[babel 8] Remove support for the 2018-09 decorators proposal (#12712)

* Remove `"legacy": true` and `"version": "2018-09"` options

* Skip 2018-09 tests for Babel 8

* Replace `"legacy": true` with `"version": "legacy"`

* Remove 2018-09 implementation

* Misc test updates

* Add error for wrong version

* Fix vue tests

* Disable test in Babel 8

* Remove `decoratorsBeforeExport` from the syntax plugin

* Remove `decoratorsBeforeExport` from generator

eslint/babel-eslint-shared-fixtures/config/babel.config.decorators-legacy.js

@@ -2,5 +2,5 @@
 
 module.exports = {
   presets: [["@babel/preset-env", { forceAllTransforms: true }]],
-  plugins: [["@babel/plugin-proposal-decorators", { legacy: true }]],
+  plugins: [["@babel/plugin-proposal-decorators", { version: "legacy" }]],
 };

eslint/babel-eslint-shared-fixtures/config/babel.config.js

@@ -9,7 +9,7 @@ module.exports = {
   plugins: [
     "@babel/plugin-syntax-export-default-from",
     "@babel/plugin-proposal-class-properties",
-    ["@babel/plugin-proposal-decorators", { decoratorsBeforeExport: false }],
+    ["@babel/plugin-proposal-decorators", { version: "2021-12" }],
     ["@babel/plugin-proposal-pipeline-operator", { proposal: "minimal" }],
     "@babel/plugin-proposal-private-methods",
     "@babel/plugin-proposal-do-expressions",

packages/babel-core/test/fixtures/option-manager/presets/es2015_default_function.js

@@ -16,7 +16,7 @@ exports.default = function () {
       [
         __dirname +
           "/../../../../../babel-plugin-syntax-decorators/lib/index.js",
-        { legacy: true },
+        { version: "legacy" },
       ],
     ],
   };

packages/babel-core/test/fixtures/option-manager/presets/es2015_default_object.js

@@ -11,7 +11,7 @@ module.exports = function () {
       [
         __dirname +
           "/../../../../../babel-plugin-syntax-decorators/lib/index.js",
-        { legacy: true },
+        { version: "legacy" },
       ],
     ],
   };

packages/babel-core/test/fixtures/option-manager/presets/es5_function.js

@@ -4,7 +4,7 @@ module.exports = function () {
       [
         __dirname +
           "/../../../../../babel-plugin-syntax-decorators/lib/index.js",
-        { legacy: true },
+        { version: "legacy" },
       ],
     ],
   };

packages/babel-core/test/fixtures/option-manager/presets/es5_object.js

@@ -4,7 +4,7 @@ module.exports = function () {
       [
         __dirname +
           "/../../../../../babel-plugin-syntax-decorators/lib/index.js",
-        { legacy: true },
+        { version: "legacy" },
       ],
     ],
   };

packages/babel-generator/src/generators/classes.ts

@@ -11,11 +11,15 @@ export function ClassDeclaration(
   node: t.ClassDeclaration,
   parent: t.Node,
 ) {
-  if (
-    !this.format.decoratorsBeforeExport ||
-    (!isExportDefaultDeclaration(parent) && !isExportNamedDeclaration(parent))
-  ) {
+  if (process.env.BABEL_8_BREAKING) {
     this.printJoin(node.decorators, node);
+  } else {
+    if (
+      !this.format.decoratorsBeforeExport ||
+      (!isExportDefaultDeclaration(parent) && !isExportNamedDeclaration(parent))
+    ) {
+      this.printJoin(node.decorators, node);
+    }
   }
 
   if (node.declare) {

packages/babel-generator/src/generators/modules.ts

@@ -90,11 +90,13 @@ export function ExportNamedDeclaration(
   this: Printer,
   node: t.ExportNamedDeclaration,
 ) {
-  if (
-    this.format.decoratorsBeforeExport &&
-    isClassDeclaration(node.declaration)
-  ) {
-    this.printJoin(node.declaration.decorators, node);
+  if (!process.env.BABEL_8_BREAKING) {
+    if (
+      this.format.decoratorsBeforeExport &&
+      isClassDeclaration(node.declaration)
+    ) {
+      this.printJoin(node.declaration.decorators, node);
+    }
   }
 
