Cache merge base

src/GitVersionCore/GitRepoMetadataProvider.cs

@@ -27,24 +27,29 @@ public IEnumerable<SemanticVersion> GetVersionTagsOnBranch(Branch branch, IRepos
         {
             if (semanticVersionTagsOnBranchCache.ContainsKey(branch))
             {
+                Logger.WriteDebug(string.Format("Cache hit for version tags on branch '{0}", branch.CanonicalName));
                 return semanticVersionTagsOnBranchCache[branch];
             }
-            var tags = repository.Tags.Select(t => t).ToList();
 
-            var versionTags = repository.Commits.QueryBy(new CommitFilter
+            using (Logger.IndentLog(string.Format("Getting version tags from branch '{0}'.", branch.CanonicalName)))
             {
-                IncludeReachableFrom = branch.Tip
-            })
-            .SelectMany(c => tags.Where(t => c.Sha == t.Target.Sha).SelectMany(t =>
-            {
-                SemanticVersion semver;
-                if (SemanticVersion.TryParse(t.FriendlyName, tagPrefixRegex, out semver))
-                    return new[] { semver };
-                return new SemanticVersion[0];
-            })).ToList();
-
-            semanticVersionTagsOnBranchCache.Add(branch, versionTags);
-            return versionTags;
+                var tags = repository.Tags.Select(t => t).ToList();
+
+                var versionTags = repository.Commits.QueryBy(new CommitFilter
+                {
+                    IncludeReachableFrom = branch.Tip
+                })
+                .SelectMany(c => tags.Where(t => c.Sha == t.Target.Sha).SelectMany(t =>
+                {
+                    SemanticVersion semver;
+                    if (SemanticVersion.TryParse(t.FriendlyName, tagPrefixRegex, out semver))
+                        return new[] { semver };
+                    return new SemanticVersion[0];
+                })).ToList();
+
+                semanticVersionTagsOnBranchCache.Add(branch, versionTags);
+                return versionTags;
+            }
         }
 
         // TODO Should we cache this?
@@ -54,7 +59,7 @@ public IEnumerable<Branch> GetBranchesContainingCommit([NotNull] Commit commit,
             {
                 throw new ArgumentNullException("commit");
             }
-
+            Logger.WriteDebug("Heh");
             using (Logger.IndentLog(string.Format("Getting branches containing the commit '{0}'.", commit.Id)))
             {
                 var directBranchHasBeenFound = false;
@@ -108,6 +113,9 @@ public Commit FindMergeBase(Branch branch, Branch otherBranch, IRepository repos
 
             if (mergeBaseCache.ContainsKey(key))
             {
+                Logger.WriteDebug(string.Format(
+                    "Cache hit for merge base between '{0}' and '{1}'.",
+                    branch.FriendlyName, otherBranch.FriendlyName));
                 return mergeBaseCache[key].MergeBase;
             }
 
@@ -183,6 +191,9 @@ List<BranchCommit> GetMergeCommitsForBranch(Branch branch)
         {
             if (mergeBaseCommitsCache.ContainsKey(branch))
             {
+                Logger.WriteDebug(string.Format(
+                    "Cache hit for getting merge commits for branch {0}.",
+                    branch.CanonicalName));
                 return mergeBaseCommitsCache[branch];
             }
 

src/GitVersionCore/GitVersionCacheKeyFactory.cs

@@ -123,7 +123,15 @@ static List<string> CalculateDirectoryContents(string root)
 
         private static string GetRepositorySnapshotHash(GitPreparer gitPreparer)
         {
-            var repositorySnapshot = gitPreparer.WithRepository(repo => string.Join(":", repo.Head.CanonicalName, repo.Head.Tip.Sha));
+            var repositorySnapshot = gitPreparer.WithRepository(repo => {
+                var head = repo.Head;
+                if (head.Tip == null)
+                {
+                    return head.CanonicalName;
+                }
+                var hash = string.Join(":", head.CanonicalName, head.Tip.Sha);
+                return hash;
+            });
             return GetHash(repositorySnapshot);
         }
 

src/GitVersionCore/GitVersionFinder.cs

@@ -8,7 +8,10 @@ public class GitVersionFinder
     {
         public SemanticVersion FindVersion(GitVersionContext context)
         {
-            Logger.WriteInfo(string.Format("Running against branch: {0} ({1})", context.CurrentBranch.FriendlyName, context.CurrentCommit.Sha));
+            Logger.WriteInfo(string.Format(
+                "Running against branch: {0} ({1})",
+                context.CurrentBranch.FriendlyName,
+                context.CurrentCommit == null ? "-" : context.CurrentCommit.Sha));
             EnsureMainTopologyConstraints(context);
 
             var filePath = Path.Combine(context.Repository.GetRepositoryDirectory(), "NextVersion.txt");

src/GitVersionTask.Tests/GitVersionTaskDirectoryTests.cs

@@ -61,6 +61,7 @@ public void Finds_GitDirectory_In_Parent()
         }
         catch (Exception ex)
         {
+            // TODO I think this test is wrong.. It throws a different exception
             // `RepositoryNotFoundException` means that it couldn't find the .git directory,
             // any other exception means that the .git was found but there was some other issue that this test doesn't care about.
             Assert.IsNotAssignableFrom<RepositoryNotFoundException>(ex);