BUG: format(numpy.void("ABC"),"") throws a RuntimeError

[jwoillez]

Using version 1.6.2. Stumbled upon this issue while using format on indexed record arrays.

>>> import numpy
>>> numpy.__version__
'1.6.2'
>>> format(numpy.void("ABC"), "")
Traceback (most recent call last):
  File "<console>", line 1, in <module>
RuntimeError: maximum recursion depth exceeded while calling a Python object

[jwoillez]

Also an issue with 1.8.0.dev-63cd8f3

[charris]

Still present in 1.9-devel.

[ddasilva]

I am unable to reproduce @jwoillez's error using NumPy built from master. Is it possible this was fixed in PR #4401?

>>> import numpy as np
>>> np.__version__
'1.9.0.dev-17227ce'
>>> format(np.void("ABC"), "")
'ABC'

[charris]

Looks like it, I'll close this. Thanks for finding it.

[charris]

Slightly different fix, yours looks more general. The other fix is at #388. Looks like there is still a void printing issue in python3.

[charris]

So this example doesn't work in python3.
In Python3,

>>> format(np.void("ABC"), "")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: expected an object with a buffer interface

In python3, strings don't have a buffer interface, although byte strings do. Hmm... and

>>> format(np.void(b"ABC"), "")
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
RuntimeError: maximum recursion depth exceeded while calling a Python object

Not sure why that happens.

[charris]

NVM the python3 RuntimeError, I didn't have latest numpy installed for python3.

[charris]

So it looks like your fix is as good as #388 in python3

>>> format(numpy.void(b"ABC"), "")
'[65 66 67]'