Cache the data in FindCommitBranchWasBranchedFrom().

Clear the caches for each new run of GitVersion.

Author: DanielRose

src/GitVersionCore/GitVersionContext.cs

@@ -16,6 +16,9 @@ public GitVersionContext(IRepository repository, Config configuration, bool isFo
 
         public GitVersionContext(IRepository repository, Branch currentBranch, Config configuration, bool onlyEvaluateTrackedBranches = true, string commitId = null)
         {
+            // With a new context, clear any in-memory caches.
+            LibGitExtensions.ClearInMemoryCache();
+
             Repository = repository;
             FullConfiguration = configuration;
             OnlyEvaluateTrackedBranches = onlyEvaluateTrackedBranches;

src/GitVersionCore/LibGitExtensions.cs

@@ -4,6 +4,7 @@ namespace GitVersion
     using System.Collections.Generic;
     using System.IO;
     using System.Linq;
+    using System.Runtime.CompilerServices;
     using JetBrains.Annotations;
 
     using LibGit2Sharp;
@@ -32,6 +33,8 @@ public static IEnumerable<SemanticVersion> GetVersionTagsOnBranch(this Branch br
             }));
         }
 
+        private static List<BranchCommit> cacheMergeBaseCommits;
+
         /// <summary>
         /// Find the commit where the given branch was branched from another branch.
         /// If there are multiple such commits and branches, returns the newest commit.
@@ -53,22 +56,22 @@ public static BranchCommit FindCommitBranchWasBranchedFrom([NotNull] this Branch
                     return BranchCommit.Empty;
                 }
 
-                var otherBranches = repository.Branches
-                    .ExcludingBranches(excludedBranches)
-                    .Where(b => !IsSameBranch(branch, b));
-                var mergeBases = otherBranches.Select(otherBranch =>
+                if (cacheMergeBaseCommits == null)
                 {
-                    if (otherBranch.Tip == null)
+                    cacheMergeBaseCommits = repository.Branches.Select(otherBranch =>
                     {
-                        Logger.WriteWarning(string.Format(missingTipFormat, otherBranch.FriendlyName));
-                        return BranchCommit.Empty;
-                    }
+                        if (otherBranch.Tip == null)
+                        {
+                            Logger.WriteWarning(string.Format(missingTipFormat, otherBranch.FriendlyName));
+                            return BranchCommit.Empty;
+                        }
 
-                    var findMergeBase = FindMergeBase(branch, otherBranch, repository);
-                    return new BranchCommit(findMergeBase,otherBranch);
-                }).Where(b => b.Commit != null).OrderByDescending(b => b.Commit.Committer.When);
+                        var findMergeBase = FindMergeBase(branch, otherBranch, repository);
+                        return new BranchCommit(findMergeBase, otherBranch);
+                    }).Where(b => b.Commit != null).OrderByDescending(b => b.Commit.Committer.When).ToList();
+                }
 
-                return mergeBases.FirstOrDefault();
+                return cacheMergeBaseCommits.ExcludingBranches(excludedBranches).FirstOrDefault(b => !IsSameBranch(branch, b.Branch));
             }
         }
 
@@ -146,6 +149,14 @@ public static bool IsSameBranch(Branch branch, Branch otherBranch)
             return otherBranchFriendlyName == branchFriendlyName;
         }
 
+        /// <summary>
+        /// Exclude the given branches (by value equality according to friendly name).
+        /// </summary>
+        public static IEnumerable<BranchCommit> ExcludingBranches([NotNull] this IEnumerable<BranchCommit> branches, [NotNull] IEnumerable<Branch> branchesToExclude)
+        {
+            return branches.Where(b => branchesToExclude.All(bte => !IsSameBranch(b.Branch, bte)));
+        }
+
         /// <summary>
         /// Exclude the given branches (by value equality according to friendly name).
         /// </summary>
@@ -210,7 +221,7 @@ public static IEnumerable<Branch> GetBranchesContainingCommit([NotNull] this Com
         public static GitObject PeeledTarget(this Tag tag)
         {
             GitObject cachedTarget;
-            if(_cachedPeeledTarget.TryGetValue(tag.Target.Sha, out cachedTarget))
+            if (_cachedPeeledTarget.TryGetValue(tag.Target.Sha, out cachedTarget))
             {
                 return cachedTarget;
             }
@@ -274,7 +285,7 @@ public static void CheckoutFilesIfExist(this IRepository repository, params stri
                     }
 
                     var fullPath = Path.Combine(repository.GetRepositoryDirectory(), fileName);
-                    using (var stream = ((Blob) treeEntry.Target).GetContentStream())
+                    using (var stream = ((Blob)treeEntry.Target).GetContentStream())
                     {
                         using (var streamReader = new BinaryReader(stream))
                         {
@@ -289,6 +300,13 @@ public static void CheckoutFilesIfExist(this IRepository repository, params stri
             }
         }
 
+        internal static void ClearInMemoryCache()
+        {
+            cacheMergeBaseCommits = null;
+            cachedMergeBase.Clear();
+            _cachedPeeledTarget.Clear();
+        }
+
         private class MergeBaseData
         {
             public Branch Branch { get; private set; }