Fix projectmodel-server regression

1. Address the null reference exception when a project dependency is
broken.
2. Address the duplicate key issues after the logic of redirecting
System pacage to reference assembly was added

Update projectmodel-server and tests

1. Fix test timeout caused by undisconnected socket;
2. Update project model server

src/Microsoft.DotNet.ProjectModel/Compilation/LibraryExporter.cs

@@ -156,6 +156,18 @@ namespace Microsoft.DotNet.ProjectModel.Compilation
 
         private LibraryExport ExportProject(ProjectDescription project)
         {
+            if (!project.Resolved)
+            {
+                // For a unresolved project reference returns a export with empty asset.
+                return new LibraryExport(library: project,
+                                         compileAssemblies: Enumerable.Empty<LibraryAsset>(),
+                                         sourceReferences: Enumerable.Empty<string>(),
+                                         nativeLibraries: Enumerable.Empty<LibraryAsset>(),
+                                         runtimeAssets: Enumerable.Empty<string>(),
+                                         runtimeAssemblies: Array.Empty<LibraryAsset>(),
+                                         analyzers: Array.Empty<AnalyzerReference>());
+            }
+
             var compileAssemblies = new List<LibraryAsset>();
             var runtimeAssets = new List<string>();
             var sourceReferences = new List<string>();

src/Microsoft.DotNet.ProjectModel/Graph/LibraryType.cs

@@ -41,7 +41,7 @@ namespace Microsoft.DotNet.ProjectModel.Graph
 
         public override string ToString()
         {
-            return Value;
+            return Value ?? nameof(Unspecified);
         }
 
         public bool CanSatisfyConstraint(LibraryType constraint)

src/Microsoft.DotNet.ProjectModel/ProjectContextBuilder.cs

@@ -267,6 +267,7 @@ namespace Microsoft.DotNet.ProjectModel
                                          ReferenceAssemblyDependencyResolver referenceAssemblyDependencyResolver,
                                          out bool requiresFrameworkAssemblies)
         {
+            // Remark: the LibraryType in the key of the given dictionary are all "Unspecified" at the beginning.
             requiresFrameworkAssemblies = false;
 
             foreach (var pair in libraries.ToList())
@@ -294,41 +295,50 @@ namespace Microsoft.DotNet.ProjectModel
                         // Remove the original package reference
                         libraries.Remove(pair.Key);
 
-                        // Add the reference to the refernce assembly.  
+                        // Insert a reference assembly key if there isn't one
-                        libraries[new LibraryKey(replacement.Identity.Name)] = replacement;
+                        var key = new LibraryKey(replacement.Identity.Name, LibraryType.ReferenceAssembly);
-
+                        if (!libraries.ContainsKey(key))
-                        continue;
+                        {
+                            libraries[key] = replacement;
+                        }
+                    }
                 }
             }
 
+            foreach (var pair in libraries.ToList())
+            {
+                var library = pair.Value;
                 library.Framework = library.Framework ?? TargetFramework;
                 foreach (var dependency in library.Dependencies)
                 {
-                    var keyType = dependency.Target == LibraryType.ReferenceAssembly ? LibraryType.ReferenceAssembly : LibraryType.Unspecified;
+                    var keyType = dependency.Target == LibraryType.ReferenceAssembly ?
+                                  LibraryType.ReferenceAssembly :
+                                  LibraryType.Unspecified;
+
                     var key = new LibraryKey(dependency.Name, keyType);
 
-                    LibraryDescription dep;
+                    LibraryDescription dependencyDescription;
-                    if (!libraries.TryGetValue(key, out dep))
+                    if (!libraries.TryGetValue(key, out dependencyDescription))
                     {
-                        if (Equals(LibraryType.ReferenceAssembly, dependency.Target))
+                        if (keyType == LibraryType.ReferenceAssembly)
                         {
-                            requiresFrameworkAssemblies = true;
+                            // a dependency is specified to be reference assembly but fail to match
-
+                            // then add a unresolved dependency
-                            dep = referenceAssemblyDependencyResolver.GetDescription(dependency, TargetFramework) ??
+                            dependencyDescription = referenceAssemblyDependencyResolver.GetDescription(dependency, TargetFramework) ??
                                                     UnresolvedDependencyProvider.GetDescription(dependency, TargetFramework);
-
+                            libraries[key] = dependencyDescription;
-                            dep.Framework = TargetFramework;
-                            libraries[key] = dep;
                         }
-                        else
+                        else if (!libraries.TryGetValue(new LibraryKey(dependency.Name, LibraryType.ReferenceAssembly), out dependencyDescription))
                         {
-                            dep = UnresolvedDependencyProvider.GetDescription(dependency, TargetFramework);
+                            // a dependency which type is unspecified fails to match, then try to find a 
-                            libraries[key] = dep;
+                            // reference assembly type dependency
+                            dependencyDescription = UnresolvedDependencyProvider.GetDescription(dependency, TargetFramework);
+                            libraries[key] = dependencyDescription;
                         }
                     }
 
