[Python-Dev] Slight wart in __all__

[Mark Hammond]

I just got caught out by this:

"""
def foo():
    pass

__all__ = [foo]
"""

Then at the interactive prompt:

>>> from foo import *
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
TypeError: attribute name must be string


The problem is that __all__ contains a function object rather than a string
object.  I had to use the debugger to determine why I was getting the
failure :(  All you 2.1 veterans will immediately pick that it should read
'__all__ = ["foo"]'

Looking at the __all__ code:

		if (skip_leading_underscores &&
		    PyString_Check(name) &&
		    PyString_AS_STRING(name)[0] == '_')
		{
			Py_DECREF(name);
			continue;
		}
		value = PyObject_GetAttr(v, name);

PyObject_GetAttr explicitly handles string and unicode objects.  However,
code here won't like Unicode that much :)

Would it make sense to a explicitly raise a more meaningful exception here
if __all__ doesnt contain strings?