Cannot resolve runtime and native assets from dependency context of a class library

[natemcmaster]

I am attempting to solve the problem of creating an AssemblyLoadContext from a class library project (dotnet/efcore#5320) with only 3 inputs: dependency context, nuget package directory, and application base path. (NB: no project context)

Problem

The build trims "runtimeTargets" from the deps.json file. In order to execute code from an ALC, we need all runtime and native assets.

Steps to reproduce

Create and compile netstandard project

public class Class1 {}

{
    "dependencies": {
        "System.Data.SqlClient": "4.1.0"
    },
    "frameworks": {
        "netstandard1.3": {}
    }
}

Expected

  "runtime.native.System.Data.SqlClient.sni/4.0.0": {
        "dependencies": {
          "runtime.win7-x64.runtime.native.System.Data.SqlClient.sni": "4.0.1",
          "runtime.win7-x86.runtime.native.System.Data.SqlClient.sni": "4.0.1"
        }
      },
      "runtime.win7-x64.runtime.native.System.Data.SqlClient.sni/4.0.1": {
        "runtimeTargets": {
          "runtimes/win7-x64/native/sni.dll": {
            "rid": "win7-x64",
            "assetType": "native"
          }
        }
      },
      "runtime.win7-x86.runtime.native.System.Data.SqlClient.sni/4.0.1": {
        "runtimeTargets": {
          "runtimes/win7-x86/native/sni.dll": {
            "rid": "win7-x86",
            "assetType": "native"
          }
        }
      },

Actual

      "runtime.native.System.Data.SqlClient.sni/4.0.0": {
        "dependencies": {
          "runtime.win7-x64.runtime.native.System.Data.SqlClient.sni": "4.0.1",
          "runtime.win7-x86.runtime.native.System.Data.SqlClient.sni": "4.0.1"
        }
      },

      "runtime.win7-x64.runtime.native.System.Data.SqlClient.sni/4.0.1": {},
      "runtime.win7-x86.runtime.native.System.Data.SqlClient.sni/4.0.1": {},

cc @davidfowl

[jcansdale]

I think I might be bumping into the same issue here:
jcansdale/TestDriven.Net-Issues#7

Have you had any luck creating an AssemblyLoadContext? I hit a bug in that when trying to find a workaround for the above issue.

[natemcmaster]

@jcansdale I've had success in creating a fully working AssemblyLoadContext from Microsoft.DotNet.ProjectModel.ProjectContext and from NuGet.ProjectModel.LockFile, but not from Microsoft.Extensions.DependencyModel.DependencyContext. I'm trying to create a tool that is project-model agnostic, but so far have found that DependencyContext doesn't provide enough information on class library projects.

[jcansdale]

I'd be interested to see your AssemblyLoadContext code if you have it checked in anywhere. 😄

[natemcmaster]

@jcansdale Checkout https://github.com/dotnet/cli/tree/rel/1.0.0/src/Microsoft.DotNet.ProjectModel.Loader for making a load context from Microsoft.DotNet.ProjectModel.ProjectContext. Bear in mind this only works on the "project.json" project system. I have not yet successfully implemented a version that works with the project system work happening on https://github.com/microsoft/msbuild/tree/xplat or one that is project-system agnostic.

[jcansdale]

That's great, thanks. It's good to some real world usage of AssemblyLoadContext.

[TheRealPiotrP]

Moved to core-setup to keep close to dependencycontext.