Add support for ZDiff3

LibGit2Sharp.Tests/MergeFixture.cs

@@ -669,6 +669,54 @@ public void CanSpecifyConflictFileStrategy(CheckoutFileConflictStrategy conflict
             }
         }
 
+        [Theory]
+        [InlineData(CheckoutFileConflictStrategy.Merge)]
+        [InlineData(CheckoutFileConflictStrategy.Diff3)]
+        [InlineData(CheckoutFileConflictStrategy.ZDiff3)]
+        public void CanSpecifyMergeConflictFileStrategy(CheckoutFileConflictStrategy conflictStrategy)
+        {
+            const string conflictFile = "a.txt";
+            const string expectedFileFormat = "a.{0}.txt";
+            const string conflictBranchName = "conflicts";
+            const string resultsBranchName = "results";
+
+            string expectedFileName = string.Format(expectedFileFormat, conflictStrategy.ToString().ToLower());
+            string path = SandboxMergeConflictTestRepo();
+
+            using (var repo = new Repository(path))
+            {
+                Branch branch = repo.Branches[conflictBranchName];
+                Assert.NotNull(branch);
+
+                // Ensure the working directory is clean before merging
+                repo.Reset(ResetMode.Hard);
+                repo.RemoveUntrackedFiles();
+
+                MergeOptions mergeOptions = new MergeOptions()
+                {
+                    FileConflictStrategy = conflictStrategy
+                };
+
+                MergeResult result = repo.Merge(branch, Constants.Signature, mergeOptions);
+                Assert.Equal(MergeStatus.Conflicts, result.Status);
+
+                // Get the information on the conflict.
+                Conflict conflict = repo.Index.Conflicts[conflictFile];
+
+                Assert.NotNull(conflict);
+                Assert.NotNull(conflict.Theirs);
+                Assert.NotNull(conflict.Ours);
+
+                Commit expectedCommit = repo.Branches[resultsBranchName].Tip;
+                Blob expectedBlob = (Blob)expectedCommit[expectedFileName].Target;
+                string expectedContent = expectedBlob.GetContentText(new FilteringOptions(expectedFileName));
+
+                // Verify the content of the file on disk contains conflict markers.
+                string fileContent = File.ReadAllText(Path.Combine(repo.Info.WorkingDirectory, conflictFile));
+                Assert.Equal(expectedContent, fileContent);
+            }
+        }
+
         [Theory]
         [InlineData(MergeFileFavor.Ours)]
         [InlineData(MergeFileFavor.Theirs)]

LibGit2Sharp.Tests/Resources/mergeconflict_testrepo_wd/a.txt

@@ -0,0 +1,7 @@
+A
+B
+C
+D
+E
+F
+G

LibGit2Sharp.Tests/Resources/mergeconflict_testrepo_wd/dot_git/HEAD

@@ -0,0 +1 @@
+ref: refs/heads/main

LibGit2Sharp.Tests/Resources/mergeconflict_testrepo_wd/dot_git/config

@@ -0,0 +1,6 @@
+[core]
+	repositoryformatversion = 0
+	filemode = false
+	bare = false
+	logallrefupdates = true
+	ignorecase = true

LibGit2Sharp.Tests/Resources/mergeconflict_testrepo_wd/dot_git/info/refs

@@ -0,0 +1,3 @@
+cd4b13da8859445f4357c1e24d92b483ffe2dc85	refs/heads/conflicts
+0076e9fe99d1c2df56cd939a897db42d714b088b	refs/heads/main
+139641856b0ef7941f583972614c1df9bb26939b	refs/heads/results

LibGit2Sharp.Tests/Resources/mergeconflict_testrepo_wd/dot_git/objects/info/packs

@@ -0,0 +1,3 @@
+P pack-5fd168964fc34fdc1e4a50ae098e21799dd906a4.pack
+P pack-9ea8f8acf571abc3f715ea91223671d542aacb6c.pack
+

LibGit2Sharp.Tests/Resources/mergeconflict_testrepo_wd/dot_git/packed-refs

@@ -0,0 +1,4 @@
+# pack-refs with: peeled fully-peeled sorted 
+cd4b13da8859445f4357c1e24d92b483ffe2dc85 refs/heads/conflicts
+0076e9fe99d1c2df56cd939a897db42d714b088b refs/heads/main
+139641856b0ef7941f583972614c1df9bb26939b refs/heads/results

