Add sparse checkout support (#772)

Author: pakrym

src/Microsoft.Build.Tasks.Git.UnitTests/GitRepositoryTests.cs

@@ -209,6 +209,32 @@ public void OpenRepository_WorkingDirectorySpecifiedInConfig()
             Assert.Equal(workingDir2.Path, repository.WorkingDirectory);
         }
 
+        [Fact]
+        public void OpenRepository_SparseV2()
+        {
+            using var temp = new TempRoot();
+
+            var workingDir = temp.CreateDirectory();
+            var gitDir = workingDir.CreateDirectory(".git");
+
+            gitDir.CreateFile("HEAD");
+            gitDir.CreateFile("config").WriteAllText(@"
+[core]
+	repositoryformatversion = 1
+[extensions]
+	worktreeConfig = true");
+
+            Assert.True(GitRepository.TryFindRepository(gitDir.Path, out var location));
+            Assert.Equal(gitDir.Path, location.CommonDirectory);
+            Assert.Equal(gitDir.Path, location.GitDirectory);
+            Assert.Null(location.WorkingDirectory);
+
+            var repository = GitRepository.OpenRepository(location, GitEnvironment.Empty);
+            Assert.Equal(gitDir.Path, repository.CommonDirectory);
+            Assert.Equal(gitDir.Path, repository.GitDirectory);
+            Assert.Null(repository.WorkingDirectory);
+        }
+
         [Fact]
         public void OpenRepository_VersionNotSupported()
         {
@@ -223,7 +249,32 @@ public void OpenRepository_VersionNotSupported()
             gitDir.CreateDirectory("refs").CreateDirectory("heads").CreateFile("master").WriteAllText("0000000000000000000000000000000000000000");
             gitDir.CreateDirectory("objects");
 
-            gitDir.CreateFile("config").WriteAllText("[core]repositoryformatversion = 1");
+            gitDir.CreateFile("config").WriteAllText("[core]repositoryformatversion = 2");
+
+            var src = workingDir.CreateDirectory("src");
+
+            Assert.Throws<NotSupportedException>(() => GitRepository.OpenRepository(src.Path, new GitEnvironment(homeDir.Path)));
+        }
+
+        [Fact]
+        public void OpenRepository_V2ExtensionNotSupported()
+        {
+            using var temp = new TempRoot();
+
+            var homeDir = temp.CreateDirectory();
+
+            var workingDir = temp.CreateDirectory();
+            var gitDir = workingDir.CreateDirectory(".git");
+
+            gitDir.CreateFile("HEAD").WriteAllText("ref: refs/heads/master");
+            gitDir.CreateDirectory("refs").CreateDirectory("heads").CreateFile("master").WriteAllText("0000000000000000000000000000000000000000");
+            gitDir.CreateDirectory("objects");
+
+            gitDir.CreateFile("config").WriteAllText(@"
+[core]
+	repositoryformatversion = 1
+[extensions]
+	newExtension = true");
 
             var src = workingDir.CreateDirectory("src");
 

src/Microsoft.Build.Tasks.Git/GitDataReader/GitRepository.cs

@@ -13,7 +13,7 @@ namespace Microsoft.Build.Tasks.Git
 {
     internal sealed class GitRepository
     {
-        private const int SupportedGitRepoFormatVersion = 0;
+        private const int SupportedGitRepoFormatVersion = 1;
 
         private const string CommonDirFileName = "commondir";
         private const string GitDirName = ".git";
@@ -23,6 +23,8 @@ internal sealed class GitRepository
         internal const string GitHeadFileName = "HEAD";
 
         private const string GitModulesFileName = ".gitmodules";
+        private static readonly string[] KnownExtensions = new[] { "noop", "preciousObjects", "partialclone", "worktreeConfig" };
+
 
         public GitConfig Config { get; }
 
@@ -124,6 +126,22 @@ public static GitRepository OpenRepository(GitRepositoryLocation location, GitEn
                 throw new NotSupportedException(string.Format(Resources.UnsupportedRepositoryVersion, versionStr, SupportedGitRepoFormatVersion));
             }
 
+            if (version == 1)
+            {
+                // When reading the core.repositoryformatversion variable, a git implementation which supports version 1 MUST
+                // also read any configuration keys found in the extensions section of the configuration file.
+                //
+                // If a version-1 repository specifies any extensions.* keys that the running git has not implemented, the operation MUST NOT proceed.
+                // Similarly, if the value of any known key is not understood by the implementation,the operation MUST NOT proceed.
+                foreach (var variable in config.Variables)
+                {
+                    if (variable.Key.SectionNameEquals("extensions") && !KnownExtensions.Contains(variable.Key.VariableName, StringComparer.OrdinalIgnoreCase))
+                    {
+                        throw new NotSupportedException(string.Format(Resources.UnsupportedRepositoryExtension, variable.Key.VariableName, string.Join(", ", KnownExtensions)));
+                    }
+                }
+            }
+
             return new GitRepository(environment, config, location.GitDirectory, location.CommonDirectory, workingDirectory);
         }
 

