Implement package auto-restore for .csproj projects

src/OmniSharp.Abstractions/Services/DotNetCliService.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Concurrent;
+using System.Collections.Generic;
 using System.Composition;
+using System.IO;
 using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Logging;
@@ -25,39 +27,50 @@ public DotNetCliService(ILoggerFactory loggerFactory, IEventEmitter eventEmitter
             this._semaphore = new SemaphoreSlim(Environment.ProcessorCount / 2);
         }
 
-        public void Restore(string projectPath, Action onFailure)
+        private static void RemoveMSBuildEnvironmentVariables(IDictionary<string, string> environment)
         {
+            // Remove various MSBuild environment variables set by OmniSharp to ensure that
+            // the .NET CLI is not launched with the wrong values.
+            environment.Remove("MSBUILD_EXE_PATH");
+            environment.Remove("MSBuildExtensionsPath");
+            environment.Remove("MSBuildSDKsPath");
+        }
+
+        public void Restore(string projectFilePath, Action onFailure = null)
+        {
+            var projectDirectory = Path.GetDirectoryName(projectFilePath);
+
             Task.Factory.StartNew(() =>
             {
-                _logger.LogInformation($"Begin restoring project {projectPath}");
+                _logger.LogInformation($"Begin restoring project {projectFilePath}");
 
-                var restoreLock = _locks.GetOrAdd(projectPath, new object());
+                var restoreLock = _locks.GetOrAdd(projectFilePath, new object());
                 lock (restoreLock)
                 {
                     var exitStatus = new ProcessExitStatus(-1);
-                    _eventEmitter.RestoreStarted(projectPath);
+                    _eventEmitter.RestoreStarted(projectFilePath);
                     _semaphore.Wait();
                     try
                     {
                         // A successful restore will update the project lock file which is monitored
                         // by the dotnet project system which eventually update the Roslyn model
-                        exitStatus = ProcessHelper.Run("dotnet", "restore", projectPath);
+                        exitStatus = ProcessHelper.Run("dotnet", "restore", projectDirectory, updateEnvironment: RemoveMSBuildEnvironmentVariables);
                     }
                     finally
                     {
                         _semaphore.Release();
 
                         object removedLock;
-                        _locks.TryRemove(projectPath, out removedLock);
+                        _locks.TryRemove(projectFilePath, out removedLock);
 
-                        _eventEmitter.RestoreFinished(projectPath, exitStatus.Succeeded);
+                        _eventEmitter.RestoreFinished(projectFilePath, exitStatus.Succeeded);
 
-                        if (exitStatus.Failed)
+                        if (exitStatus.Failed && onFailure != null)
                         {
                             onFailure();
                         }
 
-                        _logger.LogInformation($"Finish restoring project {projectPath}. Exit code {exitStatus}");
+                        _logger.LogInformation($"Finish restoring project {projectFilePath}. Exit code {exitStatus}");
                     }
                 }
             });

src/OmniSharp.Abstractions/Utilities/ProcessExitStatus.cs

@@ -17,5 +17,20 @@ public ProcessExitStatus(int code, bool started = true, bool timedOut = false)
             this.Started = started;
             this.TimedOut = timedOut;
         }
+
+        public override string ToString()
+        {
+            var suffix = string.Empty;
+            if (!Started)
+            {
+                suffix = " (not started)";
+            }
+            else if (TimedOut)
+            {
+                suffix = " (timed out)";
+            }
+
+            return Code.ToString() + suffix;
+        }
     }
 }

src/OmniSharp.Abstractions/Utilities/ProcessHelper.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Threading.Tasks;
 
@@ -41,17 +42,20 @@ public static ProcessExitStatus Run(
             string arguments,
             string workingDirectory = null,
             Action<string> outputDataReceived = null,
-            Action<string> errorDataReceived = null)
+            Action<string> errorDataReceived = null,
+            Action<IDictionary<string, string>> updateEnvironment = null)
         {
             var startInfo = new ProcessStartInfo(fileName, arguments)
             {
-                RedirectStandardOutput = outputDataReceived != null,
-                RedirectStandardError = errorDataReceived != null,
+                RedirectStandardOutput = true,
+                RedirectStandardError = true,
                 CreateNoWindow = true,
                 UseShellExecute = false,
                 WorkingDirectory = workingDirectory ?? string.Empty,
             };
 
