Add CherryPickCommitIntoIndex to ObjectDatabase

LibGit2Sharp.Tests/CherryPickFixture.cs

@@ -162,6 +162,56 @@ public void CherryPickWithConflictsReturnsConflicts()
             }
         }
 
+        [Fact]
+        public void CanCherryPickCommitIntoIndex()
+        {
+            string path = SandboxMergeTestRepo();
+            using (var repo = new Repository(path))
+            {
+                var ours = repo.Head.Tip;
+
+                Commit commitToMerge = repo.Branches["fast_forward"].Tip;
+
+                using (TransientIndex index = repo.ObjectDatabase.CherryPickCommitIntoIndex(commitToMerge, ours, 0, null))
+                {
+                    var tree = index.WriteToTree();
+                    Assert.Equal(commitToMerge.Tree.Id, tree.Id);
+                }
+            }
+        }
+
+        [Fact]
+        public void CanCherryPickIntoIndexWithConflicts()
+        {
+            const string conflictBranchName = "conflicts";
+
+            string path = SandboxMergeTestRepo();
+            using (var repo = new Repository(path))
+            {
+                Branch branch = repo.Branches[conflictBranchName];
+                Assert.NotNull(branch);
+
+                using (TransientIndex index = repo.ObjectDatabase.CherryPickCommitIntoIndex(branch.Tip, repo.Head.Tip, 0, null))
+                {
+                    Assert.False(index.IsFullyMerged);
+
+                    var conflict = index.Conflicts.First();
+
+                    //Resolve the conflict by taking the blob from branch
+                    var blob = repo.Lookup<Blob>(conflict.Theirs.Id);
+                    //Add() does not remove conflict entries for the same path, so they must be explicitly removed first.
+                    index.Remove(conflict.Ours.Path);
+                    index.Add(blob, conflict.Ours.Path, Mode.NonExecutableFile);
+
+                    Assert.True(index.IsFullyMerged);
+                    var tree = index.WriteToTree();
+
+                    //Since we took the conflicted blob from the branch, the merged result should be the same as the branch.
+                    Assert.Equal(branch.Tip.Tree.Id, tree.Id);
+                }
+            }
+        }
+
         private Commit AddFileCommitToRepo(IRepository repository, string filename, string content = null)
         {
             Touch(repository.Info.WorkingDirectory, filename, content);

LibGit2Sharp/ObjectDatabase.cs

@@ -562,37 +562,26 @@ public virtual HistoryDivergence CalculateHistoryDivergence(Commit one, Commit a
         public virtual MergeTreeResult CherryPickCommit(Commit cherryPickCommit, Commit cherryPickOnto, int mainline, MergeTreeOptions options)
         {
             Ensure.ArgumentNotNull(cherryPickCommit, "cherryPickCommit");
-            Ensure.ArgumentNotNull(cherryPickOnto, "ours");
+            Ensure.ArgumentNotNull(cherryPickOnto, "cherryPickOnto");
 
-            options = options ?? new MergeTreeOptions();
+            var modifiedOptions = new MergeTreeOptions();
 
             // We throw away the index after looking at the conflicts, so we'll never need the REUC
             // entries to be there
-            GitMergeFlag mergeFlags = GitMergeFlag.GIT_MERGE_NORMAL | GitMergeFlag.GIT_MERGE_SKIP_REUC;
-            if (options.FindRenames)
-            {
-                mergeFlags |= GitMergeFlag.GIT_MERGE_FIND_RENAMES;
-            }
-            if (options.FailOnConflict)
-            {
-                mergeFlags |= GitMergeFlag.GIT_MERGE_FAIL_ON_CONFLICT;
-            }
-
+            modifiedOptions.SkipReuc = true;
 
-            var opts = new GitMergeOpts
+            if (options != null)
             {
-                Version = 1,
-                MergeFileFavorFlags = options.MergeFileFavor,
-                MergeTreeFlags = mergeFlags,
-                RenameThreshold = (uint)options.RenameThreshold,
-                TargetLimit = (uint)options.TargetLimit
-            };
+                modifiedOptions.FailOnConflict = options.FailOnConflict;
+                modifiedOptions.FindRenames = options.FindRenames;
+                modifiedOptions.MergeFileFavor = options.MergeFileFavor;
+                modifiedOptions.RenameThreshold = options.RenameThreshold;
+                modifiedOptions.TargetLimit = options.TargetLimit;
+            }
 
             bool earlyStop;
 
-            using (var cherryPickOntoHandle = Proxy.git_object_lookup(repo.Handle, cherryPickOnto.Id, GitObjectType.Commit))
-            using (var cherryPickCommitHandle = Proxy.git_object_lookup(repo.Handle, cherryPickCommit.Id, GitObjectType.Commit))
-            using (var indexHandle = Proxy.git_cherrypick_commit(repo.Handle, cherryPickCommitHandle, cherryPickOntoHandle, (uint)mainline, opts, out earlyStop))
+            using (var indexHandle = CherryPickCommit(cherryPickCommit, cherryPickOnto, mainline, modifiedOptions, out earlyStop))
             {
                 MergeTreeResult cherryPickResult;
 
