如何解决NuGet.exe命令行无法安装xunit 2.1.0？

Question

使用更新5和NuGet软件包管理器2.8.60610.756在Visual 2013中创建一个全新的项目，可以完美地安装xunit 2.1.0

------- Installing...xunit 2.1.0 -------
Attempting to resolve dependency 'xunit.core (= 2.1.0)'.
Attempting to resolve dependency 'xunit.extensibility.core (= 2.1.0)'.
Attempting to resolve dependency 'xunit.abstractions (= 2.0.0)'.
Attempting to resolve dependency 'xunit.extensibility.execution (= 2.1.0)'.
Attempting to resolve dependency 'xunit.assert (= 2.1.0)'.
Installing 'xunit.abstractions 2.0.0'.
Added file 'xunit.abstractions.dll' to folder 'xunit.abstractions.2.0.0\lib\net35'.
Added file 'xunit.abstractions.xml' to folder 'xunit.abstractions.2.0.0\lib\net35'.
Added file 'xunit.abstractions.dll' to folder 'xunit.abstractions.2.0.0\lib\portable-net45+win+wpa81+wp80+monotouch+monoandroid+Xamarin.iOS'.
Added file 'xunit.abstractions.xml' to folder 'xunit.abstractions.2.0.0\lib\portable-net45+win+wpa81+wp80+monotouch+monoandroid+Xamarin.iOS'.
Added file 'xunit.abstractions.2.0.0.nupkg' to folder 'xunit.abstractions.2.0.0'.
Successfully installed 'xunit.abstractions 2.0.0'.
Installing 'xunit.extensibility.core 2.1.0'.
Added file 'xunit.core.dll' to folder 'xunit.extensibility.core.2.1.0\lib\dotnet'.
Added file 'xunit.core.dll.tdnet' to folder 'xunit.extensibility.core.2.1.0\lib\dotnet'.
Added file 'xunit.core.pdb' to folder 'xunit.extensibility.core.2.1.0\lib\dotnet'.
Added file 'xunit.core.xml' to folder 'xunit.extensibility.core.2.1.0\lib\dotnet'.
Added file 'xunit.runner.tdnet.dll' to folder 'xunit.extensibility.core.2.1.0\lib\dotnet'.
Added file 'xunit.runner.utility.desktop.dll' to folder 'xunit.extensibility.core.2.1.0\lib\dotnet'.
Added file 'xunit.core.dll' to folder 'xunit.extensibility.core.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.core.dll.tdnet' to folder 'xunit.extensibility.core.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.core.pdb' to folder 'xunit.extensibility.core.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.core.xml' to folder 'xunit.extensibility.core.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.runner.tdnet.dll' to folder 'xunit.extensibility.core.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.runner.utility.desktop.dll' to folder 'xunit.extensibility.core.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.extensibility.core.2.1.0.nupkg' to folder 'xunit.extensibility.core.2.1.0'.
Successfully installed 'xunit.extensibility.core 2.1.0'.
Installing 'xunit.extensibility.execution 2.1.0'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\dnx451'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\dnx451'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\dnx451'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\dotnet'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\dotnet'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\dotnet'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\monoandroid'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\monoandroid'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\monoandroid'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\monotouch'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\monotouch'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\monotouch'.
Added file 'xunit.execution.desktop.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\net45'.
Added file 'xunit.execution.desktop.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\net45'.
Added file 'xunit.execution.desktop.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\net45'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\win8'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\win8'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\win8'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\wp8'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\wp8'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\wp8'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\wpa81'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\wpa81'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\wpa81'.
