[Bug] Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with xamarinios10, monoandroid10.0, netstandard2.0, netstandard2.1

[JunkyXL86]

Description

Developing my app on Visual Studio 2019 16.10.4 using Xamarin.Forms 5.0.0.2012.
After updating to 2019 16.11, updating to Visual Studio 2022 Preview 3 and installing the latest MAUI workloads yesterday using maui-check (.NET 6 Preview 7) my app stopped building because of NuGet Package Xamarin.CommunityToolkit.Markup 1.2.0 that could not be resolved anymore. Reinstalling the Markup package produced following errors:

NU1202: Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with xamarinios10 (Xamarin.iOS,Version=v1.0). Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks.
NU1202: Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with xamarinios10 (Xamarin.iOS,Version=v1.0) / win. Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks.
NU1202: Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with xamarinios10 (Xamarin.iOS,Version=v1.0) / win-x64. Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks.
NU1202: Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with xamarinios10 (Xamarin.iOS,Version=v1.0) / win-x86. Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks.
NU1202: Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with monoandroid10.0 (MonoAndroid,Version=v10.0). Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks.
NU1202: Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with netstandard2.1 (.NETStandard,Version=v2.1). Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks.

Tried to downgrade to .NET Standard 2.0 but same error messages accordingly

...
NU1202: Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with netstandard2.0 (.NETStandard,Version=v2.0). Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks.

Downgrading XCT.Markup to 1.1.0 works. App will also start debugging.

Steps to Reproduce

• Create new Xamarin.Forms app (Android, iOS)
• Install XCT 1.2.0 (works)
• Install XCT.Markup 1.2.0 (fails)

Basic Information

• Version with issue:

  • Visual Studio 2019 16.10.4
  • Visual Studio 2019 16.11
  • Visual Studio 2019 16.11 Preview 4
  • Visual Studio 2022 Preview 3

• Last known good version:

  • 2019 16.10.4 (before updating machine to VS 2022 Preview 3, .NET 6 Preview 7)
  • 2019 16.11 Preview 3

• Platform Target Frameworks: Does not apply, installing NuGet package in shared project already fails.

Edit: attached screenshot

"Package Xamarin.CommunityToolkit.Markup 1.2.0 is not compatible with netstandard2.1 (.NETStandard,Version=v2.1). Package Xamarin.CommunityToolkit.Markup 1.2.0 does not support any target frameworks."

[pictos]

@JunkyXL86 If I'm not wrong you should install the Markup package just in your shared project. There's no need to install them into the platform projects.

[JunkyXL86]

I didn't even install it in the Android proj. As I said, error occurs when I try to install the package in the shared project.
I tried it over and over again using VS 2019 16.11 and VS 2022 P3.
New clean fresh Xamarin.Forms Mobile App, simply try to install the XCT.Markup 1.2 package.

[pictos]

@JunkyXL86 could you attach a small repro? I couldn't reproduce the error

[JunkyXL86]

@pictos I tested it again today (09/01/21) with the newest VS update. Still facing the issue. Maybe something is broken on my old machine. As the error is pretty certain, I'm still interested what the real cause is.

Meanwhile I got a new PC, Windows 11. On this machine using VS 2022 Preview 3.1 installing XCT.Markup 1.2 works as expected.

I've attached the Solution and a GIF showing the steps. Nothing special to it.
XCT.Markup.1.2.zip

[pictos]

@JunkyXL86 I tried to reproduce it and everything works as expected. This error is very odd, since our package has a dependency on .netstandard 2.0. So this should be something in your environment.