Use the environment variable GIT_BRANCH as the current branch everywhere

src/GitVersion.Core.Tests/Extensions/GitToolsTestingExtensions.cs

@@ -54,10 +54,16 @@ public static IBranch CreateMockBranch(string name, params ICommit[] commits)
 
     public static void DumpGraph(this IRepository repository, Action<string>? writer = null, int? maxCommits = null) => GitExtensions.DumpGraph(repository.ToGitRepository().Path, writer, maxCommits);
 
-    public static VersionVariables GetVersion(this RepositoryFixtureBase fixture, Config? configuration = null, IRepository? repository = null, string? commitId = null, bool onlyTrackedBranches = true, string? branch = null)
+    public static VersionVariables GetVersion(
+        this RepositoryFixtureBase fixture,
+        Config? configuration = null,
+        IRepository? repository = null,
+        string? commitId = null,
+        bool onlyTrackedBranches = true,
+        string? branch = null,
+        Action<IServiceProvider>? configureServices = null)
     {
         configuration ??= new ConfigurationBuilder().Build();
-
         repository ??= fixture.Repository;
 
         var options = Options.Create(new GitVersionOptions
@@ -73,11 +79,11 @@ public static VersionVariables GetVersion(this RepositoryFixtureBase fixture, Co
         });
 
         var sp = ConfigureServices(services => services.AddSingleton(options));
+        configureServices?.Invoke(sp);
 
         var variableProvider = sp.GetRequiredService<IVariableProvider>();
         var nextVersionCalculator = sp.GetRequiredService<INextVersionCalculator>();
         var contextOptions = sp.GetRequiredService<Lazy<GitVersionContext>>();
-
         var context = contextOptions.Value;
 
         try
@@ -104,15 +110,23 @@ public static void WriteVersionVariables(this RepositoryFixtureBase fixture, str
         writer.Write(versionInfo.ToString());
     }
 
-    public static void AssertFullSemver(this RepositoryFixtureBase fixture, string fullSemver, Config? configuration = null, IRepository? repository = null, string? commitId = null, bool onlyTrackedBranches = true, string? targetBranch = null)
+    public static void AssertFullSemver(
+        this RepositoryFixtureBase fixture,
+        string fullSemver,
+        Config? configuration = null,
+        IRepository? repository = null,
+        string? commitId = null,
+        bool onlyTrackedBranches = true,
+        string? targetBranch = null,
+        Action<IServiceProvider>? configureServices = null)
     {
         configuration ??= new Config();
         configuration = new ConfigurationBuilder().Add(configuration).Build();
         Console.WriteLine("---------");
 
         try
         {
-            var variables = fixture.GetVersion(configuration, repository, commitId, onlyTrackedBranches, targetBranch);
+            var variables = fixture.GetVersion(configuration, repository, commitId, onlyTrackedBranches, targetBranch, configureServices);
             variables.FullSemVer.ShouldBe(fullSemver);
         }
         catch (Exception)

src/GitVersion.Core.Tests/IntegrationTests/RemoteRepositoryScenarios.cs

@@ -98,6 +98,23 @@ public void GivenARemoteGitRepositoryWhenCheckingOutDetachedHeadUsingExistingImp
             $"It looks like the branch being examined is a detached Head pointing to commit '{fixture.LocalRepositoryFixture.Repository.Head.Tip.Id.ToString(7)}'. Without a proper branch name GitVersion cannot determine the build version.");
     }
 
+    [Test]
+    public void GivenARemoteGitRepositoryWhenCheckingOutDetachedHeadWithEnvironmentVariableSucceeds()
+    {
+        using var fixture = new RemoteRepositoryFixture();
+        var local = fixture.LocalRepositoryFixture;
+        Commands.Checkout(local.Repository, local.Repository.Head.Tip);
+
+        fixture.AssertFullSemver("0.1.0+4",
+            repository: local.Repository,
+            configureServices: sp =>
+            {
+                sp.GetRequiredService<IEnvironment>().SetEnvironmentVariable("GIT_BRANCH", "main");
+                sp.GetRequiredService<IGitPreparer>().Prepare();
+            });
+    }
+
+
     [Test]
     [Ignore("Needs more investigations.")]
     public void GivenARemoteGitRepositoryWhenCheckingOutDetachedHeadUsingTrackingBranchOnlyBehaviourShouldReturnVersion014Plus5()

src/GitVersion.Core/BuildAgents/LocalBuild.cs

@@ -5,10 +5,13 @@ namespace GitVersion.BuildAgents;
 
 public class LocalBuild : BuildAgentBase
 {
-    public LocalBuild(IEnvironment environment, ILog log) : base(environment, log)
+    public LocalBuild(IEnvironment environment, ILog log)
+        : base(environment, log)
     {
     }
+
     protected override string EnvironmentVariable => string.Empty;
+    public override string? GetCurrentBranch(bool usingDynamicRepos) => Environment.GetEnvironmentVariable("GIT_BRANCH");
     public override bool CanApplyToCurrentContext() => true;
     public override string? GenerateSetVersionMessage(VersionVariables variables) => null;
     public override string[] GenerateSetParameterMessage(string name, string value) => Array.Empty<string>();

