Check that repository isn't a shallow clone and show an error if it is

docs/input/docs/reference/build-servers/azure-devops.md

@@ -14,6 +14,14 @@ either using the Command Line build step or install an extension / custom build
 step. The custom build step requires a one-time setup to import the GitVersion
 task into your TFS or Azure DevOps Pipeline instance.
 
+:::{.alert .alert-danger}
+**Important**
+
+You must disable shallow fetch, either in the pipeline settings UI or by setting `fetchDepth: 0` in your `checkout` step;
+without it, Azure DevOps Pipelines will perform a shallow clone, which will cause GitVersion to display an error message.
+See [the Azure DevOps documentation](https://learn.microsoft.com/en-us/azure/devops/pipelines/yaml-schema/steps-checkout?view=azure-pipelines#shallow-fetch) for more information.
+:::
+
 ## Executing GitVersion
 
 ### Using GitVersion with the MSBuild Task NuGet Package

src/GitVersion.Core.Tests/Core/GitVersionExecutorTests.cs

@@ -544,6 +544,27 @@ public void CalculateVersionVariables_TwoBranchHasSameCommitHeadDetachedAndTagge
         version.Sha.ShouldBe(commits.First().Sha);
     }
 
+    [Test]
+    public void CalculateVersionVariables_ShallowFetch_ThrowException()
+    {
+        // Setup
+        using var fixture = new RemoteRepositoryFixture();
+        fixture.LocalRepositoryFixture.MakeShallow();
+
+        using var worktreeFixture = new LocalRepositoryFixture(new Repository(fixture.LocalRepositoryFixture.RepositoryPath));
+        var gitVersionOptions = new GitVersionOptions { WorkingDirectory = worktreeFixture.RepositoryPath };
+
+        var environment = new TestEnvironment();
+        environment.SetEnvironmentVariable(AzurePipelines.EnvironmentVariableName, "true");
+
+        this.sp = GetServiceProvider(gitVersionOptions, environment: environment);
+        var sut = sp.GetRequiredService<IGitVersionCalculateTool>();
+
+        // Execute & Verify
+        var exception = Assert.Throws<WarningException>(() => sut.CalculateVersionVariables());
+        exception?.Message.ShouldBe("Repository is a shallow clone. Git repositories must contain the full history. See https://gitversion.net/docs/reference/requirements#unshallow for more info.");
+    }
+
     private IGitVersionCalculateTool GetGitVersionCalculator(GitVersionOptions gitVersionOptions, ILog? logger = null, IGitRepository? repository = null, IFileSystem? fs = null)
     {
         this.sp = GetServiceProvider(gitVersionOptions, logger, repository, fs);

src/GitVersion.Core/Core/GitPreparer.cs

@@ -183,6 +183,11 @@ private void NormalizeGitDirectory(bool noFetch, string? currentBranchName, bool
 
         EnsureHeadIsAttachedToBranch(currentBranchName, authentication);
         EnsureRepositoryHeadDuringNormalisation(nameof(EnsureHeadIsAttachedToBranch), expectedSha);
+
+        if (this.repository.IsShallow)
+        {
+            throw new WarningException("Repository is a shallow clone. Git repositories must contain the full history. See https://gitversion.net/docs/reference/requirements#unshallow for more info.");
+        }
     }
 
     private void EnsureRepositoryHeadDuringNormalisation(string occasion, string? expectedSha)

src/GitVersion.Core/Git/IGitRepository.cs

@@ -5,6 +5,7 @@ public interface IGitRepository : IDisposable
     string Path { get; }
     string WorkingDirectory { get; }
     bool IsHeadDetached { get; }
+    bool IsShallow { get; }
     IBranch Head { get; }
     ITagCollection Tags { get; }
     IReferenceCollection Refs { get; }

src/GitVersion.Core/PublicAPI.Unshipped.txt

@@ -335,6 +335,7 @@ GitVersion.IGitRepository.FindMergeBase(GitVersion.ICommit! commit, GitVersion.I
 GitVersion.IGitRepository.GetNumberOfUncommittedChanges() -> int
 GitVersion.IGitRepository.Head.get -> GitVersion.IBranch!
 GitVersion.IGitRepository.IsHeadDetached.get -> bool
+GitVersion.IGitRepository.IsShallow.get -> bool
 GitVersion.IGitRepository.Path.get -> string!
 GitVersion.IGitRepository.Refs.get -> GitVersion.IReferenceCollection!
 GitVersion.IGitRepository.Remotes.get -> GitVersion.IRemoteCollection!

src/GitVersion.LibGit2Sharp/Git/GitRepository.cs

@@ -20,6 +20,7 @@ private IRepository RepositoryInstance
     public string Path => RepositoryInstance.Info.Path;
     public string WorkingDirectory => RepositoryInstance.Info.WorkingDirectory;
     public bool IsHeadDetached => RepositoryInstance.Info.IsHeadDetached;
+    public bool IsShallow => RepositoryInstance.Info.IsShallow;
     public IBranch Head => new Branch(RepositoryInstance.Head);
     public ITagCollection Tags => new TagCollection(RepositoryInstance.Tags);
     public IReferenceCollection Refs => new ReferenceCollection(RepositoryInstance.Refs);

src/GitVersion.Testing/Fixtures/RepositoryFixtureBase.cs

@@ -127,6 +127,15 @@ public LocalRepositoryFixture CloneRepository()
         return new LocalRepositoryFixture(new Repository(localPath));
     }
 
+    /// <summary>
+    ///     Pulls with a depth of 1 and prunes all older commits, making the repository shallow.
+    /// </summary>
+    public void MakeShallow()
+    {
+        GitTestExtensions.ExecuteGitCmd($"-C {RepositoryPath} pull --depth 1");
+        GitTestExtensions.ExecuteGitCmd($"-C {RepositoryPath} gc --prune=all");
+    }
+
     public void Fetch(string remote, FetchOptions? options = null)
         => Commands.Fetch(Repository, remote, Array.Empty<string>(), options, null);
 }