[mono][workloads] Support building net-6.0 wasm workload apps in a net-7.0 sdk

[lewing]

The workload tooling doesn't currently have a way to package packs produced outside of the current build as part of a workload. This makes it impossible for a 700 series wasm-tools workload to pull in the right workload packs to build a net-6.0 blowser-wasm app that requires the wasm-tools tooling (wrong cross-compiler and runtime packs).

The same issue will apply to maui workloads once they have an official release.

• Create net7 workloads following Add design for cross-version workloads sdk#24070
  • dotnet/emsdk
  • dotnet/runtime
  • maui
• Create net6 workloads
  • dotnet/emsdk
  • dotnet/runtime
  • maui

[steveisok]

/cc @jonathanpeppers so that you understand MAUI implications.

[jonathanpeppers]

It does seems like MAUI might hit an issue here, when MAUI is GA at some point a .NET 7 SDK will want to build a .NET 6 MAUI application?

It seems like the way things are setup right now, you'd get build errors and have to use a global.json to point at a .NET 6 version.

[lewing]

sdk design is here dotnet/sdk#24070

[ahmed-salem-me]

@lewing @radical #69731

[thaystg]

This is the error that I got when I tried to build a net6 app using net7.

1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018: The "PInvokeTableGenerator" task failed unexpectedly.
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018: System.BadImageFormatException: Expected signature header for 'Property' or 'Method', but found '9' (0x09).
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.Metadata.Ecma335.SignatureDecoder`2.CheckMethodOrPropertyHeader(SignatureHeader header)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.Metadata.Ecma335.SignatureDecoder`2.DecodeMethodSignature(BlobReader& blobReader)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.Metadata.Ecma335.SignatureDecoder`2.DecodeType(BlobReader& blobReader, Boolean allowTypeSpecifications, Int32 typeCode)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.Metadata.Ecma335.SignatureDecoder`2.DecodeMethodSignature(BlobReader& blobReader)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.Metadata.MethodDefinition.DecodeSignature[TType,TGenericContext](ISignatureTypeProvider`2 provider, TGenericContext genericContext)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.TypeLoading.Ecma.EcmaMethodDecoder.SpecializeMethodSigStrings(TypeContext& typeContext)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.TypeLoading.RoDefinitionMethod`1.ComputeMethodSigStrings()
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Reflection.TypeLoading.RoMethod.ToString()
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Text.StringBuilder.AppendFormatHelper(IFormatProvider provider, String format, ParamsArray args)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.String.FormatHelper(IFormatProvider provider, String format, ParamsArray args)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at PInvokeComparer.GetHashCode(PInvoke pinvoke)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Linq.Set`1.InternalGetHashCode(TElement value)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Linq.Set`1.Find(TElement value, Boolean add)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Linq.Enumerable.<DistinctIterator>d__64`1.MoveNext()
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Linq.Buffer`1..ctor(IEnumerable`1 source)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at System.Linq.Enumerable.ToArray[TSource](IEnumerable`1 source)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at PInvokeTableGenerator.EmitPInvokeTable(StreamWriter w, Dictionary`2 modules, List`1 pinvokes)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at PInvokeTableGenerator.GenPInvokeTable(String[] pinvokeModules, String[] assemblies)
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at PInvokeTableGenerator.Execute()
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
1>C:\Program Files\dotnet\packs\Microsoft.NET.Runtime.WebAssembly.Sdk\7.0.0-preview.4.22229.4\Sdk\WasmApp.Native.targets(275,5): error MSB4018:    at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext()

[lewing]

fixed in rc1