Preserve class id when transforming using declarations with exported class (#17257)

JLHwung · web-flow · commit 1d4546bcb800 · 2025-05-17T22:42:42.000-04:00
diff --git a/packages/babel-helper-module-transforms/src/normalize-and-load-metadata.ts b/packages/babel-helper-module-transforms/src/normalize-and-load-metadata.ts
@@ -447,7 +447,10 @@ function getLocalExportMetadata(
 ): Map<string, LocalExportMetadata> {
   const bindingKindLookup = new Map();
 
-  programPath.get("body").forEach((child: NodePath) => {
+  const programScope = programPath.scope;
+  const programChildren = programPath.get("body");
+
+  programChildren.forEach((child: NodePath) => {
     let kind: ModuleBindingKind;
     if (child.isImportDeclaration()) {
       kind = "import";
@@ -495,7 +498,12 @@ function getLocalExportMetadata(
     let metadata = localMetadata.get(localName);
 
     if (!metadata) {
-      const kind = bindingKindLookup.get(localName);
+      // If localName is not found in the bindingKindLookup generated
+      // from top level declarations, it could be a reference to a var
+      // declaration defined within block statement or switch case
+      const kind: ModuleBindingKind =
+        bindingKindLookup.get(localName) ??
+        (programScope.getBinding(localName)?.kind as "var" | undefined);
 
       if (kind === undefined) {
         throw idPath.buildCodeFrameError(
@@ -512,7 +520,7 @@ function getLocalExportMetadata(
     return metadata;
   };
 
-  programPath.get("body").forEach(child => {
+  programChildren.forEach(child => {
     if (
       child.isExportNamedDeclaration() &&
       (initializeReexports || !child.node.source)
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/src/index.ts b/packages/babel-plugin-proposal-explicit-resource-management/src/index.ts
@@ -290,7 +290,10 @@ export default declare(api => {
               let varId;
               if (t.isClassDeclaration(declaration)) {
                 varId = declaration.id;
-                declaration.id = null;
+                // Move the class id to the var binding such that the scope binding
+                // info is correct. Then we clone one to ensure inner class reference
+                // will stay same if the outer binding is mutated.
+                declaration.id = t.cloneNode(varId);
                 declaration = t.toExpression(declaration);
               } else if (!t.isExpression(declaration)) {
                 continue;
@@ -332,7 +335,7 @@ export default declare(api => {
 