-                    dep.RequestedRanges.Add(dependency);
+                    dependencyDescription.RequestedRanges.Add(dependency);
-                    dep.Parents.Add(library);
+                    dependencyDescription.Parents.Add(library);
                 }
             }
         }

src/Microsoft.DotNet.ProjectModel/Resolution/FrameworkReferenceResolver.cs

@@ -63,7 +63,7 @@ namespace Microsoft.DotNet.ProjectModel.Resolution
             if (!RuntimeInformation.IsOSPlatform(OSPlatform.Windows))
             {
                 // There is no reference assemblies path outside of windows
-                // The enviorment variable can be used to specify one
+                // The environment variable can be used to specify one
                 return null;
             }
 

src/dotnet/commands/dotnet-projectmodel-server/InternalModels/ProjectContextSnapshot.cs

@@ -34,7 +34,8 @@ namespace Microsoft.DotNet.ProjectModel.Server
 
             var allExports = context.CreateExporter(configuration)
                                     .GetAllExports()
-                                    .ToDictionary(export => export.Library.GetUniqueName());
+                                    .ToDictionary(export => export.Library.Identity.Name);
+
             var allSourceFiles = new List<string>(context.ProjectFile.Files.SourceFiles);
             var allFileReferences = new List<string>();
             var allProjectReferences = new List<ProjectReferenceDescription>();
@@ -42,10 +43,8 @@ namespace Microsoft.DotNet.ProjectModel.Server
 
             // All exports are returned. When the same library name have a ReferenceAssembly type export and a Package type export
             // both will be listed as dependencies. Prefix "fx/" will be added to ReferenceAssembly type dependency.
-            foreach (var pair in allExports)
+            foreach (var export in allExports.Values)
             {
-                var export = pair.Value;
-
                 allSourceFiles.AddRange(export.SourceReferences);
                 allFileReferences.AddRange(export.CompilationAssemblies.Select(asset => asset.ResolvedPath));
 

src/dotnet/commands/dotnet-projectmodel-server/Models/DependencyDescription.cs

@@ -4,6 +4,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using Microsoft.DotNet.ProjectModel.Compilation;
+using Microsoft.DotNet.ProjectModel.Graph;
 using Microsoft.DotNet.ProjectModel.Server.Helpers;
 
 namespace Microsoft.DotNet.ProjectModel.Server.Models
@@ -54,27 +55,32 @@ namespace Microsoft.DotNet.ProjectModel.Server.Models
 
         public static DependencyDescription Create(LibraryDescription library,
                                                    List<DiagnosticMessage> diagnostics,
-                                                   Dictionary<string, LibraryExport> allExports)
+                                                   IDictionary<string, LibraryExport> exportsLookup)
         {
-            var name = library.GetUniqueName();
             return new DependencyDescription
             {
-                Name = name,
+                Name = library.Identity.Name,
                 DisplayName = library.Identity.Name,
                 Version = library.Identity.Version?.ToNormalizedString(),
                 Type = library.Identity.Type.Value,
                 Resolved = library.Resolved,
                 Path = library.Path,
-                Dependencies = library.Dependencies.Select(dependency => new DependencyItem
+                Dependencies = library.Dependencies.Select(dependency => GetDependencyItem(dependency, exportsLookup)),
-                {
-                    Name = dependency.GetUniqueName(),
-                    Version = allExports[dependency.GetUniqueName()].Library.Identity.Version?.ToNormalizedString()
-                }),
                 Errors = diagnostics.Where(d => d.Severity == DiagnosticMessageSeverity.Error)
                                     .Select(d => new DiagnosticMessageView(d)),
                 Warnings = diagnostics.Where(d => d.Severity == DiagnosticMessageSeverity.Warning)
                                       .Select(d => new DiagnosticMessageView(d))
             };
         }
+
+        private static DependencyItem GetDependencyItem(LibraryRange dependency,
+                                                        IDictionary<string, LibraryExport> exportsLookup)
+        {
+            return new DependencyItem
+            {
+                Name = dependency.Name,
+                Version = exportsLookup[dependency.Name].Library.Identity.Version?.ToNormalizedString()
+            };
+        }
     }
 }

