From b508781ea5e1fa81c0e6e41214184cd8e8bdbc57 Mon Sep 17 00:00:00 2001
From: Haoqun Jiang <haoqunjiang@gmail.com>
Date: Wed, 24 Mar 2021 16:09:02 +0800
Subject: [PATCH 1/2] Revert "fix: work around npm6/postcss8 hoisting issue
 (#6358)"

This reverts commit 27b4263ed299e219aa5fbe7b024c226e5775c549.
---
 packages/@vue/cli-service/bin/postinstall.js  | 31 -------------------
 .../cli-service/generator/hotfix-npm6only.js  |  8 -----
 packages/@vue/cli-service/generator/index.js  |  7 -----
 packages/@vue/cli-service/package.json        |  3 --
 4 files changed, 49 deletions(-)
 delete mode 100644 packages/@vue/cli-service/bin/postinstall.js
 delete mode 100644 packages/@vue/cli-service/generator/hotfix-npm6only.js

diff --git a/packages/@vue/cli-service/bin/postinstall.js b/packages/@vue/cli-service/bin/postinstall.js
deleted file mode 100644
index b134954d1c..0000000000
--- a/packages/@vue/cli-service/bin/postinstall.js
+++ /dev/null
@@ -1,31 +0,0 @@
-const fs = require('fs')
-const path = require('path')
-
-const { semver } = require('@vue/cli-shared-utils')
-
-const cwd = process.cwd()
-
-const userAgent = process.env.npm_config_user_agent
-const usesNpm6 = userAgent && userAgent.startsWith('npm/6.')
-if (!usesNpm6) {
-  process.exit()
-}
-
-const pkgPath = path.resolve(cwd, './package.json')
-const pkg = fs.existsSync(pkgPath) ? require(pkgPath) : {}
-const deps = {
-  ...pkg.dependencies,
-  ...pkg.devDependencies,
-  ...pkg.optionalDependencies
-}
-
-let hasPostCSS8 = false
-if (deps.postcss) {
-  hasPostCSS8 = semver.intersects(deps.postcss, '8.x')
-}
-
-if (!hasPostCSS8) {
-  const hotfixPath = path.resolve(__dirname, '../generator/hotfix-npm6only.js')
-  const targetPath = path.resolve(__dirname, '../generator/hotfix.js')
-  fs.renameSync(hotfixPath, targetPath)
-}
diff --git a/packages/@vue/cli-service/generator/hotfix-npm6only.js b/packages/@vue/cli-service/generator/hotfix-npm6only.js
deleted file mode 100644
index 6141487f06..0000000000
--- a/packages/@vue/cli-service/generator/hotfix-npm6only.js
+++ /dev/null
@@ -1,8 +0,0 @@
-// this file will be renamed to hotfix.js if the package is installed by npm 6
-module.exports = (api) => {
-  api.extendPackage({
-    dependencies: {
-      postcss: '^8.2.6'
-    }
-  })
-}
diff --git a/packages/@vue/cli-service/generator/index.js b/packages/@vue/cli-service/generator/index.js
index 643f4abe0c..d5b1c8ae58 100644
--- a/packages/@vue/cli-service/generator/index.js
+++ b/packages/@vue/cli-service/generator/index.js
@@ -1,6 +1,3 @@
-const fs = require('fs-extra')
-const path = require('path')
-
 module.exports = (api, options) => {
   api.render('./template', {
     doesCompile: api.hasPlugin('babel') || api.hasPlugin('typescript')
@@ -77,8 +74,4 @@ module.exports = (api, options) => {
   if (options.configs) {
     api.extendPackage(options.configs)
   }
-
-  if (fs.existsSync(path.resolve(__dirname, './hotfix.js'))) {
-    require('./hotfix')(api, options, options)
-  }
 }
diff --git a/packages/@vue/cli-service/package.json b/packages/@vue/cli-service/package.json
index 47e8a2ecb3..986a0f05c4 100644
--- a/packages/@vue/cli-service/package.json
+++ b/packages/@vue/cli-service/package.json
@@ -7,9 +7,6 @@
   "bin": {
     "vue-cli-service": "bin/vue-cli-service.js"
   },
-  "scripts": {
-    "postinstall": "node bin/postinstall.js"
-  },
   "repository": {
     "type": "git",
     "url": "git+https://github.com/vuejs/vue-cli.git",

From fc91fb7e07f9109f7b1ccf27b1af07d45a7d79ae Mon Sep 17 00:00:00 2001
From: Haoqun Jiang <haoqunjiang@gmail.com>
Date: Wed, 24 Mar 2021 17:53:06 +0800
Subject: [PATCH 2/2] fix: check hoisted postcss version and prompt user on how
 to fix the bug

---
 packages/@vue/cli-service/lib/config/css.js | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/packages/@vue/cli-service/lib/config/css.js b/packages/@vue/cli-service/lib/config/css.js
index acfa1f7a1c..e8b5061356 100644
--- a/packages/@vue/cli-service/lib/config/css.js
+++ b/packages/@vue/cli-service/lib/config/css.js
@@ -1,5 +1,6 @@
 const fs = require('fs')
 const path = require('path')
+const { chalk, semver, loadModule } = require('@vue/cli-shared-utils')
 const isAbsoluteUrl = require('../util/isAbsoluteUrl')
 
 const findExisting = (context, files) => {
@@ -58,6 +59,19 @@ module.exports = (api, rootOptions) => {
     ]))
 
     if (!hasPostCSSConfig) {
+      // #6342
+      // NPM 6 may incorrectly hoist postcss 7 to the same level of autoprefixer
+      // So we have to run a preflight check to tell the users how to fix it
+      const autoprefixerDirectory = path.dirname(require.resolve('autoprefixer/package.json'))
+      const postcssPkg = loadModule('postcss/package.json', autoprefixerDirectory)
+      const postcssVersion = postcssPkg.version
+      if (!semver.satisfies(postcssVersion, '8.x')) {
+        throw new Error(
+          `The package manager has hoisted a wrong version of ${chalk.cyan('postcss')}, ` +
+          `please run ${chalk.cyan('npm i postcss@8 -D')} to fix it.`
+        )
+      }
+
       loaderOptions.postcss = {
         postcssOptions: {
           plugins: [