toThrowError fails to compare subclass of Error (ZodError).

[Amorim33]

Describe the bug

Description

toThrow and toThrowError are failing to compare a thrown ZodError.

import { z } from 'zod';

it('throws a zod error', () => {
  expect(() => {
    throw new z.ZodError([
      {
        received: 'aa',
        code: 'invalid_enum_value',
        options: ['development', 'production', 'test'],
        path: ['NODE_ENV'],
        message:
          "Invalid enum value. Expected 'development' | 'production' | 'test', received 'aa'",
      },
    ]);
  }).toThrowError(
    new z.ZodError([
      {
        received: 'aa',
        code: 'invalid_enum_value',
        options: ['development', 'production', 'test'],
        path: ['NODE_ENV'],
        message:
          "Invalid enum value. Expected 'development' | 'production' | 'test', received 'aa'",
      },
    ]),
  );
});

The test case above successfuly passes using the vitest version 2.1.8. However it fails with version 3.0.2

v2.1.8

v3.0.2

Additional Context

ZodError is a class that extends Error:
https://github.com/colinhacks/zod/blob/main/src/ZodError.ts#L200

It sets the prototype chain and defines additional methods.
This may be happening with other subclasses of Error

Although, the tests don't pass for Zod, they work fine for a simple CustomError:

it.only('throws a custom error', () => {
  class CustomError extends Error {
    constructor(message: string) {
      super(message);
      this.name = 'CustomError';
    }
  }
  expect(() => {
    throw new CustomError('Custom error message');
  }).toThrowError(new CustomError('Custom error message'));
});

---

I believe it was introduced in this PR: #5876

---

i'm opening this issue because I use Zod extensively and love Vitest, but this behavior is preventing me from upgrading to the latest version

If this is not a bug, I apologize and would humbly ask for some guidance on how to make this work.
If this aligns with the library's goals, I'd be thrilled to contribute a PR! ✨

Thank you for your attention and for your amazing open-source work! 🙏

Reproduction

• Install zod

pnpm add zod

• Install the latest version of vitest

pnpm add vitest

• Run the code

import { z } from 'zod';

it('throws a zod error', () => {
  expect(() => {
    throw new z.ZodError([
      {
        received: 'aa',
        code: 'invalid_enum_value',
        options: ['development', 'production', 'test'],
        path: ['NODE_ENV'],
        message:
          "Invalid enum value. Expected 'development' | 'production' | 'test', received 'aa'",
      },
    ]);
  }).toThrowError(
    new z.ZodError([
      {
        received: 'aa',
        code: 'invalid_enum_value',
        options: ['development', 'production', 'test'],
        path: ['NODE_ENV'],
        message:
          "Invalid enum value. Expected 'development' | 'production' | 'test', received 'aa'",
      },
    ]),
  );
});

System Info

System:
    OS: Linux 6.12 Fedora Linux 40 (Workstation Edition)
    CPU: (16) x64 AMD Ryzen 7 7800X3D 8-Core Processor
    Memory: 11.43 GB / 30.49 GB
    Container: Yes
    Shell: 3.7.0 - /usr/bin/fish
  Binaries:
    Node: 20.18.1 - /usr/bin/node
    npm: 10.8.2 - /usr/bin/npm
    pnpm: 9.12.1 - ~/.local/share/pnpm/pnpm
    bun: 1.1.38 - ~/.bun/bin/bun
  npmPackages:
    @vitest/coverage-v8: 3.0.2 => 3.0.2 
    @vitest/ui: 3.0.2 => 3.0.2 
    vitest: 3.0.2 => 3.0.2

Used Package Manager

pnpm

Validations

• Follow our Code of Conduct
• Read the Contributing Guidelines.
• Read the docs.
• Check that there isn't already an issue that reports the same bug to avoid creating a duplicate.
• Check that this is a concrete bug. For Q&A open a GitHub Discussion or join our Discord Chat Server.
• The provided reproduction is a minimal reproducible example of the bug.

[hi-ogawa]

I created a stackblitz repro to start with https://stackblitz.com/edit/vitest-dev-vitest-v3sys5ph?file=test%2Frepro.test.ts
Node's assert.deepStrictEqual also fails, so probably there's some hidden property inside somewhere different between the two, but I cannot tell yet.

It would be great if you can check with Zod side to see what's potential issue.

[hi-ogawa]

The issue is because of ZodError.addIssue/addIssues properties.
https://stackblitz.com/edit/vitest-dev-vitest-bruhvcfu?file=test%2Frepro.test.ts

it('vitest', () => {
  console.log({ ...e1 });
  // {
  //   issues: [
  //     {
  //       received: 'aa',
  //       code: 'invalid_enum_value',
  //       options: [Array],
  //       path: [Array],
  //       message: "Invalid enum value. Expected 'development' | 'production' | 'test', received 'aa'"
  //     }
  //   ],
  //   addIssue: [Function (anonymous)],
  //   addIssues: [Function (anonymous)],
  //   name: 'ZodError'
  // }
  expect(e1.addIssue).toEqual(e2.addIssue);
});

I'm not sure if we need to change something on our side since generalizing toThrowError to work more like toEqual is the spirit of the change, which also more aligns with assert.deepStrictEqual.

One workaround is to use custom equality tester to customize ZodError equality to only compare ZodError.issues https://vitest.dev/api/expect.html#expect-addequalitytesters.

A fix possible on Zod side is to make these two properties addIssue/addIssues as non enumerable. https://github.com/colinhacks/zod/blob/f7ad26147ba291cb3fb257545972a8e00e767470/src/ZodError.ts#L294-L300

[Amorim33]

Thank you very much for your debug and response @hi-ogawa !!

It was extremely helpful! 🙏

I've opened an issue on the Zod side: colinhacks/zod#3950