Migrating .NET 7 to 8 with gRPC - No marshaller available for Dictionary<string, string>

[japtar10101]

When upgrading a working .NET 7 project using gRPC service to .NET 8, following the Update a Blazor WebAssembly app guide, running the code under Docker causes the following error to appear on the browser console:

crit: Microsoft.AspNetCore.Components.WebAssembly.Rendering.WebAssemblyRenderer[100]
      Unhandled exception rendering component: TypeInitialization_Type, DefaultProxyCache`1
System.TypeInitializationException: TypeInitialization_Type, DefaultProxyCache`1
 ---> System.Reflection.TargetInvocationException: Arg_TargetInvocationException
 ---> System.InvalidOperationException: No marshaller available for System.Collections.Generic.Dictionary`2[[System.String, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e],[System.String, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]]
   at ProtoBuf.Grpc.Internal.MarshallerCache.<GetMarshaller>g__Throw|5_0[Dictionary`2]()
   at ProtoBuf.Grpc.Internal.MarshallerCache.GetMarshaller[Dictionary`2]()
   at System.Reflection.MethodBaseInvoker.InterpretedInvoke_Method(Object obj, IntPtr* args)
   at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object , BindingFlags )
   Exception_EndOfInnerExceptionStack
   at System.Reflection.MethodBaseInvoker.InvokeWithNoArgs(Object , BindingFlags )
   at System.Reflection.RuntimeMethodInfo.Invoke(Object , BindingFlags , Binder , Object[] , CultureInfo )
   at System.Reflection.MethodBase.Invoke(Object obj, Object[] parameters)
   at ProtoBuf.Grpc.Internal.ProxyEmitter.<EmitFactory>g__Marshaller|11_0[IDictionaryService](Type forType, <>c__DisplayClass11_0`1& , <>c__DisplayClass11_1`1& )
   at ProtoBuf.Grpc.Internal.ProxyEmitter.EmitFactory[IDictionaryService](BinderConfiguration binderConfig)
   at ProtoBuf.Grpc.Internal.ProxyEmitter.CreateFactory[IDictionaryService](BinderConfiguration binderConfig)
   at ProtoBuf.Grpc.Configuration.ClientFactory.DefaultProxyCache`1[[TestGrpc7.Client.Services.IDictionaryService, TestGrpc7.Client, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]..cctor()
   Exception_EndOfInnerExceptionStack
   at ProtoBuf.Grpc.Configuration.ClientFactory.DefaultClientFactory.CreateClient[IDictionaryService](CallInvoker channel)
   at Program.<>c.<<Main>$>b__0_1(IServiceProvider provider)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitFactory(FactoryCallSite , RuntimeResolverContext )
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeResolverContext, Microsoft.Extensions.DependencyInjection, Version=8.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].VisitCallSiteMain(ServiceCallSite , RuntimeResolverContext )
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitCache(ServiceCallSite , RuntimeResolverContext , ServiceProviderEngineScope , RuntimeResolverLock )
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.VisitScopeCache(ServiceCallSite , RuntimeResolverContext )
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteVisitor`2[[Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeResolverContext, Microsoft.Extensions.DependencyInjection, Version=8.0.0.0, Culture=neutral, PublicKeyToken=adb9793829ddae60],[System.Object, System.Private.CoreLib, Version=8.0.0.0, Culture=neutral, PublicKeyToken=7cec85d7bea7798e]].VisitCallSite(ServiceCallSite callSite, RuntimeResolverContext argument)
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.CallSiteRuntimeResolver.Resolve(ServiceCallSite , ServiceProviderEngineScope )
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.RuntimeServiceProviderEngine.<>c__DisplayClass4_0.<RealizeService>b__0(ServiceProviderEngineScope scope)
   at Microsoft.Extensions.DependencyInjection.ServiceProvider.GetService(ServiceIdentifier , ServiceProviderEngineScope )
   at Microsoft.Extensions.DependencyInjection.ServiceLookup.ServiceProviderEngineScope.GetService(Type )
   at Microsoft.AspNetCore.Components.ComponentFactory.<>c__DisplayClass9_0.<CreatePropertyInjector>g__Initialize|1(IServiceProvider serviceProvider, IComponent component)
   at Microsoft.AspNetCore.Components.ComponentFactory.InstantiateComponent(IServiceProvider , Type , IComponentRenderMode , Nullable`1 )
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.InstantiateChildComponentOnFrame(RenderTreeFrame[] , Int32 , Int32 )
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewComponentFrame(DiffContext& , Int32 )
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InitializeNewSubtree(DiffContext& , Int32 )
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.InsertNewFrame(DiffContext& , Int32 )
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.AppendDiffEntriesForRange(DiffContext& , Int32 , Int32 , Int32 , Int32 )
   at Microsoft.AspNetCore.Components.RenderTree.RenderTreeDiffBuilder.ComputeDiff(Renderer , RenderBatchBuilder , Int32 , ArrayRange`1 , ArrayRange`1 )
   at Microsoft.AspNetCore.Components.Rendering.ComponentState.RenderIntoBatch(RenderBatchBuilder , RenderFragment , Exception& )
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.RenderInExistingBatch(RenderQueueEntry )
   at Microsoft.AspNetCore.Components.RenderTree.Renderer.ProcessRenderQueue()