             if (t.isClassDeclaration(node)) {
               const { id } = node;
-              node.id = null;
+              node.id = t.cloneNode(id);
               innerBlockBody.push(
                 t.variableDeclaration("var", [
                   t.variableDeclarator(id, t.toExpression(node)),
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/integration/commonjs-transform/input.js b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/integration/commonjs-transform/input.js
@@ -0,0 +1,18 @@
+import { doSomething } from "somewhere";
+export * from "somewhere else";
+export * as ns from "somewhere else";
+
+function f() { a; B; }
+function h() { b; A; }
+export function g() { c; }
+
+doSomething();
+
+export { f };
+export let { b } = {};
+
+let c = 2;
+class A {}
+export class B {}
+
+using x = null;
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/integration/commonjs-transform/options.json b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/integration/commonjs-transform/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "module",
+  "plugins": ["transform-modules-commonjs", "transform-export-namespace-from", "proposal-explicit-resource-management"]
+}
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/integration/commonjs-transform/output.js b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/integration/commonjs-transform/output.js
@@ -0,0 +1,56 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+var _exportNames = {
+  g: true,
+  f: true,
+  b: true,
+  B: true,
+  ns: true
+};
+exports.b = exports.B = void 0;
+exports.f = f;
+exports.g = g;
+exports.ns = void 0;
+var _somewhere = require("somewhere");
+var _ns = babelHelpers.interopRequireWildcard(require("somewhere else"));
+exports.ns = _ns;
+Object.keys(_ns).forEach(function (key) {
+  if (key === "default" || key === "__esModule") return;
+  if (Object.prototype.hasOwnProperty.call(_exportNames, key)) return;
+  if (key in exports && exports[key] === _ns[key]) return;
+  Object.defineProperty(exports, key, {
+    enumerable: true,
+    get: function () {
+      return _ns[key];
+    }
+  });
+});
+function f() {
+  a;
+  B;
+}
+function h() {
+  b;
+  A;
+}
+function g() {
+  c;
+}
+try {
+  var _usingCtx = babelHelpers.usingCtx();
+  (0, _somewhere.doSomething)();
+  var {
+    b
+  } = {};
+  var c = 2;
+  var A = class A {};
+  var B = class B {};
+  var x = _usingCtx.u(null);
+} catch (_) {
+  _usingCtx.e = _;
+} finally {
+  _usingCtx.d();
+}
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-default-class/output.mjs b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-default-class/output.mjs
@@ -2,7 +2,7 @@ export { C as default };
 try {
   var _usingCtx = babelHelpers.usingCtx();
   var x = _usingCtx.u(null);
-  var C = class {};
+  var C = class C {};
 } catch (_) {
   _usingCtx.e = _;
 } finally {
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/exec.js b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/exec.js
@@ -0,0 +1,11 @@
+export class A { static get self() { return A } }
+
+using x = null;
+
+export class B { static get self() { return B } }
+
+const AO = A, BO = B;
+A = B = null;
+
+expect(AO.self).toBe(AO);
+expect(BO.self).toBe(BO);
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/input.js b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/input.js
@@ -0,0 +1,7 @@
+export class A { static get self() { return A } }
+
+using x = null;
+
+export class B { static get self() { return B } }
+
+A = B = null;
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/options.json b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "module",
+  "plugins": ["transform-modules-commonjs", "proposal-explicit-resource-management"]
+}
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/output.js b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting-mutate-outer-class-binding/output.js
@@ -0,0 +1,25 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.B = exports.A = void 0;
+try {
+  var _usingCtx = babelHelpers.usingCtx();
+  var A = class A {
+    static get self() {
+      return A;
+    }
+  };
+  var x = _usingCtx.u(null);
+  var B = class B {
+    static get self() {
+      return B;
+    }
+  };
+  exports.A = A = exports.B = B = null;
+} catch (_) {
+  _usingCtx.e = _;
+} finally {
+  _usingCtx.d();
+}
diff --git a/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting/output.mjs b/packages/babel-plugin-proposal-explicit-resource-management/test/fixtures/transform-top-level/hoisting/output.mjs
@@ -22,8 +22,8 @@ try {
     b
   } = {};
   var c = 2;
-  var A = class {};
-  var B = class {};
+  var A = class A {};
+  var B = class B {};
   var x = _usingCtx.u(null);
 } catch (_) {
   _usingCtx.e = _;
diff --git a/packages/babel-plugin-transform-modules-amd/test/fixtures/misc/local-exports-var-declarations/input.js b/packages/babel-plugin-transform-modules-amd/test/fixtures/misc/local-exports-var-declarations/input.js
@@ -0,0 +1,10 @@
+export { A, B, C }
+
+{
+  var A;
+  switch (0) {
+    case 1:
+      var B;
+      if (2) var C;
+  }
+}
diff --git a/packages/babel-plugin-transform-modules-amd/test/fixtures/misc/local-exports-var-declarations/options.json b/packages/babel-plugin-transform-modules-amd/test/fixtures/misc/local-exports-var-declarations/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "module",
+  "plugins": ["transform-modules-amd"]
+}
diff --git a/packages/babel-plugin-transform-modules-amd/test/fixtures/misc/local-exports-var-declarations/output.js b/packages/babel-plugin-transform-modules-amd/test/fixtures/misc/local-exports-var-declarations/output.js
@@ -0,0 +1,16 @@
+define(["exports"], function (_exports) {
+  "use strict";
+
+  Object.defineProperty(_exports, "__esModule", {
+    value: true
+  });
+  _exports.C = _exports.B = _exports.A = void 0;
+  {
+    var A;
+    switch (0) {
+      case 1:
