Babel 8 misc changes (#15068)

Co-authored-by: Nicolò Ribaudo <nicolo.ribaudo@gmail.com>

.github/workflows/ci.yml

@@ -113,8 +113,9 @@ jobs:
           cache: "yarn"
       - name: Build babel artifacts
         run: |
-          BABEL_ENV=test-legacy make -j build-standalone-ci
+          make -j build-standalone-ci
         env:
+          BABEL_ENV: test-legacy
           BABEL_8_BREAKING: false
           STRIP_BABEL_8_FLAG: true
       - name: Build Makefile.js
@@ -133,7 +134,7 @@ jobs:
           retention-days: 5
 
   build-windows:
-    name: Build Babel Artifacts On Windows
+    name: Build Babel Artifacts on Windows
     runs-on: windows-latest
     # Yarn PnP does not support native ESM yet (https://github.com/yarnpkg/berry/issues/638)
     # env:
@@ -150,8 +151,9 @@ jobs:
       - name: Build babel artifacts
         shell: bash
         run: |
-          BABEL_ENV=test-legacy make -j build-standalone-ci
+          make -j build-standalone-ci
         env:
+          BABEL_ENV: test-legacy
           BABEL_8_BREAKING: false
           STRIP_BABEL_8_FLAG: true
       - name: Ensure cwd does not contain uncommitted changes
@@ -241,7 +243,7 @@ jobs:
           node-version: latest
 
   build-babel8:
-    name: Build Babel 8 Artifacts for tests
+    name: Build Babel 8 Artifacts
     needs: prepare-yarn-cache
     runs-on: ubuntu-latest
     # Yarn PnP does not support native ESM yet (https://github.com/yarnpkg/berry/issues/638)
@@ -250,15 +252,17 @@ jobs:
     steps:
       - name: Checkout code
         uses: actions/checkout@v3
-      - name: Use Node.js 14.17
+      - name: Use Node.js latest
         uses: actions/setup-node@v3
         with:
-          node-version: "14.17" # Node.js 14.17 is the first LTS supported by Babel 8
+          node-version: latest
+          check-latest: true
           cache: "yarn"
-      - name: Install and build
-        run: make -j bootstrap
+      - name: Build babel artifacts
+        run: |
+          make -j build-standalone-ci
         env:
-          BABEL_ENV: test
+          BABEL_ENV: test-legacy
           BABEL_8_BREAKING: true
           STRIP_BABEL_8_FLAG: true
       - name: Lint
@@ -299,8 +303,6 @@ jobs:
           name: babel8-artifact
       - name: Extract artifacts
         run: tar -xf babel-artifact.tar; rm babel-artifact.tar
-      - name: Generate runtime helpers
-        run: make build-plugin-transform-runtime-dist
       - name: Test
         run: |
           yarn jest --ci

packages/babel-cli/src/babel/util.ts

@@ -89,13 +89,14 @@ export async function compile(filename: string, opts: InputOptions) {
     caller: CALLER,
   };
 
-  // TODO (Babel 8): Use `babel.transformFileAsync`
-  const result = await new Promise<FileResult>((resolve, reject) => {
-    babel.transformFile(filename, opts, (err, result) => {
-      if (err) reject(err);
-      else resolve(result);
-    });
-  });
+  const result = process.env.BABEL_8_BREAKING
+    ? await babel.transformFileAsync(filename, opts)
+    : await new Promise<FileResult>((resolve, reject) => {
+        babel.transformFile(filename, opts, (err, result) => {
+          if (err) reject(err);
+          else resolve(result);
+        });
+      });
 
   if (result) {
     if (!process.env.BABEL_8_BREAKING) {

packages/babel-compat-data/corejs2-built-ins.js

@@ -1 +1,2 @@
+// Todo (Babel 8): remove this file as Babel 8 drop support of core-js 2
 module.exports = require("./data/corejs2-built-ins.json");

packages/babel-compat-data/corejs3-shipped-proposals.js

@@ -1 +1,2 @@
+// Todo (Babel 8): remove this file now that it is included in babel-plugin-polyfill-corejs3
 module.exports = require("./data/corejs3-shipped-proposals.json");

