On 22/06/2013 03:18, Chris Angelico wrote:
On Sat, Jun 22, 2013 at 12:01 PM, Rotwang <sg...@hotmail.co.uk> wrote:
class hashablelist(list):
... def __hash__(self):
... return hash(tuple(self))
There's a vulnerability in that definition:
a=hashablelist((1,[],3))
a
[1, [], 3]
{a:1}
Traceback (most recent call last):
File "<pyshell#255>", line 1, in <module>
{a:1}
File "<pyshell#249>", line 3, in __hash__
return hash(tuple(self))
TypeError: unhashable type: 'list'
Of course, if you monkey-patch list itself to have this functionality,
or always use hashablelist instead of list, then it will work. But
it's still vulnerable.
Quite right, sorry. I should have called my class
"sometimeshashablelist", or something.
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