This looks like a bug, but it actually may be legitimate functionality. If this is the case, this ticket might be better served as a feature request to change the name of pylab's all to something else to allow use of "from pylab import*" without harm to existing code.
Pylab simply dumps everything from pyplot and numpy into its namespace, and
all() comes from numpy. That is the way it has been for a long time, so I
don't think we are going to change anything unless numpy does so. A name
change such as you suggest could harm existing code that is assuming the
present behavior. In the meantime, this illustrates why we discourage use
of "from pylab import *", especially for new code.
Activity
efiring commented on Jun 21, 2011
Pylab simply dumps everything from pyplot and numpy into its namespace, and
all() comes from numpy. That is the way it has been for a long time, so I
don't think we are going to change anything unless numpy does so. A name
change such as you suggest could harm existing code that is assuming the
present behavior. In the meantime, this illustrates why we discourage use
of "from pylab import *", especially for new code.