Tensorflow 2 C&W2 implementation targeted bug

[ugorsahin]

Hello, I have seen one possible bug in the tensorflow C&W2 implementation.

The targeted parameter does not pass to function body, instead it is defined with respect to y parameter being None or not. This causes problems when labels are explicitly given in untargeted scenario.

cleverhans/cleverhans/tf2/attacks/carlini_wagner_l2.py

Line 25 in e5d00e5

targeted=False,

cleverhans/cleverhans/tf2/attacks/carlini_wagner_l2.py

Line 82 in e5d00e5

self.targeted = y is not None

There might be two ways to fix this:

• One would be
  self.targeted = targeted
• The other solution would be replacing default value of targeted to None and fixing line
  targeted = None
  on the argument list and

if targeted is not None:
    self.targeted=targeted
else:
    self.targeted = y is not None

in the body