Pass references from projects to ResolveAssemblyReferences.AssemblyFiles

If we pass a full path to ResolveAssemblyReferences.Assemblies, it will
remove the file and not pass it along to the compiler. This is bad
for project-to-project references, since the Visual Studio IDE still
needs to know about them to make sure everything is wired up correctly.
With this, we now pass project-to-project references to AssemblyFiles,
matching the behavior of the ResolveProjectReferences target.

There is a deeper question of whether or not we should pass all our
full paths along to AssemblyFiles, but that's something which requires
fairly extensive testing and might have back-compat problems that need
to be dealt with.

Author: jasonmalinowski

src/Microsoft.NuGet.Build.Tasks.Tests/ProjectReferences/ProjectReferenceTests.cs

@@ -45,6 +45,7 @@ public void ProjectReferenceToXProjWithAssetsAndPathSucceeds()
             Assert.Empty(result.Analyzers);
             AssertHelpers.PathEndsWith(@"XProjOutputDirectory\net452\XProjClassLib.dll", result.CopyLocalItems.Single().ItemSpec);
             AssertHelpers.PathEndsWith(@"XProjOutputDirectory\net452\XProjClassLib.dll", result.References.Single().ItemSpec);
+            Assert.All(result.References, r => Assert.Equal(ResolveNuGetPackageAssets.NuGetSourceType_Project, r.GetMetadata(ResolveNuGetPackageAssets.NuGetSourceType)));
             Assert.Empty(result.ReferencedPackages);
         }
 

src/Microsoft.NuGet.Build.Tasks.Tests/ReferenceResolutionTests.cs

@@ -217,6 +217,20 @@ public static void IncludingFrameworkReferencesActuallyIncludesFrameworkReferenc
             Assert.Contains("FluentAssertions", packageNames);
         }
 
+        [Fact]
+        public static void AllPackageReferencesAreMarkedAsSuch()
+        {
+            var result = NuGetTestHelpers.ResolvePackagesWithJsonFileContents(
+                Json.Json.FluentAssertions,
+                targetMoniker: ".NETFramework,Version=v4.5.2",
+                runtimeIdentifier: "",
+                includeFrameworkReferences: true);
+
+            // We should have references to the package itself plus framework packages
+            AssertHelpers.AssertCountOf(4, result.References);
+            Assert.All(result.References, r => Assert.Equal(ResolveNuGetPackageAssets.NuGetSourceType_Package, r.GetMetadata(ResolveNuGetPackageAssets.NuGetSourceType)));
+        }
+
         [Fact]
         public static void CopyLocalContentsIncludePdbsIfAvailable()
         {

src/Microsoft.NuGet.Build.Tasks/Microsoft.NuGet.targets

@@ -164,8 +164,11 @@ Copyright (c) .NET Foundation. All rights reserved.
       <!-- Remove simple name references that are already implicitly added -->
       <_ReferencesFromNuGetPackages Remove="%(ReferencePath.FileName)" Condition="'%(ReferencePath.ResolvedFrom)' == 'ImplicitlyExpandTargetFramework'" />
 
-      <!-- Include NuGet references -->
-      <Reference Include="@(_ReferencesFromNuGetPackages)" />
+      <!-- Include NuGet references in the proper groups. Project-to-project references must go in the
+           _ResolvedProjectReferencePaths group which matches the behavior of the ResolveProjectReferences
+           target. This ensures that even if the assembly is missing on disk, it still makes it to the compiler. -->
+      <Reference Include="@(_ReferencesFromNuGetPackages)" Condition="'%(_ReferencesFromNuGetPackages.NuGetSourceType)' != 'Project'" />
+      <_ResolvedProjectReferencePaths Include="@(_ReferencesFromNuGetPackages)" Condition="'%(_ReferencesFromNuGetPackages.NuGetSourceType)' == 'Project'" />
 