@@ -879,6 +868,36 @@ public virtual TransientIndex MergeCommitsIntoIndex(Commit ours, Commit theirs,
             return result;
         }
 
+        /// <summary>
+        /// Performs a cherry-pick of <paramref name="cherryPickCommit"/> onto <paramref name="cherryPickOnto"/> commit.
+        /// </summary>
+        /// <param name="cherryPickCommit">The commit to cherry-pick.</param>
+        /// <param name="cherryPickOnto">The commit to cherry-pick onto.</param>
+        /// <param name="mainline">Which commit to consider the parent for the diff when cherry-picking a merge commit.</param>
+        /// <param name="options">The options for the merging in the cherry-pick operation.</param>
+        /// <returns>The <see cref="TransientIndex"/> containing the cherry-pick result tree and any conflicts, or null if the merge stopped early due to conflicts.
+        /// The index must be disposed by the caller. </returns>
+        public virtual TransientIndex CherryPickCommitIntoIndex(Commit cherryPickCommit, Commit cherryPickOnto, int mainline, MergeTreeOptions options)
+        {
+            Ensure.ArgumentNotNull(cherryPickCommit, "cherryPickCommit");
+            Ensure.ArgumentNotNull(cherryPickOnto, "cherryPickOnto");
+
+            options = options ?? new MergeTreeOptions();
+
+            bool earlyStop;
+            var indexHandle = CherryPickCommit(cherryPickCommit, cherryPickOnto, mainline, options, out earlyStop);
+            if (earlyStop)
+            {
+                if (indexHandle != null)
+                {
+                    indexHandle.Dispose();
+                }
+                return null;
+            }
+            var result = new TransientIndex(indexHandle, repo);
+            return result;
+        }
+
         /// <summary>
         /// Perform a three-way merge of two commits, looking up their
         /// commit ancestor. The returned index will contain the results
@@ -921,6 +940,48 @@ private IndexHandle MergeCommits(Commit ours, Commit theirs, MergeTreeOptions op
             }
         }
 
+        /// <summary>
+        /// Performs a cherry-pick of <paramref name="cherryPickCommit"/> onto <paramref name="cherryPickOnto"/> commit.
+        /// </summary>
+        /// <param name="cherryPickCommit">The commit to cherry-pick.</param>
+        /// <param name="cherryPickOnto">The commit to cherry-pick onto.</param>
+        /// <param name="mainline">Which commit to consider the parent for the diff when cherry-picking a merge commit.</param>
+        /// <param name="options">The options for the merging in the cherry-pick operation.</param>
+        /// <param name="earlyStop">True if the cherry-pick stopped early due to conflicts</param>
+        /// <returns>The <see cref="IndexHandle"/> containing the cherry-pick result tree and any conflicts</returns>
+        private IndexHandle CherryPickCommit(Commit cherryPickCommit, Commit cherryPickOnto, int mainline, MergeTreeOptions options, out bool earlyStop)
+        {
+            GitMergeFlag mergeFlags = GitMergeFlag.GIT_MERGE_NORMAL;
+            if (options.SkipReuc)
+            {
+                mergeFlags |= GitMergeFlag.GIT_MERGE_SKIP_REUC;
+            }
+            if (options.FindRenames)
+            {
+                mergeFlags |= GitMergeFlag.GIT_MERGE_FIND_RENAMES;
+            }
+            if (options.FailOnConflict)
+            {
+                mergeFlags |= GitMergeFlag.GIT_MERGE_FAIL_ON_CONFLICT;
+            }
+
+            var mergeOptions = new GitMergeOpts
+            {
+                Version = 1,
+                MergeFileFavorFlags = options.MergeFileFavor,
+                MergeTreeFlags = mergeFlags,
+                RenameThreshold = (uint)options.RenameThreshold,
+                TargetLimit = (uint)options.TargetLimit,
+            };
+
+            using (var cherryPickOntoHandle = Proxy.git_object_lookup(repo.Handle, cherryPickOnto.Id, GitObjectType.Commit))
+            using (var cherryPickCommitHandle = Proxy.git_object_lookup(repo.Handle, cherryPickCommit.Id, GitObjectType.Commit))
+            {
+                var indexHandle = Proxy.git_cherrypick_commit(repo.Handle, cherryPickCommitHandle, cherryPickOntoHandle, (uint)mainline, mergeOptions, out earlyStop);
+                return indexHandle;
+            }
+        }
+
 
         /// <summary>
         /// Packs objects in the <see cref="ObjectDatabase"/> and write a pack (.pack) and index (.idx) files for them.