KeyNotFoundException thrown when compiling optional generic partial methods (no modifier)

[datvm]

Version Used: Microsoft (R) Visual C# Compiler version 4.9.0-3.24121.1 (a98c90d)

Steps to Reproduce:

Unfortunately I cannot reproduce it in a new project so I do not know what causes it. I hope you can find out from the stack trace. Originally reported at dotnet/sdk#39033:

I have a class with this declaration:

partial void AddPlatformDailyRewards<T>(MauiAppBuilder builder) where T : DailyRewardItem;

According to the documentation, I should not need to implement this mehtod. However, if I do not implement it for each platform, I would encounter this issue when building (the exception is from CSC.exe):

16:18:31:714	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error : Unhandled Exception: System.Collections.Generic.KeyNotFoundException: The given key was not present in the dictionary.
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at System.ThrowHelper.ThrowKeyNotFoundException()
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at System.Collections.Generic.Dictionary`2.get_Item(TKey key)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.FullMetadataWriter.GetMethodDefinitionHandle(IMethodDefinition def)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.GetMethodDefinitionOrReferenceHandle(IMethodReference methodReference)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MethodSpecComparer.GetHashCode(IGenericMethodInstanceReference methodInstanceReference)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at System.Collections.Generic.Dictionary`2.FindEntry(TKey key)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at System.Collections.Generic.Dictionary`2.TryGetValue(TKey key, TValue& value)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.InstanceAndStructuralReferenceIndex`1.TryGetValue(T item, Int32& index)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.FullMetadataWriter.GetOrAddMethodSpecificationHandle(IGenericMethodInstanceReference reference)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.GetMethodHandle(IMethodReference methodReference)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.GetHandle(Object reference)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.ResolveEntityHandleFromPseudoToken(Int32 pseudoSymbolToken)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.WriteInstructions(Blob finalIL, ImmutableArray`1 generatedIL, UserStringHandle& mvidStringHandle, Blob& mvidStringFixup)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.SerializeMethodBody(MethodBodyStreamEncoder encoder, IMethodBody methodBody, StandaloneSignatureHandle localSignatureHandleOpt, UserStringHandle& mvidStringHandle, Blob& mvidStringFixup)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.SerializeMethodBodies(BlobBuilder ilBuilder, PdbWriter nativePdbWriterOpt, Blob& mvidStringFixup)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.MetadataWriter.BuildMetadataAndIL(PdbWriter nativePdbWriterOpt, BlobBuilder ilBuilder, BlobBuilder mappedFieldDataBuilder, BlobBuilder managedResourceDataBuilder, Blob& mvidFixup, Blob& mvidStringFixup)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.Cci.PeWriter.WritePeToStream(EmitContext context, CommonMessageProvider messageProvider, Func`1 getPeStream, Func`1 getPortablePdbStreamOpt, PdbWriter nativePdbWriterOpt, String pdbPathOpt, Boolean metadataOnly, Boolean isDeterministic, Boolean emitTestCoverageData, Nullable`1 privateKeyOpt, CancellationToken cancellationToken)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.Compilation.SerializePeToStream(CommonPEModuleBuilder moduleBeingBuilt, DiagnosticBag metadataDiagnostics, CommonMessageProvider messageProvider, Func`1 getPeStream, Func`1 getMetadataPeStreamOpt, Func`1 getPortablePdbStreamOpt, PdbWriter nativePdbWriterOpt, String pdbPathOpt, RebuildData rebuildData, Boolean metadataOnly, Boolean includePrivateMembers, Boolean isDeterministic, Boolean emitTestCoverageData, Nullable`1 privateKeyOpt, CancellationToken cancellationToken)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.Compilation.SerializeToPeStream(CommonPEModuleBuilder moduleBeingBuilt, EmitStreamProvider peStreamProvider, EmitStreamProvider metadataPEStreamProvider, EmitStreamProvider pdbStreamProvider, RebuildData rebuildData, Func`2 testSymWriterFactory, DiagnosticBag diagnostics, EmitOptions emitOptions, Nullable`1 privateKeyOpt, CancellationToken cancellationToken)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CommonCompiler.CompileAndEmit(TouchedFileLogger touchedFilesLogger, Compilation& compilation, ImmutableArray`1 analyzers, ImmutableArray`1 generators, ImmutableArray`1 additionalTextFiles, AnalyzerConfigSet analyzerConfigSet, ImmutableArray`1 sourceFileAnalyzerConfigOptions, ImmutableArray`1 embeddedTexts, DiagnosticBag diagnostics, ErrorLogger errorLogger, CancellationToken cancellationToken, CancellationTokenSource& analyzerCts, AnalyzerDriver& analyzerDriver, Nullable`1& generatorTimingInfo)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CommonCompiler.RunCore(TextWriter consoleOutput, ErrorLogger errorLogger, CancellationToken cancellationToken)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CommonCompiler.Run(TextWriter consoleOutput, CancellationToken cancellationToken)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CSharp.CommandLine.Csc.<>c__DisplayClass1_0.<Run>b__0(TextWriter tw)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CommandLine.ConsoleUtil.RunWithUtf8Output[T](Func`2 func)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CSharp.CommandLine.Csc.Run(String[] args, BuildPaths buildPaths, TextWriter textWriter, IAnalyzerAssemblyLoader analyzerLoader)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CommandLine.BuildClient.RunLocalCompilation(String[] arguments, BuildPaths buildPaths, TextWriter textWriter)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CommandLine.BuildClient.RunCompilation(IEnumerable`1 originalArguments, BuildPaths buildPaths, TextWriter textWriter, String pipeName)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CommandLine.BuildClient.Run(IEnumerable`1 arguments, RequestLanguage language, CompileFunc compileFunc, CompileOnServerFunc compileOnServerFunc, ICompilerServerLogger logger)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CSharp.CommandLine.Program.MainCore(String[] args)
16:18:31:767	2>C:\Program Files\Microsoft Visual Studio\2022\Community\MSBuild\Current\Bin\Roslyn\Microsoft.CSharp.Core.targets(84,5): error :    at Microsoft.CodeAnalysis.CSharp.CommandLine.Program.Main(String[] args)
16:18:34:793	2>Done building project "MyProjectName.csproj" -- FAILED.