LibGit2Sharp.Tests/TestHelpers/BaseFixture.cs

@@ -36,6 +36,7 @@ static BaseFixture()
         public static string ShallowTestRepoPath { get; private set; }
         public static string MergedTestRepoWorkingDirPath { get; private set; }
         public static string MergeTestRepoWorkingDirPath { get; private set; }
+        public static string MergeConflictTestRepoWorkingDirPath { get; private set; }
         public static string MergeRenamesTestRepoWorkingDirPath { get; private set; }
         public static string RevertTestRepoWorkingDirPath { get; private set; }
         public static string SubmoduleTestRepoWorkingDirPath { get; private set; }
@@ -81,6 +82,7 @@ private static void SetUpTestEnvironment()
             MergedTestRepoWorkingDirPath = Path.Combine(ResourcesDirectory.FullName, "mergedrepo_wd");
             MergeRenamesTestRepoWorkingDirPath = Path.Combine(ResourcesDirectory.FullName, "mergerenames_wd");
             MergeTestRepoWorkingDirPath = Path.Combine(ResourcesDirectory.FullName, "merge_testrepo_wd");
+            MergeConflictTestRepoWorkingDirPath = Path.Combine(ResourcesDirectory.FullName, "mergeconflict_testrepo_wd");
             RevertTestRepoWorkingDirPath = Path.Combine(ResourcesDirectory.FullName, "revert_testrepo_wd");
             SubmoduleTestRepoWorkingDirPath = Path.Combine(ResourcesDirectory.FullName, "submodule_wd");
             SubmoduleTargetTestRepoWorkingDirPath = Path.Combine(ResourcesDirectory.FullName, "submodule_target_wd");
@@ -201,6 +203,11 @@ protected string SandboxMergeTestRepo()
             return Sandbox(MergeTestRepoWorkingDirPath);
         }
 
+        protected string SandboxMergeConflictTestRepo()
+        {
+            return Sandbox(MergeConflictTestRepoWorkingDirPath);
+        }
+
         protected string SandboxRevertTestRepo()
         {
             return Sandbox(RevertTestRepoWorkingDirPath);

LibGit2Sharp/CheckoutFileConflictStrategy.cs

@@ -33,6 +33,11 @@ public enum CheckoutFileConflictStrategy
         /// <summary>
         /// Write diff3 formated files for conflicts.
         /// </summary>
-        Diff3
+        Diff3,
+
+        /// <summary>
+        /// Write zdiff3 formated files for conflicts.
+        /// </summary>
+        ZDiff3
     }
 }

LibGit2Sharp/Core/GitCheckoutOpts.cs

@@ -105,6 +105,11 @@ internal enum CheckoutStrategy
         /// </summary>
         GIT_CHECKOUT_DONT_WRITE_INDEX = (1 << 23),
 
+		/// <summary>
+		/// Include common ancestor data in zdiff3 format for conflicts
+		/// </summary>
+		GIT_CHECKOUT_CONFLICT_STYLE_ZDIFF3 = (1 << 25),
+
         // THE FOLLOWING OPTIONS ARE NOT YET IMPLEMENTED
 
         /// <summary>

LibGit2Sharp/Core/GitCheckoutOptsWrapper.cs

@@ -78,6 +78,10 @@ internal static CheckoutStrategy CheckoutStrategyFromFileConflictStrategy(Checko
                 case CheckoutFileConflictStrategy.Diff3:
                     flags = CheckoutStrategy.GIT_CHECKOUT_CONFLICT_STYLE_DIFF3;
                     break;
+
+                case CheckoutFileConflictStrategy.ZDiff3:
+                    flags = CheckoutStrategy.GIT_CHECKOUT_CONFLICT_STYLE_ZDIFF3;
+                    break;
             }
 
             return flags;

LibGit2Sharp/Core/GitMergeOpts.cs

@@ -194,5 +194,10 @@ internal enum GitMergeFileFlag
         /// Take extra time to find minimal diff
         /// </summary>
         GIT_MERGE_FILE_DIFF_MINIMAL = (1 << 7),
+
+        /// <summary>
+        /// Create zdiff3 ("zealous diff3")-style files
+        /// </summary>
+        GIT_MERGE_FILE_STYLE_ZDIFF3 = (1 << 8),
     }
 }