I'm familiar with the new deployment/installation design of VS 2017, and the way it leaves no footprint on registry.
And I'm also familiar with how we need to change our check-in policy installation from registry manipulation to VS extension creation.
However, now I need to create check-in policies in .NET Core 2.0. The problem is that I need to use Microsoft.TeamFoundation.VersionControl.Client dll to be able to access PolicyBase and also PendingChange classes. This results in FileNotFoundException.
Also I need to use Mono.Cecil as the reflection library, to be able to process things in more detail before checking-in. I can't find if Mono.Cecil supports .NET Core 2.0 or not. Nuget page is not informative and the libraries page on GitHub is also not easy to understand.
And another obstacle is to create a VS Extension. I can't find out the required package definition items to be added to source control.
Can you please provide a simple example of how to create a custom TFS Check-in Policy in VS 2017 via .NET Core 2.0?
Since the policy ends up running in the context of Visual Studio itself, I believe you have to be compatible with the .NET framework that Visual Studio is running in, and that is the "classic" .NET Framework, not .NET Core. Libraries written to a .NET Standard can potentially be consumed by both .NET Framework and .NET Core applications, and I believe you could also include separate executables in an extension and run them as separate processes if there's some piece that absolutely must run in a .NET Core environment, but you can't mix-and-match within a single process, and the extension code itself doesn't get a choice: it runs in the Visual Studio process.