src/GitVersion.Core/Core/GitPreparer.cs

@@ -44,8 +44,7 @@ public void Prepare()
         // Normalize if we are running on build server
         var normalizeGitDirectory = !gitVersionOptions.Settings.NoNormalize && this.buildAgent is not LocalBuild;
         var shouldCleanUpRemotes = this.buildAgent.ShouldCleanUpRemotes();
-        var currentBranch = ResolveCurrentBranch();
-
+        var currentBranch = this.context.CurrentBranch?.Name.WithoutRemote;
         var dotGitDirectory = this.repositoryInfo.DotGitDirectory;
         var projectRoot = this.repositoryInfo.ProjectRootDirectory;
 
@@ -79,18 +78,6 @@ private void PrepareInternal(bool normalizeGitDirectory, string? currentBranch,
         }
     }
 
-    private string? ResolveCurrentBranch()
-    {
-        var gitVersionOptions = this.options.Value;
-        var targetBranch = gitVersionOptions.RepositoryInfo.TargetBranch;
-
-        var isDynamicRepository = !gitVersionOptions.RepositoryInfo.DynamicRepositoryClonePath.IsNullOrWhiteSpace();
-        var currentBranch = this.buildAgent.GetCurrentBranch(isDynamicRepository) ?? targetBranch;
-        this.log.Info("Branch from build environment: " + currentBranch);
-
-        return currentBranch;
-    }
-
     private void CleanupDuplicateOrigin()
     {
         var remoteToKeep = DefaultRemoteName;

src/GitVersion.Core/Core/GitVersionContextFactory.cs

@@ -1,6 +1,8 @@
+using GitVersion.BuildAgents;
 using GitVersion.Common;
 using GitVersion.Configuration;
 using GitVersion.Extensions;
+using GitVersion.Logging;
 using Microsoft.Extensions.Options;
 
 namespace GitVersion;
@@ -10,36 +12,81 @@ public class GitVersionContextFactory : IGitVersionContextFactory
     private readonly IConfigProvider configProvider;
     private readonly IRepositoryStore repositoryStore;
     private readonly IBranchConfigurationCalculator branchConfigurationCalculator;
+    private readonly IBuildAgent buildAgent;
+    private readonly ILog log;
     private readonly IOptions<GitVersionOptions> options;
 
-    public GitVersionContextFactory(IConfigProvider configProvider, IRepositoryStore repositoryStore, IBranchConfigurationCalculator branchConfigurationCalculator, IOptions<GitVersionOptions> options)
+    public GitVersionContextFactory(IConfigProvider configProvider, IRepositoryStore repositoryStore, IBranchConfigurationCalculator branchConfigurationCalculator, IBuildAgentResolver buildAgentResolver, ILog log, IOptions<GitVersionOptions> options)
     {
         this.configProvider = configProvider.NotNull();
         this.repositoryStore = repositoryStore.NotNull();
         this.branchConfigurationCalculator = branchConfigurationCalculator.NotNull();
+        this.buildAgent = buildAgentResolver.NotNull().Resolve();
+        this.log = log.NotNull();
         this.options = options.NotNull();
     }
 
     public GitVersionContext Create(GitVersionOptions gitVersionOptions)
     {
-        var currentBranch = this.repositoryStore.GetTargetBranch(gitVersionOptions.RepositoryInfo.TargetBranch);
-        if (currentBranch == null)
-            throw new InvalidOperationException("Need a branch to operate on");
+        var branchCommit = ResolveCurrentBranchCommit(gitVersionOptions);
+        var currentBranch = branchCommit.Branch;
+        var currentCommit = branchCommit.Commit;
+        var configuration = this.configProvider.Provide(this.options.Value.ConfigInfo.OverrideConfig);
+        var currentBranchConfig = this.branchConfigurationCalculator.GetBranchConfiguration(currentBranch, currentCommit, configuration);
+        var effectiveConfiguration = configuration.CalculateEffectiveConfiguration(currentBranchConfig);
+        var currentCommitTaggedVersion = this.repositoryStore.GetCurrentCommitTaggedVersion(currentCommit, effectiveConfiguration);
+        var numberOfUncommittedChanges = this.repositoryStore.GetNumberOfUncommittedChanges();
 
+        return new GitVersionContext(currentBranch, currentCommit, configuration, effectiveConfiguration, currentCommitTaggedVersion, numberOfUncommittedChanges);
+    }
+
+    private BranchCommit ResolveCurrentBranchCommit(GitVersionOptions gitVersionOptions)
+    {
+        var currentBranch = ResolveCurrentBranch();
         var currentCommit = this.repositoryStore.GetCurrentCommit(currentBranch, gitVersionOptions.RepositoryInfo.CommitId);
 
