Array item could not be an Error

[jurecka]

Support plan

• which support plan is this issue covered by? (e.g. Community, Core, Plus, or Enterprise): Community
• is this issue currently blocking your project? (yes/no): no
• is this issue affecting a production system? (yes/no): yes

Context

• node version: 12.14.1
• module version with issue: 16.1.1
• last module version without issue: 16.0.1
• environment (e.g. node, browser, native): node
• used with (e.g. hapi application, another framework, standalone, ...): standalone
• any other relevant information:

What are you trying to achieve or the steps to reproduce?

I am trying validate that an array contains an Error.

/** run the next tests by ./node_modules/jest/bin/jest.js joi.test.js */
const Joi = require('@hapi/joi');

const ErrorSchema = Joi.object().instance(Error)
const CustomErrorSchema = Joi
  .any()
  .custom((error) => {
    if (error instanceof Error) {
      return true;
    }
    throw new Error('Error validation fail');
  })
  .raw(true);
const createArraySchema = (...items) => Joi.array().items(...items);

it('1# should pass validation of Error schema', () => {
  expect(ErrorSchema.validate(new Error('test error')))
    .toEqual({
      value: new Error('test error')
    });
});

it('2# should pass validation of Error schema in array', () => {
  expect(createArraySchema(ErrorSchema).validate([new Error('test error')]))
    .toEqual({
      value: [new Error('test error')]
    });
});

it('3# should pass validation of Error schema in array (workaround)', () => {
  expect(createArraySchema(CustomErrorSchema.raw(false))
    .raw(true)
    .validate([new Error('test error')])
  )
    .toEqual({
      value: [new Error('test error')]
    });
});

What was the result you got?

Test 2# fails due to validation always fails even though the Error is valid item of the array.

What result did you expect?

Array item could be an Error.

I see the #2118 where this issue was introduced. Due to missing description there I created this issue.

[tmartin1]

Ran into the same problem. I believe the ret[0] instanceof Error is the culprit here: https://github.com/hapijs/joi/blob/v16/lib/validator.js#L419

The way it is now, if there is an Error at index zero, even if it is supposed to be there, the validation fails.

[hueniverse]

I'm marking this as a breaking change (released as a non-breaking version) because it is possible someone has written an extension that uses this bug to send multiple errors from a custom rule using an array. If that's the case, this will break that because it now requires a special array generated by helpers.errorsArray(). Since this wasn't documented and was a bug, I am releasing this as a non-breaking release.