Improve getting .git directory

When using worktrees we want to get the .git directory of the main repo
(main working tree). This fixes calculating system hashs and the
location of the GitVersion cache. When determining the root directory
we have to use the .git directory of the linked working tree.

Fixes #1063.

Author: ermshiperete

src/GitVersionCore.Tests/ExecuteCoreTests.cs

@@ -299,7 +299,7 @@ public void WorkingDirectoryWithoutGit()
     [Test]
     [Category("NoMono")]
     [Description("LibGit2Sharp fails when running under Mono")]
-    public void WorkingDirectoryWithWorktree()
+    public void GetProjectRootDirectory_WorkingDirectoryWithWorktree()
     {
         var versionAndBranchFinder = new ExecuteCore(fileSystem);
 
@@ -323,6 +323,20 @@ public void WorkingDirectoryWithWorktree()
         });
     }
 
+    [Test]
+    public void GetProjectRootDirectory_NoWorktree()
+    {
+        var versionAndBranchFinder = new ExecuteCore(fileSystem);
+
+        RepositoryScope(versionAndBranchFinder, (fixture, vv) =>
+        {
+            var targetUrl = "https://github.com/GitTools/GitVersion.git";
+            var gitPreparer = new GitPreparer(targetUrl, null, new Authentication(), false, fixture.RepositoryPath);
+            var expectedPath = fixture.RepositoryPath.TrimEnd('/', '\\');
+            gitPreparer.GetProjectRootDirectory().TrimEnd('/', '\\').ShouldBe(expectedPath);
+        });
+    }
+
     [Test]
     public void DynamicRepositoriesShouldNotErrorWithFailedToFindGitDirectory()
     {
@@ -334,6 +348,48 @@ public void DynamicRepositoriesShouldNotErrorWithFailedToFindGitDirectory()
         });
     }
 
+    [Test]
+    public void GetDotGitDirectory_NoWorktree()
+    {
+        var versionAndBranchFinder = new ExecuteCore(fileSystem);
+
+        RepositoryScope(versionAndBranchFinder, (fixture, vv) =>
+        {
+            var targetUrl = "https://github.com/GitTools/GitVersion.git";
+            var gitPreparer = new GitPreparer(targetUrl, null, new Authentication(), false, fixture.RepositoryPath);
+            var expectedPath = Path.Combine(fixture.RepositoryPath, ".git");
+            gitPreparer.GetDotGitDirectory().ShouldBe(expectedPath);
+        });
+    }
+
+    [Test]
+    [Category("NoMono")]
+    [Description("LibGit2Sharp fails when running under Mono")]
+    public void GetDotGitDirectory_Worktree()
+    {
+        var versionAndBranchFinder = new ExecuteCore(fileSystem);
+
+        RepositoryScope(versionAndBranchFinder, (fixture, vv) =>
+        {
+            var worktreePath = Path.Combine(Directory.GetParent(fixture.RepositoryPath).FullName, Guid.NewGuid().ToString());
+            try
+            {
+                // create a branch and a new worktree for it
+                var repo = new Repository(fixture.RepositoryPath);
+                repo.Worktrees.Add("worktree", worktreePath, false);
+
+                var targetUrl = "https://github.com/GitTools/GitVersion.git";
+                var gitPreparer = new GitPreparer(targetUrl, null, new Authentication(), false, worktreePath);
+                var expectedPath = Path.Combine(fixture.RepositoryPath, ".git");
+                gitPreparer.GetDotGitDirectory().ShouldBe(expectedPath);
+            }
+            finally
+            {
+                DirectoryHelper.DeleteDirectory(worktreePath);
+            }
+        });
+    }
+
     LogMessages RepositoryScope(ExecuteCore executeCore = null, Action<EmptyRepositoryFixture, VersionVariables> fixtureAction = null)
     {
         // Make sure GitVersion doesn't trigger build server mode when we are running the tests

src/GitVersionCore/GitPreparer.cs

@@ -135,17 +135,14 @@ static bool GitRepoHasMatchingRemote(string possiblePath, string targetUrl)
 
         public string GetDotGitDirectory()
         {
-            if (IsDynamicGitRepository)
-                return DynamicGitRepositoryPath;
-
-            var dotGitDirectory = Repository.Discover(targetPath);
+            var dotGitDirectory = IsDynamicGitRepository ? DynamicGitRepositoryPath : Repository.Discover(targetPath);
 
+            dotGitDirectory = dotGitDirectory?.TrimEnd('/', '\\');
             if (string.IsNullOrEmpty(dotGitDirectory))
                 throw new DirectoryNotFoundException("Can't find the .git directory in " + targetPath);
 
-            dotGitDirectory = dotGitDirectory.TrimEnd('/', '\\');
-            if (string.IsNullOrEmpty(dotGitDirectory))
-                throw new DirectoryNotFoundException("Can't find the .git directory in " + targetPath);
+            if (dotGitDirectory.Contains(Path.Combine(".git", "worktrees")))
+                return Directory.GetParent(Directory.GetParent(dotGitDirectory).FullName).FullName;
 
             return dotGitDirectory;
         }
@@ -159,11 +156,15 @@ public string GetProjectRootDirectory()
                 return targetPath;
             }
 
-            var dotGetGitDirectory = GetDotGitDirectory();
-            using (var repo = new Repository(dotGetGitDirectory))
+            var dotGitDirectory = Repository.Discover(targetPath);
+
+            if (string.IsNullOrEmpty(dotGitDirectory))
+                throw new DirectoryNotFoundException($"Can't find the .git directory in {targetPath}");
+
+            using (var repo = new Repository(dotGitDirectory))
             {
                 var result = repo.Info.WorkingDirectory;
-                Logger.WriteInfo($"Returning Project Root from DotGitDirectory: {dotGetGitDirectory} - {result}");
+                Logger.WriteInfo($"Returning Project Root from DotGitDirectory: {dotGitDirectory} - {result}");
                 return result;
             }
         }