+            updateEnvironment(startInfo.Environment);
+
             var process = new Process();
             process.StartInfo = startInfo;
 

src/OmniSharp.DotNet/DotNetProjectSystem.cs

@@ -296,7 +296,7 @@ private void UpdateUnresolvedDependencies(ProjectState state, bool allowRestore)
             {
                 if (allowRestore && _enableRestorePackages)
                 {
-                    _dotNetCliService.Restore(state.ProjectContext.ProjectDirectory, onFailure: () =>
+                    _dotNetCliService.Restore(state.ProjectContext.ProjectFile.ProjectFilePath, onFailure: () =>
                     {
                         _eventEmitter.Emit(EventTypes.UnresolvedDependencies, new UnresolvedDependenciesMessage()
                         {

src/OmniSharp.MSBuild/MSBuildEnvironment.cs

@@ -6,6 +6,10 @@ namespace OmniSharp.MSBuild
 {
     public static class MSBuildEnvironment
     {
+        public const string MSBuildExePathName = "MSBUILD_EXE_PATH";
+        public const string MSBuildExtensionsPathName = "MSBuildExtensionsPath";
+        public const string MSBuildSDKsPathName = "MSBuildSDKsPath";
+
         private static bool s_isInitialized;
         private static string s_msbuildFolder;
         private static string s_msbuildExtensionsPath;
@@ -77,24 +81,24 @@ public static void Initialize(ILogger logger)
                 return;
             }
 
-            Environment.SetEnvironmentVariable("MSBUILD_EXE_PATH", msbuildExePath);
-            logger.LogInformation($"MSBUILD_EXE_PATH environment variable set to {msbuildExePath}");
+            Environment.SetEnvironmentVariable(MSBuildExePathName, msbuildExePath);
+            logger.LogInformation($"{MSBuildExePathName} environment variable set to {msbuildExePath}");
 
             // Set the MSBuildExtensionsPath environment variable to the msbuild folder.
-            Environment.SetEnvironmentVariable("MSBuildExtensionsPath", msbuildFolder);
-            logger.LogInformation($"MSBuildExtensionsPath environment variable set to {msbuildFolder}");
+            Environment.SetEnvironmentVariable(MSBuildExtensionsPathName, msbuildFolder);
+            logger.LogInformation($"{MSBuildExtensionsPathName} environment variable set to {msbuildFolder}");
 
             // Set the MSBuildSDKsPath environment variable to the location of the SDKs.
             var msbuildSdksFolder = Path.Combine(msbuildFolder, "Sdks");
             if (Directory.Exists(msbuildSdksFolder))
             {
                 s_msbuildSDKsPath = msbuildSdksFolder;
-                Environment.SetEnvironmentVariable("MSBuildSDKsPath", msbuildSdksFolder);
-                logger.LogInformation($"MSBuildSDKsPath environment variable set to {msbuildSdksFolder}");
+                Environment.SetEnvironmentVariable(MSBuildSDKsPathName, msbuildSdksFolder);
+                logger.LogInformation($"{MSBuildSDKsPathName} environment variable set to {msbuildSdksFolder}");
             }
             else
             {
-                logger.LogError("Could not locate MSBuild Sdks path to set MSBuildSDKsPath");
+                logger.LogError($"Could not locate MSBuild Sdks path to set {MSBuildSDKsPathName}");
             }
 
             s_msbuildFolder = msbuildFolder;

