Migrate P2P references

- Given a project migrate all the project references recursively.
- Add a boolean option '--skip-project-references' to skip migrating P2P references. By default P2P references are migrated.
- Remove the '--output' since it is not used heavily and makes migrating multiple projects easier.
- Add tests

TestAssets/TestProjects/TestAppDependencyGraph/ProjectA/Program.cs

@@ -0,0 +1,17 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using System.Diagnostics;
+
+namespace TestApp
+{
+    public class Program
+    {
+        public static int Main(string[] args)
+        {
+            Console.WriteLine("This string came from ProjectA");
+            return 100;
+        }
+    }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectA/project.json

@@ -0,0 +1,34 @@
+{
+  "version": "1.0.0-*",
+  "buildOptions": {
+    "emitEntryPoint": true,
+    "preserveCompilationContext": true
+  },
+  "dependencies": {
+    "ProjectB": {
+      "target": "project",
+      "version": "1.0.0-*"
+    },
+    "ProjectC": {
+      "target": "project",
+      "version": "1.0.0-*"
+    },
+    "Microsoft.NETCore.App": "1.0.1"
+  },
+  "frameworks": {
+    "netcoreapp1.0": {}
+  },
+  "runtimes": {
+    "win7-x64": {},
+    "win7-x86": {},
+    "osx.10.10-x64": {},
+    "osx.10.11-x64": {},
+    "ubuntu.14.04-x64": {},
+    "ubuntu.16.04-x64": {},
+    "centos.7-x64": {},
+    "rhel.7.2-x64": {},
+    "debian.8-x64": {},
+    "fedora.23-x64": {},
+    "opensuse.13.2-x64": {}
+  }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectB/Helper.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+
+namespace TestLibrary
+{
+    public static class ProjectB
+    {
+        public static string GetMessage()
+        {
+            return "This string came from ProjectB";
+        }
+    }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectB/project.json

@@ -0,0 +1,26 @@
+{
+  "version": "1.0.0-*",
+  "buildOptions": {
+    "nowarn": [
+      "CS1591"
+    ],
+    "xmlDoc": true,
+    "additionalArguments": [
+      "-highentropyva+"
+    ]
+  },
+  "dependencies": {
+    "ProjectC": {
+      "target": "project",
+      "version": "1.0.0-*"
+    },
+    "ProjectD": {
+      "target": "project",
+      "version": "1.0.0-*"
+    },
+    "NETStandard.Library": "1.6.0"
+  },
+  "frameworks": {
+    "netstandard1.5": {}
+  }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectC/Helper.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+
+namespace TestLibrary
+{
+    public static class ProjectC
+    {
+        public static string GetMessage()
+        {
+            return "This string came from ProjectC";
+        }
+    }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectC/project.json

@@ -0,0 +1,26 @@
+{
+  "version": "1.0.0-*",
+  "buildOptions": {
+    "nowarn": [
+      "CS1591"
+    ],
+    "xmlDoc": true,
+    "additionalArguments": [
+      "-highentropyva+"
+    ]
+  },
+  "dependencies": {
+    "ProjectD": {
+      "target": "project",
+      "version": "1.0.0-*"
+    },
+    "ProjectE": {
+      "target": "project",
+      "version": "1.0.0-*"
+    },
+    "NETStandard.Library": "1.6.0"
+  },
+  "frameworks": {
+    "netstandard1.5": {}
+  }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectD/Helper.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+
+namespace TestLibrary
+{
+    public static class ProjectD
+    {
+        public static string GetMessage()
+        {
+            return "This string came from ProjectD";
+        }
+    }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectD/project.json

@@ -0,0 +1,18 @@
+{
+  "version": "1.0.0-*",
+  "buildOptions": {
+    "nowarn": [
+      "CS1591"
+    ],
+    "xmlDoc": true,
+    "additionalArguments": [
+      "-highentropyva+"
+    ]
+  },
+  "dependencies": {
+    "NETStandard.Library": "1.6.0"
+  },
+  "frameworks": {
+    "netstandard1.5": {}
+  }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectE/Helper.cs

@@ -0,0 +1,15 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+
+namespace TestLibrary
+{
+    public static class ProjectE
+    {
+        public static string GetMessage()
+        {
+            return "This string came from ProjectE";
+        }
+    }
+}

