np.array([], dtype=object) triggers error when copied with copy.deepcopy() #8536
Description
The following code fails with numpy 1.12.0 (this is the only version we have tested).
>>> arr = np.array([], dtype=object)
>>> copy.deepcopy(arr)
Traceback (most recent call last):
File "/usr/lib/python3/dist-packages/IPython/core/interactiveshell.py", line 2821, in run_code
exec(code_obj, self.user_global_ns, self.user_ns)
File "<ipython-input-16-e314fe8a32a6>", line 1, in <module>
copy.deepcopy(arr)
File "/usr/lib/python3.4/copy.py", line 166, in deepcopy
y = copier(memo)
ValueError: Iteration of zero-sized operands is not enabled
Note that this code already works if the dtype was not object but, e.g., int or str.