FluentValidation version

10.4.0

ASP.NET version

6.0.202

Summary

System.Text.Json is unable to deserialize FluentValidation.Results.ValidationResult, while Newtonsoft.Json is able to do it.

I filled an issue on dotnet runtime repo (dotnet/runtime#68280) but they suggested to open one here because it might be that FluentValidation relies on conventions not supported by System.Text.Json or that it implements a converter only for Json.NET.

Steps to Reproduce

Check this code in .NET 6:

var validationResult = new ValidationResult
{
    Errors = { new ValidationFailure("MyProperty", "Invalid MyProperty") }
};

// System.Text.Json
var serialized = JsonSerializer.Serialize(validationResult);
var deserialized = JsonSerializer.Deserialize<ValidationResult>(serialized);

// Newtonsoft.Json
var serialized2 = JsonConvert.SerializeObject(validationResult, Formatting.Indented);
var deserialized2 = JsonConvert.DeserializeObject<ValidationResult>(serialized2);

The deserialized variable contains a ValidationResult object with IsValid = true, and 0 Errors.
The deserialized2 variable contains a ValidationResult object with IsValid = false, and 1 Error.

The serialization operation produces an identical json string for both libraries, but the System.Text.Json fails to deserialize it back to a ValidationResult object.