Lazy-load postcss

.gitignore

@@ -13,6 +13,7 @@ test/node_modules
 # logs & pids
 *.log
 pids
+*.cpuprofile
 
 # coverage
 .nyc_output
@@ -41,4 +42,4 @@ test-timings.json
 .now
 
 # Cache
-*.tsbuildinfo
+*.tsbuildinfo

packages/next/build/webpack-config.ts

@@ -33,7 +33,6 @@ import { NextConfigComplete } from '../server/config-shared'
 import { finalizeEntrypoint } from './entries'
 import * as Log from './output/log'
 import { build as buildConfiguration } from './webpack/config'
-import { __overrideCssConfiguration } from './webpack/config/blocks/css/overrideCssConfiguration'
 import MiddlewarePlugin from './webpack/plugins/middleware-plugin'
 import BuildManifestPlugin from './webpack/plugins/build-manifest-plugin'
 import { JsConfigPathsPlugin } from './webpack/plugins/jsconfig-paths-plugin'
@@ -1707,6 +1706,7 @@ export default async function getBaseWebpackConfig(
     future: config.future,
     experimental: config.experimental,
     disableStaticImages: config.images.disableStaticImages,
+    disablePostcssPresetEnv: config.disablePostcssPresetEnv,
   })
 
   // @ts-ignore Cache exists
@@ -1896,8 +1896,6 @@ export default async function getBaseWebpackConfig(
           (e) => (e as any).__next_css_remove !== true
         )
     }
-  } else if (!config.future.strictPostcssConfiguration) {
-    await __overrideCssConfiguration(dir, supportedBrowsers, webpackConfig)
   }
 
   // Inject missing React Refresh loaders so that development mode is fast:

packages/next/build/webpack/config/blocks/css/index.ts

@@ -11,69 +11,6 @@ import {
   getLocalModuleImportError,
 } from './messages'
 import { getPostCssPlugins } from './plugins'
-import postcss from 'postcss'
-
-// @ts-ignore backwards compat
-postcss.plugin = function postcssPlugin(name, initializer) {
-  function creator(...args: any) {
-    let transformer = initializer(...args)
-    transformer.postcssPlugin = name
-    // transformer.postcssVersion = new Processor().version
-    return transformer
-  }
-
-  let cache: any
-  Object.defineProperty(creator, 'postcss', {
-    get() {
-      if (!cache) cache = creator()
-      return cache
-    },
-  })
-
-  creator.process = function (css: any, processOpts: any, pluginOpts: any) {
-    return postcss([creator(pluginOpts)]).process(css, processOpts)
-  }
-
-  return creator
-}
-
-// @ts-ignore backwards compat
-postcss.vendor = {
-  /**
-   * Returns the vendor prefix extracted from an input string.
-   *
-   * @param {string} prop String with or without vendor prefix.
-   *
-   * @return {string} vendor prefix or empty string
-   *
-   * @example
-   * postcss.vendor.prefix('-moz-tab-size') //=> '-moz-'
-   * postcss.vendor.prefix('tab-size')      //=> ''
-   */
-  prefix: function prefix(prop: any) {
-    const match = prop.match(/^(-\w+-)/)
-
-    if (match) {
-      return match[0]
-    }
-
-    return ''
-  },
-
-  /**
-   * Returns the input string stripped of its vendor prefix.
-   *
-   * @param {string} prop String with or without vendor prefix.
-   *
-   * @return {string} String name without vendor prefixes.
-   *
-   * @example
-   * postcss.vendor.unprefixed('-moz-tab-size') //=> 'tab-size'
-   */
-  unprefixed: function unprefixed(prop: any) {
-    return prop.replace(/^-\w+-/, '')
-  },
-}
 
 // RegExps for all Style Sheet variants
 export const regexLikeCss = /\.(css|scss|sass)$/
@@ -86,6 +23,94 @@ const regexCssModules = /\.module\.css$/
 const regexSassGlobal = /(?<!\.module)\.(scss|sass)$/
 const regexSassModules = /\.module\.(scss|sass)$/
 
