Dependency on Mono.Unix breaks .NET Framework 4.6.1 support

[fdmarc]

I'm trying to upgrade from version 8 to 9 but I'm blocked by the new dependency on Mono.Unix.

https://www.nuget.org/packages/DogStatsD-CSharp-Client shows support for:

• NETCoreApp 3.1
• .NETFramework 4.6.1
• .NETStandard 2.0
• net6.0

Meanwhile https://www.nuget.org/packages/Mono.Unix/ supports

• .NETCoreApp 3.1
• .NETFramework 4.5
• .NETStandard 2.0
• .NETStandard 2.1
• net6.0

I'm on .NETFramework 4.6.1, and I can't install DogStatsD 9, since .NETFramework 4.6.1 is not in the intersection of those two sets.

12:41:27|NUGET|INFOR| Attempting to resolve dependencies for package 'DogStatsD-CSharp-Client.9.0.0' with DependencyBehavior 'Lowest'
12:41:27|RIDER|ERROR| Unable to resolve dependency 'Mono.Unix'. Source(s) used: 'Flipdish', 'Flipdish.Messaging.Contracts', 'Flipdish.SREToolbox', 'nuget.org', 'Microsoft Visual Studio Offline Packages'.
System.InvalidOperationException: Unable to resolve dependency 'Mono.Unix'. Source(s) used: 'Flipdish', 'Flipdish.Messaging.Contracts', 'Flipdish.SREToolbox', 'nuget.org', 'Microsoft Visual Studio Offline Packages'.
 ---> NuGet.Resolver.NuGetResolverConstraintException: Unable to resolve dependency 'Mono.Unix'. Source(s) used: 'Flipdish', 'Flipdish.Messaging.Contracts', 'Flipdish.SREToolbox', 'nuget.org', 'Microsoft Visual Studio Offline Packages'.
   at NuGet.Resolver.PackageResolver.Resolve(PackageResolverContext context, CancellationToken token)
   at NuGet.PackageManagement.NuGetPackageManager.PreviewInstallPackageAsync(NuGetProject nuGetProject, PackageIdentity packageIdentity, ResolutionContext resolutionContext, INuGetProjectContext nuGetProjectContext, IEnumerable`1 primarySources, IEnumerable`1 secondarySources, VersionRange versionRange, CancellationToken token)
   --- End of inner exception stack trace ---
   at NuGet.PackageManagement.NuGetPackageManager.PreviewInstallPackageAsync(NuGetProject nuGetProject, PackageIdentity packageIdentity, ResolutionContext resolutionContext, INuGetProjectContext nuGetProjectContext, IEnumerable`1 primarySources, IEnumerable`1 secondarySources, VersionRange versionRange, CancellationToken token)
   at NuGet.PackageManagement.NuGetPackageManager.PreviewInstallPackageAsync(NuGetProject nuGetProject, PackageIdentity packageIdentity, ResolutionContext resolutionContext, INuGetProjectContext nuGetProjectContext, IEnumerable`1 primarySources, IEnumerable`1 secondarySources, CancellationToken token)
   at NuGet.PackageManagement.NuGetPackageManager.InstallPackageAsync(NuGetProject nuGetProject, PackageIdentity packageIdentity, ResolutionContext resolutionContext, INuGetProjectContext nuGetProjectContext, PackageDownloadContext downloadContext, IEnumerable`1 primarySources, IEnumerable`1 secondarySources, CancellationToken token)
   at NuGet.PackageManagement.NuGetPackageManager.InstallPackageAsync(NuGetProject nuGetProject, PackageIdentity packageIdentity, ResolutionContext resolutionContext, INuGetProjectContext nuGetProjectContext, IEnumerable`1 primarySources, IEnumerable`1 secondarySources, CancellationToken token)
   at JetBrains.ProjectModel.NuGet.Operations.NuGetInstallOperation.<>c__DisplayClass7_0.<<InstallAsync>b__0>d.MoveNext()
--- End of stack trace from previous location ---
   at JetBrains.ProjectModel.NuGet.Operations.NuGetInstallOperation.InstallInternal(IProject project, String packageId, String packgeUserStr, NuGetFeedContext feedContext, Int32 nestedLevel, NuGetNotificationMode mode, NuGetOperationReporter reporter, Func`3 nativeInstall, NuGetProject givenNuGetProject)
NuGet.Resolver.NuGetResolverConstraintException: Unable to resolve dependency 'Mono.Unix'. Source(s) used: 'Flipdish', 'Flipdish.Messaging.Contracts', 'Flipdish.SREToolbox', 'nuget.org', 'Microsoft Visual Studio Offline Packages'.
   at NuGet.Resolver.PackageResolver.Resolve(PackageResolverContext context, CancellationToken token)
   at NuGet.PackageManagement.NuGetPackageManager.PreviewInstallPackageAsync(NuGetProject nuGetProject, PackageIdentity packageIdentity, ResolutionContext resolutionContext, INuGetProjectContext nuGetProjectContext, IEnumerable`1 primarySources, IEnumerable`1 secondarySources, VersionRange versionRange, CancellationToken token)

12:41:27|RIDER|ERROR| [Notification][Install] Install failed (project: Flipdish.API, package: DogStatsD-CSharp-Client v9.0.0)
Unable to resolve dependency 'Mono.Unix'. Source(s) used: 'Flipdish', 'Flipdish.Messaging.Contracts', 'Flipdish.SREToolbox', 'nuget.org', 'Microsoft Visual Studio Offline Packages'.

[lucaspimentel]

Hey, @fdmarc. That seems strange. Mono.Unix's target for .NET Framework 4.5 which should cover all versions of .NET Framework 4.5 and above, including .NET Framework 4.6.1.

---

Ah, I think I see the issue. All versions of Mono.Unix are considered pre-releases by NuGet because they have a version suffix like 7.1.0-final.1.21458.1: https://www.nuget.org/packages/Mono.Unix/#versions-body-tab

Your build process may be excluding pre-release packages by default, which means there are no Mono.Unix packages available since all of them are pre-release versions.

[lucaspimentel]

If this is the case, the short-term workaround is to enable pre-release NuGet packages in your build, if possible.

For a better fix, I think we can remove the Mono.Unix dependency on .NET Framework since we only use it on Linux.

[fdmarc]

Thanks @lucaspimentel

I'd like to avoid enabling pre-release Nugets from being installed by my team here, to prevent people from accidentally depending on something untested.

I've logged this issue to see if we can it fixed upstream mono/mono.posix#73

[lucaspimentel]

@fdmarc the Mono.Unix nuget package hasn't been updated since 2021, so I'm not hopeful. We're going to explore other options to remove our dependency on Mono.Unix. It should be straight-forward on .NET Framework at least, since it's not used at all there 😅

[fdmarc]

True, but there is activity on the repo this week:

It might be all automated commits though.

[Jeripy]

@fdmarc the Mono.Unix nuget package hasn't been updated since 2021, so I'm not hopeful. We're going to explore other options to remove our dependency on Mono.Unix. It should be straight-forward on .NET Framework at least, since it's not used at all there 😅

Are there any updates on this issue, we can't upgrade for the same reason?