Use the project.lock.json to determine the compatible framework for projects

src/Microsoft.Dnx.Runtime/ApplicationHostContext.cs

@@ -188,7 +188,7 @@ private static Result InitializeCore(ApplicationHostContext context)
 
                             var path = Path.GetFullPath(Path.Combine(context.ProjectDirectory, projectLibrary.Path));
 
-                            var projectDescription = projectResolver.GetDescription(context.TargetFramework, path, library);
+                            var projectDescription = projectResolver.GetDescription(path, library);
 
                             libraries.Add(projectDescription);
                         }

src/Microsoft.Dnx.Runtime/DependencyManagement/ProjectDependencyProvider.cs

@@ -12,7 +12,7 @@ namespace Microsoft.Dnx.Runtime
 {
     public class ProjectDependencyProvider
     {
-        public ProjectDescription GetDescription(FrameworkName targetFramework, string path, LockFileTargetLibrary targetLibrary)
+        public ProjectDescription GetDescription(string path, LockFileTargetLibrary targetLibrary)
         {
             Project project;
 
@@ -22,7 +22,7 @@ public ProjectDescription GetDescription(FrameworkName targetFramework, string p
                 return null;
             }
 
-            return GetDescription(targetFramework, project);
+            return GetDescription(targetLibrary.TargetFramework, project);
         }
 
         public ProjectDescription GetDescription(FrameworkName targetFramework, Project project)
@@ -31,7 +31,7 @@ public ProjectDescription GetDescription(FrameworkName targetFramework, Project
             var targetFrameworkInfo = project.GetTargetFramework(targetFramework);
             var targetFrameworkDependencies = new List<LibraryDependency>(targetFrameworkInfo.Dependencies);
 
-            if (VersionUtility.IsDesktop(targetFramework))
+            if (targetFramework != null && VersionUtility.IsDesktop(targetFramework))
             {
                 targetFrameworkDependencies.Add(new LibraryDependency
                 {
@@ -71,8 +71,7 @@ public ProjectDescription GetDescription(FrameworkName targetFramework, Project
 
             // Mark the library as unresolved if there were specified frameworks
             // and none of them resolved
-            bool unresolved = targetFrameworkInfo.FrameworkName == null &&
-                              project.GetTargetFrameworks().Any();
+            bool unresolved = targetFrameworkInfo.FrameworkName == null;
 
             return new ProjectDescription(
                 new LibraryRange(project.Name, frameworkReference: false),

src/Microsoft.Dnx.Runtime/Project.cs

@@ -169,19 +169,12 @@ public ICompilerOptions GetCompilerOptions(FrameworkName targetFramework,
 
         public TargetFrameworkInformation GetTargetFramework(FrameworkName targetFramework)
         {
-            TargetFrameworkInformation targetFrameworkInfo;
-            if (_targetFrameworks.TryGetValue(targetFramework, out targetFrameworkInfo))
+            TargetFrameworkInformation targetFrameworkInfo = null;
+            if (targetFramework != null && _targetFrameworks.TryGetValue(targetFramework, out targetFrameworkInfo))
             {
                 return targetFrameworkInfo;
             }
 
-            IEnumerable<TargetFrameworkInformation> compatibleConfigurations;
-            if (VersionUtility.GetNearest(targetFramework, GetTargetFrameworks(), out compatibleConfigurations) &&
-                compatibleConfigurations.Any())
-            {
-                targetFrameworkInfo = compatibleConfigurations.FirstOrDefault();
-            }
-
             return targetFrameworkInfo ?? _defaultTargetFrameworkConfiguration;
         }
 