VS Error List also goes crazy and list each exception line as an error:

If I run dotnet build from the CLI instead of VS, at least I get the detailed info of which causes the problem:

C:\Program Files\dotnet\sdk\8.0.200\Roslyn\Microsoft.CSharp.Core.targets(84,5): error : Unhandled exception. System.Col
lections.Generic.KeyNotFoundException: The given key '<ProjectName>.SetupOptions.AddPlatformDailyRewards<T>(Microsoft.Maui.Hosting.MauiAppBuilder)' was not present in the dictionary.

By adding an empty implementation to all files (iOS/Windows etc), the error disappears.

Diagnostic Id: N/A

Expected Behavior: The build should be successful as the method is optional. At least it should tell me where the problem is.

Actual Behavior: Exception is thrown by CSC.

[jaredpar]

Unfortunately I'm not able to reproduce this issue. Do you have a smaller sample project where this repros that we could look at?

[datvm]

@jaredpar unfortunately not. I tried recreating a new project but the issue didn't happen. I was hoping you could find out what causes it from the stack trace. The project is private so if you give me a private channel I can send it over to you.

[jaredpar]

@datvm can you file a VS feedback bug? That will give us a channel where we can share private files. Choose "Report a Problem" from this menu in Visual Studio

[jaredpar]

Closing as we haven't heard back on this. If you're able to submit a VS Feedback bug or have more insights into what is causing the issue we will re-open.

[datvm]

@jaredpar Hello, sorry about the long delay. I am just back from a long vacation. I have submitted the feedback and attached the problematic project here: https://developercommunity.visualstudio.com/t/KeyNotFoundException-thrown-when-compili/10630851

[jaredpar]

Thanks for uploading the repro. I've assigned out the VS feedback bug for investigation.