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Package Validation

I recently discovered a .NET feature I didn’t know it existed; Package validation. Package validation was introduced as a part of the .NET 6 SDK. It allows you as a package author to check if your NuGet packages are consistent and well formed. At the moment of writing this post, the tooling provides the following checks:

  • Validates that there are no breaking changes across versions.
  • Validates that the package has the same set of publics APIs for all the different runtime-specific implementations.
  • Helps developers catch any applicability holes.

Enabling package validation is nothing more than setting the EnablePackageValidation property to true in your csproj file:

Now 3 different validators can kick in everytime you run dotnet pack:

  • The Baseline version validator validates your library project against a previously released, stable version of your package.
  • The Compatible runtime validator validates that your runtime-specific implementation assemblies are compatible with each other and with the compile-time assemblies.
  • The Compatible framework validator validates that code compiled against one framework can run against all the others in a multi-targeting package.

I’m interested in the Baseline version validator so let us focus on that one in this post.

The baseline validator allows you to validate your library project against a previously released, stable version of your package. It will detect any breaking change.

Before you can use the baseline validator, you first need to specify the baseline package that should be used as a comparison.

NuGet hosted packages

If your package is hosted on NuGet you can use the PackageValidationBaselineVersion property.Set it to a previous version you want to compare to. For example:

If I now run dotnet pack, I get an error message:

In this example it is because in the deployed package I have set both the AssemblyVersion and PackageVersion and in the local version I have only  set the PackageVersion.

But you also get errors when you do a breaking change. For example, I added an extra parameter to a public function. This results in the following error message:

Other package sources

If your package is not hosted on NuGet, you can still use the Baseline version validator but you should use the PackageValidationBaselinePath property and point it to the file location of your baseline NuGet package:

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