Some extra details:

• The .NET 8 version of the project does run fine under Visual Studio 2022, Debug config.
• According to my colleague, they were able to get a similar result with dotnet TestGrpc7.Server.dll, so we believe Docker isn't the source of the problem
• There is this documentation page on .NET 8: Breaking Changes: Custom marshallers require additional members.

Expected Behavior

When running the attached projects in Docker, a web page will show up, indicating the base address of the website (e.g. http://localhost:8080/), as well as a table with key value pairs of:

Keys	Values
Hello	World
Greetings	Nice to meet you, "[base address]"

Steps To Reproduce

The following steps was replicated in Windows 10 Powershell terminal:

1. Download, then extract the source code below:
   • net7-grpc-dictionary-bug-1.1.1-net8.zip
2. At the root of each project (where the Dockerfile is), run: docker build -t test-grpc-7:net8 . This may take a few minutes.
3. Once the build is finished, run docker run -p 127.0.0.1:8080:8080 test-grpc-7:net8.
4. Open a web browser (e.g. Chrome or Edge), and navigate to localhost:8080.

The net7-grpc-dictionary-bug-1.1.1-net7.zip -- the original .NET 7 version of the same project above -- has been uploaded as well for comparison. Running all the steps above with the .NET 7 version of the project, except changing the version of each docker build from :net8 to :net7, should open the webpage described in the Expected Behavior section without error.

protobuf-net.Grpc.AspNetCore Version

1.1.1

Visual Studio 2022 version

17.10.6

Docker version

> docker --version
Docker version 27.2.0, build 3ab4256

Dotnet Info

> dotnet --info
.NET SDK:
 Version:           8.0.304
 Commit:            352dc5a01f
 Workload version:  8.0.300-manifests.113cb230
 MSBuild version:   17.10.4+10fbfbf2e

Runtime Environment:
 OS Name:     Windows
 OS Version:  10.0.19045
 OS Platform: Windows
 RID:         win-x64
 Base Path:   C:\Program Files\dotnet\sdk\8.0.304\

.NET workloads installed:
 [wasm-tools]
   Installation Source: VS 17.10.35201.131
   Manifest Version:    8.0.8/8.0.100
   Manifest Path:       C:\Program Files\dotnet\sdk-manifests\8.0.100\microsoft.net.workload.mono.toolchain.current\8.0.8\WorkloadManifest.json
   Install Type:        FileBased


Host:
  Version:      8.0.8
  Architecture: x64
  Commit:       08338fcaa5

.NET SDKs installed:
  2.2.109 [C:\Program Files\dotnet\sdk]
  5.0.416 [C:\Program Files\dotnet\sdk]
  7.0.410 [C:\Program Files\dotnet\sdk]
  8.0.304 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
  Microsoft.AspNetCore.All 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
  Microsoft.AspNetCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 6.0.33 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.AspNetCore.App 8.0.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
  Microsoft.NETCore.App 2.2.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.12 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 6.0.33 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.NETCore.App 8.0.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 6.0.33 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 7.0.20 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
  Microsoft.WindowsDesktop.App 8.0.8 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
  x86   [C:\Program Files (x86)\dotnet]
    registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
  Not set

global.json file:
  Not found

Learn more:
  https://aka.ms/dotnet/info

Download .NET:
  https://aka.ms/dotnet/download

[mgravell]

gRPC is limited to a few scenarios, and to avoid ambiguity the library doesn't try to play too loose with that fact; rather than trying to send a dictionary, send a simple DTO that has a dictionary