packages/babel-compat-data/package.json

@@ -12,6 +12,17 @@
   "publishConfig": {
     "access": "public"
   },
+  "conditions": {
+    "BABEL_8_BREAKING": [
+      {
+        "./plugins": "./plugins.js",
+        "./native-modules": "./native-modules.js",
+        "./overlapping-plugins": "./overlapping-plugins.js",
+        "./plugin-bugfixes": "./plugin-bugfixes.js"
+      },
+      null
+    ]
+  },
   "exports": {
     "./plugins": "./plugins.js",
     "./native-modules": "./native-modules.js",

packages/babel-compat-data/scripts/build-bugfixes-targets.js

@@ -8,7 +8,7 @@ const {
   generateData,
   environments,
   writeFile,
-  defineLegacyPluginAliases,
+  maybeDefineLegacyPluginAliases,
 } = require("./utils-build-data");
 
 const pluginBugfixes = require("./data/plugin-bugfixes");
@@ -39,7 +39,7 @@ for (const [filename, data] of [
 ]) {
   const dataPath = path.join(__dirname, `../data/${filename}.json`);
 
-  if (!writeFile(defineLegacyPluginAliases(data), dataPath, filename)) {
+  if (!writeFile(maybeDefineLegacyPluginAliases(data), dataPath, filename)) {
     process.exitCode = 1;
     break;
   }

packages/babel-compat-data/scripts/build-data.js

@@ -2,12 +2,12 @@
 
 const path = require("path");
 const compatData = require("@mdn/browser-compat-data").javascript;
-const { process: processData } = require("./build-modules-support");
+const { generateModuleSupport } = require("./build-modules-support");
 const {
   generateData,
   environments,
   writeFile,
-  defineLegacyPluginAliases,
+  maybeDefineLegacyPluginAliases,
 } = require("./utils-build-data");
 
 if (process.cwd().endsWith("scripts")) {
@@ -24,7 +24,7 @@ for (const target of ["plugin", "corejs2-built-in"]) {
   );
   if (target === "plugin") {
     // add export-namespace-from from @mdn/browser-compat-data
-    const exportNamespaceFromCompatData = processData(
+    const exportNamespaceFromCompatData = generateModuleSupport(
       compatData.statements.export.namespace
     );
     // the node.js compat data is 12.0, the first node version ships `export *` behind a flag
@@ -33,8 +33,7 @@ for (const target of ["plugin", "corejs2-built-in"]) {
     newData["transform-export-namespace-from"] = exportNamespaceFromCompatData;
 
     // Add proposal-* aliases for backward compatibility.
-    // TODO(Babel 7): This won't be needed anymore.
-    newData = defineLegacyPluginAliases(newData);
+    newData = maybeDefineLegacyPluginAliases(newData);
   }
   const dataPath = path.join(__dirname, `../data/${target}s.json`);
 

packages/babel-compat-data/scripts/build-modules-support.js

@@ -1,8 +1,8 @@
 const path = require("path");
-const fs = require("fs");
 
 const compatData = require("@mdn/browser-compat-data").javascript;
 const { addElectronSupportFromChromium } = require("./chromium-to-electron");
+const { writeFile, babel7Only } = require("./utils-build-data");
 
 // Map mdn-browser-compat-data to browserslist browser names
 const browserNameMap = {
@@ -31,7 +31,7 @@ function browserVersion(browser, version_added) {
   return version_added;
 }
 
-function process(source) {
+function generateModuleSupport(source) {
   const stats = source.__compat.support;
   const allowedBrowsers = {};
 
@@ -60,13 +60,14 @@ function process(source) {
 }
 
 const dataPath = path.join(__dirname, "../data/native-modules.json");
-const processed = process(compatData.statements.export);
-// Todo(Babel 8): remove `ios_saf` as it is identical to ios
-if (processed.ios) {
-  processed.ios_saf = processed.ios;
-}
+const processed = generateModuleSupport(compatData.statements.export);
+babel7Only(() => {
+  if (processed.ios) {
+    processed.ios_saf = processed.ios;
+  }
+});
 const data = {
   "es6.module": processed,
 };
-fs.writeFileSync(dataPath, `${JSON.stringify(data, null, 2)}\n`);
-exports.process = process;
+writeFile(data, dataPath, "native-modules");
+exports.generateModuleSupport = generateModuleSupport;

packages/babel-compat-data/scripts/data/legacy-plugin-aliases.js

@@ -1,4 +1,4 @@
-// TODO(Babel 7): This won't be needed anymore
+// TODO(Babel 8): This won't be needed anymore
 
