asarray() with __array_interface__ doesn't set .base

[Andreas Kloeckner]

import numpy as np

class _DummyArray(object):
    """ Dummy object that just exists to hang __array_interface__ dictionaries
    and possibly keep alive a reference to a base array.
    """
    def __init__(self, interface, base=None):
        self.__array_interface__ = interface
        self.base = base

x = np.zeros(10000)
d = _DummyArray(x.__array_interface__, base=x)
y = np.asarray(d)

assert y.base is d

succeeds on numpy, fails on numpypy

[mattip]

It seems we do not call __init__ for a class with an __array_interface__ attribute like numpy does. I linked in the test in issue #53 and rewrote a bit (to allow running on a vanilla PyPy without the numpy fork)

try:
    import _numpypy.multiarray as np
except:
    import numpy as np

class _DummyArray(object):
    """ Dummy object that just exists to hang __array_interface__ dictionaries
    and possibly keep alive a reference to a base array.
    """
    def __init__(self, interface, base=None):
        self.__array_interface__ = interface
        print 'in init'
        self.base = base

x = np.zeros(10000)
d = _DummyArray(x.__array_interface__, base=x)
print 'calling array of d'
y = np.array(d, copy=False)

if not y.base is d:
    print 'y.base is', type(y.base), 'not d'

x = np.zeros((0,), dtype='float32')
d = _DummyArray(x.__array_interface__, base=x)
print 'd.strides', d.__array_interface__['strides']
d.__array_interface__["strides"] = x.strides
print(d.__array_interface__)
y = np.array(d, copy=False)

PyPy does not print in init like CPython does

[mattip]

Fixed in 4916eb438de5 as part of the buffer-interface branch, merged to default in 03fc4cb79e37

[Andreas Kloeckner]

Thanks!