Multitarget O# external access projects to fix issues accessing prope…

[dibarbet]

…rties on records

The last PR - #67106 was slightly incorrect - it fixed the build, but caused a bunch of test failures trying to call methods on records

System.MissingMethodException : Method not found: 'Void Microsoft.CodeAnalysis.Completion.CompletionOptions.set_ShowItemsFromUnimportedNamespaces(System.Nullable`1<Boolean>)'.[xUnit.net 00:00:19.95]       Stack Trace:[xUnit.net 00:00:19.95]            at Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.Completion.OmniSharpCompletionOptions.ToCompletionOptions()[xUnit.net 00:00:19.95]            at Microsoft.CodeAnalysis.ExternalAccess.OmniSharp.Completion.OmniSharpCompletionService.GetCompletionsAsync(CompletionService completionService, Document document, Int32 caretPosition, CompletionTrigger trigger, ImmutableHashSet`1 roles, OmniSharpCompletionOptions options, CancellationToken cancellationToken)[xUnit.net 00:00:19.95]         /home/runner/work/omnisharp-roslyn/omnisharp-roslyn/src/OmniSharp.Roslyn.CSharp/Services/Completion/CompletionService.cs(95,0): at OmniSharp.Roslyn.CSharp.Services.Completion.CompletionService.Handle(CompletionRequest request, Boolean forceExpandedCompletionIndexCreation)[xUnit.net 00:00:19.95]         /home/runner/work/omnisharp-roslyn/omnisharp-roslyn/tests/OmniSharp.Roslyn.CSharp.Tests/CompletionFacts.cs(2281,0): at OmniSharp.Roslyn.CSharp.Tests.CompletionFacts.FindCompletionsAsync(String filename, String source, OmniSharpTestHost testHost, Nullable`1 triggerChar, TestFile[] additionalFiles, Boolean forceExpandedCompletionIndexCreation)[xUnit.net 00:00:19.95]         /home/runner/work/omnisharp-roslyn/omnisharp-roslyn/tests/OmniSharp.Roslyn.CSharp.Tests/CompletionFacts.cs(301,0): at OmniSharp.Roslyn.CSharp.Tests.CompletionFacts.ImportCompletion_OnLine0(String filename, Boolean useAsyncCompletion)[xUnit.net 00:00:19.95]         --- End of stack trace from previous location ---

The root cause of that failure appeared to be a mismatch in the method signatures caused by the workspace version of IsExternalInit

.method public hidebysig specialname         instance void modreq([System.Runtime]System.Runtime.CompilerServices.IsExternalInit) set_ShowItemsFromUnimportedNamespaces (            valuetype [System.Runtime]System.Nullable`1<bool> 'value'        ) cil managed

vs the caller

IL_0016: callvirt instance void modreq([Microsoft.CodeAnalysis.Workspaces]System.Runtime.CompilerServices.IsExternalInit) [Microsoft.CodeAnalysis.Features]Microsoft.CodeAnalysis.Completion.CompletionOptions::set_ShowItemsFromUnimportedNamespaces(valuetype [netstandard]System.Nullable`1<bool>)

Switching over to appropriately multi-target the external access project appears to have fixed the issue in build and in the tests (so far).

[sharwell]

Are you interested in the other option here? All we need to do is add a TypeForwardedTo to IsExternalInit.cs so that it's part of the API surface in both binaries. As it stands, we still are creating a netstandard2.0 binary which can't be loaded on a net6.0 execution of the compiler.

[sharwell]

Need to answer the question before proceeding

[sharwell]

I'll send a PR for a concrete example here

[sharwell]

Submitted #67171

[dibarbet]

@sharwell I'm not necessarily opposed to another fix, but O# multi-targets netframework and .netcore already, so multi-targeting the external access project doesn't seem inappropriate to me.

I can try out your change, but I don't think I'll be able to get to it until late this afternoon / Monday.

Withdrawing by block on the basis that both binaries here will be used. If we were only building downstream for one target, this wouldn't be an appropriate resolution.

[dibarbet]

Going ahead with this change since O# multi-targets and I already tested this one (and CI already finished).