Runtime: System.Text.Json fails to deserialize datetime

[radek7210]

Repro steps:

public class MyRecord
{
    public int IDValue { get; set; }
    public string NameValue { get; set; }
    public DateTime DateTimeValue { get; set; }
    public Decimal DecimalValue { get; set; }
}

...
// create a record, fill-in only some properties
MyRecord myRecord = new MyRecord { IDValue = 1 };

// serialize to string
string serializedValue = System.Text.Json.Serialization.JsonSerializer.ToString(myRecord);

// deserialize
MyRecord deserializedRecord = System.Text.Json.Serialization.JsonSerializer.Parse<MyRecord>(serializedValue);

This produces an error:
System.Text.Json.JsonException
Message=The JSON value could not be converted to System.DateTime. Path: $.DateTimeValue | LineNumber: 0 | BytePositionInLine: 67.
Source=System.Text.Json

Is this a bug in System.Text.Json, or is there any recommendation how to handle "empty" datetimes?

Thanks

[Gnbrkm41]

Looks like you're on .NET Core 3.0 P5 or the NuGet pacakge before P6; have you tried it on P6? it seems to work fine on the latest...ish master branch.

(Note that JsonSerializer has been moved to System.Text.Json out of the Serialization namespace)

[radek7210]

I'm on P6 (don't have P5 installed) -

λ dotnet --list-runtimes
Microsoft.AspNetCore.All 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0-preview6.19307.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.1.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.0.0-preview6-27804-01 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.0.0-preview6-27804-01 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

λ dotnet --list-sdks
2.1.507 [C:\Program Files\dotnet\sdk]
2.1.700 [C:\Program Files\dotnet\sdk]
2.1.800-preview-009696 [C:\Program Files\dotnet\sdk]
2.2.300 [C:\Program Files\dotnet\sdk]
3.0.100-preview6-012264 [C:\Program Files\dotnet\sdk]

And this is from the compiler output:
C:\Program Files\dotnet\sdk\3.0.100-preview6-012264\Sdks\Microsoft.NET.Sdk\targets\Microsoft.NET.RuntimeIdentifierInference.targets(158,5): message NETSDK1057: You are using a preview version of .NET Core.

[Gnbrkm41]

Hmm, maybe it's fixed post-P6 perhaps. (I'm on 3.0.100-preview7-012426) I'm able to deserialize the JSON string back and read the properties:

// create a record, fill-in only some properties
MyRecord myRecord = new MyRecord { IDValue = 1 };

// serialize to string
string serializedValue = JsonSerializer.ToString(myRecord);

// deserialize
MyRecord deserializedRecord = JsonSerializer.Parse<MyRecord>(serializedValue);

Console.ReadLine();
Console.WriteLine($"DateTimeValue: {deserializedRecord.DateTimeValue:O}");
Console.WriteLine($"DecimalValue: {deserializedRecord.DecimalValue}");
Console.WriteLine($"IDValue: {deserializedRecord.IDValue}");
Console.WriteLine($"NameValue: {deserializedRecord.NameValue ?? "null"}");
// Outputs:
// DateTimeValue: 0001-01-01T00:00:00.0000000
// DecimalValue: 0
// IDValue: 1
// NameValue: null

[radek7210]

ok then, I will wait for P7, no problem.
Thanks for your time.

[Gnbrkm41]

If you want to try it yourself, you could follow this:
https://github.com/dotnet/corefx/blob/master/Documentation/project-docs/dogfooding.md

[layomia]

As @Gnbrkm41 pointed out, this issue is not reproducible in the current build, so I'm closing this for now.
@radek7210 , please feel free to re-open if you sync to the latest build and still get this issue - https://github.com/dotnet/core-sdk#installers-and-binaries.