copying generators error

[Aahz]

In article <mailman.1046640064.16956.python-list at python.org>,
Gerrit Holl  <gerrit at nl.linux.org> wrote:
>
>when copying a listiterator, I get the following error:
>
>22:21:29:3:gerrit at stopcontact:~/cvs/pygame/examples$ python
>Python 2.3a2+ (#6, Mar  2 2003, 14:26:40)
>[GCC 2.96 20000731 (Red Hat Linux 7.3 2.96-110)] on linux2
>Type "help", "copyright", "credits" or "license" for more information.
>  0 >>> import copy
>  1 >>> copy.copy(iter([]))
>Traceback (most recent call last):
>  File "<stdin>", line 1, in ?
>  File "/usr/local/lib/python2.3/copy.py", line 95, in copy
>    return _reconstruct(x, rv, 0)
>  File "/usr/local/lib/python2.3/copy.py", line 336, in _reconstruct
>    y = callable(*args)
>  File "/usr/local/lib/python2.3/copy_reg.py", line 84, in __newobj__
>    return cls.__new__(cls, *args)
>TypeError: object.__new__(listiterator) is not safe, use listiterator.__new__()
>
>Is this a bug?

Don't think so:

Python 2.2.2 (#1, Oct 17 2002, 12:22:01)
[GCC egcs-2.91.66 19990314 (egcs-1.1.2 release)] on netbsd1
Type "help", "copyright", "credits" or "license" for more information.
>>> import copy
>>> f = open('x')
>>> copy.copy(f)
Traceback (most recent call last):
  File "<stdin>", line 1, in ?
  File "/pkg/python-2.2.2/lib/python2.2/copy.py", line 84, in copy
    y = _reconstruct(x, reductor(), 0)
  File "/pkg/python-2.2.2/lib/python2.2/copy_reg.py", line 57, in _reduce
    raise TypeError, "can't pickle %s objects" % base.__name__
TypeError: can't pickle file objects

You might argue that iterators should return a different error, but
stateful objects like files and iterators shouldn't be copied.
-- 
Aahz (aahz at pythoncraft.com)           <*>         http://www.pythoncraft.com/

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