[Python-Dev] Re: [snake-farm] test test_slice failed -- [9, 7, 5, 3, 1] == 
Tue, 05 Nov 2002 18:23:19 -0500
On Tue, Nov 05, 2002 at 10:38:18PM +0100, Anders Qvist wrote:
> Between 1036491804 and 1036522446 (should be GMT 2002-11-05, 10:20 and
> 2002-11-05, 18:54 respectively), test_slice started failing with the
> following message:
> test test_slice failed -- [9, 7, 5, 3, 1] == 
> om moghedien; linux/alpha. There has been some changes containing
> pointer arithmetic around line 160 of sliceobjects.c, which might be
> guilty (just a shot in the dark; 64-bit clean?):
It is a 64-bit problem, but doesn't have to do with the checkin to
sliceobject. The new test (below) broke with old code too.
vereq(range(10)[::sys.maxint - 1], )
The problem is that sizeof(int) != sizeof(long). The parameters for
PySlice_GetIndices() and PySlice_GetIndicesEx() take ints, not longs.
So the code is doing:
since the high 32 bits are lost.
The only solution I can think of is to have 2 interfaces:
- the old API which takes int/int*, PySlice_GetIndices()
deprecate this API and raise overflow exception
if (int)value != (long)value
- the new API which takes long/long*, PySlice_GetIndicesEx()
PySlice_GetIndicesEx() was added in 2.3.
Otherwise, we are stuck with slices only being able to support
32 bits even on 64 bit architectures.