Sdk: Missing closure of project references leads to crash in GenerateDepsFile

[nguerrera]

Repro steps

• Make new projects with following P2P reference graph
  
  
  
  • ConsoleApp (.NET Core) -> ClassLibrary1 (.NET Standard) -> ClassLibrary2 (.NET Standard)
  
  
• Add reference to nuget package in ClassLibrary2 (say Newtonsoft.Json)
• build

Expected result

• While transitive P2P refs are still not supported:
  
  
  
  • Build warns about missing project reference, or fails with a clear error.
  
  
• When transitive P2P refs are supported (https://github.com/dotnet/roslyn-project-system/issues/199, https://github.com/dotnet/sdk/issues/200):
  
  
  
  • Build succeeds and all dependencies are handled correctly in deps file.
  
  

Actual result

3>ConsoleApp -> C:\...\bin\Debug\netcoreapp1.0\ConsoleApp.dll
3>C:\...\Microsoft.NET.Sdk.targets(77,5): error MSB4018: The "GenerateDepsFile" task failed unexpectedly.
3>C:\...\Microsoft.NET.Sdk.targets(77,5): error MSB4018: System.Exception: Could not find valid a SingleProjectInfo for project 'C:\...\ClassLibrary2.csproj'

[nguerrera]

@piotrpMSFT, @livarcocc, @jgoshi: let us know if this gives you enough info to get unblocked by adding appropriate project refs.

@srivatsn, @dsplaisted: FYI

[jgoshi]

@nguerrera Yes this got us unblocked.

[RainingNight]

+1

[kant2002]

For whose like me trying to figure out what's wrong with build, I post workaround here:
Just add reference to ClassLibrary2 to your ConsoleApp project, and build will succeed.

[rocifier]

Well, this sucks. Just started a new enterprise-scale application and it's broken already. After trying the workaround above, I get the following exception:

Error   MSB4018 The "GenerateDepsFile" task failed unexpectedly.
System.ArgumentException: An item with the same key has already been added.
   at System.ThrowHelper.ThrowArgumentException(ExceptionResource resource)
   at System.Collections.Generic.Dictionary`2.Insert(TKey key, TValue value, Boolean add)
   at System.Linq.Enumerable.ToDictionary[TSource,TKey,TElement](IEnumerable`1 source, Func`2 keySelector, Func`2 elementSelector, IEqualityComparer`1 comparer)
   at Microsoft.Extensions.DependencyModel.DependencyContextWriter.WritePortableTarget(IReadOnlyList`1 runtimeLibraries, IReadOnlyList`1 compilationLibraries)
   at Microsoft.Extensions.DependencyModel.DependencyContextWriter.WriteTargets(DependencyContext context)
   at Microsoft.Extensions.DependencyModel.DependencyContextWriter.Write(DependencyContext context)
   at Microsoft.Extensions.DependencyModel.DependencyContextWriter.Write(DependencyContext context, Stream stream)
   at Microsoft.NET.Build.Tasks.GenerateDepsFile.ExecuteCore()
   at Microsoft.NET.Build.Tasks.TaskBase.Execute()
   at Microsoft.Build.BackEnd.TaskExecutionHost.Microsoft.Build.BackEnd.ITaskExecutionHost.Execute()
   at Microsoft.Build.BackEnd.TaskBuilder.<ExecuteInstantiatedTask>d__26.MoveNext() fluid-cms-site  C:\Users\Ryan\.nuget\packages\microsoft.net.sdk\1.0.0-alpha-20161104-2\build\Microsoft.NET.Sdk.targets  77

[nguerrera]

@rocifier Sorry about that. Would you mind opening a separate issue and providing the repro steps?

[rocifier]

@nguerrera It's strange. I don't feel confident to open a new issue about this yet. Sometimes I can fix the problem by rebuilding the solution. Restoring packages for the solution is what seems to break it. The problem now is that I can't consistently reproduce this, but I am living in fear of it breaking at any moment..

[srivatsn]

The error message here was improved. However since we are doing transitive P2Ps now we shouldn't get into this situation. Closing this issue. @rocifier if you see a repro for the crash mentioned above please file a separate issue.

[pl89]

@rocifier did you ever open a separate issue for the problem you raised on Dec 12? I'm running into the same issue you are seeing (using dotnet 2.0.0-preview1-005977).

[rocifier]

No, I was never able to reproduce it again. I think I re-opened visual studio and rebuilt or something, and the problem went away. These days I tend to see better errors such as a trace of which packages are conflicting and from where. 95% of the time it is different versions of Newtonsoft.Json being used from different libraries.