TestAssets/TestProjects/TestAppDependencyGraph/ProjectE/project.json

@@ -0,0 +1,18 @@
+{
+  "version": "1.0.0-*",
+  "buildOptions": {
+    "nowarn": [
+      "CS1591"
+    ],
+    "xmlDoc": true,
+    "additionalArguments": [
+      "-highentropyva+"
+    ]
+  },
+  "dependencies": {
+    "NETStandard.Library": "1.6.0"
+  },
+  "frameworks": {
+    "netstandard1.5": {}
+  }
+}

src/Microsoft.DotNet.ProjectJsonMigration/ProjectDependencyComparer.cs

@@ -0,0 +1,23 @@
+// Copyright (c) .NET Foundation and contributors. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+using System;
+using  System.Collections.Generic;
+
+namespace Microsoft.DotNet.ProjectJsonMigration
+{
+    public class ProjectDependencyComparer : IEqualityComparer<ProjectDependency>
+    {
+        public bool Equals(ProjectDependency one, ProjectDependency two)
+        {
+                return StringComparer.OrdinalIgnoreCase
+                                    .Equals(one.ProjectFilePath, two.ProjectFilePath);
+        }
+
+        public int GetHashCode(ProjectDependency item)
+        {
+                return StringComparer.OrdinalIgnoreCase
+                                    .GetHashCode(item.ProjectFilePath);
+        }
+    }
+}

src/Microsoft.DotNet.ProjectJsonMigration/ProjectDependencyFinder.cs

@@ -14,6 +14,17 @@ namespace Microsoft.DotNet.ProjectJsonMigration
 {
     public class ProjectDependencyFinder 
     {
+        public IEnumerable<ProjectDependency> ResolveProjectDependencies(IEnumerable<ProjectContext> projectContexts)
+        {
+            foreach(var projectContext in projectContexts)
+            {
+                foreach(var projectDependency in ResolveProjectDependencies(projectContext))
+                {
+                    yield return projectDependency;
+                }
+            }
+        }
+
         public IEnumerable<ProjectDependency> ResolveProjectDependencies(ProjectContext projectContext, HashSet<string> preResolvedProjects=null)
         {
             preResolvedProjects = preResolvedProjects ?? new HashSet<string>();
@@ -54,6 +65,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration
 
             var projectSearchPaths = new List<string>();
             projectSearchPaths.Add(projectDirectory);
+            projectSearchPaths.Add(Path.GetDirectoryName(projectDirectory));
 
             var globalPaths = GetGlobalPaths(projectDirectory);
             projectSearchPaths = projectSearchPaths.Union(globalPaths).ToList();

src/Microsoft.DotNet.ProjectJsonMigration/ProjectMigrator.cs

@@ -5,6 +5,8 @@ using System;
 using System.Collections.Generic;
 using Microsoft.Build.Construction;
 using Microsoft.DotNet.ProjectModel;
+using Microsoft.DotNet.ProjectModel.Graph;
+using Microsoft.DotNet.Cli;
 using System.Linq;
 using System.IO;
 using Microsoft.DotNet.ProjectJsonMigration.Rules;
@@ -22,6 +24,7 @@ namespace Microsoft.DotNet.ProjectJsonMigration
         //     - Migrating Deprecated project.jsons
 
         private readonly IMigrationRule _ruleSet;
+        private readonly ProjectDependencyFinder _projectDependencyFinder = new ProjectDependencyFinder();
 
         public ProjectMigrator() : this(new DefaultMigrationRuleSet()) { }
 
@@ -30,9 +33,73 @@ namespace Microsoft.DotNet.ProjectJsonMigration
             _ruleSet = ruleSet;
         }
 
