Perché NuGet scarica dipendenze apparentemente non necessarie?

Question

Quando si installa System.Collections.Immutable NuGet scarica assiemi come System.Runtime, anche se l'assembly è già stato installato con .NET 4.6.1.

Inoltre, le directory sotto lib (come pacchetti \ System.Runtime.4.0.0 \ lib \ net45) contengono nessun file dll, solo i file vuoto chiamato _._.

Perché sta succedendo? Perché è necessario? Cosa mi manca qui?

NuGet registro:

Install-Package System.Collections.Immutable -Version 1.1.37 
Attempting to gather dependency information for package 'System.Collections.Immutable.1.1.37' with respect to project 'ConsoleApplication1', targeting '.NETFramework,Version=v4.6.1' 
Attempting to resolve dependencies for package 'System.Collections.Immutable.1.1.37' with DependencyBehavior 'Lowest' 
Resolving actions to install package 'System.Collections.Immutable.1.1.37' 
Resolved actions to install package 'System.Collections.Immutable.1.1.37' 
    GET https://www.nuget.org/api/v2/package/System.Collections/4.0.0 
Installing System.Collections 4.0.0. 
Adding package 'System.Collections.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Collections.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Collections.4.0.0' to 'packages.config' 
Successfully installed 'System.Collections 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Diagnostics.Debug/4.0.0 
Installing System.Diagnostics.Debug 4.0.0. 
Adding package 'System.Diagnostics.Debug.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Diagnostics.Debug.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Diagnostics.Debug.4.0.0' to 'packages.config' 
Successfully installed 'System.Diagnostics.Debug 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Globalization/4.0.0 
Installing System.Globalization 4.0.0. 
Adding package 'System.Globalization.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Globalization.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Globalization.4.0.0' to 'packages.config' 
Successfully installed 'System.Globalization 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Linq/4.0.0 
Installing System.Linq 4.0.0. 
Adding package 'System.Linq.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Linq.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Linq.4.0.0' to 'packages.config' 
Successfully installed 'System.Linq 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Resources.ResourceManager/4.0.0 
Installing System.Resources.ResourceManager 4.0.0. 
Adding package 'System.Resources.ResourceManager.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Resources.ResourceManager.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Resources.ResourceManager.4.0.0' to 'packages.config' 
Successfully installed 'System.Resources.ResourceManager 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Runtime/4.0.0 
Installing System.Runtime 4.0.0. 
Adding package 'System.Runtime.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Runtime.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Runtime.4.0.0' to 'packages.config' 
Successfully installed 'System.Runtime 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Runtime.Extensions/4.0.0 
Installing System.Runtime.Extensions 4.0.0. 
Adding package 'System.Runtime.Extensions.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Runtime.Extensions.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Runtime.Extensions.4.0.0' to 'packages.config' 
Successfully installed 'System.Runtime.Extensions 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Threading/4.0.0 
Installing System.Threading 4.0.0. 
Adding package 'System.Threading.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Threading.4.0.0' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Threading.4.0.0' to 'packages.config' 
Successfully installed 'System.Threading 4.0.0' to ConsoleApplication1 
    GET https://www.nuget.org/api/v2/package/System.Collections.Immutable/1.1.37 
Installing System.Collections.Immutable 1.1.37. 
Adding package 'System.Collections.Immutable.1.1.37' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Collections.Immutable.1.1.37' to folder 'd:\workspace\ConsoleApplication1\packages' 
Added package 'System.Collections.Immutable.1.1.37' to 'packages.config' 
Successfully installed 'System.Collections.Immutable 1.1.37' to ConsoleApplication1 

Answer 1

ho che questo è a causa dei cambiamenti che stanno arrivando con anima dotnet/CLI. Sta mantenendo la catena di dipendenze, che è molto più importante nel core di donet perché non hai una struttura completamente installata. Questo spiega perché le cartelle lib\net45 sono vuote, non c'è nulla da includere perché sono parte del BCL installato sul tuo computer.