pychecker - sets.Set need to be overridden

[Istvan Albert]

Hello all,

if I have this code:

import sets

class Foo:
x = sets.Set()

then pychecker says:

test.py:4: Methods (__cmp__, __hash__) in sets.Set need to be overridden in a subclass

I don't get this message. What is it trying to say, and why?

Istvan.

[wittempj@hotmail.com]

Re: pychecker - sets.Set need to be overridden

mport sets

class Foo:
def __init__(self):
self.x = sets.Set()

x = Foo()
print x, getattr(x, 'x')

gives for me:
<__main__.Foo instance at 0x00C578A0> Set([])
on 2.4. on WinXP. What environment do you run in?

[Istvan Albert]

Re: pychecker - sets.Set need to be overridden

wittempj@hotmai l.com wrote:
[color=blue]
> <__main__.Foo instance at 0x00C578A0> Set([])
> on 2.4. on WinXP. What environment do you run in?[/color]

I'm running it on cygwin,

but still don't get it, why the warning?

Istvan.

[Peter Otten]

Re: pychecker - sets.Set need to be overridden

Istvan Albert wrote:
[color=blue]
> if I have this code:
>
> import sets
>
> class Foo:
> x = sets.Set()
>
> then pychecker says:
>
> test.py:4: Methods (__cmp__, __hash__) in sets.Set need to be overridden
> in a subclass
>
> I don't get this message. What is it trying to say, and why?[/color]

The minimal example is actually

import sets
sets.Set()

The Set class has implementations for __cmp__() and __hash__() that
unconditionally raise an exception. pychecker assumes that these methods
are "abstract", i. e. meant to be overriden by a subclass, and warns that
you are instantiating an abstract base class, while the intention of the
Set class author was to make Sets "uncomparab le" and unhashable by
overriding the corresponding superclass methods.

Peter

[wittempj@hotmail.com]

Re: pychecker - sets.Set need to be overridden

I don't know pychecker, maybe there's something wrong with it as your
code seems valid to me.

[Istvan Albert]

Re: pychecker - sets.Set need to be overridden

Peter Otten wrote:
[color=blue]
> The Set class has implementations for __cmp__() and __hash__() that
> unconditionally raise an exception. pychecker assumes that these methods
> are "abstract", i. e. meant to be overriden by a subclass, and warns that
> you are instantiating an abstract base class, while the intention of the[/color]

I see. Thanks!

Istvan.