+        var B;
+        if (2) var C;
+    }
+  }
+});
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/input.js b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/input.js
@@ -0,0 +1 @@
+
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/options.json b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "module",
+  "plugins": ["./plugin.js", "transform-modules-commonjs"]
+}
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/output.js b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/output.js
@@ -0,0 +1,7 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.injected = void 0;
+var injected;
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/plugin.js b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-inject-var-declarations/plugin.js
@@ -0,0 +1,30 @@
+/**
+ * local-exports-inject-var-declarations plugin
+ * @param {import("@babel/core").PluginAPI} api
+ * @returns
+ */
+module.exports = function(api) {
+  const { types: t } = api;
+  /**
+   * @type {import("@babel/core").PluginObject}
+   */
+  const plugin = {
+    name: "local-exports-inject-var-declarations",
+    visitor: {
+      Program(path) {
+        path.node.body.push(
+          t.exportNamedDeclaration(
+            null,
+            [t.exportSpecifier(t.identifier("injected"), t.identifier("injected"))]
+          ),
+          t.variableDeclaration(
+            "var",
+            [t.variableDeclarator(t.identifier("injected"))]
+          )
+        );
+      }
+    }
+  }
+
+  return plugin;
+}
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-invalid-inject-undefined/input.js b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-invalid-inject-undefined/input.js
@@ -0,0 +1 @@
+
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-invalid-inject-undefined/options.json b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-invalid-inject-undefined/options.json
@@ -0,0 +1,5 @@
+{
+  "sourceType": "module",
+  "plugins": ["./plugin.js", "transform-modules-commonjs"],
+  "throws": "Exporting local \"invalid\", which is not declared. (This is an error on an internal node. Probably an internal error.)"
+}
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-invalid-inject-undefined/plugin.js b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-invalid-inject-undefined/plugin.js
@@ -0,0 +1,28 @@
+/**
+ * local-exports-invalid-inject-undefined plugin
+ * @param {import("@babel/core").PluginAPI} api
+ * @returns
+ */
+module.exports = function(api) {
+  const { types: t } = api;
+  /**
+   * @type {import("@babel/core").PluginObject}
+   */
+  const plugin = {
+    name: "local-exports-invalid-inject-undefined",
+    visitor: {
+      Program(path) {
+        // Injected `export { invalid }` without defining `invalid`.
+        // The invalid AST should then trigger an internal error.
+        path.node.body.push(
+          t.exportNamedDeclaration(
+            null,
+            [t.exportSpecifier(t.identifier("invalid"), t.identifier("invalid"))]
+          )
+        );
+      }
+    }
+  }
+
+  return plugin;
+}
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-var-declarations/input.js b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-var-declarations/input.js
@@ -0,0 +1,10 @@
+export { A, B, C }
+
+{
+  var A;
+  switch (0) {
+    case 1:
+      var B;
+      if (2) var C;
+  }
+}
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-var-declarations/options.json b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-var-declarations/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "module",
+  "plugins": ["transform-modules-commonjs"]
+}
diff --git a/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-var-declarations/output.js b/packages/babel-plugin-transform-modules-commonjs/test/fixtures/misc/local-exports-var-declarations/output.js
@@ -0,0 +1,14 @@
+"use strict";
+
+Object.defineProperty(exports, "__esModule", {
+  value: true
+});
+exports.C = exports.B = exports.A = void 0;
+{
+  var A;
+  switch (0) {
+    case 1:
+      var B;
+      if (2) var C;
+  }
+}
diff --git a/packages/babel-plugin-transform-modules-umd/test/fixtures/misc/local-exports-var-declarations/input.js b/packages/babel-plugin-transform-modules-umd/test/fixtures/misc/local-exports-var-declarations/input.js
@@ -0,0 +1,10 @@
+export { A, B, C }
+
+{
+  var A;
+  switch (0) {
+    case 1:
+      var B;
+      if (2) var C;
+  }
+}
diff --git a/packages/babel-plugin-transform-modules-umd/test/fixtures/misc/local-exports-var-declarations/options.json b/packages/babel-plugin-transform-modules-umd/test/fixtures/misc/local-exports-var-declarations/options.json
@@ -0,0 +1,4 @@
+{
+  "sourceType": "module",
+  "plugins": ["transform-modules-umd"]
+}
diff --git a/packages/babel-plugin-transform-modules-umd/test/fixtures/misc/local-exports-var-declarations/output.js b/packages/babel-plugin-transform-modules-umd/test/fixtures/misc/local-exports-var-declarations/output.js
@@ -0,0 +1,28 @@
+(function (global, factory) {
+  if (typeof define === "function" && define.amd) {
+    define(["exports"], factory);
+  } else if (typeof exports !== "undefined") {
+    factory(exports);
+  } else {
+    var mod = {
+      exports: {}
+    };
+    factory(mod.exports);
+    global.input = mod.exports;
+  }
+})(typeof globalThis !== "undefined" ? globalThis : typeof self !== "undefined" ? self : this, function (_exports) {
+  "use strict";
+
+  Object.defineProperty(_exports, "__esModule", {
+    value: true
+  });
+  _exports.C = _exports.B = _exports.A = void 0;
+  {
+    var A;
+    switch (0) {
+      case 1:
+        var B;
+        if (2) var C;
+    }
+  }
+});

-Original file line number
+Diff line change
@@ @@ -0,0 +1,4 @@ @@
 +{
 +  "sourceType": "module",
 +  "plugins": ["transform-modules-commonjs", "transform-export-namespace-from", "proposal-explicit-resource-management"]
 +}