fix: use absolute import path for injected core-js polyfills (#3710)

fixes #3678

packages/@vue/babel-preset-app/__tests__/babel-preset.spec.js

@@ -7,6 +7,11 @@ const defaultOptions = {
   filename: 'test-entry-file.js'
 }
 
+const genCoreJSImportRegExp = mod => {
+  // expected to include a `node_modules` in the import path because we use absolute path for core-js
+  return new RegExp(`import "${['.*node_modules', 'core-js', 'modules', mod].join(`[\\${path.sep}]+`)}`)
+}
+
 beforeEach(() => {
   process.env.VUE_CLI_ENTRY_FILES = JSON.stringify([path.join(process.cwd(), 'test-entry-file.js')])
 })
@@ -22,9 +27,9 @@ test('polyfill detection', () => {
     filename: 'test-entry-file.js'
   })
   // default includes
-  expect(code).not.toMatch(`import "core-js/modules/es6.promise"`)
+  expect(code).not.toMatch(genCoreJSImportRegExp('es6.promise'))
   // usage-based detection
-  expect(code).not.toMatch(`import "core-js/modules/es6.map"`)
+  expect(code).not.toMatch(genCoreJSImportRegExp('es6.map'))
 
   ;({ code } = babel.transformSync(`
     const a = new Map()
@@ -36,9 +41,9 @@ test('polyfill detection', () => {
     filename: 'test-entry-file.js'
   }))
   // default includes
-  expect(code).toMatch(`import "core-js/modules/es6.promise"`)
+  expect(code).toMatch(genCoreJSImportRegExp('es6.promise'))
   // promise polyfill alone doesn't work in IE, needs this as well. fix: #1642
-  expect(code).toMatch(`import "core-js/modules/es6.array.iterator"`)
+  expect(code).toMatch(genCoreJSImportRegExp('es6.array.iterator'))
   // usage-based detection
   expect(code).toMatch(/import _Map from ".*runtime-corejs2\/core-js\/map"/)
 })
@@ -56,7 +61,7 @@ test('modern mode always skips polyfills', () => {
     filename: 'test-entry-file.js'
   })
   // default includes
-  expect(code).not.toMatch(`import "core-js/modules/es6.promise"`)
+  expect(code).not.toMatch(genCoreJSImportRegExp('es6.promise'))
   // usage-based detection
   expect(code).not.toMatch(/import _Map from ".*runtime-corejs2\/core-js\/map"/)
 
@@ -71,7 +76,7 @@ test('modern mode always skips polyfills', () => {
     filename: 'test-entry-file.js'
   }))
   // default includes
-  expect(code).not.toMatch(`import "core-js/modules/es6.promise"`)
+  expect(code).not.toMatch(genCoreJSImportRegExp('es6.promise'))
   // usage-based detection
   expect(code).not.toMatch(/import _Map from ".*runtime-corejs2\/core-js\/map"/)
   delete process.env.VUE_CLI_MODERN_BUILD
@@ -98,7 +103,7 @@ test('async/await', () => {
     }
     hello()
   `.trim(), defaultOptions)
-  expect(code).toMatch(`import "core-js/modules/es6.promise"`)
+  expect(code).toMatch(genCoreJSImportRegExp('es6.promise'))
   // should use regenerator runtime
   expect(code).toMatch(`import "regenerator-runtime/runtime"`)
   // should use required helper instead of inline

packages/@vue/babel-preset-app/package.json

@@ -22,6 +22,7 @@
   },
   "homepage": "https://github.com/vuejs/vue-cli/tree/dev/packages/@vue/babel-preset-app#readme",
   "dependencies": {
+    "@babel/helper-module-imports": "^7.0.0",
     "@babel/plugin-proposal-class-properties": "^7.0.0",
     "@babel/plugin-proposal-decorators": "^7.1.0",
     "@babel/plugin-syntax-dynamic-import": "^7.0.0",

packages/@vue/babel-preset-app/polyfillsPlugin.js

@@ -1,3 +1,19 @@
+const { addSideEffect } = require('@babel/helper-module-imports')
+
+// slightly modifiled from @babel/preset-env/src/utils
+// use an absolute path for core-js modules, to fix conflicts of different core-js versions
+function getModulePath (mod) {
+  if (mod === 'regenerator-runtime') {
+    return require.resolve('regenerator-runtime/runtime')
+  }
+
+  return require.resolve(`core-js/modules/${mod}`)
+}
+
+function createImport (path, mod) {
+  return addSideEffect(path, getModulePath(mod))
+}
+
 // add polyfill imports to the first file encountered.
 module.exports = ({ types }, { entryFiles = [] }) => {
   return {
@@ -9,11 +25,13 @@ module.exports = ({ types }, { entryFiles = [] }) => {
         }
 
         const { polyfills } = state.opts
-        const { createImport } = require('@babel/preset-env/lib/utils')
         // imports are injected in reverse order
-        polyfills.slice().reverse().forEach(p => {
-          createImport(path, p)
-        })
+        polyfills
+          .slice()
+          .reverse()
+          .forEach(p => {
+            createImport(path, p)
+          })
       }
     }
   }