Made FindCommitBranchWasBranchedFrom way more efficient

Author: JakeGinnivan

GitVersionCore.Tests/IntegrationTests/FeatureBranchScenarios.cs

@@ -1,5 +1,3 @@
-using System;
-using System.Collections.Generic;
 using GitVersion;
 using LibGit2Sharp;
 using NUnit.Framework;
@@ -23,7 +21,7 @@ public void ShouldInheritIncrementCorrectlyWithMultiplePossibleParentsAndWeirdly
 
             //Merge it
             fixture.Repository.Checkout("development");
-            fixture.Repository.Merge(feature123, new Signature("me", "[email protected]", DateTimeOffset.Now));
+            fixture.Repository.Merge(feature123, SignatureBuilder.SignatureNow());
 
             //Create a second feature branch
             fixture.Repository.CreateBranch("feature/JIRA-124");
@@ -53,7 +51,7 @@ public void BranchCreatedAfterFastForwardMergeShouldInheritCorrectly()
 
             //Merge it
             fixture.Repository.Checkout("unstable");
-            fixture.Repository.Merge(feature123, new Signature("me", "[email protected]", DateTimeOffset.Now));
+            fixture.Repository.Merge(feature123, SignatureBuilder.SignatureNow());
 
             //Create a second feature branch
             fixture.Repository.CreateBranch("feature/JIRA-124");

GitVersionCore/LibGitExtensions.cs

@@ -26,15 +26,13 @@ public static Branch FindBranch(this IRepository repository, string branchName)
 
         public static Commit FindCommitBranchWasBranchedFrom(this Branch branch, IRepository repository, bool onlyTrackedBranches, params Branch[] excludedBranches)
         {
-            var currentBranches = branch.Tip.GetBranchesContainingCommit(repository, onlyTrackedBranches).ToList();
-            var tips = repository.Branches.Except(excludedBranches).Where(b => b != branch && !b.IsRemote).Select(b => b.Tip).ToList();
-            var branchPoint = branch.Commits.FirstOrDefault(c =>
+            var otherBranches = repository.Branches.Where(b => !b.IsRemote).Except(excludedBranches).Except(new [] { branch });
+            var mergeBases = otherBranches.Select(b =>
             {
-                if (tips.Contains(c)) return true;
-                var branchesContainingCommit = c.GetBranchesContainingCommit(repository, onlyTrackedBranches).ToList();
-                return branchesContainingCommit.Count > currentBranches.Count;
-            });
-            return branchPoint ?? branch.Tip;
+                var mergeBase = repository.Commits.FindMergeBase(b.Tip, branch.Tip);
+                return mergeBase;
+            }).Where(b => b != null);
+            return mergeBases.OrderByDescending(b => b.Committer.When).FirstOrDefault();
         }
 
         public static IEnumerable<Branch> GetBranchesContainingCommit(this Commit commit, IRepository repository, bool onlyTrackedBranches)