Resolving Pull Requests in TeamCity context

GitFlowVersion/BranchClassifier.cs

@@ -42,7 +42,7 @@ public static bool IsFeature(this Branch branch)
 
         public static bool IsPullRequest(this Branch branch)
         {
-            return branch.CanonicalName.Contains("/pull/") || TeamCity.IsBuildingAPullRequest();
+            return branch.CanonicalName.Contains("/pull/");
         }
     }
-}
+}

GitFlowVersion/BranchFinders/DevelopVersionFinder.cs

@@ -35,7 +35,7 @@ SemanticVersion GetSemanticVersion()
                                         };
             var versionFromMaster = versionOnMasterFinder.Execute();
 
-            var developBranch = Repository.GetBranch("develop");
+            var developBranch = Repository.Branches["develop"];
             var preReleasePartOne = developBranch.Commits
                 .SkipWhile(x => x != Commit)
                 .TakeWhile(x => x.When() >= versionFromMaster.Timestamp)

GitFlowVersion/BranchFinders/FeatureVersionFinder.cs

@@ -18,9 +18,11 @@ public FeatureVersionFinder()
 
         public VersionAndBranch FindVersion()
         {
+            var ancestor = FindCommonAncestorWithDevelop();
+
             var firstCommitOnBranch = FindFirstCommitOnBranchFunc();
 
-            if (firstCommitOnBranch == Commit.Id) //no commits on branch. use develop approach
+            if (firstCommitOnBranch == null) //no commits on branch. use develop approach
             {
                 var developVersionFinder = new DevelopVersionFinder
                 {
@@ -52,15 +54,45 @@ public VersionAndBranch FindVersion()
                     Patch = 0,
                     Stability = Stability.Unstable,
                     PreReleasePartOne = 0,
-                    Suffix = firstCommitOnBranch.Prefix()
+                    Suffix = ancestor.Prefix()
                 }
             };
         }
 
+        private Commit FindCommonAncestorWithDevelop()
+        {
+            var ancestor = Repository.Commits.FindCommonAncestor(
+                Repository.Branches["develop"].Tip,
+                FeatureBranch.Tip);
+
+            if (ancestor != null)
+            {
+                return ancestor;
+            }
+
+            throw new ErrorException(
+                "A feature branch is expected to branch off of 'develop'. " 
+                + string.Format("However, branch 'develop' and '{0}' do not share a common ancestor."
+                , FeatureBranch.Name));
+        }
+
 
         public ObjectId FindFirstCommitOnBranch()
         {
-            return Repository.Refs.Log(FeatureBranch.CanonicalName).Last().To;
+            var filter = new CommitFilter
+                         {
+                             Since = FeatureBranch,
+                             Until = Repository.Branches["develop"]
+                         };
+
+            var commits = Repository.Commits.QueryBy(filter).ToList();
+
+            if (commits.Count == 0)
+            {
+                return null;
+            }
+
+            return commits.Last().Id;
         }
     }
 

GitFlowVersion/BranchFinders/HotfixVersionFinder.cs

@@ -12,6 +12,8 @@ class HotfixVersionFinder
 
         public VersionAndBranch FindVersion()
         {
+            EnsureHotfixBranchShareACommonAncestorWithMaster();
+
             var versionString = HotfixBranch.GetHotfixSuffix();
 
             int patch;
@@ -63,5 +65,22 @@ public VersionAndBranch FindVersion()
             throw new Exception(message);
 
         }
+
+        private void EnsureHotfixBranchShareACommonAncestorWithMaster()
+        {
+            var ancestor = Repository.Commits.FindCommonAncestor(
+                Repository.Branches["master"].Tip,
+                HotfixBranch.Tip);
+
+            if (ancestor != null)
+            {
+                return;
+            }
+
+            throw new ErrorException(
+                "A hotfix branch is expected to branch off of 'master'. "
+                + string.Format("However, branch 'master' and '{0}' do not share a common ancestor."
+                , HotfixBranch.Name));
+        }
     }
-}
+}

GitFlowVersion/BranchFinders/PullVersionFinder.cs

@@ -10,6 +10,8 @@ class PullVersionFinder
 
         public VersionAndBranch FindVersion()
         {
+            EnsurePullBranchShareACommonAncestorWithDevelop();
+
             var versionOnMasterFinder = new VersionOnMasterFinder
             {
                 Repository = Repository,
@@ -18,16 +20,7 @@ public VersionAndBranch FindVersion()
             var versionFromMaster = versionOnMasterFinder
                 .Execute();
 
