specific scenario causes infinite recursion in util.inspect (max stack size exceeded)

[timotejroiko]

• Version: v15.6.0
• Platform: Microsoft Windows NT 10.0.19042.0 x64
• Subsystem: util

What steps will reproduce the bug?

const { inspect } = require("util");

class A {
    constructor(B) {
        this.B = B;
    }
    get b() {
        return this.B;
    }
}

class B {
    constructor() {
        this.A = new A(this);
    }
    get a() {
        return this.A;
    }
}

const test = new B();
const result = inspect(test, {
    depth:1,
    getters:true,
    showHidden:true
});

console.log(result);

How often does it reproduce? Is there a required condition?

Happens when both getters and showHidden are enabled and the class contains circular references accessible by getters

What is the expected behavior?

The depth option should short circuit the circular references and display no more than 2 levels of depth.

What do you see instead?

A giant wall of text.

Additional information

Also tested on node v15.4.0 and NWJS running node v15.3.0 but did not test in v14.

Issue discovered when attempting to inspect a client instance from the discord.js library, which makes use of such circular references.

EDIT: just tested in v15.2.0 and it works correctly. It seems the issue was introduced with v15.3.0

[RaisinTen]

This runs correctly in v15.2.0:

❯ node test.js
<ref *1> B {
  A: A { B: [Circular *1], [b]: [Getter: undefined] },
  [a]: [Getter: undefined]
}

[timotejroiko]

This runs correctly in v15.2.0:

Can confirm, just tested myself on 15.2 and it worked correctly. Issue happens on 15.3+

[targos]

Probably introduced by #36052

[BridgeAR]

I got a fix locally and I'll submit the PR later on.

> console.log(result);
<ref *1> B {
  A: A { B: [Circular *1], [b]: [Getter] [Circular *1] },
  [a]: [Getter] A { B: [Circular *1], [b]: [Getter] [Circular *1] }
}