Resource server returned an error while navigating around the dashboard

[davidfowl]

fail: Grpc.AspNetCore.Server.ServerCallHandler[6]
      Error when executing service method 'WatchResources'.
      System.ArgumentNullException: Value cannot be null. (Parameter 'value')
         at Google.Protobuf.ProtoPreconditions.CheckNotNull[T](T value, String name)
         at Aspire.V1.Resource.set_State(String value) in /_/artifacts/obj/Aspire.Hosting/Release/net8.0/Dashboard/proto/ResourceService.cs:line 2574
         at Aspire.V1.Resource.FromSnapshot(ResourceSnapshot snapshot) in /_/src/Aspire.Hosting/Dashboard/proto/Partials.cs:line 13
         at Aspire.Hosting.Dashboard.DashboardService.<>c__DisplayClass6_0.<<WatchResources>g__WatchResourcesInternal|0>d.MoveNext() in /_/src/Aspire.Hosting/Dashboard/DashboardService.cs:line 88
      --- End of stack trace from previous location ---
         at Aspire.Hosting.Dashboard.DashboardService.<>c__DisplayClass6_0.<<WatchResources>g__WatchResourcesInternal|0>d.MoveNext() in /_/src/Aspire.Hosting/Dashboard/DashboardService.cs:line 78
      --- End of stack trace from previous location ---
         at Aspire.Hosting.Dashboard.DashboardService.WatchResources(WatchResourcesRequest request, IServerStreamWriter`1 responseStream, ServerCallContext context) in /_/src/Aspire.Hosting/Dashboard/DashboardService.cs:line 58
         at Grpc.Shared.Server.ServerStreamingServerMethodInvoker`3.Invoke(HttpContext httpContext, ServerCallContext serverCallContext, TRequest request, IServerStreamWriter`1 streamWriter)
         at Grpc.Shared.Server.ServerStreamingServerMethodInvoker`3.Invoke(HttpContext httpContext, ServerCallContext serverCallContext, TRequest request, IServerStreamWriter`1 streamWriter)
         at Grpc.AspNetCore.Server.Internal.CallHandlers.ServerStreamingServerCallHandler`3.HandleCallAsyncCore(HttpContext httpContext, HttpContextServerCallContext serverCallContext)
         at Grpc.AspNetCore.Server.Internal.CallHandlers.ServerCallHandlerBase`3.<HandleCallAsync>g__AwaitHandleCall|8_0(HttpContextServerCallContext serverCallContext, Method`2 method, Task handleCall)

[kvenkatrajan]

@drewnoakes can you have a look please?

[drewnoakes]

This stems from the Protobuf codegen we use not producing null-annotated code.

In this instance, the ResourceSnapshot.State value is null, which is not allowed in the .proto we have.

Options to fix this:

1. Make the field optional (a breaking change, so not a great option)
2. Pass a default value when null

• Empty string
• "Unknown" (would this need to be localised?)

I'll submit a PR with the empty string for now.