Fix support for import/export in .cts files (#15478)

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

Makefile

@@ -177,15 +177,14 @@ test-test262-update-allowlist:
 
 
 new-version-checklist:
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @echo "!!!!!!                                                   !!!!!!"
-	# @echo "!!!!!!   Write any release-blocking message here, and    !!!!!!"
-	# @echo "!!!!!!              UNCOMMENT THESE LINES                !!!!!!"
-	# @echo "!!!!!!                                                   !!!!!!"
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
-	# @exit 1
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@echo "!!!!!!                                                   !!!!!!"
+	@echo "!!!!!!  Update the semver.lte check in module-types.ts   !!!!!!"
+	@echo "!!!!!!                                                   !!!!!!"
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@echo "!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!"
+	@exit 1
 
 new-version:
 	$(MAKE) new-version-checklist

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

@@ -66,18 +66,18 @@ function loadCtsDefault(filepath: string) {
     const opts: InputOptions = {
       babelrc: false,
       configFile: false,
-      sourceType: "script",
+      sourceType: "unambiguous",
       sourceMaps: "inline",
+      sourceFileName: path.basename(filepath),
       presets: [
         [
           getTSPreset(filepath),
           {
-            disallowAmbiguousJSXLike: true,
             onlyRemoveTypeImports: true,
             optimizeConstEnums: true,
             ...(process.env.BABEL_8_BREAKING
-              ? { ignoreExtensions: true }
-              : { allExtensions: true, allowDeclareFields: true }),
+              ? {}
+              : { allowDeclareFields: true }),
           },
         ],
       ],
@@ -86,21 +86,43 @@ function loadCtsDefault(filepath: string) {
     handler = function (m, filename) {
       // If we want to support `.ts`, `.d.ts` must be handled specially.
       if (handler && filename.endsWith(ext)) {
-        // @ts-expect-error Undocumented API
-        return m._compile(
-          transformFileSync(filename, {
-            ...opts,
+        try {
+          // @ts-expect-error Undocumented API
+          return m._compile(
+            transformFileSync(filename, {
+              ...opts,
+              filename,
+            }).code,
             filename,
-          }).code,
-          filename,
-        );
+          );
+        } catch (error) {
+          if (!hasTsSupport) {
+            const packageJson = require("@babel/preset-typescript/package.json");
+
+            if (
+              semver.lte(
+                // eslint-disable-next-line import/no-extraneous-dependencies
+                packageJson.version,
+                "7.21.0",
+              ) &&
+              // ignore the version check if not published
+              !packageJson.conditions
+            ) {
+              console.error(
+                "`.cts` configuration file failed to load, please try to update `@babel/preset-typescript`.",
+              );
+            }
+          }
+          throw error;
+        }
       }
       return require.extensions[".js"](m, filename);
     };
     require.extensions[ext] = handler;
   }
   try {
-    return endHiddenCallStack(require)(filepath);
+    const module = endHiddenCallStack(require)(filepath);
+    return module?.__esModule ? module.default : module;
   } finally {
     if (!hasTsSupport) {
       if (require.extensions[ext] === handler) delete require.extensions[ext];

packages/babel-core/test/config-ts.js

@@ -42,10 +42,12 @@ const shouldSkip = semver.lt(process.version, "12.0.0") || USE_ESM;
     });
 
     expect(config.options.targets).toMatchInlineSnapshot(`
-          Object {
-            "node": "12.0.0",
-          }
-        `);
+      Object {
+        "node": "12.0.0",
+      }
+    `);
+
+    expect(config.options.sourceRoot).toMatchInlineSnapshot(`"/a/b"`);
   });
 
   it("should throw with invalid .ts register", () => {
@@ -89,10 +91,12 @@ const shouldSkip = semver.lt(process.version, "12.0.0") || USE_ESM;
       });
 
       expect(config.options.targets).toMatchInlineSnapshot(`
-            Object {
-              "node": "12.0.0",
-            }
-          `);
+        Object {
+          "node": "12.0.0",
+        }
+      `);
+
+      expect(config.options.sourceRoot).toMatchInlineSnapshot(`"/a/b"`);
     } finally {
       service.enabled(false);
     }

packages/babel-core/test/fixtures/config-ts/invalid-cts-register/babel.config.cts

@@ -1,2 +1 @@
 type config = any;
-module.exports = { targets: "node 12.0.0" } as config;

packages/babel-core/test/fixtures/config-ts/simple-cts-with-ts-node/babel.config.cts

@@ -1,2 +1,6 @@
+import path from "path";
 type config = any;
-module.exports = { targets: "node 12.0.0" } as config;
+export default {
+  targets: "node 12.0.0",
+  sourceRoot: path.posix.join("/a", "b"),
+} as config;

packages/babel-core/test/fixtures/config-ts/simple-cts/babel.config.cts

@@ -1,2 +1,6 @@
+import path from "path";
 type config = any;
-module.exports = { targets: "node 12.0.0" } as config;
+export default {
+  targets: "node 12.0.0",
+  sourceRoot: path.posix.join("/a", "b"),
+} as config;

packages/babel-helper-module-imports/src/is-module.ts

@@ -5,12 +5,5 @@ import type * as t from "@babel/types";
  * A small utility to check if a file qualifies as a module.
  */
 export default function isModule(path: NodePath<t.Program>) {
-  const { sourceType } = path.node;
-  if (sourceType !== "module" && sourceType !== "script") {
-    throw path.buildCodeFrameError(
-      `Unknown sourceType "${sourceType}", cannot transform.`,
-    );
-  }
-
   return path.node.sourceType === "module";
 }

packages/babel-preset-typescript/package.json

@@ -20,6 +20,7 @@
     "@babel/helper-plugin-utils": "workspace:^",
     "@babel/helper-validator-option": "workspace:^",
     "@babel/plugin-syntax-jsx": "workspace:^",
+    "@babel/plugin-transform-modules-commonjs": "workspace:^",
     "@babel/plugin-transform-typescript": "workspace:^"
   },
   "peerDependencies": {

packages/babel-preset-typescript/src/index.ts

@@ -1,6 +1,7 @@
 import { declarePreset } from "@babel/helper-plugin-utils";
 import transformTypeScript from "@babel/plugin-transform-typescript";
 import syntaxJSX from "@babel/plugin-syntax-jsx";
+import transformModulesCommonJS from "@babel/plugin-transform-modules-commonjs";
 import normalizeOptions from "./normalize-options";
 import type { Options } from "./normalize-options";
 
@@ -77,8 +78,11 @@ export default declarePreset((api, opts: Options) => {
             test: !process.env.BABEL_8_BREAKING
               ? /\.cts$/
               : filename => filename?.endsWith(".cts"),
-            sourceType: "script",
-            plugins: getPlugins(false, true),
+            sourceType: "unambiguous",
+            plugins: [
+              [transformModulesCommonJS, { allowTopLevelThis: true }],
+              [transformTypeScript, pluginOptions(true)],
+            ],
           },
           {
             test: !process.env.BABEL_8_BREAKING

packages/babel-preset-typescript/test/fixtures/node-extensions/import-in-cts/output.js

@@ -0,0 +1,3 @@
+"use strict";
+
+require("x");

yarn.lock

@@ -3603,6 +3603,7 @@ __metadata:
     "@babel/helper-plugin-utils": "workspace:^"
     "@babel/helper-validator-option": "workspace:^"
     "@babel/plugin-syntax-jsx": "workspace:^"
+    "@babel/plugin-transform-modules-commonjs": "workspace:^"
     "@babel/plugin-transform-typescript": "workspace:^"
   peerDependencies:
     "@babel/core": ^7.0.0-0