Obsoleting StrongNameKeyPair type in .NetCore

[buyaa-n]

As part of dotnet/runtime#47228 we are obsoleting APIs not supported in .Net Core. The APIs we are obsoleting in reflection are listed in dotnet/runtime#50529. Where we found that System.Reflection.StrongNameKeyPair is not supported in .NetCore and existing APIs only throwing PNSE or no-op. We are planning to update the no-op constructor overloads to throw PNSE and [Obsolete] the entire type. Which also causing to Obsolete AssemblyName.KeyPair property. This type and API doesn't have real usage in runtime repo but from https://source.dot.net/ we see it is referenced a lot from MSBuild repo.

Please let us know if you have any issue with Obsoleting this type and API

Originally posted by @buyaa-n in dotnet/runtime#50941 (comment)

[buyaa-n]

The Obsoletion will be added only into .Net 6. So if this type and API is not referenced from .Net 6 context then there will be no issue

[benvillalobos]

rg StrongNameKeyPair

C:\src\git\msbuild>rg StrongNameKeyPair
src\Tasks\TlbReference.cs
232:                GetAndValidateStrongNameKey(out StrongNameKeyPair keyPair, out byte[] publicKey);

src\Tasks\StrongNameUtils.cs
32:        internal static void ReadKeyFile(TaskLoggingHelper log, string keyFile, out StrongNameKeyPair keyPair, out byte[] publicKey)
69:            var snp = new StrongNameKeyPair(keyFileContents);
90:        internal static void GetStrongNameKey(TaskLoggingHelper log, string keyFile, string keyContainer, out StrongNameKeyPair keyPair, out byte[] publicKey)
101:                    keyPair = new StrongNameKeyPair(keyContainer);

src\Tasks\AxTlbBaseReference.cs
249:        internal void GetAndValidateStrongNameKey(out StrongNameKeyPair keyPair, out byte[] publicKey)

src\Tasks\AxTlbBaseTask.cs
214:                StrongNameKeyPair keyPair;

src\Shared\TranslatorHelpers.cs
264:                    // AssemblyName.KeyPair is not used anywhere, additionally StrongNameKeyPair is not supported in .net core 5-

src\Shared\AssemblyNameExtension.cs
151:                var keyPair = (StrongNameKeyPair) info.GetValue("keypair", typeof(StrongNameKeyPair));

src\Build.UnitTests\BackEnd\BinaryTranslator_Tests.cs
548:                KeyPair = new StrongNameKeyPair(new byte[] { 4, 3, 2, 1 })

[rainersigwald]

@buyaa-n We looked at this in triage. If we do reference it in .NET 5/6, we should be able to ifdef it out. Thanks for the heads up.

[buyaa-n]

Thanks, @rainersigwald the PR for obsoleting StrongNameKeyPair is merged, closing the issue as no immediate action needed.