src/dotnet/commands/dotnet-projectmodel-server/ProcessingQueue.cs

@@ -43,7 +43,7 @@ namespace Microsoft.DotNet.ProjectModel.Server
                 catch (IOException ex)
                 {
                     // swallow
-                    _log.LogWarning($"Ignore {nameof(IOException)} during sending message: \"{ex.Message}\".");
+                    _log.LogInformation($"Ignore {nameof(IOException)} during sending message: \"{ex.Message}\".");
                 }
                 catch (Exception ex)
                 {
@@ -79,7 +79,7 @@ namespace Microsoft.DotNet.ProjectModel.Server
             }
             catch (IOException ex)
             {
-                _log.LogWarning($"Ignore {nameof(IOException)} during receiving messages: \"{ex}\".");
+                _log.LogInformation($"Ignore {nameof(IOException)} during receiving messages: \"{ex}\".");
             }
             catch (Exception ex)
             {

test/dotnet-projectmodel-server.Tests/DthTestClient.cs

@@ -9,6 +9,7 @@ using System.Net;
 using System.Net.Sockets;
 using System.Threading;
 using System.Threading.Tasks;
+using Microsoft.Extensions.Logging;
 using Newtonsoft.Json;
 using Xunit;
 
@@ -29,18 +30,19 @@ namespace Microsoft.DotNet.ProjectModel.Server.Tests
         // works in visual studio
         private readonly Dictionary<string, int> _projectContexts = new Dictionary<string, int>();
         private int _nextContextId;
+        private readonly Socket _socket;
 
         public DthTestClient(DthTestServer server)
         {
-            var socket = new Socket(AddressFamily.InterNetwork,
+            _socket = new Socket(AddressFamily.InterNetwork,
                                  SocketType.Stream,
                                  ProtocolType.Tcp);
 
-            socket.Connect(new IPEndPoint(IPAddress.Loopback, server.Port));
+            _socket.Connect(new IPEndPoint(IPAddress.Loopback, server.Port));
 
             _hostId = server.HostId;
 
-            _networkStream = new NetworkStream(socket);
+            _networkStream = new NetworkStream(_socket);
             _reader = new BinaryReader(_networkStream);
             _writer = new BinaryWriter(_networkStream);
 
@@ -221,6 +223,7 @@ namespace Microsoft.DotNet.ProjectModel.Server.Tests
             _writer.Dispose();
             _networkStream.Dispose();
             _readCancellationToken.Cancel();
+            _socket.Shutdown(SocketShutdown.Both);
         }
 
         private void ReadMessage(CancellationToken cancellationToken)

test/dotnet-projectmodel-server.Tests/DthTestServer.cs

@@ -5,13 +5,14 @@ using System;
 using System.Net;
 using System.Net.Sockets;
 using System.Threading;
+using Microsoft.DotNet.ProjectModel.Server;
 using Microsoft.Extensions.Logging;
 
 namespace Microsoft.DotNet.ProjectModel.Server.Tests
 {
     public class DthTestServer : IDisposable
     {
-        private readonly Program _program;
+        private readonly ProjectModelServerCommand _program;
         private readonly Thread _thread;
 
         public DthTestServer(ILoggerFactory loggerFactory)
@@ -21,9 +22,9 @@ namespace Microsoft.DotNet.ProjectModel.Server.Tests
             Port = FindFreePort();
             HostId = Guid.NewGuid().ToString();
 
-            _program = new Program(Port, HostId, LoggerFactory);
+            _program = new ProjectModelServerCommand(Port, HostId, LoggerFactory);
 
-            _thread = new Thread(() => { _program.OpenChannel(); });
+            _thread = new Thread(() => { _program.OpenChannel(); }) { IsBackground = true };
             _thread.Start();
         }
 

test/dotnet-projectmodel-server.Tests/DthTests.cs

@@ -86,7 +86,7 @@ namespace Microsoft.DotNet.ProjectModel.Server.Tests
         [Theory]
         [InlineData("Project", "UnresolvedProjectSample", "EmptyLibrary", "Project")]
         [InlineData("Package", "UnresolvedPackageSample", "NoSuchPackage", null)]
-        [InlineData("Package", "IncompatiblePackageSample", "Newtonsoft.Json", "Package")]
+        [InlineData("Package", "IncompatiblePackageSample", "Microsoft.Web.Administration", "Package")]
         public void DthCompilation_Initialize_UnresolvedDependency(string referenceType,
                                                                    string testProjectName,
                                                                    string expectedUnresolvedDependency,

testapp/DthTestProjects/src/BrokenProjectPathSample/project.json

@@ -1,5 +1,6 @@
 {
     "dependencies": {
+        "NETStandard.Library": "1.0.0-rc2-23728",
         "EmptyLibrary": ""
     },
     "frameworks": {

testapp/DthTestProjects/src/IncompatiblePackageSample/project.json

@@ -1,6 +1,7 @@
 {
     "dependencies": {
-        "Newtonsoft.Json": "4.5.11"
+        "NETStandard.Library": "1.0.0-rc2-23728",
+        "Microsoft.Web.Administration": "7.0.0"
     },
     "frameworks": {
         "dnxcore50": {