Auto-generated Dockerfile fails with Invalid framework identifier ''

Version Used:
6.0.406 Steps to Reproduce:

1. Create a .NET 6 library ./Src/MyLib
2. Create a .NET 6 asp.net core hosted Blazor Wasm Application ./BlazorWasmDemo without docker support
3. Add docker support to BlazorWasmDemo.Server project
4. Build docker image from Dockerfile
5. dotnet restore in build stage of Dockerfile fails

Actual Branch with problem: https://github.com/Regenhardt/fido2-net-lib/tree/feature/blazor-wasm

Diagnostic Id:

NETSDK 1013

Expected Behavior:

Dockerfile should build a runnable docker image.

Actual Behavior:

dotnet restore fails with /usr/share/dotnet/sdk/6.0.406/NuGet.targets(132,5): error : Invalid framework identifier ''. [/src/BlazorWasmDemo/Server/BlazorWasmDemo.Server.csproj]

** Additional info**:

I started up the image from a state just before the error occurs:

FROM mcr.microsoft.com/dotnet/sdk:6.0 AS prebuild
WORKDIR /src
COPY ["nuget.config", "."]
COPY ["BlazorWasmDemo/Server/BlazorWasmDemo.Server.csproj", "BlazorWasmDemo/Server/"]
COPY ["Src/Fido2.AspNet/Fido2.AspNet.csproj", "Src/Fido2.AspNet/"]
COPY ["Src/Fido2/Fido2.csproj", "Src/Fido2/"]
COPY ["Src/Fido2.Models/Fido2.Models.csproj", "Src/Fido2.Models/"]
COPY ["BlazorWasmDemo/Client/BlazorWasmDemo.Client.csproj", "BlazorWasmDemo/Client/"]
COPY ["Src/Fido2.BlazorWebAssembly/Fido2.BlazorWebAssembly.csproj", "Src/Fido2.BlazorWebAssembly/"]
COPY ["BlazorWasmDemo/Shared/BlazorWasmDemo.Shared.csproj", "BlazorWasmDemo/Shared/"]

FROM prebuild as build
# This one crashes:
RUN dotnet restore "BlazorWasmDemo/Server/BlazorWasmDemo.Server.csproj"
COPY . .
WORKDIR "/src/BlazorWasmDemo/Server"
RUN dotnet build "BlazorWasmDemo.Server.csproj" -c Release -o /app/build

I then ran the dotnet restore command from a bash within the image, hoping to get more information, but I got exactly the same as before without extra information. I did however check the files before running it:

root@af1009dcaf2c:/src# ls BlazorWasmDemo/Server
BlazorWasmDemo.Server.csproj
root@af1009dcaf2c:/src# cat BlazorWasmDemo/Server/BlazorWasmDemo.Server.csproj
<Project Sdk="Microsoft.NET.Sdk.Web">

  <PropertyGroup>
    <TargetFramework>net6.0</TargetFramework>
    <Nullable>enable</Nullable>
    <ImplicitUsings>enable</ImplicitUsings>
    <UserSecretsId>d4e312c9-f55a-43e0-b3ea-699aa6421a5c</UserSecretsId>
    <DockerDefaultTargetOS>Linux</DockerDefaultTargetOS>
    <DockerfileContext>..\..</DockerfileContext>
  </PropertyGroup>

  <ItemGroup>
    <PackageReference Include="Microsoft.AspNetCore.Components.WebAssembly.Server" Version="6.0.13" />
    <PackageReference Include="Microsoft.VisualStudio.Azure.Containers.Tools.Targets" Version="1.17.2" />
    <PackageReference Include="Swashbuckle.AspNetCore" Version="6.5.0" />
  </ItemGroup>

  <ItemGroup>
    <ProjectReference Include="..\..\Src\Fido2.AspNet\Fido2.AspNet.csproj" />
    <ProjectReference Include="..\..\Src\Fido2\Fido2.csproj" />
    <ProjectReference Include="..\Client\BlazorWasmDemo.Client.csproj" />
  </ItemGroup>


</Project>
root@af1009dcaf2c:/src# dotnet restore BlazorWasmDemo/Server/BlazorWasmDemo.Server.csproj
  Determining projects to restore...
/usr/share/dotnet/sdk/6.0.406/NuGet.targets(132,5): error : Invalid framework identifier ''. [/src/BlazorWasmDemo/Server/BlazorWasmDemo.Server.csproj]

And I’m pretty sure the <TargetFramework>net6.0</TargetFramework> should be used by dotnet. I did however replace it with <TargetFrameworks> (plural) but the same error happens.

Without this dockerfile, the application works, both running as exe and starting in docker from within VS.

[Regenhardt]

Alright I submitted a ticket describing the issue.

[baronfel]

If you have time, submitting the need to include Directory.Build.props (and many other necessary files like Directory.Build.targets, Directory.Packages.props, etc) in the generated Dockerfile over at VS Feedback would be great - the Docker tooling team does get feedback submitted through that method.