Package Manager in VS2015 RC fails on installing/restoring some packages

Question

I'm trying to install a nuget package - NGenerics.1.4.1 from nuget.org ( https://www.nuget.org/packages/NGenerics/ ) into a ASP.NET 5 project (website). Package Manager fails with UriFormatException. After that a reference is added into Reference folder in the Solution Explorer but with yellow triangle ('warning').
The error added into the Error List: "Dependency NGenerics >= 1.4.1.0 could not be resolved".
I also tried to install from a local folder registry.

Here's the bug on msconnect .

I wonder whether somebody experienced the same issue as I couldn't find anything in google. Also any workarounds are welcome.

Package Manager's Output:

Installing NuGet package NGenerics.1.4.1.
Successfully installed 'NGenerics.1.4.1' to Samples.AjaxDemo2.
========== Finished ==========
Restoring packages for D:\Work\Apps\Samples.AjaxDemo2\project.json
----------
System.UriFormatException: Invalid URI: The format of the URI could not be determined.
   at System.Uri.CreateThis(String uri, Boolean dontEscape, UriKind uriKind)
   at System.Uri..ctor(String uriString)
   at Microsoft.Framework.PackageManager.PackageSourceUtils.CreatePackageFeed(PackageSource source, Boolean noCache, Boolean ignoreFailedSources, Reports reports)
   at Microsoft.Framework.PackageManager.RestoreCommand.AddRemoteProvidersFromSources(List`1 remoteProviders, List`1 effectiveSources)
   at Microsoft.Framework.PackageManager.RestoreCommand.<RestoreForProject>d__74.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Framework.PackageManager.RestoreCommand.<>c__DisplayClass73_0.<<ExecuteCommand>b__0>d.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Microsoft.Framework.PackageManager.RestoreCommand.<ExecuteCommand>d__73.MoveNext()
----------
Restore failed
Invalid URI: The format of the URI could not be determined.

Answer 1

I stumbled across the same issue today with NuGet 2.8.5 on Visual Studio 2013. @Shrike's answer helped me find out it's the specification of my relative path in a custom NuGet.config. Since it appears System.Uri must be able to parse it, all you have to do is ensure the relative path is a proper, legal URI. Relative file URIs must start with './' (obv don't use backslashes either, they're a Windows Thing!). See c# type to handle relative and absolute URI's and local file paths

Eg Use:

<add key="local-feed" value="./lib/nuget-feed" />

instead of:

<add key="local-feed" value="lib/nuget-feed" />

Removing the local feed is not a good idea, as you now have to restore from a different feed, which may not be what you want (personally, I wouldn't bet my builds on the nuget gallery given it's track record of downtime...)

Answer 2

Finally I found out what was wrong. I had ".nuget\\NuGet.config" file somewhere above of my solution in folder structure.
That NuGet.config contained a package source with relative file path:

<configuration>
  <packageSources>
    <add key="local" value="..\..\..\Release"/>
  </packageSources>
</configuration>

As I removed that packageSource Package Manager in VS started working.

It's kinda ridiculous.

Hope it helps somebody not to loose so many hours as me.

Answer 3

After wasting about two hours on the exception I found that my package source is added to the disabledPackageSources section in .nuget\\NuGet.config. I just had to remove it from the disabled list.

 <disabledPackageSources>
    <add key="RaNuget" value="true" />
  </disabledPackageSources>