[dotnet-sdk-10.0.100-rc.2.25474.116] grandnode2 build get error: The call is ambiguous between the following methods or properties: 'JsonSerializer.Deserialize<TValue>(ReadOnlySpan<byte>, JsonSerializerOptions?)'...

[Junjun-zhao]

Application Name: grandnode2
OS： Windows 10 22H2
CPU: X64
.NET Build Number: dotnet-sdk-10.0.100-rc.2.25474.116
App Source checking at: https://devdiv.visualstudio.com/DevDiv/_workitems/edit/2582392
Github Link: https://github.com/grandnode/grandnode2

Verify Scenarios
Windows10 22h2 x64 + dotnet-sdk-9.0.305: Pass
Windows10 22h2 x64 + dotnet-sdk-10.0.100-preview.7.25380.108: Pass
Windows10 22h2 x64 + dotnet-sdk-10.0.100-rc.1.25451.107: Fail
Windows10 22h2 x64 + dotnet-sdk-10.0.100-rc.2.25474.116: Fail

Description:

We build the third-party app with dotnet-sdk-10.0.100-rc.2.25474.116, it failed with error: The call is ambiguous between the following methods or properties: 'JsonSerializer.Deserialize<TValue>(ReadOnlySpan<byte>, JsonSerializerOptions?)' and 'JsonSerializer.Deserialize<TValue>(string, JsonSerializerOptions?)'.

Repro steps:

The machine needs to install dotnet-sdk-10.0.100-rc.2.25474.116

1. Run command: "dotnet build" in \grandnode2\src\Core\Grand.Infrastructure.

Expected Result:

Build successfully.

Actual Result:
Build failed with error:

The call is ambiguous between the following methods or properties: 'JsonSerializer.Deserialize<TValue>(ReadOnlySpan<byte>, JsonSerializerOptions?)' and 'JsonSerializer.Deserialize<TValue>(string, JsonSerializerOptions?)'

DotNet Info:

.NET SDK:
 Version:           10.0.100-rc.2.25474.116
 Commit:            54303ce0f4
 Workload version:  10.0.100-manifests.62cb6acc
 MSBuild version:   18.0.0-preview-25474-116+54303ce0f

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19045
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\10.0.100-rc.2.25474.116\

Host:
  Version:      10.0.0-rc.2.25474.116
  Architecture: x64
  Commit:       54303ce0f4

.NET SDKs installed:
  10.0.100-rc.2.25474.116 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.App 10.0.0-rc.2.25474.116 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 10.0.0-rc.2.25474.116 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 10.0.0-rc.2.25474.116 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

@dotnet-actwx-bot @dotnet/compat

[jjonescz]

Looks like an expected breaking change because RedisValue is implicitly convertible (via user-defined conversions) to both string and byte[] and first-class span feature allows implicit conversion from byte[] to ReadOnlySpan<byte> hence both overloads (JsonSerializer.Deserialize<TValue>(ReadOnlySpan<byte>, JsonSerializerOptions?) and JsonSerializer.Deserialize<TValue>(string, JsonSerializerOptions?)) are now equally applicable. FYI @jaredpar.

The workaround is adding (string) cast to the error location:

var message = JsonSerializer.Deserialize<MessageEventClient>((string)redisValue);

[jaredpar]

@jjonescz agree on the analysis. Curious though, should we recommend that JsonSerializer add an ORPA annotation here? Basically should they prefer the ROS<byte> overload?

[jjonescz]

I'm not sure, it would work for RedisValue afaict but what if there is another custom type convertible to both string and byte[] but with different semantics such that they are not interchangeable (e.g., the byte[] conversion only works if the custom type instance was created from a byte[] and doesn't represent UTF8 version of the string). Then the ORPA would change behavior. Maybe ambiguity is better.

[jaredpar]

This behavior is "By Design" with the new C# 14 first class span support.

[CancanTang]

Thanks. Yes, the workaround of adding a (string) cast at the error location works .