src/OmniSharp.MSBuild/MSBuildProjectSystem.cs

@@ -11,6 +11,7 @@
 using Microsoft.CodeAnalysis.MSBuild;
 using Microsoft.Extensions.Configuration;
 using Microsoft.Extensions.Logging;
+using NuGet.ProjectModel;
 using OmniSharp.Models;
 using OmniSharp.Models.v1;
 using OmniSharp.MSBuild.ProjectFile;
@@ -25,6 +26,7 @@ public class MSBuildProjectSystem : IProjectSystem
     {
         private readonly IOmniSharpEnvironment _environment;
         private readonly OmniSharpWorkspace _workspace;
+        private readonly DotNetCliService _dotNetCliService;
         private readonly IMetadataFileReferenceCache _metadataFileReferenceCache;
         private readonly IEventEmitter _eventEmitter;
         private readonly IFileSystemWatcher _fileSystemWatcher;
@@ -52,13 +54,15 @@ public class MSBuildProjectSystem : IProjectSystem
         public MSBuildProjectSystem(
             IOmniSharpEnvironment environment,
             OmniSharpWorkspace workspace,
+            DotNetCliService dotNetCliService,
             IMetadataFileReferenceCache metadataFileReferenceCache,
             IEventEmitter eventEmitter,
             IFileSystemWatcher fileSystemWatcher,
             ILoggerFactory loggerFactory)
         {
             _environment = environment;
             _workspace = workspace;
+            _dotNetCliService = dotNetCliService;
             _metadataFileReferenceCache = metadataFileReferenceCache;
             _eventEmitter = eventEmitter;
             _fileSystemWatcher = fileSystemWatcher;
@@ -88,22 +92,26 @@ public void Initalize(IConfiguration configuration)
 
             foreach (var projectFileInfo in _projects)
             {
-                UpdateProject(projectFileInfo);
+                var projectFilePath = projectFileInfo.ProjectFilePath;
+                var projectAssetsFile = projectFileInfo.ProjectAssetsFile;
 
                 // TODO: This needs some improvement. Currently, it tracks both deletions and changes
                 // as "updates". We should properly remove projects that are deleted.
-                _fileSystemWatcher.Watch(projectFileInfo.ProjectFilePath, file =>
+                _fileSystemWatcher.Watch(projectFilePath, file =>
                 {
-                    OnProjectChanged(projectFileInfo.ProjectFilePath);
+                    OnProjectChanged(projectFilePath, allowAutoRestore: true);
                 });
 
-                if (!string.IsNullOrEmpty(projectFileInfo.ProjectAssetsFile))
+                if (!string.IsNullOrEmpty(projectAssetsFile))
                 {
-                    _fileSystemWatcher.Watch(projectFileInfo.ProjectAssetsFile, file =>
+                    _fileSystemWatcher.Watch(projectAssetsFile, file =>
                     {
-                        OnProjectChanged(projectFileInfo.ProjectFilePath);
+                        OnProjectChanged(projectFilePath, allowAutoRestore: false);
                     });
                 }
+
+                UpdateProject(projectFileInfo);
+                CheckForUnresolvedDependences(projectFileInfo, allowAutoRestore: true);
             }
         }
 
@@ -319,11 +327,10 @@ private ProjectFileInfo CreateProjectFileInfo(string projectFilePath, bool isUni
             return projectFileInfo;
         }
 
-        private void OnProjectChanged(string projectFilePath)
+        private void OnProjectChanged(string projectFilePath, bool allowAutoRestore)
         {
             var newProjectFileInfo = CreateProjectFileInfo(projectFilePath);
 
-            // TODO: Should we remove the entry if the project is malformed?
             if (newProjectFileInfo != null)
             {
                 lock (_gate)
@@ -333,7 +340,9 @@ private void OnProjectChanged(string projectFilePath)
                     {
                         _projects[projectFilePath] = newProjectFileInfo;
                         newProjectFileInfo.SetProjectId(oldProjectFileInfo.ProjectId);
+
                         UpdateProject(newProjectFileInfo);
+                        CheckForUnresolvedDependences(newProjectFileInfo, oldProjectFileInfo, allowAutoRestore);
                     }
                 }
             }
@@ -483,6 +492,104 @@ private void UpdateReferences(Project project, IList<string> references)
             }
         }
 
