Postcss7 compatibility (#2773)

* add postcss7 compatibility layers

* add compatibility mode scripts

package.json

@@ -23,7 +23,10 @@
     "rebuild-fixtures": "npm run babelify && babel-node scripts/rebuildFixtures.js",
     "prepublishOnly": "npm run babelify && babel-node scripts/build.js",
     "style": "eslint .",
-    "test": "jest && eslint ."
+    "test": "jest && eslint .",
+    "precompat": "npm run babelify",
+    "compat": "node scripts/compat.js --prepare",
+    "compat:restore": "node scripts/compat.js --restore"
   },
   "files": [
     "dist/*.css",

package.postcss7.json

@@ -0,0 +1,9 @@
+{
+  "dependencies": {
+    "autoprefixer": "^9",
+    "postcss": "^7",
+    "postcss-functions": "^3",
+    "postcss-js": "^2",
+    "postcss-nested": "^4"
+  }
+}

scripts/compat.js

@@ -0,0 +1,59 @@
+const fs = require('fs')
+const path = require('path')
+const merge = require('lodash/merge')
+
+function fromRootPath(...paths) {
+  return path.resolve(process.cwd(), ...paths)
+}
+
+function backupPath(...paths) {
+  return path.resolve(process.cwd(), 'node_modules', '__tw_cache__', ...paths)
+}
+
+function copy(fromPath, toPath) {
+  fs.mkdirSync(path.dirname(toPath), { recursive: true })
+  fs.copyFileSync(fromPath, toPath)
+}
+
+if (process.argv.includes('--prepare')) {
+  const mainPackageJson = require('../package.json')
+  const compatPackageJson = require('../package.postcss7.json')
+
+  // 1. Backup original package.json file
+  copy(fromRootPath('package.json'), backupPath('package.json'))
+
+  // 2. Backup lib/index.js file
+  copy(fromRootPath('lib', 'index.js'), backupPath('lib', 'index.js'))
+
+  // 3. Use the postcss7 compat file
+  copy(fromRootPath('lib', 'index.postcss7.js'), fromRootPath('lib', 'index.js'))
+
+  // 4. Deep merge package.json contents
+  const packageJson = merge({}, mainPackageJson, compatPackageJson)
+
+  // 5. Write package.json with the new contents
+  fs.writeFileSync(fromRootPath('package.json'), JSON.stringify(packageJson, null, 2), 'utf8')
+
+  // 6. Print some useful information to make publishing easy
+  console.log()
+  console.log('You can safely publish `tailwindcss` in PostCSS 7 compatibility mode:\n')
+  console.log(
+    ['npm version', 'npm publish --tag compat', 'npm run compat:restore']
+      .map((v) => `  ${v}`)
+      .join('\n')
+  )
+  console.log()
+} else if (process.argv.includes('--restore')) {
+  // 1. Restore original package.json file
+  copy(backupPath('package.json'), fromRootPath('package.json'))
+  fs.unlinkSync(backupPath('package.json'))
+
+  // 2. Restore lib/index.js file
+  copy(backupPath('lib', 'index.js'), fromRootPath('lib', 'index.js'))
+  fs.unlinkSync(backupPath('lib', 'index.js'))
+
+  // 3. Done
+  console.log()
+  console.log('Restored from PostCSS 7 mode to latest PostCSS mode!')
+  console.log()
+}

src/index.postcss7.js

@@ -0,0 +1,80 @@
+import path from 'path'
+import fs from 'fs'
+
+import _ from 'lodash'
+
+import getModuleDependencies from './lib/getModuleDependencies'
+import registerConfigAsDependency from './lib/registerConfigAsDependency'
+import processTailwindFeatures from './processTailwindFeatures'
+import formatCSS from './lib/formatCSS'
+import resolveConfig from './util/resolveConfig'
+import getAllConfigs from './util/getAllConfigs'
+import { defaultConfigFile } from './constants'
+import defaultConfig from '../stubs/defaultConfig.stub.js'
+
+function resolveConfigPath(filePath) {
+  // require('tailwindcss')({ theme: ..., variants: ... })
+  if (_.isObject(filePath) && !_.has(filePath, 'config') && !_.isEmpty(filePath)) {
+    return undefined
+  }
+
+  // require('tailwindcss')({ config: 'custom-config.js' })
+  if (_.isObject(filePath) && _.has(filePath, 'config') && _.isString(filePath.config)) {
+    return path.resolve(filePath.config)
+  }
+
+  // require('tailwindcss')({ config: { theme: ..., variants: ... } })
+  if (_.isObject(filePath) && _.has(filePath, 'config') && _.isObject(filePath.config)) {
+    return undefined
+  }
+
+  // require('tailwindcss')('custom-config.js')
+  if (_.isString(filePath)) {
+    return path.resolve(filePath)
+  }
+
+  // require('tailwindcss')
+  try {
+    const defaultConfigPath = path.resolve(defaultConfigFile)
+    fs.accessSync(defaultConfigPath)
+    return defaultConfigPath
+  } catch (err) {
+    return undefined
+  }
+}
+
+const getConfigFunction = (config) => () => {
+  if (_.isUndefined(config)) {
+    return resolveConfig([...getAllConfigs(defaultConfig)])
+  }
+
+  // Skip this if Jest is running: https://github.com/facebook/jest/pull/9841#issuecomment-621417584
+  if (process.env.JEST_WORKER_ID === undefined) {
+    if (!_.isObject(config)) {
+      getModuleDependencies(config).forEach((mdl) => {
+        delete require.cache[require.resolve(mdl.file)]
+      })
+    }
+  }
+
+  const configObject = _.isObject(config) ? _.get(config, 'config', config) : require(config)
+
+  return resolveConfig([...getAllConfigs(configObject)])
+}
+
+const plugin = postcss.plugin('tailwind', (config) => {
+  const plugins = []
+  const resolvedConfigPath = resolveConfigPath(config)
+
+  if (!_.isUndefined(resolvedConfigPath)) {
+    plugins.push(registerConfigAsDependency(resolvedConfigPath))
+  }
+
+  return postcss([
+    ...plugins,
+    processTailwindFeatures(getConfigFunction(resolvedConfigPath || config)),
+    formatCSS,
+  ])
+})
+
+module.exports = plugin