Object properties in array items get set to null when cleared

[filbertteo]

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, Codesandbox.io or preferably a shared playground link demonstrating the issue.

What theme are you using?

core

Version

6.x

Current Behavior

Validation error is shown when submitting a form for a field when it is being cleared, because it is set to null by ArrayField onChange.

Expected Behavior

No validation error is shown when submitting.

Steps To Reproduce

1. Visit this playground link
2. Clear the age field for the 1st array item.
3. Click submit. Notice that the error message "must be number" appears for the age field.

Environment

- OS:
- Node:
- npm:

Anything else?

Here's my proposed fix in ArrayField.tsx:

  const handleChange = useCallback(
    (value: any, path: FieldPathList, newErrorSchema?: ErrorSchema<T>, id?: string) => {
      const isArrayItemChange = typeof path.at(-1) === "number";
      onChange(
        // We need to treat undefined items as nulls to have validation.
        // See https://github.com/tdegrunt/jsonschema/issues/206
        // Only set to null for array items, and not for object properties within array items.
        isArrayItemChange && value === undefined ? null : value,
        path,
        newErrorSchema as ErrorSchema<T[]>,
        id,
      );
    },
    [onChange],
  );

[heath-freenome]

@filbertteo We welcome a PR with your change in it, along with a unit test that verifies it works correctly

[hirenr]

Seems related to #4483