Conflict when using an optional array with minItems set

[ThomasAribart]

Prerequisites

• I have searched the existing issues
• I understand that providing a SSCCE example is tremendously useful to the maintainers.
• I have read the documentation
• Ideally, I'm providing a sample JSFiddle or a shared playground link demonstrating the issue.

What theme are you using?

material-ui

Version

5.x

Current Behavior

Hi and thanks for this great lib 🙌

When setting an optional property in an "object", which is of type "array" with a "minItem" set to 1 or more, it's not possible to remove the property from the said object.

By default, the array property widget appears with items that can be empty, which can cause bugs.

Expected Behavior

I don't have any design proposal, I know it's tricky to represent, but the default items should only appear when deciding that the property is not undefined somehow.

Steps To Reproduce

const mySchema = {
  type: "object,
  properties: {
    optionalArray: {
      type: "array",
      items: { type: "string" },
      minItems: 2
    }
  }
}

Environment

- OS: Any
- Node: Any
- npm: Any

Anything else?

No response

[heath-freenome]

Here's a playground for it

[heath-freenome]

@ThomasAribart Good bug. The code is not taking into account the required-ness of the property. This seems like an easy fix in the @rjsf/utils getDefaultFormState() function's helper computeDefaults(). Are you willing to fix this for us? If so, I can point you in the right direction.

[kuosandys]

Hi there 👋 we’re also encountering the same bug in our project. Is there currently work in progress to fix it? If not, could we offer our help with fixing it?

[RPiAwesomeness]

Same here. Would be willing to help out to get this fixed.

[heath-freenome]

Yes please! Any help fixing issues is highly encouraged as we are a small team of volunteers who fix things because we want this project to succeed but do so only when we have a little free time.

[RPiAwesomeness]

@heath-freenome Question for you. I'm working on this and ran into a situation where I think one of the existing tests conflicts with this bug. Here's the console output:

I think the consensus here is that if the field isn't required and has minItems set, that no items will be automatically added. Correct? In that case, I would argue that if the field isn't required, has minItems set > 0, has no explicit default(s) defined, and no items have been added by the user, then the field shouldn't be included in the output (and thus the default form state) at all. Having an empty array included in the data seems to contradict the minItems requirement. Thus making this test invalid.

Are you okay with me removing this test or is there a part of the JSON Schema spec that I'm missing that specifies this behavior?

[RPiAwesomeness]

Another one that's similar:

Seems odd to be auto-filling default values when they're not marked as required.

For clarity's sake, these are more to spark discussion than making a statement one way or the other.

[heath-freenome]

@RPiAwesomeness These are great questions and merit a verbal conversation with the rest of the current maintainers (all 2 of us). Are you able to come to the weekly meeting that we have every Friday at 11am Eastern time? See this post for the deets

[RPiAwesomeness]

Potentially. I'll double-check my schedule but that should work for me. Anything in particular that I should prep to help the discussion?

[heath-freenome]

Potentially. I'll double-check my schedule but that should work for me. Anything in particular that I should prep to help the discussion?

Not really, if anything there might be a new minor feature that will need to be added to support the work you are doing in a backwards-compatible way. We can talk about it Friday and give you a bit more background than is here in this bug.