   this.word("export");
@@ -156,11 +158,13 @@ export function ExportDefaultDeclaration(
   this: Printer,
   node: t.ExportDefaultDeclaration,
 ) {
-  if (
-    this.format.decoratorsBeforeExport &&
-    isClassDeclaration(node.declaration)
-  ) {
-    this.printJoin(node.declaration.decorators, node);
+  if (!process.env.BABEL_8_BREAKING) {
+    if (
+      this.format.decoratorsBeforeExport &&
+      isClassDeclaration(node.declaration)
+    ) {
+      this.printJoin(node.declaration.decorators, node);
+    }
   }
 
   this.word("export");

packages/babel-generator/src/index.ts

@@ -66,7 +66,6 @@ function normalizeOptions(
       style: "  ",
       base: 0,
     },
-    decoratorsBeforeExport: !!opts.decoratorsBeforeExport,
     jsescOption: {
       quotes: "double",
       wrap: true,
@@ -78,6 +77,7 @@ function normalizeOptions(
   };
 
   if (!process.env.BABEL_8_BREAKING) {
+    format.decoratorsBeforeExport = !!opts.decoratorsBeforeExport;
     format.jsonCompatibleStrings = opts.jsonCompatibleStrings;
   }
 
@@ -193,6 +193,7 @@ export interface GeneratorOptions {
   /**
    * Set to true to enable support for experimental decorators syntax before module exports.
    * Defaults to `false`.
+   * @deprecated Removed in Babel 8
    */
   decoratorsBeforeExport?: boolean;
 

packages/babel-generator/src/printer.ts

@@ -35,7 +35,6 @@ export type Format = {
     style: string;
     base: number;
   };
-  decoratorsBeforeExport: boolean;
   recordAndTupleSyntaxType: RecordAndTuplePluginOptions["syntaxType"];
   jsescOption: jsescOptions;
   jsonCompatibleStrings?: boolean;
@@ -44,6 +43,10 @@ export type Format = {
    * Changes what token is used for pipe bodies’ topic references.
    */
   topicToken?: PipelineOperatorPluginOptions["topicToken"];
+  /**
+   * @deprecated Removed in Babel 8
+   */
+  decoratorsBeforeExport?: boolean;
 };
 
 interface AddNewlinesOptions {

packages/babel-generator/test/fixtures/decoratorsBeforeExport/false-to-false/options.json

@@ -1,4 +1,5 @@
 {
+  "BABEL_8_BREAKING": false,
   "plugins": [["decorators", { "decoratorsBeforeExport": false }]],
   "decoratorsBeforeExport": false
 }

packages/babel-generator/test/fixtures/decoratorsBeforeExport/false-to-true/options.json

@@ -1,4 +1,5 @@
 {
+  "BABEL_8_BREAKING": false,
   "plugins": [["decorators", { "decoratorsBeforeExport": false }]],
   "decoratorsBeforeExport": true
 }

packages/babel-generator/test/fixtures/decoratorsBeforeExport/true-to-false/options.json

@@ -1,4 +1,5 @@
 {
+  "BABEL_8_BREAKING": false,
   "plugins": [["decorators", { "decoratorsBeforeExport": true }]],
   "decoratorsBeforeExport": false
 }

packages/babel-generator/test/fixtures/decoratorsBeforeExport/true-to-true/options.json

@@ -1,4 +1,5 @@
 {
+  "BABEL_8_BREAKING": false,
   "plugins": [["decorators", { "decoratorsBeforeExport": true }]],
   "decoratorsBeforeExport": true
 }

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

@@ -1,3 +1,5 @@
+// TODO(Babel 8): Remove this file
+
 import { types as t, template } from "@babel/core";
 import type { File } from "@babel/core";
 import type { NodePath } from "@babel/traverse";