+let postcssInstancePromise: Promise<any>
+async function lazyPostCSS(ctx: ConfigurationContext) {
+  if (!postcssInstancePromise) {
+    postcssInstancePromise = (async () => {
+      const postcss = require('postcss')
+      // @ts-ignore backwards compat
+      postcss.plugin = function postcssPlugin(name, initializer) {
+        function creator(...args: any) {
+          let transformer = initializer(...args)
+          transformer.postcssPlugin = name
+          // transformer.postcssVersion = new Processor().version
+          return transformer
+        }
+
+        let cache: any
+        Object.defineProperty(creator, 'postcss', {
+          get() {
+            if (!cache) cache = creator()
+            return cache
+          },
+        })
+
+        creator.process = function (
+          css: any,
+          processOpts: any,
+          pluginOpts: any
+        ) {
+          return postcss([creator(pluginOpts)]).process(css, processOpts)
+        }
+
+        return creator
+      }
+
+      // @ts-ignore backwards compat
+      postcss.vendor = {
+        /**
+         * Returns the vendor prefix extracted from an input string.
+         *
+         * @param {string} prop String with or without vendor prefix.
+         *
+         * @return {string} vendor prefix or empty string
+         *
+         * @example
+         * postcss.vendor.prefix('-moz-tab-size') //=> '-moz-'
+         * postcss.vendor.prefix('tab-size')      //=> ''
+         */
+        prefix: function prefix(prop: any) {
+          const match = prop.match(/^(-\w+-)/)
+
+          if (match) {
+            return match[0]
+          }
+
+          return ''
+        },
+
+        /**
+         * Returns the input string stripped of its vendor prefix.
+         *
+         * @param {string} prop String with or without vendor prefix.
+         *
+         * @return {string} String name without vendor prefixes.
+         *
+         * @example
+         * postcss.vendor.unprefixed('-moz-tab-size') //=> 'tab-size'
+         */
+        unprefixed: function unprefixed(prop: any) {
+          return prop.replace(/^-\w+-/, '')
+        },
+      }
+
+      const postCssPlugins = await getPostCssPlugins(
+        ctx.rootDirectory,
+        ctx.supportedBrowsers,
+        !ctx.future.strictPostcssConfiguration,
+        ctx.experimental.disablePostcssPresetEnv
+      )
+
+      return {
+        postcss,
+        postcssWithPlugins: postcss(postCssPlugins),
+      }
+    })()
+  }
+
+  return postcssInstancePromise
+}
+
 export const css = curry(async function css(
   ctx: ConfigurationContext,
   config: webpack.Configuration
@@ -137,12 +162,6 @@ export const css = curry(async function css(
     }),
   ]
 
