[Issue] Fix handling of mixins for modules with no dependencies defined

This issue is automatically created based on existing pull request: #27690: Fix handling of mixins for modules with no dependencies defined

---

Description (*)

This PR addresses an issue that was outlined in #25587 (comment) and investigated by me afterwards.

This is a regression I have introduced when refactoring mixins module, but it applies only in two cases which are not present in the Magento itself:

// Module defined as anything else then a function with dependencies skipped.
define('my-module', {
  foo: 'bar'
});
// Module defined with dependencies passed as "null".
define('my-module', null, {
  foo: 'bar'
});

which both results in special case where second element of RequireJS's defQueue is null and made the script throw an error when somebody required such module.

Manual testing scenarios (*)

1. Open the store.
2. Open browser console.
3. Paste and execute the following code:

define('my-module', {
  foo: 'bar'
});
require(['my-module', function(){});

4. Verify that no error similar to TypeError: Cannot read property 'map' of null is thrown.

Questions or comments

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• All automated tests passed successfully (all builds are green)

[magento-engcom-team]

Based on the provided information internal tickets MC-34579 for 2.4.x were created.

[slavvka]

Hi @m2-backlog[bot]. Thank you for your report.
The issue has been fixed in #27690 by @krzksz in 2.4-develop branch
Related commit(s):

• 97f0a1f34efc7c40c97014800cc876e9aedcdc0f
• 16444d01be029f23aa9909cf901aef19380598cc

The fix will be available with the upcoming 2.4.1 release.