[Bug]: Stackoverflow in toMatchObject when matching w/ recursive object

[connorjclark]

Version

29.7.0

Steps to reproduce

Using expect 29.7.0

Here is a contrived example (real usage here / here)

const a = {
  v: 1,
};
const b = {
  v: 1,
};
const c1 = {
  ref: [],
};
c1.ref.push(c1);
const c2 = {
  ref: [],
};
c2.ref.push(c2);

a.ref = c1;
b.ref = c2;
expect(a).toMatchObject(b);

Expected behavior

Either document that recursive objects are not supported, or support them.

Actual behavior

RangeError: Maximum call stack size exceeded

Additional context

No response

Environment

n/a

[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.

[SimenB]

We should start by adding a warning to the docs I guess, but it would be nice to support this

[KhaledElmorsy]

As far as I've tested, the issue doesn't happen if the circular reference is not in an array nor if it's in a set. It also works if it's nested deeper in. I can take a crack at fixing this issue if no one else is working on it.

[github-actions]

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[SimenB]

https://github.com/jestjs/jest/releases/tag/v30.0.0-alpha.4