[ python-Bugs-908441 ] default index for __getslice__ is not sys.maxint

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Bugs item #908441, was opened at 2004-03-02 18:41
Message generated for change (Comment added) made by birkenfeld
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Category: Python Interpreter Core
Group: Python 2.3
Status: Open
Resolution: None
Priority: 5
Submitted By: Matthias Drochner (drochner)
Assigned to: Nobody/Anonymous (nobody)
Summary: default index for __getslice__ is not sys.maxint

Initial Comment:
(This applies also to __setslice__ and possibly more.)
(This was already present in Python-2.2.)

If the upper slice index is omitted, a default is
passed to the __getslice__ method.
Documentation claims this is sys.maxint.
This is wrong if INT_MAX and LONG_MAX differ; what
is passed is INT_MAX while sys.maxint is LONG_MAX.

I'm not sure whether to call it a code bug or a
documentation bug; at least there is code out there
which compares to sys.maxint.

The whole code path from ceval.c:_PyEval_SliceIndex()
to operator.c:op_getslice() to 
abstract.c:PySequence_GetSlice() to
classobject.c:instance_slice() has just room for
an "int", so a code fix is pretty invasive...

A small test program to check this:
==========
import sys

class sl(object):
        def __getslice__(self, a, b):
                return (a, b)

print "sys.maxint = %ld" % sys.maxint
bounds = sl()[:]
print "default bounds = [%ld, %ld]" % bounds
==========
gives on NetBSD/amd64:
sys.maxint = 9223372036854775807
default bounds = [0, 2147483647]



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>Comment By: Georg Brandl (birkenfeld)
Date: 2006-01-10 23:20

Message:
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user_id=1188172

Do we want to support long slice indices?

----------------------------------------------------------------------

You can respond by visiting: 
https://sourceforge.net/tracker/?func=detail&atid=105470&aid=908441&group_id=5470