Objective-Git Merge - objective-c

Question

I am using Objective-Git. I cannot get the following method to work:
- (GTIndex *)merge:(GTTree *)otherTree ancestor:(GTTree *)ancestorTree error:(NSError **)error
No error is returned, but the index returned is empty, while it exists, all attributes are nil. The merge operation does not take place, I can't write out a tree as I cannot obtain the index resulting from the attempted merge.
Has anybody managed to successfully perform a merge using objective git - How? Help!
GTBranch *branch1 = branches[0];
GTCommit *commit1 = [branch1 targetCommitAndReturnError:NULL];
GTOID *oid1 = commit1.OID;
GTTree *tree1 = commit1.tree;
GTBranch *branch2 = branches[1];
GTCommit *commit2 = [branch2 targetCommitAndReturnError:NULL];
GTTree *tree2 = commit2.tree;
GTOID *oid2 = commit2.OID;
GTRepository *repo = branch1.repository;
NSError *error;
GTCommit *ancestor = [repo mergeBaseBetweenFirstOID:oid1 secondOID:oid2 error:&error];
if (error){
NSLog(#"%#", error.description);
}
GTTree *ancTree = ancestor.tree;
NSError *someError;
NSLog(#"attempting merge into ""%#"" from ""%#"" with ancestor ""%#""", commit2.message, commit1.message,ancestor.message);
GTIndex *mergedIndex = [tree2 merge:tree1 ancestor: ancTree error:&someError]; //returns index not backed by existing repo --> index_file_path = nil, all attributes of git_index are nil
if (someError){
NSLog(#"%#", someError.description);
}
NSError *theError;
GTTree *mergedtree = [mergedIndex writeTree:&theError]; //can't write out the tree as the index given back by merge: ancestor: error: does not reference a repo
if (theError){
NSLog(#"%#",theError);
}
}
}

Answer 1

The index that is returned by merging the trees together is not bound to the repository. Unfortunately, the operation to write the index as a tree to a specific repository (git_index_write_tree_to) is not exposed yet through Objective-Git.
You probably want to open a ticket in their issue tracker.