add merge has conflicts

joshvera · joshvera · commit 30e64272ff77 · 2015-01-21T00:07:45.000-05:00
diff --git a/LibGit2Sharp/Core/NativeMethods.cs b/LibGit2Sharp/Core/NativeMethods.cs
@@ -657,6 +657,15 @@ internal static extern int git_merge(
             ref GitMergeOpts merge_opts,
             ref GitCheckoutOpts checkout_opts);
 
+        [DllImport(libgit2)]
+        internal static extern int git_merge_trees(
+            out IndexSafeHandle index,
+            RepositorySafeHandle repo,
+            GitObjectSafeHandle ancestor_tree,
+            GitObjectSafeHandle our_tree,
+            GitObjectSafeHandle their_tree,
+            ref GitMergeOpts merge_opts);
+
         [DllImport(libgit2)]
         internal static extern int git_merge_analysis(
             out GitMergeAnalysis status_out,
diff --git a/LibGit2Sharp/Core/Proxy.cs b/LibGit2Sharp/Core/Proxy.cs
@@ -1012,6 +1012,22 @@ public static void git_index_clear(Index index)
 
         #region git_merge_
 
+        public static IndexSafeHandle git_merge_trees(RepositorySafeHandle repo, GitObjectSafeHandle ancestorTree, GitObjectSafeHandle ourTree, GitObjectSafeHandle theirTree)
+        {
+            using (ThreadAffinity())
+            {
+                IndexSafeHandle index;
+                GitMergeOpts opts = new GitMergeOpts { Version = 1 };
+                int res = NativeMethods.git_merge_trees(out index, repo, ancestorTree, ourTree, theirTree, ref opts);
+                if (res != (int) GitErrorCode.Ok || index == null)
+                {
+                    return null;
+                }
+
+                return index;
+            }
+        }
+
         public static ObjectId git_merge_base_many(RepositorySafeHandle repo, GitOid[] commitIds)
         {
             using (ThreadAffinity())
diff --git a/LibGit2Sharp/IRepository.cs b/LibGit2Sharp/IRepository.cs
@@ -196,6 +196,16 @@ public interface IRepository : IDisposable
         /// <returns>The result of the revert.</returns>
         RevertResult Revert(Commit commit, Signature reverter, RevertOptions options);
 
+        /// <summary>
+        /// Returns whether merging <paramref name="theirTree"/> into <paramref name="ourTree"/>
+        /// would result in merge conflicts.
+        /// </summary>
+        /// <param name="ourTree">The base tree to merge into.</param>
+        /// <param name="theirTree">The tree to merge into <paramref name="ourTree"/>.</param>
+        /// <param name="ancestorTree">The common ancestor of the two trees, or null if none exists.</param>
+        /// <returns>Whether a merge would result in conflicts</returns>
+        bool MergeHasConflicts(Tree ourTree, Tree theirTree, Tree ancestorTree);
+
         /// <summary>
         /// Merge changes from commit into the branch pointed at by HEAD..
         /// </summary>
diff --git a/LibGit2Sharp/Repository.cs b/LibGit2Sharp/Repository.cs
@@ -974,6 +974,25 @@ public static string Version
             get { return GlobalSettings.Version.ToString(); }
         }
 
+        /// <summary>
+        /// Returns whether merging <paramref name="theirTree"/> into <paramref name="ourTree"/>
+        /// would result in merge conflicts.
+        /// </summary>
+        /// <param name="ourTree">The base tree to merge into.</param>
+        /// <param name="theirTree">The tree to merge into <paramref name="ourTree"/>.</param>
+        /// <param name="ancestorTree">The common ancestor of the two trees, or null if none exists.</param>
+        /// <returns>Whether a merge would result in conflicts</returns>
+        public bool MergeHasConflicts(Tree ourTree, Tree theirTree, Tree ancestorTree)
+        {
+            using (var ourHandle = Proxy.git_object_peel(Handle, ourTree.Id, GitObjectType.Tree, true))
+            using (var theirHandle = Proxy.git_object_peel(Handle, theirTree.Id, GitObjectType.Tree, true))
+            using (var ancestorHandle = Proxy.git_object_peel(Handle, ancestorTree.Id, GitObjectType.Tree, false))
+            using (var indexHandle = Proxy.git_merge_trees(Handle, ourHandle, theirHandle, ancestorHandle))
+            {
+                return Proxy.git_index_has_conflicts(indexHandle);
+            }
+        }
+
         /// <summary>
         /// Merges changes from commit into the branch pointed at by HEAD.
         /// </summary>
