Guess when there are two branches pointing at the same commit. Trying…

GitVersionCore.Tests/Fixtures/RemoteRepositoryFixture.cs

@@ -20,6 +20,14 @@ public RemoteRepositoryFixture(Config configuration)
         CloneRepository();
     }
 
+    /// <summary>
+    /// Simulates running on build server
+    /// </summary>
+    public void InitialiseRepo()
+    {
+        new GitPreparer(null, null, new Authentication(), null, false, LocalRepositoryPath).Initialise(true);
+    }
+
     static IRepository CreateNewRepository(string path)
     {
         LibGit2Sharp.Repository.Init(path);

GitVersionCore.Tests/GitVersionCore.Tests.csproj

@@ -85,6 +85,7 @@
     <Compile Include="Fixtures\BaseGitFlowRepositoryFixture.cs" />
     <Compile Include="GitVersionContextTests.cs" />
     <Compile Include="Helpers\DirectoryHelper.cs" />
+    <Compile Include="IntegrationTests\OtherScenarios.cs" />
     <Compile Include="IntegrationTests\PullRequestScenarios.cs" />
     <Compile Include="IntegrationTests\RemoteRepositoryScenarios.cs" />
     <Compile Include="IntegrationTests\DevelopScenarios.cs" />

GitVersionCore.Tests/Helpers/GitTestExtensions.cs

@@ -1,42 +1,13 @@
 using System;
-using System.Diagnostics;
 using System.IO;
 using System.Linq;
-using System.Text;
 using GitVersion;
-using GitVersion.Helpers;
 using LibGit2Sharp;
 
 public static class GitTestExtensions
 {
     static int pad = 1;
 
-    public static void DumpGraph(this IRepository repository)
-    {
-        var output = new StringBuilder();
-
-        try
-        {
-            ProcessHelper.Run(
-                o => output.AppendLine(o),
-                e => output.AppendLineFormat("ERROR: {0}", e),
-                null,
-                "git",
-                @"log --graph --abbrev-commit --decorate --date=relative --all --remotes=*",
-                repository.Info.Path);
-        }
-        catch (FileNotFoundException exception)
-        {
-            if (exception.FileName != "git")
-                throw;
-
-            output.AppendLine("Could not execute 'git log' due to the following error:");
-            output.AppendLine(exception.ToString());
-        }
-
-        Trace.Write(output.ToString());
-    }
-
     public static Commit MakeACommit(this IRepository repository)
     {
         return CreateFileAndCommit(repository, Guid.NewGuid().ToString());

GitVersionCore.Tests/IntegrationTests/OtherScenarios.cs

@@ -0,0 +1,53 @@
+namespace GitVersionCore.Tests.IntegrationTests
+{
+    using System.Linq;
+    using GitVersion;
+    using LibGit2Sharp;
+    using NUnit.Framework;
+
+    [TestFixture]
+    public class OtherScenarios
+    {
+        // This is an attempt to automatically resolve the issue where you cannot build
+        // when multiple branches point at the same commit
+        // Current implementation favors master, then branches without - or / in their name
+
+        [Test]
+        public void DoNotBlowUpWhenMasterAndDevelopPointAtSameCommit()
+        {
+            using (var fixture = new RemoteRepositoryFixture(new Config()))
+            {
+                fixture.Repository.MakeACommit();
+                fixture.Repository.MakeATaggedCommit("1.0.0");
+                fixture.Repository.MakeACommit();
+                fixture.Repository.CreateBranch("develop");
+
+                fixture.LocalRepository.Network.Fetch(fixture.LocalRepository.Network.Remotes.First());
+                fixture.LocalRepository.Checkout(fixture.Repository.Head.Tip);
+                fixture.LocalRepository.Branches.Remove("master");
+                fixture.InitialiseRepo();
+                fixture.AssertFullSemver("1.0.1+1");
+            }
+        }
+
+        [Test]
+        public void DoNotBlowUpWhenDevelopAndFeatureBranchPointAtSameCommit()
+        {
+            using (var fixture = new RemoteRepositoryFixture(new Config()))
+            {
+                fixture.Repository.MakeACommit();
+                fixture.Repository.CreateBranch("develop").Checkout();
+                fixture.Repository.MakeACommit();
+                fixture.Repository.MakeATaggedCommit("1.0.0");
+                fixture.Repository.MakeACommit();
+                fixture.Repository.CreateBranch("feature/someFeature");
+
+                fixture.LocalRepository.Network.Fetch(fixture.LocalRepository.Network.Remotes.First());
+                fixture.LocalRepository.Checkout(fixture.Repository.Head.Tip);
+                fixture.LocalRepository.Branches.Remove("master");
+                fixture.InitialiseRepo();
+                fixture.AssertFullSemver("1.1.0-unstable.1");
+            }
+        }
+    }
+}

