Use ensure_ndarray to view chunk as an array (#360)

* Use `ensure_ndarray` to view chunk as an array

Simplifies the process of constructing an `ndarray` to view the chunk
data when writing the result to a destination.

* Drop trailing whitespace

* Link this PR to Numcodecs upgrade release note

Author: jakirkham

docs/release.rst

@@ -29,7 +29,7 @@ Bug fixes
 
 * The required version of the `numcodecs <http://numcodecs.rtfd.io>`_ package has been upgraded 
   to 0.6.2, which has enabled some code simplification and fixes a failing test involving
-  msgpack encoding. By :user:`John Kirkham <jakirkham>`, :issue:`352`, :issue:`355`, 
+  msgpack encoding. By :user:`John Kirkham <jakirkham>`, :issue:`360`, :issue:`352`, :issue:`355`,
   :issue:`324`.
 
 * Failing tests related to pickling/unpickling have been fixed. By :user:`Ryan Williams <ryan-williams>`,

zarr/core.py

@@ -1604,10 +1604,7 @@ def _chunk_getitem(self, chunk_coords, chunk_selection, out, out_selection,
                     if self._compressor:
                         self._compressor.decode(cdata, dest)
                     else:
-                        if isinstance(cdata, np.ndarray):
-                            chunk = cdata.view(self._dtype)
-                        else:
-                            chunk = np.frombuffer(cdata, dtype=self._dtype)
+                        chunk = ensure_ndarray(cdata).view(self._dtype)
                         chunk = chunk.reshape(self._chunks, order=self._order)
                         np.copyto(dest, chunk)
                     return