Make sure that we're not evaluating excluded branches

.gitignore

@@ -90,3 +90,4 @@ NuGetExeBuild/
 NuGetRefBuild/
 Packages/
 NuGetTaskBuild/
+GitVersionTfsTaskBuild/

src/GitVersionCore/BranchConfigurationCalculator.cs

@@ -65,29 +65,33 @@ static KeyValuePair<string, BranchConfig> InheritBranchConfiguration(bool onlyEv
                 {
                     excludedBranches = CalculateWhenMultipleParents(repository, currentCommit, ref currentBranch, excludedBranches);
                 }
+
                 if (excludedInheritBranches == null)
                 {
                     excludedInheritBranches = repository.Branches.Where(b =>
                     {
                         var branchConfig = LookupBranchConfiguration(config, b);
-                        return branchConfig.Length == 1 && branchConfig[0].Value.Increment == IncrementStrategy.Inherit;
+
+                        // NOTE: if length is 0 we couldn't find the configuration for the branch e.g. "origin/master"
+                        // NOTE: if the length is greater than 1 we cannot decide which merge strategy to pick
+                        return (branchConfig.Length != 1) || (branchConfig.Length == 1 && branchConfig[0].Value.Increment == IncrementStrategy.Inherit);
                     }).ToList();
                 }
                 excludedBranches.ToList().ForEach(excludedInheritBranches.Add);
+                var branchesToEvaluate = repository.Branches.Except(excludedInheritBranches).ToList();
 
                 var branchPoint = currentBranch.FindCommitBranchWasBranchedFrom(repository, excludedInheritBranches.ToArray());
-
                 List<Branch> possibleParents;
                 if (branchPoint == null)
                 {
-                    possibleParents = currentCommit.GetBranchesContainingCommit(repository, true).Except(excludedInheritBranches).ToList();
+                    possibleParents = currentCommit.GetBranchesContainingCommit(repository, branchesToEvaluate, true).ToList();
                 }
                 else
                 {
-                    var branches = branchPoint.GetBranchesContainingCommit(repository, true).Except(excludedInheritBranches).ToList();
+                    var branches = branchPoint.GetBranchesContainingCommit(repository, branchesToEvaluate, true).ToList();
                     if (branches.Count > 1)
                     {
-                        var currentTipBranches = currentCommit.GetBranchesContainingCommit(repository, true).Except(excludedInheritBranches).ToList();
+                        var currentTipBranches = currentCommit.GetBranchesContainingCommit(repository, branchesToEvaluate, true).ToList();
                         possibleParents = branches.Except(currentTipBranches).ToList();
                     }
                     else

src/GitVersionCore/GitVersionContext.cs

@@ -48,7 +48,7 @@ public GitVersionContext(IRepository repository, Branch currentBranch, Config co
 
             if (currentBranch.IsDetachedHead())
             {
-                CurrentBranch = CurrentCommit.GetBranchesContainingCommit(repository, OnlyEvaluateTrackedBranches).OnlyOrDefault() ?? currentBranch;
+                CurrentBranch = CurrentCommit.GetBranchesContainingCommit(repository, repository.Branches.ToList(), OnlyEvaluateTrackedBranches).OnlyOrDefault() ?? currentBranch;
             }
             else
             {

src/GitVersionCore/LibGitExtensions.cs

@@ -92,15 +92,15 @@ static bool IsSameBranch(Branch branch, Branch b)
             return (b.IsRemote ? b.Name.Replace(b.Remote.Name + "/", string.Empty) : b.Name) != branch.Name;
         }
 
-        public static IEnumerable<Branch> GetBranchesContainingCommit([NotNull] this Commit commit, IRepository repository, bool onlyTrackedBranches)
+        public static IEnumerable<Branch> GetBranchesContainingCommit([NotNull] this Commit commit, IRepository repository, IList<Branch> branches, bool onlyTrackedBranches)
         {
             if (commit == null)
             {
                 throw new ArgumentNullException("commit");
             }
 
             var directBranchHasBeenFound = false;
-            foreach (var branch in repository.Branches)
+            foreach (var branch in branches)
             {
                 if (branch.Tip != null && branch.Tip.Sha != commit.Sha || (onlyTrackedBranches && !branch.IsTracking))
                 {
@@ -116,7 +116,7 @@ public static IEnumerable<Branch> GetBranchesContainingCommit([NotNull] this Com
                 yield break;
             }
 
-            foreach (var branch in repository.Branches.Where(b => (onlyTrackedBranches && !b.IsTracking)))
+            foreach (var branch in branches.Where(b => (onlyTrackedBranches && !b.IsTracking)))
             {
                 var commits = repository.Commits.QueryBy(new CommitFilter { Since = branch }).Where(c => c.Sha == commit.Sha);