Suppose I have a class library which I want to target netstandard1.3, but also use BigInteger. Here's a trivial example - the sole source file is Adder.cs:
using System;
using System.Numerics;
namespace Calculator
{
public class Adder
{
public static BigInteger Add(int x, int y)
=> new BigInteger(x) + new BigInteger(y);
}
}
Back in the world of project.json, I would target netstandard1.3 in the frameworks section, and have an explicit dependency on System.Runtime.Numerics, e.g. version 4.0.1. The nuget package I create will list just that dependency.
In the brave new world of csproj-based dotnet tooling (I'm using v1.0.1 of the command-line tools) there's an implicit metapackage package reference to NETStandard.Library 1.6.1 when targeting netstandard1.3. This means that my project file is really small, because it doesn't need the explicit dependency:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netstandard1.3</TargetFramework>
</PropertyGroup>
</Project>
... but the nuget package produced has a dependency on NETStandard.Library, which suggests that in order to use my small library, you need everything there.
It turns out I can disable that functionality using DisableImplicitFrameworkReferences, then add in the dependency manually again:
<Project Sdk="Microsoft.NET.Sdk">
<PropertyGroup>
<TargetFramework>netstandard1.3</TargetFramework>
<DisableImplicitFrameworkReferences>true</DisableImplicitFrameworkReferences>
</PropertyGroup>
<ItemGroup>
<PackageReference Include="System.Runtime.Numerics" Version="4.0.1" />
</ItemGroup>
</Project>
Now my NuGet package says exactly what it depends on. Intuitively, this feels like a "leaner" package.
So what's the exact difference for a consumer of my library? If someone tries to use it in a UWP application, does the second, "trimmed" form of dependencies mean that the resulting application will be smaller?
By not documenting DisableImplicitFrameworkReferences clearly (as far as I've seen; I read about it in an issue) and by making the implicit dependency the default when creating a project, Microsoft are encouraging users to just depend on the metapackage - but how can I be sure that doesn't have disadvantages when I'm producing a class library package?