GitVersionCore/BuildServers/GitHelper.cs

@@ -50,12 +50,33 @@ public static void NormalizeGitDirectory(string gitDirectory, Authentication aut
 
                 if (localBranchesWhereCommitShaIsHead.Count > 1)
                 {
-                    var names = string.Join(", ", localBranchesWhereCommitShaIsHead.Select(r => r.CanonicalName));
-                    var message = string.Format("Found more than one local branch pointing at the commit '{0}'. Unable to determine which one to use ({1}).", headSha, names);
-                    throw new WarningException(message);
+                    var branchNames = localBranchesWhereCommitShaIsHead.Select(r => r.CanonicalName);
+                    var csvNames = string.Join(", ", branchNames);
+                    const string moveBranchMsg = "Move one of the branches along a commit to remove warning";
+
+                    Logger.WriteWarning(string.Format("Found more than one local branch pointing at the commit '{0}' ({1}).", headSha, csvNames));
+                    var master = localBranchesWhereCommitShaIsHead.SingleOrDefault(n => n.Name == "master");
+                    if (master != null)
+                    {
+                        Logger.WriteWarning("Because one of the branches is 'master', will build master." + moveBranchMsg);
+                        master.Checkout();
+                    }
+                    else
+                    {
+                        var branchesWithoutSeparators = localBranchesWhereCommitShaIsHead.Where(b => !b.Name.Contains('/') && !b.Name.Contains('-')).ToList();
+                        if (branchesWithoutSeparators.Count == 1)
+                        {
+                            var branchWithoutSeparator = branchesWithoutSeparators[0];
+                            Logger.WriteWarning(string.Format("Choosing {0} as it is the only branch without / or - in it. " + moveBranchMsg, branchWithoutSeparator.CanonicalName));
+                            branchWithoutSeparator.Checkout();
+                        }
+                        else
+                        {
+                            throw new WarningException("Failed to try and guess branch to use. " + moveBranchMsg);
+                        }
+                    }
                 }
-
-                if (localBranchesWhereCommitShaIsHead.Count == 0)
+                else if (localBranchesWhereCommitShaIsHead.Count == 0)
                 {
                     Logger.WriteInfo(string.Format("No local branch pointing at the commit '{0}'. Fake branch needs to be created.", headSha));
                     CreateFakeBranchPointingAtThePullRequestTip(repo, authentication);

GitVersionCore/LibGitExtensions.cs

@@ -2,8 +2,11 @@ namespace GitVersion
 {
     using System;
     using System.Collections.Generic;
+    using System.Diagnostics;
     using System.IO;
     using System.Linq;
+    using System.Text;
+    using GitVersion.Helpers;
     using LibGit2Sharp;
 
     static class LibGitExtensions
@@ -174,5 +177,40 @@ public static void CheckoutFilesIfExist(this IRepository repository, params stri
                 }
             }
         }
+
+        public static void DumpGraph(this IRepository repository, Action<string> writer = null, int? maxCommits = null)
+        {
+            DumpGraph(repository.Info.Path, writer, maxCommits);
+        }
+
+        public static void DumpGraph(string workingDirectory, Action<string> writer = null, int? maxCommits = null)
+        {
+            var output = new StringBuilder();
+
+            try
+            {
+                ProcessHelper.Run(
+                    o => output.AppendLine(o),
+                    e => output.AppendLineFormat("ERROR: {0}", e),
+                    null,
+                    "git",
+                    @"log --graph --format=""%h %cr %d"" --decorate --date=relative --all --remotes=*" + (maxCommits != null ? string.Format(" -n {0}", maxCommits) : null),
+                    //@"log --graph --abbrev-commit --decorate --date=relative --all --remotes=*",
+                    workingDirectory);
+            }
+            catch (FileNotFoundException exception)
+            {
+                if (exception.FileName != "git")
+                {
+                    throw;
+                }
+
+                output.AppendLine("Could not execute 'git log' due to the following error:");
+                output.AppendLine(exception.ToString());
+            }
+
+            if (writer != null) writer(output.ToString());
+            else Trace.Write(output.ToString());
+        }
     }
 }

GitVersionExe/Program.cs

@@ -32,11 +32,11 @@ static void Main()
 
         static int VerifyArgumentsAndRun()
         {
+            Arguments arguments = null;
             try
             {
                 var fileSystem = new FileSystem();
 
-                Arguments arguments;
                 var argumentsWithoutExeName = GetArgumentsWithoutExeName();
                 try
                 {
@@ -99,6 +99,14 @@ static int VerifyArgumentsAndRun()
             {
                 var error = string.Format("An unexpected error occurred:\r\n{0}", exception);
                 Logger.WriteError(error);
+
+                if (arguments != null)
+                {
+                    Logger.WriteInfo(string.Empty);
+                    Logger.WriteInfo("Here is the current git graph (please include in issue): ");
+                    Logger.WriteInfo("Showing max of 100 commits");
+                    LibGitExtensions.DumpGraph(arguments.TargetPath, Logger.WriteInfo, 100);
+                }
                 return 1;
             }