Return TransientIndex from ObjectDatabase.MergeCommitsIntoIndex

Author: tyrielv

LibGit2Sharp.Tests/MergeFixture.cs

@@ -910,9 +910,11 @@ public void CanMergeIntoIndex()
             {
                 var master = repo.Lookup<Commit>("master");
 
-                Index index = repo.ObjectDatabase.MergeCommitsIntoIndex(master, master, null);
-                var tree = index.WriteToTree();
-                Assert.Equal(master.Tree.Id, tree.Id);
+                using (TransientIndex index = repo.ObjectDatabase.MergeCommitsIntoIndex(master, master, null))
+                {
+                    var tree = index.WriteToTree();
+                    Assert.Equal(master.Tree.Id, tree.Id);
+                }
             }
         }
 
@@ -925,22 +927,24 @@ public void CanMergeIntoIndexWithConflicts()
                 var master = repo.Lookup<Commit>("master");
                 var branch = repo.Lookup<Commit>("conflicts");
 
-                Index index = repo.ObjectDatabase.MergeCommitsIntoIndex(branch, master, null);
-                Assert.False(index.IsFullyMerged);
+                using (TransientIndex index = repo.ObjectDatabase.MergeCommitsIntoIndex(branch, master, null))
+                {
+                    Assert.False(index.IsFullyMerged);
 
-                var conflict = index.Conflicts.First();
+                    var conflict = index.Conflicts.First();
 
-                //Resolve the conflict by taking the blob from branch
-                var blob = repo.Lookup<Blob>(conflict.Ours.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);
+                    //Resolve the conflict by taking the blob from branch
+                    var blob = repo.Lookup<Blob>(conflict.Ours.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();
+                    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.Tree.Id, tree.Id);
+                    //Since we took the conflicted blob from the branch, the merged result should be the same as the branch.
+                    Assert.Equal(branch.Tree.Id, tree.Id);
+                }
             }
         }
 

LibGit2Sharp/Index.cs

@@ -31,13 +31,12 @@ internal Index(IndexHandle handle, Repository repo)
             this.repo = repo;
             this.handle = handle;
             conflicts = new ConflictCollection(this);
-
-            repo.RegisterForCleanup(handle);
         }
 
         internal Index(Repository repo)
             : this(Proxy.git_repository_index(repo.Handle), repo)
         {
+            repo.RegisterForCleanup(handle);
         }
 
         internal Index(Repository repo, string indexPath)

LibGit2Sharp/ObjectDatabase.cs

@@ -856,8 +856,9 @@ public virtual PackBuilderResults Pack(PackBuilderOptions options, Action<PackBu
         /// <param name="ours">The first tree</param>
         /// <param name="theirs">The second tree</param>
         /// <param name="options">The <see cref="MergeTreeOptions"/> controlling the merge</param>
-        /// <returns>The <see cref="Index"/> containing the merged trees and any conflicts, or null if the merge stopped early due to conflicts</returns>
-        public virtual Index MergeCommitsIntoIndex(Commit ours, Commit theirs, MergeTreeOptions options)
+        /// <returns>The <see cref="TransientIndex"/> containing the merged trees 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 MergeCommitsIntoIndex(Commit ours, Commit theirs, MergeTreeOptions options)
         {
             Ensure.ArgumentNotNull(ours, "ours");
             Ensure.ArgumentNotNull(theirs, "theirs");
@@ -874,7 +875,7 @@ public virtual Index MergeCommitsIntoIndex(Commit ours, Commit theirs, MergeTree
                 }
                 return null;
             }
-            var result = new Index(indexHandle, repo);
+            var result = new TransientIndex(indexHandle, repo);
             return result;
         }
 

LibGit2Sharp/TransientIndex.cs

@@ -0,0 +1,31 @@
+using System;
+using LibGit2Sharp.Core.Handles;
+
+namespace LibGit2Sharp
+{
+    /// <summary>
+    /// An implementation of <see cref="Index"/> with disposal managed by the caller
+    /// (instead of automatically disposing when the repository is disposed)
+    /// </summary>
+    public class TransientIndex: Index, IDisposable
+    {
+        /// <summary>
+        /// Needed for mocking purposes.
+        /// </summary>
+        protected TransientIndex()
+        { }
+
+        internal TransientIndex(IndexHandle handle, Repository repo)
+            : base(handle, repo)
+        {
+        }
+
+        /// <summary>
+        /// Performs application-defined tasks associated with freeing, releasing, or resetting unmanaged resources.
+        /// </summary>
+        public void Dispose()
+        {
+            this.Handle.SafeDispose();
+        }
+    }
+}