[.net] NuGet auto package restore does not work with MSBuild

I'm trying to build a solution with packages content missing (except repositories.config inside) with MSBuild 12.0. I expect it to auto restore all missing packages before building but this is not the case - MsBuild reports tons of errors:

"are you missing a using directive or an assembly reference?"

NuGet Manager is 2.7 (I see this in Visual Studio 2013 about box). I even tried to pass EnableNuGetPackageRestore=true parameter - no luck. What am I missing?

In Visual Studio 2017 - When you compile using IDE - It will download all the missing nuget packages and save in the folder "packages".

But on the build machine compilation was done using msbuild.exe. In that case, I downloaded nuget.exe and kept in path.

During each build process before executing msbuild.exe. It will execute -> nuget.exe restore NAME_OF_SLN_File (if there is only one .SLN file then you can ignore that parameter)

I had an issue with nuget packages not being included in a scripted nightly build that builds the sln file using devenv.exe.

I followed the advice from Microsoft, and the key step was updating the NuGet config in %AppData%/NuGet so that it contained:

<configuration>
    <packageRestore>
        <add key="automatic" value="True" />
    </packageRestore>
</configuration>

MSBuild 15 has a /t:restore option that does this. it comes with Visual Studio 2017.

If you want to use this, you also have to use the new PackageReference, which means replacing the packages.config file with elements like this (do this in *.csproj):

<ItemGroup>
  <!-- ... -->
  <PackageReference Include="Contoso.Utility.UsefulStuff" Version="3.6.0" />
  <!-- ... -->
</ItemGroup>

There is an automated migration to this format if you right click on 'References' (it might not show up if you just opened visual studio, rebuild or open up the 'Manage NuGet packages for solution' window and it will start appearing).

You can also use

Update-Package -reinstall

to restore the NuGet packages on the Package Management Console in Visual Studio.

Note that if you are using TeamCity as a build server, you get a "NuGet Installer" step that you can use to restore all the packages before the build step.

Ian Kemp has the answer (have some points btw..), this is to simply add some meat to one of his steps.

The reason I ended up here was that dev's machines were building fine, but the build server simply wasn't pulling down the packages required (empty packages folder) and therefore the build was failing. Logging onto the build server and manually building the solution worked, however.

To fulfil the second of Ians 3 point steps (running nuget restore), you can create an MSBuild target running the exec command to run the nuget restore command, as below (in this case nuget.exe is in the .nuget folder, rather than on the path), which can then be run in a TeamCity build step (other CI available...) immediately prior to building the solution

<Target Name="BeforeBuild">
  <Exec Command="..\.nuget\nuget restore ..\MySolution.sln"/>
</Target>

For the record I'd already tried the "nuget installer" runner type but this step was hanging on web projects (worked for DLL's and Windows projects)

If you are using Visual Studio 2017 or later which ships with MSBuild 15 or later, and your .csproj files are in the new PackageReference format, the simplest method is to use the new MSBuild Restore target.

No-one has actually answered the original question, which is "how do I get NuGet packages to auto-restore when building from the command-line with MSBuild?" The answer is: unless you are using the "Enable NuGet package restore" option (which is now deprecated as per this reference), you can't (but see below). If you are trying to do e.g. automated builds on a CI server, this sucks.

However there is a slightly roundabout way to get the desired behaviour:

1. Download the latest NuGet executable from https://dist.nuget.org/win-x86-commandline/latest/nuget.exe and place it somewhere in your PATH. (You can do this as a pre-build step.)
2. Run nuget restore which will auto-download all the missing packages.
3. Run msbuild to build your solution.

Aside: while the new and recommended way to do auto package restore involves less clutter in your version control, it also makes command-line package restore impossible unless you jump through the extra hoop of downloading and running nuget.exe. Progress?

It took me some time to figure out the whole picture and I'd like to share here.

Visual Studio has two approaches to use package restore: Automatic Package Restore and MSBuild-Integrated package restore. The 'MSBuild-Integrated Package Restore' restores packages DURING the building process that might cause issues in some scenarios. The 'Automatic Package Restore' is the recommended approach by the NuGet team.

There are several steps to to make 'Automatic Package Restore' work:

1. In Visual Studio, Tools -> Extensions and Updates, Upgrade NuGet if there is a newer version (Version 2.7 or later)

2. If you use TFS, in your solution's .nuget folder, remove the NuGet.exe and NuGet.targes files. Then edit NuGet.Config to not check in NuGet packages:

   <configuration>  
     <solution>  
       <add key="disableSourceControlIntegration" value="true" />  
     </solution>  
   </configuration> 
   

   If you checked in the solution's packages folder to TFS before, delete the folder and check in the deletion of package folder deletion.

   If you don't use TFS, delete the .nuget folder.

3. In each project file (.csproj or .vbproj) in your solution, remove the line that references NuGet.targets file. The reference looks like this:

   <Import Project="$(SolutionDir)\.nuget\NuGet.targets" Condition="Exists('$(SolutionDir)\.nuget\NuGet.targets')" />
   

   Remove this line in every project file in your solution.

4. In Visual Studio menu, either through

   Tools -> Options -> Package Manager -> General or Tools -> NuGet Package Manager -> Package Manager Settings

   please enable the following two options 1) 'Allow NuGet to download missing packages' 2) 'Automatically check for missing packages during build in Visual Studio'

5. Test your package restore configuration by the following steps

   • Save your solution and close Visual Studio
   • Delete your solution's packages folder
   • Start Visual Studio, open your solution and rebuild it.

There is a packages.config file with the project, it contains the package details.

Also there is a .nuget folder which contains the NuGet.exe and NuGet.targets. if any one of the file is missing it will not restore the missing package and cause "are you missing a using directive or an assembly reference?" error

Sometimes this occurs when you have the folder of the package you are trying to restore inside the "packages" folder (i.e. "Packages/EntityFramework.6.0.0/") but the "DLLs" are not inside it (most of the version control systems automatically ignore ".dll" files). This occurs because before NuGet tries to restore each package it checks if the folders already exist, so if it exists, NuGet assumes that the "dll" is inside it. So if this is the problem for you just delete the folder that NuGet will restore it correctly.

Nuget's Automatic Package Restore is a feature of the Visual Studio (starting in 2013), not MSBuild. You'll have to run nuget.exe restore if you want to restore packages from the command line.

You can also use the Enable Nuget Package Restore feature, but this is no longer recommended by the nuget folks because it makes intrusive changes to the project files and may cause problems if you build those projects in another solution.