-        public void Migrate(MigrationSettings migrationSettings)
+        public void Migrate(MigrationSettings rootSettings, bool skipProjectReferences = false)
+        {
+            if (rootSettings == null)
+            {
+                throw new ArgumentNullException();
+            }
+
+            MigrateHelper(rootSettings);
+
+            if (skipProjectReferences)
+            {
+                return;
+            }
+
+            var projectDependencies = ResolveTransitiveClosureProjectDependencies(rootSettings.ProjectDirectory);
+
+            foreach(var project in projectDependencies)
+            {
+                var projectDir = Path.GetDirectoryName(project.ProjectFilePath);
+                var settings = new MigrationSettings(projectDir,
+                                                     projectDir,
+                                                     rootSettings.SdkPackageVersion,
+                                                     rootSettings.MSBuildProjectTemplate);
+                MigrateHelper(settings);
+            }
+        }
+
+        private IEnumerable<ProjectDependency> ResolveTransitiveClosureProjectDependencies(string rootProject)
+        {
+            HashSet<ProjectDependency> projectsMap = new HashSet<ProjectDependency>(new ProjectDependencyComparer());
+            var projectContexts = ProjectContext.CreateContextForEachFramework(rootProject);
+            var projectDependencies = _projectDependencyFinder.ResolveProjectDependencies(projectContexts);
+            Queue<ProjectDependency> projectsQueue = new Queue<ProjectDependency>(projectDependencies);
+
+            while(projectsQueue.Count() != 0)
+            {
+                var projectDependency = projectsQueue.Dequeue();
+
+                if (projectsMap.Contains(projectDependency))
+                {
+                    continue;
+                }
+
+                projectsMap.Add(projectDependency);
+
+                projectContexts = ProjectContext.CreateContextForEachFramework(projectDependency.ProjectFilePath);
+                projectDependencies = _projectDependencyFinder.ResolveProjectDependencies(projectContexts);
+
+                foreach(var project in projectDependencies)
+                {
+                    projectsQueue.Enqueue(project);
+                }
+            }
+
+            return projectsMap;
+        }
+
+        private void MigrateHelper(MigrationSettings migrationSettings)
         {
             var migrationRuleInputs = ComputeMigrationRuleInputs(migrationSettings);
+
+            if (IsMigrated(migrationSettings, migrationRuleInputs))
+            {
+                // TODO : Adding user-visible logging
+                return;
+            }
+
             VerifyInputs(migrationRuleInputs, migrationSettings);
 
             SetupOutputDirectory(migrationSettings.ProjectDirectory, migrationSettings.OutputDirectory);
@@ -146,5 +213,14 @@ namespace Microsoft.DotNet.ProjectJsonMigration
             }
         }
 
+        public bool IsMigrated(MigrationSettings migrationSettings, MigrationRuleInputs migrationRuleInputs)
+        {
+            var outputName = Path.GetFileNameWithoutExtension(
+                migrationRuleInputs.DefaultProjectContext.GetOutputPaths("_").CompilationFiles.Assembly);
+
+            var outputProject = Path.Combine(migrationSettings.OutputDirectory, outputName + ".csproj");
+            return File.Exists(outputProject);
+        }
+
     }
 }

src/dotnet/commands/dotnet-migrate/MigrateCommand.cs

@@ -13,21 +13,20 @@ namespace Microsoft.DotNet.Tools.Migrate
     public partial class MigrateCommand
     {
         private readonly string _templateFile;
-        private readonly string _outputDirectory;
         private readonly string _projectJson;
         private readonly string _sdkVersion;
         private readonly string _xprojFilePath;
+        private readonly bool _skipProjectReferences;
 
         private readonly TemporaryDotnetNewTemplateProject _temporaryDotnetNewProject;
 
-        public MigrateCommand(string templateFile, string outputDirectory, string projectJson, string sdkVersion, string xprojFilePath)
+        public MigrateCommand(string templateFile, string projectJson, string sdkVersion, string xprojFilePath, bool skipProjectReferences)
         {
             _templateFile = templateFile;
-            _outputDirectory = outputDirectory;
             _projectJson = projectJson;
             _sdkVersion = sdkVersion;
             _xprojFilePath = xprojFilePath;
-
+            _skipProjectReferences = skipProjectReferences;
             _temporaryDotnetNewProject = new TemporaryDotnetNewTemplateProject();
         }
 
@@ -40,14 +39,13 @@ namespace Microsoft.DotNet.Tools.Migrate
             var msBuildTemplate = _templateFile != null ?
                 ProjectRootElement.TryOpen(_templateFile) : _temporaryDotnetNewProject.MSBuildProject;
 
-            var outputDirectory = _outputDirectory ?? projectDirectory;
-            EnsureNotNull(outputDirectory, "Null output directory");
+            var outputDirectory = projectDirectory;
 
             var sdkVersion = _sdkVersion ?? new ProjectJsonParser(_temporaryDotnetNewProject.ProjectJson).SdkPackageVersion;
             EnsureNotNull(sdkVersion, "Null Sdk Version");
 
             var migrationSettings = new MigrationSettings(projectDirectory, outputDirectory, sdkVersion, msBuildTemplate, _xprojFilePath);
-            new ProjectMigrator().Migrate(migrationSettings);
+            new ProjectMigrator().Migrate(migrationSettings, _skipProjectReferences);
 
             return 0;
         }

src/dotnet/commands/dotnet-migrate/Program.cs

@@ -21,19 +21,19 @@ namespace Microsoft.DotNet.Tools.Migrate
             app.HelpOption("-h|--help");
 