src/Microsoft.Build.Tasks.Git/Resources.resx

@@ -129,6 +129,9 @@
   <data name="UnsupportedRepositoryVersion" xml:space="preserve">
     <value>Unsupported repository version {0}. Only versions up to {1} are supported.</value>
   </data>
+  <data name="UnsupportedRepositoryExtension" xml:space="preserve">
+    <value>Unsupported repository extension {0}. Only {1} are supported.</value>
+  </data>
   <data name="PathSpecifiedInFileIsNotAbsolute" xml:space="preserve">
     <value>Path specified in file '{0}' is not absolute: '{1}'.</value>
   </data>

src/Microsoft.Build.Tasks.Git/xlf/Resources.cs.xlf

@@ -117,6 +117,11 @@
         <target state="translated">Nejde najít úložiště s pracovním adresářem, který obsahuje adresář {0}.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnsupportedRepositoryExtension">
+        <source>Unsupported repository extension {0}. Only {1} are supported.</source>
+        <target state="new">Unsupported repository extension {0}. Only {1} are supported.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UnsupportedRepositoryVersion">
         <source>Unsupported repository version {0}. Only versions up to {1} are supported.</source>
         <target state="translated">Nepodporovaná verze úložiště: {0}. Podporují se jenom verze do {1}.</target>

src/Microsoft.Build.Tasks.Git/xlf/Resources.de.xlf

@@ -117,6 +117,11 @@
         <target state="translated">Das Repository mit dem Arbeitsverzeichnis, welches das Verzeichnis "{0}" enthält, wurde nicht gefunden.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnsupportedRepositoryExtension">
+        <source>Unsupported repository extension {0}. Only {1} are supported.</source>
+        <target state="new">Unsupported repository extension {0}. Only {1} are supported.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UnsupportedRepositoryVersion">
         <source>Unsupported repository version {0}. Only versions up to {1} are supported.</source>
         <target state="translated">Nicht unterstützte Repositoryversion {0}. Nur Versionen bis {1} werden unterstützt.</target>

src/Microsoft.Build.Tasks.Git/xlf/Resources.es.xlf

@@ -117,6 +117,11 @@
         <target state="translated">No se puede encontrar el repositorio con el directorio de trabajo que contiene el directorio "{0}".</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnsupportedRepositoryExtension">
+        <source>Unsupported repository extension {0}. Only {1} are supported.</source>
+        <target state="new">Unsupported repository extension {0}. Only {1} are supported.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UnsupportedRepositoryVersion">
         <source>Unsupported repository version {0}. Only versions up to {1} are supported.</source>
         <target state="translated">Versión de repositorio {0} no admitida. Solo se admiten las versiones hasta {1}.</target>

src/Microsoft.Build.Tasks.Git/xlf/Resources.fr.xlf

@@ -117,6 +117,11 @@
         <target state="translated">Impossible de localiser le dépôt avec le répertoire de travail contenant le répertoire '{0}'.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnsupportedRepositoryExtension">
+        <source>Unsupported repository extension {0}. Only {1} are supported.</source>
+        <target state="new">Unsupported repository extension {0}. Only {1} are supported.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UnsupportedRepositoryVersion">
         <source>Unsupported repository version {0}. Only versions up to {1} are supported.</source>
         <target state="translated">La version du dépôt {0} n'est pas prise en charge. Seules les versions jusqu'à {1} sont prises en charge.</target>

src/Microsoft.Build.Tasks.Git/xlf/Resources.it.xlf

@@ -117,6 +117,11 @@
         <target state="translated">Non è possibile individuare il repository con la directory di lavoro che contiene la directory '{0}'.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnsupportedRepositoryExtension">
+        <source>Unsupported repository extension {0}. Only {1} are supported.</source>
+        <target state="new">Unsupported repository extension {0}. Only {1} are supported.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UnsupportedRepositoryVersion">
         <source>Unsupported repository version {0}. Only versions up to {1} are supported.</source>
         <target state="translated">La versione {0} del repository non è supportata. Sono supportate solo le versioni fino alla {1}.</target>

src/Microsoft.Build.Tasks.Git/xlf/Resources.ja.xlf

@@ -117,6 +117,11 @@
         <target state="translated">ディレクトリ '{0}' を含む作業ディレクトリがあるリポジトリが見つかりません。</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnsupportedRepositoryExtension">
+        <source>Unsupported repository extension {0}. Only {1} are supported.</source>
+        <target state="new">Unsupported repository extension {0}. Only {1} are supported.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UnsupportedRepositoryVersion">
         <source>Unsupported repository version {0}. Only versions up to {1} are supported.</source>
         <target state="translated">サポートされていないリポジトリ バージョン {0}。{1} までのバージョンのみがサポートされています。</target>

src/Microsoft.Build.Tasks.Git/xlf/Resources.ko.xlf

@@ -117,6 +117,11 @@
         <target state="translated">디렉터리 '{0}'이(가) 포함된 작업 디렉터리로 리포지토리를 찾을 수 없습니다.</target>
         <note />
       </trans-unit>
+      <trans-unit id="UnsupportedRepositoryExtension">
+        <source>Unsupported repository extension {0}. Only {1} are supported.</source>
+        <target state="new">Unsupported repository extension {0}. Only {1} are supported.</target>
+        <note />
+      </trans-unit>
       <trans-unit id="UnsupportedRepositoryVersion">
         <source>Unsupported repository version {0}. Only versions up to {1} are supported.</source>
         <target state="translated">{0}은(는) 지원되지 않는 리포지토리 버전입니다. 버전은 최대 {1}까지만 지원됩니다.</target>