[CPM] Don't add Package versions when creating a new project if CPM is enabled

[adcloeshelle]

NuGet Product(s) Affected

Visual Studio, dotnet.exe

Current Behavior

When you create a new project with certain templates, PackageReferences are added by default. Even if CPM is enabled, the Package version is specified in the PackageReference which leads to a compile error.

Desired Behavior

If CPM is enabled, the package version should not be specified by default.

Additional Context

This allows a developer to create a new project and compile it without any initial errors.

[kartheekp-ms]

I am able to reproduce the issue, and it makes sense to me. The repro steps are simple.

• Open any solution that is already onboarded to CPM in Visual Studio. https://github.com/NuGet/Samples/tree/main/CentralPackageManagementExample
• Add a new project (.NET MAUI Class Library) to the solution.
• Restore fails with https://learn.microsoft.com/nuget/reference/errors-and-warnings/nu1008 error message.

However, my understanding is that new project template implementations are maintained by our partner teams. They leverage the NuGet SDK to add a package reference. @jeffkl, should this request be routed to the project system team? Does the NuGet SDK have any API to identify if the solution has been onboarded onto CPM? If yes, I believe partner teams can leverage the SDK to add the package version to the Directory.Packages.Props file if the solution is already onboarded onto CPM. May be the presence of Directory.Packages.Props is sufficient to ensure that project has been onboarded onto CPM.

I think similar feature requests may arise in the future for dotnet new CLI commands.

[nkolev92]

There's a duplicating in templating: dotnet/aspnetcore#48569

They have a feature ask for us, but there's some other ways of doing it that are not complete blocked on
#12629

dotnet/templating#6187 (comment)

[nkolev92]

I think this is more templating work than NuGet, since we don't really control all the templates. The templates themselves add a PackageReference item directly in the project, and that's simply hard to control.

[nkolev92]

Team Triage: Assigning to @jeffkl to help us better understand the pieces and the ownership of the bugs.