Restore fails with error NU1605 when RuntimeIdentifier is set and ProjectReference is used to netcoreapp2.1 project

Repro repro.zip

Create two projects:

• src/src.csproj
  • TargetFramework = netcoreapp2.1
  • RuntimeIdentifer = win-x64
• test/test.csproj
  • TargetFramework = netcoreapp2.1
  • ProjectReference to src/src.sproj

Run dotnet restore with the 2.1.301 SDK or newer

Result Restore fails

/private/tmp/console1/test/test.csproj : error NU1605: Detected package downgrade: Microsoft.NETCore.App from 2.1.1 to 2.1.0. Reference the package directly from the project to select a different version.  [/private/tmp/console1/console1.sln]
/private/tmp/console1/test/test.csproj : error NU1605:  test -> src -> Microsoft.NETCore.App (>= 2.1.1)  [/private/tmp/console1/console1.sln]
/private/tmp/console1/test/test.csproj : error NU1605:  test -> Microsoft.NETCore.App (>= 2.1.0) [/private/tmp/console1/console1.sln]
  Restore failed in 396.65 ms for /private/tmp/console1/test/test.csproj.

Workarounds

• Add <TargetLatestRuntimePatch>true</TargetLatestRuntimePatch> to test.csproj ( suggested by @dsplaisted )
• Add <RuntimeFrameworkVersion>2.1.1</RuntimeFrameworkVersion> to test.csproj
• Add <RuntimeIdentifier>win-x64</RuntimeIdentifier> and <OutputType>exe</OutputType> to test.csproj
• Change <RuntimeIdentifier> to <RuntimeIdentifiers> (plural) in src.csproj

Details

.NET Core SDK (reflecting any global.json):
 Version:   2.1.301
 Commit:    59524873d6

Runtime Environment:
 OS Name:     Mac OS X
 OS Version:  10.13
 OS Platform: Darwin
 RID:         osx.10.13-x64
 Base Path:   /Users/namc/.dotnet/sdk/2.1.301/

cc @dsplaisted

[dsplaisted]

The workaround I would suggest is to set TargetLatestRuntimePatch to true in the test project.

Some related info: https://docs.microsoft.com/en-us/dotnet/core/deploying/runtime-patch-selection

[natemcmaster]

One more idea: what if we set PrivateAssets=All even when OutputType == exe? Based on this comment, it seems like we don’t generally need Microsoft.NETCore.App in the .nuspec with the notable exception (and edge case) of '$(PackageType)' == 'DotnetCliTool'

https://github.com/dotnet/sdk/blob/1512386f2c279f2146d7c58cecde989bc2ec9176/src/Tasks/Microsoft.NET.Build.Tasks/targets/Microsoft.NET.Sdk.DefaultItems.props#L51-L56