       <!-- Remove simple name references if we're directly providing a reference assembly to the compiler. For example,
            consider a project with an Reference Include="System", and some NuGet package is providing System.dll -->

src/Microsoft.NuGet.Build.Tasks/NuGetPackageObject.cs

@@ -23,17 +23,19 @@ internal sealed class NuGetPackageObject
         /// </summary>
         private readonly Lazy<string> _fullPackagePath;
 
-        public NuGetPackageObject(string id, string version, Func<string> fullPackagePathGenerator, JObject targetObject, JObject libraryObject)
+        public NuGetPackageObject(string id, string version, bool isProject, Func<string> fullPackagePathGenerator, JObject targetObject, JObject libraryObject)
         {
             Id = id;
             Version = version;
+            IsProject = isProject;
             _fullPackagePath = new Lazy<string>(fullPackagePathGenerator);
             TargetObject = targetObject;
             LibraryObject = libraryObject;
         }
 
         public string Id { get; }
         public string Version { get; }
+        public bool IsProject { get; }
 
         /// <summary>
         /// The JSON object from the "targets" section in the project.lock.json for this package.

src/Microsoft.NuGet.Build.Tasks/ResolveNuGetPackageAssets.cs

@@ -22,6 +22,10 @@ public sealed class ResolveNuGetPackageAssets : Task
         internal const string NuGetPackageIdMetadata = "NuGetPackageId";
         internal const string NuGetPackageVersionMetadata = "NuGetPackageVersion";
         internal const string NuGetIsFrameworkReference = "NuGetIsFrameworkReference";
+        internal const string NuGetSourceType = "NuGetSourceType";
+        internal const string NuGetSourceType_Project = "Project";
+        internal const string NuGetSourceType_Package = "Package";
+
         internal const string ReferenceImplementationMetadata = "Implementation";
         internal const string ReferenceImageRuntimeMetadata = "ImageRuntime";
         internal const string ReferenceWinMDFileMetadata = "WinMDFile";
@@ -286,6 +290,7 @@ private void GetReferences(JObject lockFile)
             {
                 var item = new TaskItem(frameworkReference);
                 item.SetMetadata(NuGetIsFrameworkReference, "true");
+                item.SetMetadata(NuGetSourceType, NuGetSourceType_Package);
                 _references.Add(item);
             }
         }
@@ -775,6 +780,7 @@ private IEnumerable<ITaskItem> CreateItems(NuGetPackageObject package, string ke
 
                 item.SetMetadata("Private", "false");
                 item.SetMetadata(NuGetIsFrameworkReference, "false");
+                item.SetMetadata(NuGetSourceType, package.IsProject ? NuGetSourceType_Project : NuGetSourceType_Package);
 
                 items.Add(item);
 
@@ -873,6 +879,7 @@ private IEnumerable<NuGetPackageObject> GetPackagesFromTarget(JObject lockFile,
                 var nameParts = package.Key.Split('/');
                 var id = nameParts[0];
                 var version = nameParts[1];
+                bool isProject = false;
 
                 var libraryObject = (JObject)lockFile["libraries"][package.Key];
 
@@ -881,6 +888,8 @@ private IEnumerable<NuGetPackageObject> GetPackagesFromTarget(JObject lockFile,
                 // If this is a project then we need to figure out it's relative output path
                 if ((string)libraryObject["type"] == "project")
                 {
+                    isProject = true;
+
                     fullPackagePathGenerator = () =>
                     {
                         var relativeMSBuildProjectPath = (string)libraryObject["msbuildProject"];
@@ -905,7 +914,7 @@ private IEnumerable<NuGetPackageObject> GetPackagesFromTarget(JObject lockFile,
                     fullPackagePathGenerator = () => GetNuGetPackagePath(id, version);
                 }
 
-                yield return new NuGetPackageObject(id, version, fullPackagePathGenerator, (JObject)package.Value, libraryObject);
+                yield return new NuGetPackageObject(id, version, isProject, fullPackagePathGenerator, (JObject)package.Value, libraryObject);
             }
         }