cache git collections with lazy initialization

Replaces direct instantiations of Tags, Commits, Remotes, and References with lazy initialization. This avoids redundant object creation and improves performance by deferring instantiation until the collection is accessed.

Author: arturcic

src/GitVersion.App.Tests/PullRequestInBuildAgentTest.cs

@@ -146,27 +146,25 @@ private static async Task VerifyPullRequestVersionIsCalculatedProperly(string pu
         using var fixture = new EmptyRepositoryFixture();
         var remoteRepositoryPath = FileSystemHelper.Path.GetRepositoryTempPath();
         RepositoryFixtureBase.Init(remoteRepositoryPath);
-        using (var remoteRepository = new Repository(remoteRepositoryPath))
-        {
-            remoteRepository.Config.Set("user.name", "Test");
-            remoteRepository.Config.Set("user.email", "[email protected]");
-            fixture.Repository.Network.Remotes.Add("origin", remoteRepositoryPath);
-            Console.WriteLine("Created git repository at {0}", remoteRepositoryPath);
-            remoteRepository.MakeATaggedCommit("1.0.3");
-
-            var branch = remoteRepository.CreateBranch("FeatureBranch");
-            Commands.Checkout(remoteRepository, branch);
-            remoteRepository.MakeCommits(2);
-            Commands.Checkout(remoteRepository, remoteRepository.Head.Tip.Sha);
-            //Emulate merge commit
-            var mergeCommitSha = remoteRepository.MakeACommit().Sha;
-            Commands.Checkout(remoteRepository, TestBase.MainBranch); // HEAD cannot be pointing at the merge commit
-            remoteRepository.Refs.Add(pullRequestRef, new ObjectId(mergeCommitSha));
-
-            // Checkout PR commit
-            Commands.Fetch(fixture.Repository, "origin", [], new FetchOptions(), null);
-            Commands.Checkout(fixture.Repository, mergeCommitSha);
-        }
+        using var remoteRepository = new Repository(remoteRepositoryPath);
+        remoteRepository.Config.Set("user.name", "Test");
+        remoteRepository.Config.Set("user.email", "[email protected]");
+        fixture.Repository.Network.Remotes.Add("origin", remoteRepositoryPath);
+        Console.WriteLine("Created git repository at {0}", remoteRepositoryPath);
+        remoteRepository.MakeATaggedCommit("1.0.3");
+
+        var branch = remoteRepository.CreateBranch("FeatureBranch");
+        Commands.Checkout(remoteRepository, branch);
+        remoteRepository.MakeCommits(2);
+        Commands.Checkout(remoteRepository, remoteRepository.Head.Tip.Sha);
+        //Emulate merge commit
+        var mergeCommitSha = remoteRepository.MakeACommit().Sha;
+        Commands.Checkout(remoteRepository, TestBase.MainBranch); // HEAD cannot be pointing at the merge commit
+        remoteRepository.Refs.Add(pullRequestRef, new ObjectId(mergeCommitSha));
+
+        // Checkout PR commit
+        Commands.Fetch(fixture.Repository, "origin", [], new FetchOptions(), null);
+        Commands.Checkout(fixture.Repository, mergeCommitSha);
 
         var programFixture = new ProgramFixture(fixture.RepositoryPath);
         programFixture.WithOverrides(services =>
@@ -199,12 +197,12 @@ private static async Task VerifyPullRequestVersionIsCalculatedProperly(string pu
     public void VerifyPullRequestInput(string pullRequestRef, string friendly, bool isBranch, bool isPullRequest, bool isRemote)
     {
         var refName = new ReferenceName(pullRequestRef);
-        Assert.Multiple(() =>
+        using (Assert.EnterMultipleScope())
         {
             Assert.That(refName.Friendly, Is.EqualTo(friendly));
             Assert.That(refName.IsLocalBranch, Is.EqualTo(isBranch));
             Assert.That(refName.IsPullRequest, Is.EqualTo(isPullRequest));
             Assert.That(refName.IsRemoteBranch, Is.EqualTo(isRemote));
-        });
+        }
     }
 }

src/GitVersion.LibGit2Sharp/Git/GitRepository.cs

@@ -23,11 +23,19 @@ private IRepository RepositoryInstance
     public bool IsShallow => RepositoryInstance.Info.IsShallow;
     public IBranch Head => this.repositoryCache.GetOrWrap(RepositoryInstance.Head, RepositoryInstance.Diff);
 
-    public ITagCollection Tags => new TagCollection(RepositoryInstance.Tags, RepositoryInstance.Diff, this.repositoryCache);
+    private ITagCollection? tags;
+    public ITagCollection Tags => this.tags ??= new TagCollection(RepositoryInstance.Tags, RepositoryInstance.Diff, this.repositoryCache);
+
     public IBranchCollection Branches => new BranchCollection(RepositoryInstance.Branches, RepositoryInstance.Diff, this.repositoryCache);
-    public ICommitCollection Commits => new CommitCollection(RepositoryInstance.Commits, RepositoryInstance.Diff, this.repositoryCache);
-    public IRemoteCollection Remotes => new RemoteCollection(RepositoryInstance.Network.Remotes, this.repositoryCache);
-    public IReferenceCollection References => new ReferenceCollection(RepositoryInstance.Refs, this.repositoryCache);
+
+    private ICommitCollection? commits;
+    public ICommitCollection Commits => this.commits ??= new CommitCollection(RepositoryInstance.Commits, RepositoryInstance.Diff, this.repositoryCache);
+
+    private IRemoteCollection? remotes;
+    public IRemoteCollection Remotes => this.remotes ??= new RemoteCollection(RepositoryInstance.Network.Remotes, this.repositoryCache);
+
+    private IReferenceCollection? references;
+    public IReferenceCollection References => this.references ??= new ReferenceCollection(RepositoryInstance.Refs, this.repositoryCache);
 
     public void DiscoverRepository(string? gitDirectory)
     {