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

@@ -6,6 +6,7 @@ export const FEATURES = Object.freeze({
   //classes: 1 << 0,
   fields: 1 << 1,
   privateMethods: 1 << 2,
+  // TODO(Babel 8): Remove this
   decorators: 1 << 3,
   privateIn: 1 << 4,
   staticBlocks: 1 << 5,
@@ -170,10 +171,10 @@ export function shouldTransform(path: NodePath<t.Class>, file: File): boolean {
     throw path.buildCodeFrameError(
       "Decorators are not enabled." +
         "\nIf you are using " +
-        '["@babel/plugin-proposal-decorators", { "legacy": true }], ' +
+        '["@babel/plugin-proposal-decorators", { "version": "legacy" }], ' +
         'make sure it comes *before* "@babel/plugin-proposal-class-properties" ' +
         "and enable loose mode, like so:\n" +
-        '\t["@babel/plugin-proposal-decorators", { "legacy": true }]\n' +
+        '\t["@babel/plugin-proposal-decorators", { "version": "legacy" }]\n' +
         '\t["@babel/plugin-proposal-class-properties", { "loose": true }]',
     );
   }

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

@@ -168,7 +168,11 @@ export function createClassFeaturePlugin({
           }
         }
 
-        if (!props.length && !isDecorated) return;
+        if (process.env.BABEL_8_BREAKING) {
+          if (!props.length) return;
+        } else {
+          if (!props.length && !isDecorated) return;
+        }
 
         const innerBinding = path.node.id;
         let ref: t.Identifier;
@@ -207,14 +211,30 @@ export function createClassFeaturePlugin({
           pureStaticNodes: t.FunctionDeclaration[],
           wrapClass: (path: NodePath<t.Class>) => NodePath;
 
-        if (isDecorated) {
-          staticNodes = pureStaticNodes = keysNodes = [];
-          ({ instanceNodes, wrapClass } = buildDecoratedClass(
-            ref,
-            path,
-            elements,
-            file,
-          ));
+        if (!process.env.BABEL_8_BREAKING) {
+          if (isDecorated) {
+            staticNodes = pureStaticNodes = keysNodes = [];
+            ({ instanceNodes, wrapClass } = buildDecoratedClass(
+              ref,
+              path,
+              elements,
+              file,
+            ));
+          } else {
+            keysNodes = extractComputedKeys(path, computedPaths, file);
+            ({ staticNodes, pureStaticNodes, instanceNodes, wrapClass } =
+              buildFieldsInitNodes(
+                ref,
+                path.node.superClass,
+                props,
+                privateNamesMap,
+                file,
+                (setPublicClassFields ?? loose) as boolean,
+                (privateFieldsAsProperties ?? loose) as boolean,
+                (constantSuper ?? loose) as boolean,
+                innerBinding,
+              ));
+          }
         } else {
           keysNodes = extractComputedKeys(path, computedPaths, file);
           ({ staticNodes, pureStaticNodes, instanceNodes, wrapClass } =
@@ -237,7 +257,9 @@ export function createClassFeaturePlugin({
             constructor,
             instanceNodes,
             (referenceVisitor, state) => {
-              if (isDecorated) return;
+              if (!process.env.BABEL_8_BREAKING) {
+                if (isDecorated) return;
+              }
               for (const prop of props) {
                 // @ts-expect-error: TS doesn't infer that prop.node is not a StaticBlock
                 if (t.isStaticBlock?.(prop.node) || prop.node.static) continue;
@@ -261,21 +283,23 @@ export function createClassFeaturePlugin({
       },
 
       ExportDefaultDeclaration(path, { file }) {
-        if (file.get(versionKey) !== version) return;
+        if (!process.env.BABEL_8_BREAKING) {
+          if (file.get(versionKey) !== version) return;
 
-        const decl = path.get("declaration");
+          const decl = path.get("declaration");
 
-        if (decl.isClassDeclaration() && hasDecorators(decl.node)) {
-          if (decl.node.id) {
-            // export default class Foo {}
-            //   -->
-            // class Foo {} export { Foo as default }
-            splitExportDeclaration(path);
-          } else {
-            // Annyms class declarations can be
-            // transformed as if they were expressions
-            // @ts-expect-error
-            decl.node.type = "ClassExpression";
+          if (decl.isClassDeclaration() && hasDecorators(decl.node)) {
+            if (decl.node.id) {
+              // export default class Foo {}
+              //   -->
+              // class Foo {} export { Foo as default }
+              splitExportDeclaration(path);
+            } else {
+              // Annyms class declarations can be
+              // transformed as if they were expressions
+              // @ts-expect-error
+              decl.node.type = "ClassExpression";
+            }
           }
         }
       },

packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-decorators/ignore-abstract-methods/options.json → packages/babel-helper-create-class-features-plugin/test/fixtures/plugin-proposal-decorators/2018-12-ignore-abstract-methods/options.json

