Move the logic which determines the desired branch to a new constructor on the GitVersionContext class

This allows this new logic introduced by the PR to be shared by the ExecuteCore class and the the unit testing fixture without having to duplicate code.

Author: Jericho

src/GitVersionCore.Tests/GitToolsTestingExtensions.cs

@@ -15,7 +15,7 @@ public static Config ApplyDefaults(this Config config)
             return config;
         }
 
-        public static VersionVariables GetVersion(this RepositoryFixtureBase fixture, Config configuration = null, IRepository repository = null, string commitId = null, bool isForTrackedBranchOnly = true)
+        public static VersionVariables GetVersion(this RepositoryFixtureBase fixture, Config configuration = null, IRepository repository = null, string commitId = null, bool isForTrackedBranchOnly = true, string targetBranch = null)
         {
             if (configuration == null)
             {
@@ -37,19 +37,19 @@ public static VersionVariables GetVersion(this RepositoryFixtureBase fixture, Co
             }
         }
 
-        public static void AssertFullSemver(this RepositoryFixtureBase fixture, string fullSemver, IRepository repository = null, string commitId = null, bool isForTrackedBranchOnly = true)
+        public static void AssertFullSemver(this RepositoryFixtureBase fixture, string fullSemver, IRepository repository = null, string commitId = null, bool isForTrackedBranchOnly = true, string targetBranch = null)
         {
-            fixture.AssertFullSemver(new Config(), fullSemver, repository, commitId, isForTrackedBranchOnly);
+            fixture.AssertFullSemver(new Config(), fullSemver, repository, commitId, isForTrackedBranchOnly, targetBranch);
         }
 
-        public static void AssertFullSemver(this RepositoryFixtureBase fixture, Config configuration, string fullSemver, IRepository repository = null, string commitId = null, bool isForTrackedBranchOnly = true)
+        public static void AssertFullSemver(this RepositoryFixtureBase fixture, Config configuration, string fullSemver, IRepository repository = null, string commitId = null, bool isForTrackedBranchOnly = true, string targetBranch = null)
         {
             ConfigurationProvider.ApplyDefaultsTo(configuration);
             Console.WriteLine("---------");
 
             try
             {
-                var variables = fixture.GetVersion(configuration, repository, commitId, isForTrackedBranchOnly);
+                var variables = fixture.GetVersion(configuration, repository, commitId, isForTrackedBranchOnly, targetBranch);
                 variables.FullSemVer.ShouldBe(fullSemver);
             }
             catch (Exception)

src/GitVersionCore.Tests/IntegrationTests/BranchWithoutCommitScenario.cs

@@ -0,0 +1,22 @@
+using GitTools.Testing;
+using GitVersionCore.Tests;
+using LibGit2Sharp;
+using NUnit.Framework;
+
+[TestFixture]
+public class BranchWithoutCommitScenario
+{
+    [Test]
+    public void CanTakeVersionFromReleaseBranch()
+    {
+        using (var fixture = new EmptyRepositoryFixture())
+        {
+            fixture.Repository.MakeATaggedCommit("1.0.3");
+            var commit = fixture.Repository.MakeACommit();
+            fixture.Repository.CreateBranch("release-4.0.123");
+            fixture.Checkout(commit.Sha);
+
+            fixture.AssertFullSemver("4.0.123-beta.1+0", fixture.Repository, commit.Sha, false, "release-4.0.123");
+        }
+    }
+}

src/GitVersionCore/ExecuteCore.cs

@@ -108,18 +108,7 @@ VersionVariables ExecuteInternal(string targetBranch, string commitId, GitPrepar
 
             return gitPreparer.WithRepository(repo =>
             {
-                // By default, we assume HEAD is pointing to the desired branch
-                var currentBranch = repo.Head;
-
-                // There are some edge cases where HEAD is not pointing to the desired branch.
-                // Therefore it's important to verify if 'currentBranch' is indeed the desired branch
-                if (currentBranch.CanonicalName != targetBranch)
-                {
-                    // In the case where HEAD is not the desired branch, try to find the branch with matching name
-                    currentBranch = repo.Branches.SingleOrDefault(b => b.CanonicalName == targetBranch) ?? repo.Head;
-                }
-
-                var gitVersionContext = new GitVersionContext(repo, currentBranch, configuration, commitId: commitId);
+                var gitVersionContext = new GitVersionContext(repo, targetBranch, configuration, commitId: commitId);
                 var semanticVersion = versionFinder.FindVersion(gitVersionContext);
 
                 return VariableProvider.GetVariablesFor(semanticVersion, gitVersionContext.Configuration, gitVersionContext.IsCurrentCommitTagged);

src/GitVersionCore/GitVersionContext.cs

@@ -14,6 +14,11 @@ public GitVersionContext(IRepository repository, Config configuration, bool isFo
         {
         }
 
+        public GitVersionContext(IRepository repository, string targetBranch, Config configuration, bool onlyEvaluateTrackedBranches = true, string commitId = null)
+             : this(repository, repository.Branches.SingleOrDefault(b => b.CanonicalName == targetBranch || b.FriendlyName == targetBranch) ?? repository.Head, configuration, onlyEvaluateTrackedBranches, commitId)
+        {
+        }
+
         public GitVersionContext(IRepository repository, Branch currentBranch, Config configuration, bool onlyEvaluateTrackedBranches = true, string commitId = null)
         {
             Repository = repository;