integer subclass range behavior

[josepharmbruster]

I was wondering what would happen, so I tried this out for the heck of
it with:
Python 3.0a2 (py3k:59572M, Dec 19 2007, 15:54:07) [MSC v.1500 32 bit
(Intel)] on win32

class a(int):
def __new__(cls,number):
return int.__new__(cls,number)

for x in range(0,a(5)):
print(x)
Which resulted in a:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "a.py", line 5, in <module>
for x in range(0,a(5)):
SystemError: ..\Objects\longobject.c:400: bad argument to internal
function
[41030 refs]
It looks like the rangeobject performs a FitsInLong test on each of
the parameters to range, which uses the function
_PyLong_FitsInLong(PyObject *vv) within longobject.c. In tern, this
performs a typecheck: #define PyLong_CheckExact(op) (Py_TYPE(op) ==
&PyLong_Type) that fails.
Interesting!

[Gabriel Genellina]

En Wed, 19 Dec 2007 18:11:49 -0300, jo**************@gmail.com
<jo**************@gmail.comescribió:

I was wondering what would happen, so I tried this out for the heck of
it with:
Python 3.0a2 (py3k:59572M, Dec 19 2007, 15:54:07) [MSC v.1500 32 bit
(Intel)] on win32

class a(int):
def __new__(cls,number):
return int.__new__(cls,number)

for x in range(0,a(5)):
print(x)
Which resulted in a:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "a.py", line 5, in <module>
for x in range(0,a(5)):
SystemError: .\Objects\longobject.c:400: bad argument to internal
function

Interesting!

Yes. But much more interesting would be to report this on the bug tracker
http://bugs.python.org else it will fade away...

--
Gabriel Genellina

[josepharmbruster]

On Dec 19, 7:42 pm, "Gabriel Genellina" <[e-mail]>
wrote:

En Wed, 19 Dec 2007 18:11:49 -0300, [e-mail]
<[e-mail]ó:

I was wondering what would happen, so I tried this out for the heck of
it with:
Python 3.0a2 (py3k:59572M, Dec 19 2007, 15:54:07) [MSC v.1500 32 bit
(Intel)] on win32

class a(int):
def __new__(cls,number):
return int.__new__(cls,number)

for x in range(0,a(5)):
print(x)

Which resulted in a:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "a.py", line 5, in <module>
for x in range(0,a(5)):
SystemError: .\Objects\longobject.c:400: bad argument to internal
function

Interesting!

Yes. But much more interesting would be to report this on the bug tracker http://bugs.python.orgelse it will fade away...

--
Gabriel Genellina

Gabriel,

I usually do that... But from what i've learned, most things i've
thought are bugs, turn out to be that way for a good reason. I was
playing it safe on this one :-)

Joseph Armbruster

[Gabriel Genellina]

En Wed, 19 Dec 2007 22:20:17 -0300, jo**************@gmail.com
<jo**************@gmail.comescribió:

On Dec 19, 7:42 pm, "Gabriel Genellina" <[e-mail]>
wrote:

>En Wed, 19 Dec 2007 18:11:49 -0300, [e-mail]
<[e-mail]ó:

I was wondering what would happen, so I tried this out for the heck of
it with:
Python 3.0a2 (py3k:59572M, Dec 19 2007, 15:54:07) [MSC v.1500 32 bit
(Intel)] on win32

class a(int):
def __new__(cls,number):
return int.__new__(cls,number)

for x in range(0,a(5)):
print(x)

Which resulted in a:

Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "a.py", line 5, in <module>
for x in range(0,a(5)):
SystemError: .\Objects\longobject.c:400: bad argument to internal
function

Interesting!

Yes. But much more interesting would be to report this on the bug
tracker http://bugs.python.org else it will fade away...

I usually do that... But from what i've learned, most things i've
thought are bugs, turn out to be that way for a good reason. I was
playing it safe on this one :-)

Well, it works on 2.5, and I don't see why it should not work on 3.0 too,
so IMHO this is a genuine bug. That means only that when some god or
demi-god explains the good reasons for this failure, we both will say a
big "Ahhhhh! That was it!" :)

--
Gabriel Genellina