-        var configuration = this.configProvider.Provide(this.options.Value.ConfigInfo.OverrideConfig);
         if (currentBranch.IsDetachedHead)
         {
-            var branchForCommit = this.repositoryStore.GetBranchesContainingCommit(currentCommit, onlyTrackedBranches: gitVersionOptions.Settings.OnlyTrackedBranches).OnlyOrDefault();
-            currentBranch = branchForCommit ?? currentBranch;
+            currentBranch = this.repositoryStore.GetBranchesContainingCommit(currentCommit,
+                onlyTrackedBranches: gitVersionOptions.Settings.OnlyTrackedBranches).OnlyOrDefault()
+                            ?? currentBranch;
         }
 
-        var currentBranchConfig = this.branchConfigurationCalculator.GetBranchConfiguration(currentBranch, currentCommit, configuration);
-        var effectiveConfiguration = configuration.CalculateEffectiveConfiguration(currentBranchConfig);
-        var currentCommitTaggedVersion = this.repositoryStore.GetCurrentCommitTaggedVersion(currentCommit, effectiveConfiguration);
-        var numberOfUncommittedChanges = this.repositoryStore.GetNumberOfUncommittedChanges();
+        return new BranchCommit(currentCommit, currentBranch);
+    }
 
-        return new GitVersionContext(currentBranch, currentCommit, configuration, effectiveConfiguration, currentCommitTaggedVersion, numberOfUncommittedChanges);
+    private IBranch ResolveCurrentBranch()
+    {
+        var currentBranchName = ResolveCurrentBranchName();
+        var currentBranch = this.repositoryStore.GetTargetBranch(currentBranchName);
+
+        if (currentBranch == null)
+            throw new InvalidOperationException("Need a branch to operate on");
+
+        return currentBranch;
+    }
+
+    private string? ResolveCurrentBranchName()
+    {
+        var gitVersionOptions = this.options.Value;
+        var isDynamicRepository = !gitVersionOptions.RepositoryInfo.DynamicRepositoryClonePath.IsNullOrWhiteSpace();
+        var currentBranch = this.buildAgent.GetCurrentBranch(isDynamicRepository);
+
+        if (!currentBranch.IsNullOrWhiteSpace())
+        {
+            this.log.Info($"Branch from build environment: {currentBranch}");
+            return currentBranch;
+        }
+
+        var targetBranch = gitVersionOptions.RepositoryInfo.TargetBranch;
+
+        if (!targetBranch.IsNullOrWhiteSpace())
+        {
+            this.log.Info($"Branch from Git repository: {targetBranch}");
+            return targetBranch;
+        }
+
+        this.log.Info($"No branch found in environment or repository; this is probably a detached HEAD.");
+        return null;
     }
 }

src/GitVersion.Core/Model/GitVersionContext.cs

@@ -3,12 +3,28 @@
 namespace GitVersion;
 
 /// <summary>
-/// Contextual information about where GitVersion is being run
+///     Contextual information about where GitVersion is being run
 /// </summary>
 public class GitVersionContext
 {
+    public GitVersionContext(
+        IBranch currentBranch,
+        ICommit? currentCommit,
+        Config configuration,
+        EffectiveConfiguration effectiveConfiguration,
+        SemanticVersion currentCommitTaggedVersion,
+        int numberOfUncommittedChanges)
+    {
+        CurrentBranch = currentBranch;
+        CurrentCommit = currentCommit;
+        FullConfiguration = configuration;
+        Configuration = effectiveConfiguration;
+        CurrentCommitTaggedVersion = currentCommitTaggedVersion;
+        NumberOfUncommittedChanges = numberOfUncommittedChanges;
+    }
+
     /// <summary>
-    /// Contains the raw configuration, use Configuration for specific config based on the current GitVersion context.
+    ///     Contains the raw configuration, use Configuration for specific config based on the current GitVersion context.
     /// </summary>
     public Config FullConfiguration { get; }
 
@@ -17,20 +33,5 @@ public class GitVersionContext
     public IBranch CurrentBranch { get; }
     public ICommit? CurrentCommit { get; }
     public bool IsCurrentCommitTagged => CurrentCommitTaggedVersion != null;
-
     public int NumberOfUncommittedChanges { get; }
-
-    public GitVersionContext(IBranch currentBranch, ICommit? currentCommit,
-        Config configuration, EffectiveConfiguration effectiveConfiguration,
-        SemanticVersion currentCommitTaggedVersion, int numberOfUncommittedChanges)
-    {
-        CurrentBranch = currentBranch;
-        CurrentCommit = currentCommit;
-
-        FullConfiguration = configuration;
-        Configuration = effectiveConfiguration;
-
-        CurrentCommitTaggedVersion = currentCommitTaggedVersion;
-        NumberOfUncommittedChanges = numberOfUncommittedChanges;
-    }
 }