MUI radio widget initializes as uncontrolled when schema has no default value

[tyrdavis]

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?

mui

Version

5.1.0

Current Behavior

When using the MUI theme, a field using RadioWidget with no default value renders as uncontrolled. In a non-production app, there is a MUI warning logged to the console, which unfortunately can't be seen in the playground. The widget being uncontrolled causes some strange behaviors, such as it no longer responding to programmatic changes to its value.

Playground link with the issue

In the above playground, if you select one of the radio options, then attempt to use the programmatic reset button, the field does not reset its value due to it being uncontrolled. Compare to this playground link using the default theme and this playground link using MUI but with a default defined to see the widget working as expected.

Expected Behavior

MUI's RadioGroup should always be controlled when instantiated by RJSF to prevent unexpected behavior.

Steps To Reproduce

1. Use a schema with a MUI 5 RadioWidget and no default defined
2. Select a value in the form
3. Attempt to programmatically change the value of the field; this will fail

Environment

- OS:Ubuntu 22.04
- Node: 16.13.0
- npm: 8.1.0

Anything else?

No response

[tyrdavis]

I believe the solution to this is to use null as the RadioGroup's value when enumOptionsIndexForValue returns undefined here. RadioGroup sets itself up as uncontrolled only when value={undefined} on its initial mount, so I believe that should satisfy keeping the component's value empty while still being controlled.

[heath-freenome]

@tyrdavis I tried your example and the same behavior occurs for chakra-ui, material-ui 4 and material-ui 5 (it works fine for all the other themes). Would you be willing to update those three themes with your fix and push a PR?