NuGet package restore with Mono on Travis CI failing

Question

My project compiles & runs fine on OSX and Windows. However, trying to get it hooked up to Travis CI, I get this error from NuGet (using version 2.8):

Could not load type 'NuGet.MSBuildProjectUtility' from assembly 'NuGet, Version=2.8.50126.400, Culture=neutral, PublicKeyToken=null'.

Not really sure what to think about this one... MSBuildProjectUtility is obviously present in the assembly.

Answer 1

Your Mono version is very old, the project built fine for me on Mono 3.2.1.

To get a more recent version you can use this PPA: https://launchpad.net/~directhex/+archive/monoxide.

Add it to your system with sudo add-apt-repository ppa:directhex/monoxide && sudo apt-get update. Then you can install Mono with sudo apt-get install mono-devel.

Xamarin now ships official Mono packages for Linux, so the PPA isn't necessary anymore. See http://www.mono-project.com/docs/getting-started/install/linux/ for the installation guide.

Note: in order for Mono to verify SSL connections, you also need to import certificates with mozroots --import --sync, otherwise downloading packages from nuget.org will fail.