GitVersion.GitRepoMetadataProvider.FindMergeBase C# (CSharp) Method

        public Commit FindMergeBase(Branch branch, Branch otherBranch)
        {
            var key = Tuple.Create(branch, otherBranch);

            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;
            }

            using (Logger.IndentLog(string.Format("Finding merge base between '{0}' and '{1}'.", branch.FriendlyName, otherBranch.FriendlyName)))
            {
                // Otherbranch tip is a forward merge
                var commitToFindCommonBase = otherBranch.Tip;
                var commit = branch.Tip;
                if (otherBranch.Tip.Parents.Contains(commit))
                {
                    commitToFindCommonBase = otherBranch.Tip.Parents.First();
                }

                var findMergeBase = this.Repository.ObjectDatabase.FindMergeBase(commit, commitToFindCommonBase);
                if (findMergeBase != null)
                {
                    Logger.WriteInfo(string.Format("Found merge base of {0}", findMergeBase.Sha));
                    // We do not want to include merge base commits which got forward merged into the other branch
                    bool mergeBaseWasForwardMerge;
                    do
                    {
                        // Now make sure that the merge base is not a forward merge
                        mergeBaseWasForwardMerge = otherBranch.Commits
                            .SkipWhile(c => c != commitToFindCommonBase)
                            .TakeWhile(c => c != findMergeBase)
                            .Any(c => c.Parents.Contains(findMergeBase));
                        if (mergeBaseWasForwardMerge)
                        {
                            var second = commitToFindCommonBase.Parents.First();
                            var mergeBase = this.Repository.ObjectDatabase.FindMergeBase(commit, second);
                            if (mergeBase == findMergeBase)
                            {
                                break;
                            }
                            findMergeBase = mergeBase;
                            Logger.WriteInfo(string.Format("Merge base was due to a forward merge, next merge base is {0}", findMergeBase));
                        }
                    } while (mergeBaseWasForwardMerge);
                }

                // Store in cache.
                mergeBaseCache.Add(key, new MergeBaseData(branch, otherBranch, this.Repository, findMergeBase));

                return findMergeBase;
            }
        }