remove coercion to Index before _ensure_index

Ben Kandel · Ben Kandel · commit d8e2c170bcc8 · 2016-10-08T23:21:58.000-04:00
diff --git a/pandas/tools/merge.py b/pandas/tools/merge.py
@@ -1370,7 +1370,7 @@ def __init__(self, objs, axis=0, join='outer', join_axes=None,
                 clean_objs.append(v)
             objs = clean_objs
             name = getattr(keys, 'name', None)
-            keys = _ensure_index(Index(clean_keys))
+            keys = _ensure_index(clean_keys)
             keys.name = name
 
         if len(objs) == 0:
