[Bug]: toStrictEquals incorrectly compares class instances with getters that access private fields

[PSanetra]

Version

29.2.2

Steps to reproduce

Execute the following test that fails:

class A {
  #_a;

  constructor(a) {
    this.#_a = a;
  }

  get a() {
    return this.#_a;
  }
}

describe('toStrictEqual', () => {
  it('should not consider class instances with getters that access private fields with different values as equal', () => {
    expect(new A('v1')).not.toStrictEqual(new A('v2'));
  });
});

with the following jest config

export default {
  testEnvironment: 'node',
  transform: {},
};

Also see stackblitz: https://stackblitz.com/edit/node-z2xset?file=index.spec.js

Expected behavior

I expect that the test above is successful.

Actual behavior

The test fails.

Additional context

This issue might be somehow related to the follwing issues, but I am not 100% sure as there are errors thrown in those issues.

• toEqual throws a TypeError when using getter to private field of class #10167
• Jest does not support private class fields #9022

Environment

System:
    OS: Linux 5.0 undefined
    CPU: (8) x64 Intel(R) Core(TM) i9-9880H CPU @ 2.30GHz
  Binaries:
    Node: 16.14.2 - /usr/local/bin/node
    Yarn: 1.22.19 - /usr/local/bin/yarn
    npm: 7.17.0 - /usr/local/bin/npm
  npmPackages:
    jest: 29.2.2 => 29.2.2

[PSanetra]

On further investigation I suspect that getters of classes are generally not considered on class instances. Otherwise getters of simple objects (e.g. { get a() { return 'v1' } }) are considered during comparing objects. In my opinion this is inconsistent.

I think the cause of this issue is the key enumeration code: https://github.com/facebook/jest/blob/54ce1053aa462cd745127ac41d571d812c268580/packages/expect-utils/src/jasmineUtils.ts#L205-L217

for (const key in obj) and generally Object.keys(obj) will enumerate the getter keys of simple objects, but not those of class instances.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.

[github-actions]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 30 days.