-            string suffix;
-            if (TeamCity.IsBuildingAPullRequest())
-            {
-                suffix = TeamCity.CurrentPullRequestNo().ToString();
-            }
-            else
-            {
-                suffix = PullBranch.CanonicalName.Substring(PullBranch.CanonicalName.IndexOf("/pull/") + 6);
-            }
-
+            var suffix = ExtractIssueNumber();
 
             return new VersionAndBranch
             {
@@ -45,5 +38,62 @@ public VersionAndBranch FindVersion()
                 }
             };
         }
+
+        private string ExtractIssueNumber()
+        {
+            const string prefix = "/pull/";
+            int start = PullBranch.CanonicalName.IndexOf(prefix, System.StringComparison.Ordinal);
+            int end = PullBranch.CanonicalName.LastIndexOf("/merge", PullBranch.CanonicalName.Length - 1,
+                System.StringComparison.Ordinal);
+
+            string issueNumber = null;
+
+            if (start != -1 && end != -1 && start + prefix.Length <= end)
+            {
+                start += prefix.Length;
+                issueNumber = PullBranch.CanonicalName.Substring(start, end - start);
+            }
+
+            if (!LooksLikeAValidPullRequestNumber(issueNumber))
+            {
+                throw new ErrorException(string.Format("Unable to extract pull request number from '{0}'.",
+                    PullBranch.CanonicalName));
+            }
+
+            return issueNumber;
+        }
+
+        private bool LooksLikeAValidPullRequestNumber(string issueNumber)
+        {
+            if (string.IsNullOrEmpty(issueNumber))
+            {
+                return false;
+            }
+
+            uint res;
+            if (!uint.TryParse(issueNumber, out res))
+            {
+                return false;
+            }
+
+            return true;
+        }
+
+        private void EnsurePullBranchShareACommonAncestorWithDevelop()
+        {
+            var ancestor = Repository.Commits.FindCommonAncestor(
+                Repository.Branches["develop"].Tip,
+                PullBranch.Tip);
+
+            if (ancestor != null)
+            {
+                return;
+            }
+
+            throw new ErrorException(
+                "A pull request branch is expected to branch off of 'develop'. "
+                + string.Format("However, branch 'develop' and '{0}' do not share a common ancestor."
+                , PullBranch.Name));
+        }
     }
-}
+}

GitFlowVersion/GitFlowVersionFinder.cs

@@ -1,5 +1,6 @@
 namespace GitFlowVersion
 {
+    using System;
     using LibGit2Sharp;
 
     public class GitFlowVersionFinder
@@ -10,6 +11,8 @@ public class GitFlowVersionFinder
 
         public VersionAndBranch FindVersion()
         {
+            EnsureMainTopologyConstraints();
+
             if (Branch.IsMaster())
             {
                 return new MasterVersionFinder
@@ -73,5 +76,35 @@ public VersionAndBranch FindVersion()
                        FeatureBranch = Branch
                    }.FindVersion();
         }
+
+        private void EnsureMainTopologyConstraints()
+        {
+            EnsureLocalBranchExists("master");
+            EnsureLocalBranchExists("develop");
+            EnsureHeadIsNotDetached();
+        }
+
+        private void EnsureHeadIsNotDetached()
+        {
+            if (!Branch.CanonicalName.Equals("(no branch)", StringComparison.OrdinalIgnoreCase))
+            {
+                return;
+            }
+
+            throw new ErrorException(
+                string.Format("It looks like the branch being examined is a detached Head pointing to commit '{0}'. "
+                + "Without a proper branch name GITFlowVersion cannot determine the build version."
+                , Branch.Tip.Id.ToString(7)));
+        }
+
+        private void EnsureLocalBranchExists(string branchName)
+        {
+            if (Repository.Branches[branchName] != null)
+            {
+                return;
+            }
+
+            throw new ErrorException(string.Format("This repository doesn't contain a branch named '{0}'. Please create one.", branchName));
+        }
     }
-}
+}

GitFlowVersion/LibGitExtensions.cs

@@ -55,51 +55,5 @@ public static IEnumerable<Commit> CommitsPriorToThan(this Branch branch, DateTim
         {
             return branch.Commits.SkipWhile(c => c.When() > olderThan);
         }
-
-        public static Branch GetBranch(this IRepository repository, string name)
-        {
-            var branch = repository.Branches.FirstOrDefault(b => b.Name == name);
-
-            if (branch == null)
-            {
-
-                if (!repository.Network.Remotes.Any())
-                {
-                    Logger.WriteInfo("No remotes found");
-                }
-                else
-                {
-                    var remote = repository.Network.Remotes.First();
-
-                    Logger.WriteInfo(string.Format("No local branch with name {0} found, going to try on the remote {1}({2})", name, remote.Name, remote.Url));
-                    try
-                    {
-                        repository.Network.Fetch(remote);
-                    }
-                    catch (LibGit2SharpException exception)
-                    {
-                        if (exception.Message.Contains("This transport isn't implemented"))
-                        {
-                            var message = string.Format("Could not fetch from '{0}' since LibGit2 does not support the transport. You have most likely cloned using SSH. If there is a remote branch named '{1}' then fetch it manually, otherwise please create a local branch named '{1}'.", remote.Url, name);
-                            throw new MissingBranchException(message, exception);
-                        }
-                        throw;
-                    }
-
-                    branch = repository.Branches.FirstOrDefault(b => b.Name.EndsWith("/" + name));
-                }
-            }
-
-            if (branch == null)
-            {
-                var branchNames = string.Join(";", repository.Branches);
-                var message = string.Format("Could not find branch '{0}' in the repository, please create one. Existing branches:{1}", name, branchNames);
-                throw new Exception(message);
-            }
-
-            return branch;
-        }
-
-
     }
 }