             CommandOption template = app.Option("-t|--template-file", "Base MSBuild template to use for migrated app. The default is the project included in dotnet new -t msbuild", CommandOptionType.SingleValue);
-            CommandOption output = app.Option("-o|--output", "Directory to output migrated project to. The default is the project directory", CommandOptionType.SingleValue);
             CommandOption project = app.Option("-p|--project", "The path to the project to run (defaults to the current directory). Can be a path to a project.json or a project directory", CommandOptionType.SingleValue);
             CommandOption sdkVersion = app.Option("-v|--sdk-package-version", "The version of the sdk package that will be referenced in the migrated app. The default is the version of the sdk in dotnet new -t msbuild", CommandOptionType.SingleValue);
             CommandOption xprojFile = app.Option("-x|--xproj-file", "The path to the xproj file to use. Required when there is more than one xproj in a project directory.", CommandOptionType.SingleValue);
+            CommandOption skipProjectReferences = app.Option("-s|--skip-project-references", "Skip migrating project references. By default project references are migrated recursively", CommandOptionType.BoolValue);
 
             app.OnExecute(() =>
             {
                 MigrateCommand migrateCommand = new MigrateCommand(
-                    template.Value(), 
-                    output.Value(), 
+                    template.Value(),
                     project.Value(), 
                     sdkVersion.Value(),
-                    xprojFile.Value());
+                    xprojFile.Value(),
+                    skipProjectReferences.BoolValue.HasValue ? skipProjectReferences.BoolValue.Value : false);
 
                 return migrateCommand.Execute();
             });

test/dotnet-migrate.Tests/GivenThatIWantToMigrateTestApps.cs

@@ -113,6 +113,48 @@ namespace Microsoft.DotNet.Migration.Tests
             outputsIdentical.Should().BeTrue();
         }
 
+        [Theory]
+        [InlineData("ProjectA", "ProjectA,ProjectB,ProjectC,ProjectD,ProjectE")]
+        [InlineData("ProjectB", "ProjectB,ProjectC,ProjectD,ProjectE")]
+        [InlineData("ProjectC", "ProjectC,ProjectD,ProjectE")]
+        [InlineData("ProjectD", "ProjectD")]
+        [InlineData("ProjectE", "ProjectE")]
+        public void It_migrates_root_project_and_references(string projectName, string expectedProjects)
+        {
+            var projectDirectory =
+                TestAssetsManager.CreateTestInstance("TestAppDependencyGraph", callingMethod: $"{projectName}.RefsTest").Path;
+
+            MigrateProject(Path.Combine(projectDirectory, projectName));
+
+            string[] migratedProjects = expectedProjects.Split(new char[] { ',' });
+            foreach(var migratedProject in migratedProjects)
+            {
+                var dirInfo = new DirectoryInfo(Path.Combine(projectDirectory, migratedProject));
+                var csproj = $"{migratedProject}.csproj";
+                dirInfo.Should().HaveFile(csproj);
+            }
+         }
+
+        [Theory]
+        [InlineData("ProjectA")]
+        [InlineData("ProjectB")]
+        [InlineData("ProjectC")]
+        [InlineData("ProjectD")]
+        [InlineData("ProjectE")]
+        public void It_migrates_root_project_and_skips_references(string projectName)
+        {
+            var projectDirectory =
+                TestAssetsManager.CreateTestInstance("TestAppDependencyGraph", callingMethod: $"{projectName}.SkipRefsTest").Path;
+
+            MigrateCommand.Run(new [] { "-p", Path.Combine(projectDirectory, projectName), "--skip-project-references" }).Should().Be(0);
+
+            var migratedProjects = Directory.EnumerateFiles(projectDirectory, "*.csproj", SearchOption.AllDirectories);
+            migratedProjects.Count().Should().Be(1, "Only the root project must be migrated");
+
+            var migratedProject = Path.GetFileName(migratedProjects.First());
+            migratedProject.Should().Be($"{projectName}.csproj");
+         }
+
         private MigratedBuildComparisonData GetDotnetNewComparisonData(string projectDirectory, string dotnetNewType)
         {
             DotnetNew(projectDirectory, dotnetNewType);