-  const postCssPlugins = await getPostCssPlugins(
-    ctx.rootDirectory,
-    ctx.supportedBrowsers,
-    !ctx.future.strictPostcssConfiguration
-  )
-
   // CSS cannot be imported in _document. This comes before everything because
   // global CSS nor CSS modules work in said file.
   fns.push(
@@ -183,7 +202,7 @@ export const css = curry(async function css(
             and: [ctx.rootDirectory],
             not: [/node_modules/],
           },
-          use: getCssModuleLoader(ctx, postCssPlugins),
+          use: getCssModuleLoader(ctx, () => lazyPostCSS(ctx)),
         },
       ],
     })
@@ -206,7 +225,11 @@ export const css = curry(async function css(
             and: [ctx.rootDirectory],
             not: [/node_modules/],
           },
-          use: getCssModuleLoader(ctx, postCssPlugins, sassPreprocessors),
+          use: getCssModuleLoader(
+            ctx,
+            () => lazyPostCSS(ctx),
+            sassPreprocessors
+          ),
         },
       ],
     })
@@ -266,7 +289,7 @@ export const css = curry(async function css(
                   and: [ctx.rootDirectory],
                   not: [/node_modules/],
                 },
-            use: getGlobalCssLoader(ctx, postCssPlugins),
+            use: getGlobalCssLoader(ctx, () => lazyPostCSS(ctx)),
           },
         ],
       })
@@ -284,7 +307,7 @@ export const css = curry(async function css(
               sideEffects: true,
               test: regexCssGlobal,
               issuer: { and: [ctx.customAppFile] },
-              use: getGlobalCssLoader(ctx, postCssPlugins),
+              use: getGlobalCssLoader(ctx, () => lazyPostCSS(ctx)),
             },
           ],
         })
@@ -300,7 +323,11 @@ export const css = curry(async function css(
               sideEffects: true,
               test: regexSassGlobal,
               issuer: { and: [ctx.customAppFile] },
-              use: getGlobalCssLoader(ctx, postCssPlugins, sassPreprocessors),
+              use: getGlobalCssLoader(
+                ctx,
+                () => lazyPostCSS(ctx),
+                sassPreprocessors
+              ),
             },
           ],
         })

packages/next/build/webpack/config/blocks/css/loaders/global.ts

@@ -1,13 +1,11 @@
-import { AcceptedPlugin } from 'postcss'
 import { webpack } from 'next/dist/compiled/webpack/webpack'
 import { ConfigurationContext } from '../../../utils'
 import { getClientStyleLoader } from './client'
 import { cssFileResolve } from './file-resolve'
-import postcss from 'postcss'
 
 export function getGlobalCssLoader(
   ctx: ConfigurationContext,
-  postCssPlugins: AcceptedPlugin[],
+  postcss: any,
   preProcessors: readonly webpack.RuleSetUseItem[] = []
 ): webpack.RuleSetUseItem[] {
   const loaders: webpack.RuleSetUseItem[] = []
@@ -27,6 +25,7 @@ export function getGlobalCssLoader(
   loaders.push({
     loader: require.resolve('../../../../loaders/css-loader/src'),
     options: {
+      postcss,
       importLoaders: 1 + preProcessors.length,
       // Next.js controls CSS Modules eligibility:
       modules: false,
@@ -41,7 +40,7 @@ export function getGlobalCssLoader(
   loaders.push({
     loader: require.resolve('../../../../loaders/postcss-loader/src'),
     options: {
-      postcss: postcss(postCssPlugins),
+      postcss,
     },
   })
 

packages/next/build/webpack/config/blocks/css/loaders/modules.ts

@@ -1,14 +1,12 @@
-import { AcceptedPlugin } from 'postcss'
 import { webpack } from 'next/dist/compiled/webpack/webpack'
 import { ConfigurationContext } from '../../../utils'
 import { getClientStyleLoader } from './client'
 import { cssFileResolve } from './file-resolve'
 import { getCssModuleLocalIdent } from './getCssModuleLocalIdent'
-import postcss from 'postcss'
 
 export function getCssModuleLoader(
   ctx: ConfigurationContext,
-  postCssPlugins: AcceptedPlugin[],
+  postcss: any,
   preProcessors: readonly webpack.RuleSetUseItem[] = []
 ): webpack.RuleSetUseItem[] {
   const loaders: webpack.RuleSetUseItem[] = []
@@ -28,6 +26,7 @@ export function getCssModuleLoader(
   loaders.push({
     loader: require.resolve('../../../../loaders/css-loader/src'),
     options: {
+      postcss,
       importLoaders: 1 + preProcessors.length,
       // Use CJS mode for backwards compatibility:
       esModule: false,
@@ -57,7 +56,7 @@ export function getCssModuleLoader(
   loaders.push({
     loader: require.resolve('../../../../loaders/postcss-loader/src'),
     options: {
-      postcss: postcss(postCssPlugins),
+      postcss,
     },
   })