Consider using a custom package type for addins / modules

[pascalberger]

We should consider using a custom package type for Cake addins, modules and recipes.

This could help in discovery of these packages from nuget.org.

[augustoproiete]

TL;DR;

Custom package types work well with Cake build scripts, but with Frosting it would impose limitations in the way a package can be installed. Namely, it's not possible to install packages with custom types via the Visual Studio User Interface... (it only works if you edit the .csproj manually yourself and type/paste a <PackageReference ... />.

For now we've decided to propose a feature request to the NuGet team which would allow the installation of NuGet packages with custom types on Frosting projects without limitations, and revisit this issue in the future.

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Long version

As as proof-of-concept I created three NuGet packages and published to nuget.org:

	Package ID	Description	Package Type
📦	Cake.PackageType.Addin	Sample Cake addin with Hello aliases	CakeAddin
📦	Cake.PackageType.Module	Sample Cake module with a hello scheme for the #tool directive	CakeModule
📦	Cake.PackageType.Recipe	Sample Cake recipe with a couple of helper methods	CakeRecipe

The source code of the packages above is available on here.

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Test Results

	Test	Result
✅	List packages via NuGet Gallery	Works as expected / No difference in behavior
✅	List packages via VS NuGet Package Manager UI	Works as expected / No difference in behavior
✅	List packages via NuGet API	Works as expected / No difference in behavior
✅	List packages via NuGet.exe	Works as expected / No difference in behavior
✅	Cake script: Use addin in a Cake build script	Works as expected / No difference in behavior
✅	Cake script: Use module in a Cake build script	Works as expected / No difference in behavior
✅	Cake script: Use recipe in a Cake build script	Works as expected / No difference in behavior
✅	Frosting: Add package to .csproj via PackageReference	Works as expected / No difference in behavior
✅	Frosting: Add package to .csproj via dotnet add package	Works as expected / No difference in behavior
❌	Frosting: Add package to .csproj via VS Package Manager UI	Error / package type not supported
❌	Frosting: Add package to .csproj via Install-Package from VS	Error / package type not supported

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Screenshots

Visual Studio NuGet Package Manager UI

Error messages in the failed tests

Conclusion

For now we've decided to propose a feature request to the NuGet team which would allow the installation of NuGet packages with custom types on Frosting projects without limitations, and revisit this issue in the future.

N.B.: Given that the limitation is only with Frosting, if we wanted to start using custom package types for Recipes today, we could.