+        private List<PackageDependency> CreatePackageDependencies(IEnumerable<PackageReference> packageReferences)
+        {
+            var list = new List<PackageDependency>();
+
+            foreach (var packageReference in packageReferences)
+            {
+                var dependency = new PackageDependency
+                {
+                    Name = packageReference.Identity.Id,
+                    Version = packageReference.Identity.Version?.ToNormalizedString()
+                };
+
+                list.Add(dependency);
+            }
+
+            return list;
+        }
+
+        private void CheckForUnresolvedDependences(ProjectFileInfo projectFileInfo, ProjectFileInfo previousProjectFileInfo = null, bool allowAutoRestore = false)
+        {
+            List<PackageDependency> unresolvedDependencies;
+
+            if (!File.Exists(projectFileInfo.ProjectAssetsFile))
+            {
+                // Simplest case: If there's no lock file and the project file has package references,
+                // there are certainly unresolved dependencies.
+                unresolvedDependencies = CreatePackageDependencies(projectFileInfo.PackageReferences);
+            }
+            else
+            {
+                // Note: This is a bit of misnmomer. It's entirely possible that a package reference has been removed
+                // and a restore needs to happen in order to update project.assets.json file. Otherwise, the MSBuild targets
+                // will still resolve the removed reference as a reference in the user's project. In that case, the package
+                // reference isn't so much "unresolved" as "incorrectly resolved".
+                IEnumerable<PackageReference> unresolvedPackageReferences;
+
+                // Did the project file change? Diff the package references and see if there are unresolved dependencies.
+                if (previousProjectFileInfo != null)
+                {
+                    var packageReferencesToRemove = new HashSet<PackageReference>(previousProjectFileInfo.PackageReferences);
+                    var packageReferencesToAdd = new HashSet<PackageReference>();
+
+                    foreach (var packageReference in projectFileInfo.PackageReferences)
+                    {
+                        if (packageReferencesToRemove.Contains(packageReference))
+                        {
+                            packageReferencesToRemove.Remove(packageReference);
+                        }
+                        else
+                        {
+                            packageReferencesToAdd.Add(packageReference);
+                        }
+                    }
+
+                    unresolvedPackageReferences = packageReferencesToAdd.Concat(packageReferencesToRemove);
+                }
+                else
+                {
+                    // Finally, if the project.assets.json file exists but there's no old project to compare against,
+                    // we'll just check to ensure that all of the project's package references can be found in the
+                    // current project.assets.json file.
+
+                    var lockFileFormat = new LockFileFormat();
+                    var lockFile = lockFileFormat.Read(projectFileInfo.ProjectAssetsFile);
+
+                    unresolvedPackageReferences = projectFileInfo.PackageReferences
+                        .Where(pr => lockFile.GetLibrary(pr.Identity.Id, pr.Identity.Version) == null);
+                }
+
+                unresolvedDependencies = CreatePackageDependencies(unresolvedPackageReferences);
+            }
+
+            if (unresolvedDependencies.Count > 0)
+            {
+                if (allowAutoRestore && _options.EnablePackageAutoRestore)
+                {
+                    _dotNetCliService.Restore(projectFileInfo.ProjectFilePath, onFailure: () =>
+                    {
+                        FireUnresolvedDependenciesEvent(projectFileInfo, unresolvedDependencies);
+                    });
+                }
+                else
+                {
+                    FireUnresolvedDependenciesEvent(projectFileInfo, unresolvedDependencies);
+                }
+            }
+        }
+
+        private void FireUnresolvedDependenciesEvent(ProjectFileInfo projectFileInfo, List<PackageDependency> unresolvedDependencies)
+        {
+            _eventEmitter.Emit(EventTypes.UnresolvedDependencies,
+                new UnresolvedDependenciesMessage()
+                {
+                    FileName = projectFileInfo.ProjectFilePath,
+                    UnresolvedDependencies = unresolvedDependencies
+                });
+        }
+
         private ProjectFileInfo GetProjectFileInfo(string path)
         {
             ProjectFileInfo projectFileInfo;