
     /next[\\/]dist[\\/]pages/,
     /[\\/](strip-ansi|ansi-regex)[\\/]/,
-    ...(config.experimental.plugins
-      ? VALID_MIDDLEWARE.map((name) => new RegExp(`src(\\\\|/)${name}`))
-      : []),
+    // Compile plugins through babel
+    ...VALID_MIDDLEWARE.map((name) => new RegExp(`src(\\\\|/)${name}`)),
   ]
 
   // Support for NODE_PATH
@@ -954,9 +943,7 @@ export default async function getBaseWebpackConfig(
         'process.env.__NEXT_BUILD_INDICATOR': JSON.stringify(
           config.devIndicators.buildActivity
         ),
-        'process.env.__NEXT_PLUGINS': JSON.stringify(
-          config.experimental.plugins
-        ),
+        'process.env.__NEXT_PLUGINS': JSON.stringify(true),
         'process.env.__NEXT_STRICT_MODE': JSON.stringify(
           config.reactStrictMode
         ),
@@ -1153,7 +1140,6 @@ export default async function getBaseWebpackConfig(
       pageExtensions: config.pageExtensions,
       trailingSlash: config.trailingSlash,
       buildActivity: config.devIndicators.buildActivity,
-      plugins: config.experimental.plugins,
       reactStrictMode: config.reactStrictMode,
       reactMode: config.experimental.reactMode,
       optimizeFonts: config.experimental.optimizeFonts,

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

@@ -28,7 +28,6 @@ module.exports = babelLoader.custom((babel) => {
       const custom = {
         isServer: opts.isServer,
         pagesDir: opts.pagesDir,
-        babelPresetPlugins: opts.babelPresetPlugins,
         development: opts.development,
         hasReactRefresh: opts.hasReactRefresh,
         hasJsxRuntime: opts.hasJsxRuntime,
@@ -64,7 +63,6 @@ module.exports = babelLoader.custom((babel) => {
       delete loader.cache
       delete loader.distDir
       delete loader.pagesDir
-      delete loader.babelPresetPlugins
       delete loader.development
       delete loader.hasReactRefresh
       delete loader.hasJsxRuntime
@@ -77,7 +75,6 @@ module.exports = babelLoader.custom((babel) => {
         customOptions: {
           isServer,
           pagesDir,
-          babelPresetPlugins,
           development,
           hasReactRefresh,
           hasJsxRuntime,
@@ -199,13 +196,6 @@ module.exports = babelLoader.custom((babel) => {
         },
       ]
 
-      for (const plugin of babelPresetPlugins) {
-        require(join(plugin.dir, 'src', 'babel-preset-build.js'))(
-          options,
-          plugin.config || {}
-        )
-      }
-
       return options
     },
   }

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

@@ -46,7 +46,6 @@ const defaultConfig: { [key: string]: any } = {
       (Number(process.env.CIRCLE_NODE_TOTAL) ||
         (os.cpus() || { length: 1 }).length) - 1
     ),
-    plugins: false,
     profiling: false,
     sprFlushToDisk: true,
     reactMode: 'legacy',

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

@@ -241,7 +241,7 @@ export default class Server {
 
     // call init-server middleware, this is also handled
     // individually in serverless bundles when deployed
-    if (!dev && this.nextConfig.experimental.plugins) {
+    if (!dev) {
       const initServer = require(join(this.serverBuildDir, 'init-server.js'))
         .default
       this.onErrorMiddleware = require(join(

test/integration/next-plugins/test/index.test.js

@@ -105,7 +105,7 @@ describe('Next.js plugins', () => {
     beforeAll(async () => {
       await fs.writeFile(
         nextConfigPath,
-        `module.exports = { env: { GA_TRACKING_ID: 'my-tracking-id' }, experimental: { plugins: true } }`
+        `module.exports = { env: { GA_TRACKING_ID: 'my-tracking-id' } }`
       )
       appPort = await findPort()
       app = await launchApp(appDir, appPort, {
@@ -128,9 +128,6 @@ describe('Next.js plugins', () => {
           nextConfigPath,
           `
         module.exports = {
-          experimental: {
-            plugins: true
-          },
           plugins: [
             {
               name: '@next/plugin-google-analytics',
@@ -171,7 +168,7 @@ describe('Next.js plugins', () => {
     beforeAll(async () => {
       await fs.writeFile(
         nextConfigPath,
-        `module.exports = { env: { GA_TRACKING_ID: 'my-tracking-id' }, experimental: { plugins: true } }`
+        `module.exports = { env: { GA_TRACKING_ID: 'my-tracking-id' } }`
       )
       const results = await nextBuild(appDir, undefined, {
         stdout: true,
@@ -194,7 +191,7 @@ describe('Next.js plugins', () => {
     beforeAll(async () => {
       await fs.writeFile(
         nextConfigPath,
-        `module.exports = { target: 'serverless', env: { GA_TRACKING_ID: 'my-tracking-id' }, experimental: { plugins: true } }`
+        `module.exports = { target: 'serverless', env: { GA_TRACKING_ID: 'my-tracking-id' } }`
       )
       const results = await nextBuild(appDir, undefined, {
         stdout: true,

test/integration/size-limit/test/index.test.js

@@ -81,6 +81,6 @@ describe('Production response size', () => {
     const delta = responseSizesBytes / 1024
 
     // Expected difference: < 0.5
-    expect(delta).toBeCloseTo(281.4, 0)
+    expect(delta).toBeCloseTo(282.4, 0)
   })
 })