In .NET 8, a request Record with a property decorated with [FromBody] is no longer model-binded

[davejclausen]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

Under .NET 6, we had a controller Patch request method taking a Record as the parameter. The Record had a bool property decorated with the [FromBody] attribute. This was correctly model-binded. But under .NET 8, it is not model-binded -- appearing instead as missing.

Expected Behavior

No response

Steps To Reproduce

No response

Exceptions (if any)

No response

.NET Version

8.0

Anything else?

No response

[captainsafia]

@davejclausen Is there a chance you can provide a minimal repro of your setup for help debugging this?

[davejclausen]

Our problem is occurring in conjunction with https://github.com/ardalis/ApiEndpoints.
Per the request above, I tried to isolate the issue, but could not.
Apologies for the probable false alarm. This issue can be closed.

[ericksonivanowski]

We recently migrated our applications to .NET 8 and noticed that cases where a property is decorated with the [FromBody] attribute are no longer being bound to the model.

For example:

public class RefundRequest
{
    [FromBody]
    public long Value { get; set; }

    [FromBody]
    public string Description { get; set; }

    [FromBody]
    public DateTime TransactionDate { get; set; }

    [FromQuery]
    public string UserId { get; set; }
    // ...
}

[HttpPost("{id}/[action]")]
public async Task<ActionResult> Refund(string id, RefundRequest request, CancellationToken cancellationToken = default)
{
    // ...
}

The bug only occurs when the property is decorated. In other words, if we decorate the entire object in the controller method signature, the bug does not occur. And note, it is only the [FromBody] attribute that exhibits this behavior.