 // prettier-ignore
 module.exports = {

packages/babel-compat-data/scripts/utils-build-data.js

@@ -54,11 +54,10 @@ const getLowestImplementedVersion = (
   exclude = () => false
 ) => {
   const tests = compatibilityTests.filter(test => {
-    // TODO (Babel 9): Use ||=, &&=
     let ok = features.includes(test.name);
-    ok = ok || (test.group && features.includes(test.group));
-    ok = ok || (features.length === 1 && test.name.startsWith(features[0]));
-    ok = ok && !exclude(test.name);
+    ok ||= test.group && features.includes(test.group);
+    ok ||= features.length === 1 && test.name.startsWith(features[0]);
+    ok &&= !exclude(test.name);
     return ok;
   });
 
@@ -156,8 +155,7 @@ exports.writeFile = function (data, dataPath, name) {
     // Compare as JSON strings to also check keys ordering
     if (currentData !== stringified) {
       console.error(
-        `The newly generated ${name} data does not match the current ` +
-          "files. Re-run `make build-compat-data`."
+        `The newly generated ${name} data does not match the current files. Re-run \`make build-compat-data\`.`
       );
 
       return false;
@@ -169,7 +167,25 @@ exports.writeFile = function (data, dataPath, name) {
 };
 
 // TODO(Babel 8): Remove this.
-exports.defineLegacyPluginAliases = function (data) {
+// Since these scripts generates different compat data files, we generate
+// Babel 7 files also when BABEL_8_BREAKING to avoid diffs during development.
+// It's safe to do so because the Babel 7 data is a superset of the Babel 8
+// data, so it works with both versions.
+// When BABEL_8_BREAKING and IS_PUBLISHING are both true, we generate
+// the actual Babel 8 files so that:
+// - we don't accidentally release Babel 8 with the Babel 7 file
+// - at lest in our e2e tests, we use the new file
+function babel7Only(fn, arg) {
+  if (process.env.BABEL_8_BREAKING && process.env.IS_PUBLISH) {
+    return arg;
+  } else {
+    return fn(arg);
+  }
+}
+exports.babel7Only = babel7Only;
+
+// TODO(Babel 8): Remove this.
+exports.maybeDefineLegacyPluginAliases = babel7Only.bind(null, function (data) {
   // We create a new object to inject legacy aliases in the correct
   // order, rather than all at the end.
   const result = {};
@@ -180,4 +196,4 @@ exports.defineLegacyPluginAliases = function (data) {
     }
   }
   return result;
-};
+});

packages/babel-core/src/config/files/module-types.ts

@@ -125,7 +125,7 @@ function loadCtsDefault(filepath: string) {
 function loadCjsDefault(filepath: string, fallbackToTranspiledModule: boolean) {
   const module = endHiddenCallStack(require)(filepath);
   return module?.__esModule
-    ? // TODO (Babel 8): Remove "module" and "undefined" fallback
+    ? // TODO(Babel 8): Remove "module" and "undefined" fallback
       module.default || (fallbackToTranspiledModule ? module : undefined)
     : module;
 }

packages/babel-helper-create-class-features-plugin/src/typescript.ts

@@ -4,7 +4,7 @@ import type * as t from "@babel/types";
 export function assertFieldTransformed(
   path: NodePath<t.ClassProperty | t.ClassDeclaration>,
 ) {
-  // TODO (Babel 8): Also check path.node.definite
+  // TODO(Babel 8): Also check path.node.definite
 
   if (path.node.declare) {
     throw path.buildCodeFrameError(

packages/babel-helper-environment-visitor/src/index.ts

@@ -1,7 +1,7 @@
 import type { NodePath, Visitor } from "@babel/traverse";
 import type * as t from "@babel/types";
 
-// TODO (Babel 8): Don't export this function.
+// TODO(Babel 8): Don't export this function.
 export function skipAllButComputedKey(
   path: NodePath<t.Method | t.ClassProperty>,
 ) {

packages/babel-helper-replace-supers/src/index.ts

@@ -19,7 +19,7 @@ import {
 } from "@babel/types";
 import type * as t from "@babel/types";
 