Added file 'xunit.execution.dotnet.dll' to folder 'xunit.extensibility.execution.2.1.0\lib\xamarinios'.
Added file 'xunit.execution.dotnet.pdb' to folder 'xunit.extensibility.execution.2.1.0\lib\xamarinios'.
Added file 'xunit.execution.dotnet.xml' to folder 'xunit.extensibility.execution.2.1.0\lib\xamarinios'.
Added file 'xunit.extensibility.execution.2.1.0.nupkg' to folder 'xunit.extensibility.execution.2.1.0'.
Successfully installed 'xunit.extensibility.execution 2.1.0'.
Installing 'xunit.core 2.1.0'.
Added file '_._' to folder 'xunit.core.2.1.0\build\dnx451'.
Added file '_._' to folder 'xunit.core.2.1.0\build\monoandroid'.
Added file '_._' to folder 'xunit.core.2.1.0\build\monotouch'.
Added file '_._' to folder 'xunit.core.2.1.0\build\net45'.
Added file 'xunit.core.props' to folder 'xunit.core.2.1.0\build\portable-net45+win8+wp8+wpa81'.
Added file '_._' to folder 'xunit.core.2.1.0\build\win8'.
Added file 'xunit.core.props' to folder 'xunit.core.2.1.0\build\win81'.
Added file '_._' to folder 'xunit.core.2.1.0\build\wp8'.
Added file 'xunit.core.props' to folder 'xunit.core.2.1.0\build\wpa81'.
Added file '_._' to folder 'xunit.core.2.1.0\build\xamarinios'.
Added file 'xunit.execution.desktop.dll' to folder 'xunit.core.2.1.0\build\_desktop'.
Added file 'xunit.core.2.1.0.nupkg' to folder 'xunit.core.2.1.0'.
Successfully installed 'xunit.core 2.1.0'.
Installing 'xunit.assert 2.1.0'.
Added file 'xunit.assert.dll' to folder 'xunit.assert.2.1.0\lib\dotnet'.
Added file 'xunit.assert.pdb' to folder 'xunit.assert.2.1.0\lib\dotnet'.
Added file 'xunit.assert.xml' to folder 'xunit.assert.2.1.0\lib\dotnet'.
Added file 'xunit.assert.dll' to folder 'xunit.assert.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.assert.pdb' to folder 'xunit.assert.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.assert.xml' to folder 'xunit.assert.2.1.0\lib\portable-net45+win8+wp8+wpa81'.
Added file 'xunit.assert.2.1.0.nupkg' to folder 'xunit.assert.2.1.0'.
Successfully installed 'xunit.assert 2.1.0'.
Installing 'xunit 2.1.0'.
Added file 'xunit.2.1.0.nupkg' to folder 'xunit.2.1.0'.
Successfully installed 'xunit 2.1.0'.
Adding 'xunit.abstractions 2.0.0' to ClassLibrary1.
For adding package 'xunit.abstractions 2.0.0' to project 'ClassLibrary1' that targets 'net45',
>> Assembly references are being added from 'lib\net35'
Added reference 'xunit.abstractions' to project 'ClassLibrary1'
Added file 'packages.config'.
Added file 'packages.config' to project 'ClassLibrary1'
Successfully added 'xunit.abstractions 2.0.0' to ClassLibrary1.
Adding 'xunit.extensibility.core 2.1.0' to ClassLibrary1.
For adding package 'xunit.extensibility.core 2.1.0' to project 'ClassLibrary1' that targets 'net45',
>> Assembly references are being added from 'lib\portable-net45+win8+wp8+wpa81'
Added reference 'xunit.core' to project 'ClassLibrary1'
Added file 'packages.config'.
Successfully added 'xunit.extensibility.core 2.1.0' to ClassLibrary1.
Adding 'xunit.extensibility.execution 2.1.0' to ClassLibrary1.
For adding package 'xunit.extensibility.execution 2.1.0' to project 'ClassLibrary1' that targets 'net45',
>> Assembly references are being added from 'lib\net45'
Added reference 'xunit.execution.desktop' to project 'ClassLibrary1'
Added file 'packages.config'.
Successfully added 'xunit.extensibility.execution 2.1.0' to ClassLibrary1.
Adding 'xunit.core 2.1.0' to ClassLibrary1.
For adding package 'xunit.core 2.1.0' to project 'ClassLibrary1' that targets 'net45',
>> Build files are being added from 'build\portable-net45+win8+wp8+wpa81'
Added file 'packages.config'.
Successfully added 'xunit.core 2.1.0' to ClassLibrary1.
Adding 'xunit.assert 2.1.0' to ClassLibrary1.
For adding package 'xunit.assert 2.1.0' to project 'ClassLibrary1' that targets 'net45',
>> Assembly references are being added from 'lib\portable-net45+win8+wp8+wpa81'
Added reference 'xunit.assert' to project 'ClassLibrary1'
Added file 'packages.config'.
Successfully added 'xunit.assert 2.1.0' to ClassLibrary1.
Adding 'xunit 2.1.0' to ClassLibrary1.
Added file 'packages.config'.
Successfully added 'xunit 2.1.0' to ClassLibrary1.
==============================

