NX20 and @nx/jest/plugin: implicit 'test' target disappeared

[stefanlivens]

Current Behavior

When migrating to NX20 in a mono-repo, the implicit 'test'-target from @nx/jest/plugin has disappeared.

Situation:
Full NX mono-repo, with components in /packages/ and supporting stuff like storybook in /libs/. Complete setup with jest, separate jest.configs in the /libs/ and /packages/, and a target setup in the root nx.json like this:

"plugins": [{
      "plugin": "@nx/jest/plugin",
      "exclude": ["libs/**/*"],
      "options": {
        "targetName": "test"
      }
 }]

A jest.config.ts like

import { getJestProjects } from '@nx/jest';

export default {
  projects: getJestProjects(),
...
};

When migrating to NX20, and after running the provided migration, this becomes:

import { getJestProjectsAsync } from '@nx/jest';

export default async () => ({
  projects: await getJestProjectsAsync(),
  ...
});

And this makes the test target disappear, meaning we get this error:
NX Cannot find configuration for task component-library:test

Upon investigating the NX -source code, we found this (plugin.ts)

if (jestConfigContent.includes('getJestProjectsAsync()')) {
  // The `getJestProjectsAsync` function uses the project graph, which leads to a
  // circular dependency. We can skip this since it's no intended to be used for
  // an Nx project.
  return {};
}

This confuses me:

• so if jestProjectAsync is present, do not add the implicit target ? But this is what the documentation says me to do, no?
• "not intended to be used for an nx project"?

I kinda get the circular dependency reference, but then how should we use this @nx/jest plugin?

Expected Behavior

I did not expect the 'test' target to disappear.
So it would be nice to have some kind of a warning/error from the @nx/jest/plugin.

GitHub Repo

No response

Steps to Reproduce

Nx Report

Node           : 20.17.0
OS             : darwin-x64
Native Target  : x86_64-macos
npm            : 10.8.2

nx (global)        : 19.5.2
nx                 : 20.1.3
@nx/js             : 20.1.3
@nx/jest           : 20.1.3
@nx/eslint         : 20.1.3
@nx/workspace      : 20.1.3
@nx/devkit         : 20.1.3
@nx/eslint-plugin  : 20.1.3
@nx/plugin         : 20.1.3
@nx/web            : 20.1.3
typescript         : 5.4.5
---------------------------------------
Registered Plugins:
@nx/jest/plugin
@nx/eslint/plugin

Failure Logs

Package Manager Version

npm

Operating System

• macOS
• Linux
• Windows
• Other (Please specify)

Additional Information

No response