src/Microsoft.Dnx.Tooling/ProjectExtensions.cs

@@ -0,0 +1,27 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Runtime.Versioning;
+using Microsoft.Dnx.Runtime;
+using NuGet;
+
+namespace Microsoft.Dnx.Tooling
+{
+    public static class ProjectExtensions
+    {
+        public static TargetFrameworkInformation GetCompatibleTargetFramework(this Runtime.Project project, FrameworkName targetFramework)
+        {
+            IEnumerable<TargetFrameworkInformation> targets;
+            if (VersionUtility.GetNearest(targetFramework, project.GetTargetFrameworks(), out targets) &&
+                targets.Any())
+            {
+                return targets.FirstOrDefault();
+            }
+
+            return new TargetFrameworkInformation
+            {
+                Dependencies = new List<LibraryDependency>()
+            };
+        }
+    }
+}

src/Microsoft.Dnx.Tooling/Restore/ProjectReferenceDependencyProvider.cs

@@ -42,7 +42,7 @@ public LibraryDescription GetDescription(LibraryRange libraryRange, FrameworkNam
             }
 
             // This never returns null
-            var targetFrameworkInfo = project.GetTargetFramework(targetFramework);
+            var targetFrameworkInfo = project.GetCompatibleTargetFramework(targetFramework);
 
             var dependencies = project.Dependencies.Concat(targetFrameworkInfo.Dependencies).ToList();
 

src/Microsoft.Dnx.Tooling/Utils/LockFileUtils.cs

@@ -83,7 +83,7 @@ public static LockFileProjectLibrary CreateLockFileProjectLibrary(Runtime.Projec
         public static LockFileTargetLibrary CreateLockFileTargetLibrary(Runtime.Project projectDependency,
                                                                         RestoreContext context)
         {
-            var targetFrameworkInfo = projectDependency.GetTargetFramework(context.FrameworkName);
+            var targetFrameworkInfo = projectDependency.GetCompatibleTargetFramework(context.FrameworkName);
 
             var lockFileLib = new LockFileTargetLibrary
             {

test/Microsoft.Dnx.ApplicationHost.FunctionalTests/AppHostTests.cs

@@ -112,7 +112,14 @@ public void AppHostShowsErrorWhenGivenSubcommandWasNotFoundInProjectJson(string
 
             using (var projectPath = TestUtils.CreateTempDir())
             {
-                DirTree.CreateFromJson(projectStructure).WriteTo(projectPath);
+                DirTree.CreateFromJson(projectStructure)
+                       .WithFileContents("project.json", @"
+{
+    ""frameworks"": {
+        ""dnx451"": { },
+        ""dnxcore50"": { }
+    }
+}").WriteTo(projectPath);
 
                 string stdOut, stdErr;
                 var exitCode = TestUtils.ExecBootstrapper(

test/Microsoft.Dnx.Tooling.FunctionalTests/DnuPackTests.cs

@@ -287,6 +287,10 @@ public void DnuPack_DoesNotExecutePostBuildScriptWhenBuildFails(string flavor, s
         {
             var runtimeHomeDir = TestUtils.GetRuntimeHomeDir(flavor, os, architecture);
             var projectJson = @"{
+  ""frameworks"": {
+      ""dnx451"": { },
+      ""dnxcore50"": { }
+  },
   ""scripts"": {
     ""postbuild"": ""echo POST_BUILD_SCRIPT_OUTPUT"",
     ""postpack"": ""echo POST_PACK_SCRIPT_OUTPUT""

test/Microsoft.Dnx.Tooling.FunctionalTests/PackageManagerFunctionalTestFixture.cs

@@ -60,7 +60,12 @@ private void CreateNewPackage(string name, string version)
                 var outputDir = dir.CreateSubdirectory("output");
                 var projectJson = Path.Combine(projectDir.FullName, "project.json");
 
-                File.WriteAllText(projectJson, "{\"version\": \"" + version + "\"}");
+                File.WriteAllText(projectJson, $@"{{
+  ""version"": ""{version}"",
+  ""frameworks"": {{ 
+      ""dnx451"": {{ }}
+  }}
+}}");
                 DnuTestUtils.ExecDnu(runtimeHomePath, "restore", projectJson);
                 DnuTestUtils.ExecDnu(runtimeHomePath, "pack", projectJson + " --out " + outputDir.FullName, environment: null, workingDir: null);