From d3d64a4033c3be76b9949e9531f33b0d19a1cd34 Mon Sep 17 00:00:00 2001
From: Bryan Thornbury <brthor@microsoft.com>
Date: Fri, 8 Apr 2016 17:07:29 -0700
Subject: [PATCH] fix the race condition when generating deps.json, and add
 some coverage of this scenario

update reporter to verbose

fix

fix usings for test

update the test
---
 .../ProjectToolsCommandResolver.cs            | 66 ++++++++++++++-----
 .../GivenAProjectToolsCommandResolver.cs      | 36 ++++++++++
 2 files changed, 84 insertions(+), 18 deletions(-)

diff --git a/src/Microsoft.DotNet.Cli.Utils/CommandResolution/ProjectToolsCommandResolver.cs b/src/Microsoft.DotNet.Cli.Utils/CommandResolution/ProjectToolsCommandResolver.cs
index 57ffb8290..49514db98 100644
--- a/src/Microsoft.DotNet.Cli.Utils/CommandResolution/ProjectToolsCommandResolver.cs
+++ b/src/Microsoft.DotNet.Cli.Utils/CommandResolution/ProjectToolsCommandResolver.cs
@@ -190,38 +190,68 @@ namespace Microsoft.DotNet.Cli.Utils
                 depsPathRoot,
                 toolLibrary.Name + FileNameSuffixes.DepsJson);
 
-            EnsureToolJsonDepsFileExists(toolLibrary, toolLockFile, depsJsonPath);
+            EnsureToolJsonDepsFileExists(toolLockFile, depsJsonPath);
 
             return depsJsonPath;
         }
 
         private void EnsureToolJsonDepsFileExists(
-            LibraryRange toolLibrary, 
             LockFile toolLockFile, 
             string depsPath)
         {
             if (!File.Exists(depsPath))
             {
-                var projectContext = new ProjectContextBuilder()
-                    .WithLockFile(toolLockFile)
-                    .WithTargetFramework(s_toolPackageFramework.ToString())
-                    .Build();
+                GenerateDepsJsonFile(toolLockFile, depsPath);
+            }
+        }
 
-                var exporter = projectContext.CreateExporter(Constants.DefaultConfiguration);
+        // Need to unit test this, so public
+        public void GenerateDepsJsonFile(
+            LockFile toolLockFile, 
+            string depsPath)
+        {
+            Reporter.Verbose.WriteLine($"Generating deps.json at: {depsPath}");
 
-                var dependencyContext = new DependencyContextBuilder()
-                    .Build(null, 
-                        null, 
-                        exporter.GetAllExports(), 
-                        true, 
-                        s_toolPackageFramework, 
-                        string.Empty);
+            var projectContext = new ProjectContextBuilder()
+                .WithLockFile(toolLockFile)
+                .WithTargetFramework(s_toolPackageFramework.ToString())
+                .Build();
 
-                using (var fileStream = File.Create(depsPath))
+            var exporter = projectContext.CreateExporter(Constants.DefaultConfiguration);
+
+            var dependencyContext = new DependencyContextBuilder()
+                .Build(null, 
+                    null, 
+                    exporter.GetAllExports(),
+                    true, 
+                    s_toolPackageFramework, 
+                    string.Empty);
+
+            var tempDepsFile = Path.GetTempFileName();
+            using (var fileStream = File.Open(tempDepsFile, FileMode.Open, FileAccess.Write))
+            {
+                var dependencyContextWriter = new DependencyContextWriter();
+
+                dependencyContextWriter.Write(dependencyContext, fileStream);
+            }
+
+            try
+            {
+                File.Copy(tempDepsFile, depsPath);
+            }
+            catch (Exception e)
+            {
+                Reporter.Verbose.WriteLine($"unable to generate deps.json, it may have been already generated: {e.Message}");
+            }
+            finally
+            {
+                try
                 {
-                    var dependencyContextWriter = new DependencyContextWriter();
-
-                    dependencyContextWriter.Write(dependencyContext, fileStream);
+                    File.Delete(tempDepsFile);
+                }
+                catch (Exception e2)
+                { 
+                    Reporter.Verbose.WriteLine($"unable to delete temporary deps.json file: {e2.Message}");
                 }
             }
         }
diff --git a/test/Microsoft.DotNet.Cli.Utils.Tests/GivenAProjectToolsCommandResolver.cs b/test/Microsoft.DotNet.Cli.Utils.Tests/GivenAProjectToolsCommandResolver.cs
index 63a85bfc7..0c556d181 100644
--- a/test/Microsoft.DotNet.Cli.Utils.Tests/GivenAProjectToolsCommandResolver.cs
+++ b/test/Microsoft.DotNet.Cli.Utils.Tests/GivenAProjectToolsCommandResolver.cs
@@ -18,6 +18,11 @@ using FluentAssertions;
 using NuGet.Frameworks;
 using NuGet.Versioning;
 using NuGet.ProjectModel;
+using Microsoft.DotNet.ProjectModel.Graph;
+using Microsoft.DotNet.ProjectModel.Compilation;
+using NuGet.ProjectModel;
+
+using LockFile = Microsoft.DotNet.ProjectModel.Graph.LockFile;
 
 namespace Microsoft.DotNet.Cli.Utils.Tests
 {
@@ -184,6 +189,37 @@ namespace Microsoft.DotNet.Cli.Utils.Tests
             depsJsonFile.Should().NotBeNull();
         }
 
+        [Fact]
+        public void Generate_deps_json_method_doesnt_overwrite_when_deps_file_already_exists()
+        {
+            var context = ProjectContext.Create(Path.Combine(s_liveProjectDirectory, "project.json"), s_toolPackageFramework);
+
+            var nugetPackagesRoot = context.PackagesDirectory;
+            var toolPathCalculator = new ToolPathCalculator(nugetPackagesRoot);
+
+            var lockFilePath = toolPathCalculator.GetLockFilePath(
+                "dotnet-portable", 
+                new NuGetVersion("1.0.0"), 
+                s_toolPackageFramework);
+
+            var lockFile = LockFileReader.Read(lockFilePath, designTime: false);
+
+            var depsJsonFile = Path.Combine(
+                Path.GetDirectoryName(lockFilePath),
+                "dotnet-portable.deps.json");
+
+            if (File.Exists(depsJsonFile))
+            {
+                File.Delete(depsJsonFile);
+            }
+            File.WriteAllText(depsJsonFile, "temp");
+
+            var projectToolsCommandResolver = SetupProjectToolsCommandResolver();
+            projectToolsCommandResolver.GenerateDepsJsonFile(lockFile, depsJsonFile);
+
+            File.ReadAllText(depsJsonFile).Should().Be("temp");
+        }
+
         private ProjectToolsCommandResolver SetupProjectToolsCommandResolver(
             IPackagedCommandSpecFactory packagedCommandSpecFactory = null)
         {