-// TODO (Babel 8): Don't export this.
+// TODO(Babel 8): Don't export this.
 export {
   default as environmentVisitor,
   skipAllButComputedKey,

packages/babel-helpers/src/helpers.ts

@@ -179,7 +179,7 @@ helpers.extends = helper("7.0.0-beta.0")`
   }
 `;
 
-// TODO(babel-8): This old helper can be removed in babel v8
+// TODO(Babel 8): This old helper can be removed in babel v8
 helpers.objectSpread = helper("7.0.0-beta.0")`
   import defineProperty from "defineProperty";
 

packages/babel-parser/src/types.d.ts

@@ -1049,7 +1049,7 @@ export interface TypeParameter extends NodeBase {
 
 export interface TsTypeParameter extends NodeBase {
   type: "TSTypeParameter";
-  // TODO(Babel-8): remove string type support
+  // TODO(Babel 8): remove string type support
   name: string | Identifier;
   in?: boolean;
   out?: boolean;
@@ -1287,7 +1287,7 @@ export interface TsSignatureDeclarationOrIndexSignatureBase extends NodeBase {
   // Not using TypeScript's "ParameterDeclaration" here, since it's inconsistent with regular functions.
   params: Array<Identifier | RestElement | ObjectPattern | ArrayPattern>;
   returnType: TsTypeAnnotation | undefined | null;
-  // TODO(Babel-8): Remove
+  // TODO(Babel 8): Remove
   parameters: Array<Identifier | RestElement | ObjectPattern | ArrayPattern>;
   typeAnnotation: TsTypeAnnotation | undefined | null;
 }

packages/babel-plugin-transform-for-of/src/no-helper-implementation.ts

@@ -3,7 +3,7 @@ import type { NodePath } from "@babel/traverse";
 
 // This is the legacy implementation, which inlines all the code.
 // It must be kept for compatibility reasons.
-// TODO (Babel 8): Remove this code.
+// TODO(Babel 8): Remove this code.
 
 export default function transformWithoutHelper(
   loose: boolean | void,

packages/babel-plugin-transform-react-jsx/src/create-plugin.ts

@@ -72,7 +72,6 @@ export default function createPlugin({
 
       throwIfNamespace = true,
 
-      // TODO (Babel 8): It should throw if this option is used with the automatic runtime
       filter,
 
       runtime: RUNTIME_DEFAULT = process.env.BABEL_8_BREAKING
@@ -107,6 +106,12 @@ export default function createPlugin({
 }`,
         );
       }
+
+      if (filter != null && RUNTIME_DEFAULT === "automatic") {
+        throw new Error(
+          '@babel/plugin-transform-react-jsx: "filter" option can not be used with automatic runtime. If you are upgrading from Babel 7, please specify `runtime: "classic"`.',
+        );
+      }
     } else {
       // eslint-disable-next-line no-var
       var { useSpread = false, useBuiltIns = false } = options;
@@ -262,7 +267,7 @@ You can set \`throwIfNamespace: false\` to bypass this warning.`,
             }
           },
 
-          // TODO (Babel 8): Decide if this should be removed or brought back.
+          // TODO(Babel 8): Decide if this should be removed or brought back.
           // see: https://github.com/babel/babel/pull/12253#discussion_r513086528
           //
           // exit(path, state) {

packages/babel-plugin-transform-react-jsx/test/fixtures/react-automatic/should-throw-when-filter-is-specified/input.js

@@ -0,0 +1 @@
+<></>

packages/babel-plugin-transform-react-jsx/test/fixtures/react-automatic/should-throw-when-filter-is-specified/options.js

@@ -0,0 +1,11 @@
+module.exports = {
+  BABEL_8_BREAKING: true,
+  throws:
+    '@babel/plugin-transform-react-jsx: "filter" option can not be used with automatic runtime. If you are upgrading from Babel 7, please specify `runtime: "classic"`.',
+  plugins: [
+    [
+      "transform-react-jsx",
+      { runtime: "automatic", filter: (node, file) => true },
+    ],
+  ],
+};