@@ -1,4 +1,5 @@
 {
+  "BABEL_8_BREAKING": false,
   "presets": [["typescript"]],
   "plugins": [
     ["proposal-decorators", { "decoratorsBeforeExport": true }],

packages/babel-plugin-proposal-class-properties/test/fixtures/decorators-legacy-interop/local-define-property/options.json

@@ -1,6 +1,6 @@
 {
   "plugins": [
-    ["proposal-decorators", { "legacy": true }],
+    ["proposal-decorators", { "version": "legacy" }],
     ["proposal-class-properties"],
     "transform-classes"
   ]

packages/babel-plugin-proposal-class-properties/test/fixtures/decorators-legacy-interop/loose/options.json

@@ -1,6 +1,6 @@
 {
   "plugins": [
-    ["proposal-decorators", { "legacy": true }],
+    ["proposal-decorators", { "version": "legacy" }],
     ["proposal-class-properties", { "loose": true }],
     "transform-classes"
   ]

packages/babel-plugin-proposal-class-properties/test/fixtures/decorators-legacy-interop/strict/options.json

@@ -1,6 +1,6 @@
 {
   "plugins": [
-    ["proposal-decorators", { "legacy": true }],
+    ["proposal-decorators", { "version": "legacy" }],
     ["proposal-class-properties"],
     "transform-classes"
   ]

packages/babel-plugin-proposal-class-properties/test/fixtures/decorators-legacy-interop/wrong-order/options.json

@@ -1,7 +1,7 @@
 {
   "plugins": [
     ["proposal-class-properties", { "loose": true }],
-    ["proposal-decorators", { "legacy": true }]
+    ["proposal-decorators", { "version": "legacy" }]
   ],
   "throws": "Decorators are not enabled."
 }

packages/babel-plugin-proposal-class-properties/test/fixtures/static-property-tdz/decorator-interop/options.json

@@ -1,6 +1,6 @@
 {
   "plugins": [
-    ["proposal-decorators", { "legacy": true }],
+    ["proposal-decorators", { "version": "legacy" }],
     ["proposal-class-properties", { "loose": true }],
     "transform-classes"
   ]

packages/babel-plugin-proposal-decorators/src/index.ts

@@ -21,17 +21,25 @@ export default declare((api, options: Options) => {
   api.assertVersion(7);
 
   // Options are validated in @babel/plugin-syntax-decorators
-  const { legacy, version } = options;
+  if (!process.env.BABEL_8_BREAKING) {
+    // eslint-disable-next-line no-var
+    var { legacy } = options;
+  }
+  const { version } = options;
 
-  if (legacy || version === "legacy") {
+  if (
+    process.env.BABEL_8_BREAKING
+      ? version === "legacy"
+      : legacy || version === "legacy"
+  ) {
     return {
       name: "proposal-decorators",
       inherits: syntaxDecorators,
       visitor: legacyVisitor,
     };
   } else if (version === "2021-12") {
     return transformer2021_12(api, options);
-  } else {
+  } else if (!process.env.BABEL_8_BREAKING) {
     return createClassFeaturePlugin({
       name: "proposal-decorators",
 
@@ -40,5 +48,9 @@ export default declare((api, options: Options) => {
       inherits: syntaxDecorators,
       // loose: options.loose, Not supported
     });
+  } else {
+    throw new Error(
+      "The '.version' option must be one of 'legacy' or '2021-12'",
+    );
   }
 });

packages/babel-plugin-proposal-decorators/test/fixtures/misc/options.json → packages/babel-plugin-proposal-decorators/test/fixtures/2018-09-duplicated-keys/options.json

@@ -1,4 +1,5 @@
 {
+  "BABEL_8_BREAKING": false,
   "plugins": [
     ["proposal-decorators", { "decoratorsBeforeExport": false }],
     "proposal-class-properties"