fix: fail with an informative error message on a file with a broken default import (#5413)

* Fixes #5411.

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

* Add debug logs to esm-utils

* Always attempt import() after failed require(). On failure, only throw the require error in case the import error is ERR_INTERNAL_ASSERTION

---------

Co-authored-by: Mark Wiemer <[email protected]>

Author: martinslota

lib/nodejs/esm-utils.js

@@ -1,5 +1,6 @@
 const path = require('node:path');
 const url = require('node:url');
+const debug = require('debug')('mocha:esm-utils');
 
 const forward = x => x;
 
@@ -95,14 +96,22 @@ const requireModule = async (file, esmDecorator) => {
   }
   try {
     return require(file);
-  } catch (err) {
-    // Import if require fails.
-    return dealWithExports(await formattedImport(file, esmDecorator));
+  } catch (requireErr) {
+    debug('requireModule caught err: %O', requireErr.message);
+    try {
+      return dealWithExports(await formattedImport(file, esmDecorator));
+    } catch (importErr) {
+      if (importErr.code === 'ERR_INTERNAL_ASSERTION') {
+        throw requireErr;
+      }
+      throw importErr;
+    }
   }
 };
 
 // We only assign this `requireOrImport` function once based on Node version
 // We check for file extensions in `requireModule` and `tryImportAndRequire`
+debug('assigning requireOrImport, require_module === %O', process.features.require_module);
 if (process.features.require_module) {
   exports.requireOrImport = requireModule;
 } else {

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;