Fixes #5411.

Fail with an informative error message on a file with a broken default import.

Author: martinslota

lib/nodejs/esm-utils.js

@@ -93,8 +93,15 @@ const requireModule = async (file, esmDecorator) => {
   try {
     return require(file);
   } catch (err) {
-    // Import if require fails.
-    return dealWithExports(await formattedImport(file, esmDecorator));
+    if (
+      err instanceof SyntaxError &&
+      err.message.includes("does not provide an export named 'default'")
+    ) {
+      throw err;
+    } else {
+      // Import if require fails.
+      return dealWithExports(await formattedImport(file, esmDecorator));
+    }
   }
 }
 

test/node-unit/esm-utils.spec.js

@@ -5,15 +5,32 @@ const sinon = require('sinon');
 const url = require('node:url');
 
 describe('esm-utils', function () {
-  beforeEach(function () {
-    sinon.stub(esmUtils, 'doImport').resolves({});
-  });
-
-  afterEach(function () {
-    sinon.restore();
+  describe('requireOrImport', function () {
+    it('should show an informative error message for a broken default import', async function () {
+      return expect(
+        () =>
+          esmUtils.requireOrImport(
+            '../../test/node-unit/fixtures/broken-default-import.mjs'
+          ),
+        'to be rejected with error satisfying',
+        {
+          name: 'SyntaxError',
+          message:
+            "The requested module './module-without-default-export.mjs' does not provide an export named 'default'"
+        }
+      );
+    });
   });
 
   describe('loadFilesAsync()', function () {
+    beforeEach(function () {
+      sinon.stub(esmUtils, 'doImport').resolves({});
+    });
+
+    afterEach(function () {
+      sinon.restore();
+    });
+
     it('should not decorate imported module if no decorator passed', async function () {
       await esmUtils.loadFilesAsync(
         ['/foo/bar.mjs'],

test/node-unit/fixtures/broken-default-import.mjs

@@ -0,0 +1,3 @@
+import moduleWithoutDefaultExport from './module-without-default-export.mjs';
+
+moduleWithoutDefaultExport;

test/node-unit/fixtures/module-without-default-export.mjs

@@ -0,0 +1 @@
+export const value = 42;