使用最新的NuGet命令行执行相同的安装步骤(2.8.60717.93)失败，说明它需要NuGet 3.0。

C:\development\tools\nuget> nuget update -self
Checking for updates from https://www.nuget.org/api/v2/.
Currently running NuGet.exe 2.8.6.
NuGet.exe is up to date.
C:\development\tools\nuget> nuget
NuGet Version: 2.8.60717.93
usage: NuGet <command> [args] [options]
Type 'NuGet help <command>' for help on a specific command.

Available commands:

 config      Gets or sets NuGet config values.

 delete      Deletes a package from the server.

 help (?)    Displays general help information and help information about other commands
             .

 install     Installs a package using the specified sources. If no sources are specified
             , all sources defined in the NuGet configuration file are used. If the conf
             iguration file specifies no sources, uses the default NuGet feed.

 list        Displays a list of packages from a given source. If no sources are specifie
             d, all sources defined in %AppData%\NuGet\NuGet.config are used. If NuGet.c
             onfig specifies no sources, uses the default NuGet feed.

 pack        Creates a NuGet package based on the specified nuspec or project file.

 push        Pushes a package to the server and publishes it.
             NuGet's default configuration is obtained by loading %AppData%\NuGet\NuGet.
             config, then loading any nuget.config or .nuget\nuget.config starting from
             root of drive and ending in current directory.

 restore     Restores NuGet packages.

 setApiKey   Saves an API key for a given server URL. When no URL is provided API key is
             saved for the NuGet gallery.

 sources     Provides the ability to manage list of sources located in %AppData%\NuGet\N
             uGet.config

 spec        Generates a nuspec for a new package. If this command is run in the same fo
             lder as a project file (.csproj, .vbproj, .fsproj), it will create a tokeni
             zed nuspec file.

 update      Update packages to latest available versions. This command also updates NuG
             et.exe itself.

For more information, visit http://docs.nuget.org/docs/reference/command-line-reference
C:\development\tools\nuget> nuget install xunit -version 2.1.0
Attempting to resolve dependency 'xunit.core (= 2.1.0)'.
Attempting to resolve dependency 'xunit.extensibility.core (= 2.1.0)'.
Attempting to resolve dependency 'xunit.abstractions (= 2.0.0)'.
Attempting to resolve dependency 'xunit.extensibility.execution (= 2.1.0)'.
Attempting to resolve dependency 'System.Collections (= 4.0.0)'.
Attempting to resolve dependency 'System.Runtime (= 4.0.0)'.
Attempting to resolve dependency 'System.Diagnostics.Debug (= 4.0.0)'.
Attempting to resolve dependency 'System.Globalization (= 4.0.0)'.
Attempting to resolve dependency 'System.IO (= 4.0.0)'.
Attempting to resolve dependency 'System.Text.Encoding (= 4.0.0)'.
Attempting to resolve dependency 'System.Threading.Tasks (= 4.0.0)'.
Attempting to resolve dependency 'System.Linq (= 4.0.0)'.
The 'System.Linq 4.0.0' package requires NuGet client version '3.0' or above, but the current NuGet version is '2.8.60717.93'.
C:\development\tools\nuget>

Visual根本没有提到系统库，并且使用VS2013“启用NuGet包恢复”也可以恢复包及其依赖项，并且运行的是NuGet.exe命令行的相同版本

Answer 1

简单地说，您不能阻止NuGet.exe版本2无法使用nuget install xunit -version 2.1.0从命令行下载xunit 2.1.0。

在Visual中执行同样的操作时，下载的依赖项仅限于项目目标框架支持的依赖项。

当您使用nuget install xunit -version 2.1.0时，没有项目，所以没有目标框架，所以所有的依赖项都被认为是兼容的，所以它们都将被下载。对于xunit 2.1.0，它的依赖项之一是System.Linq 4.0.0，它需要NuGet 3.0。

你的解决办法是：

1. 使用packages.config文件代替。packages.config文件中将存储目标框架信息。
2. 使用NuGet.exe版本3。