[Python-Dev] test_struct failure on 64 bit platforms

[Neal Norwitz]

On 5/31/06, Bob Ippolito <bob at redivi.com> wrote:
>
> On May 31, 2006, at 12:49 AM, Neal Norwitz wrote:
>
> > Bob,
> >
> > There are a couple of things I don't understand about the new struct.
> > Below is a test that fails.
> >
> > $ ./python ./Lib/test/regrtest.py test_tarfile test_struct
> > test_tarfile
> > /home/pybot/test-trunk/build/Lib/struct.py:63: DeprecationWarning: 'l'
> > format requires -2147483648 <= number <= 2147483647
> >  return o.pack(*args)
> > test_struct
> > test test_struct failed -- pack('>l', -2147483649) did not raise error
> > 1 test OK.
> > 1 test failed:
> >    test_struct
> >
> > ####
> >
> > I fixed the error message (the min value was off by one before).  I
> > think I fixed a few ssize_t issues too.
> >
> > The remaining issues I know of are:
> >  * The warning only appears on 64-bit platforms.
> >  * The warning doesn't seem correct for 64-bit platforms (l is 8
> > bytes, not 4).
> >  * test_struct only fails if run after test_tarfile.
> >  * The msg from test_struct doesn't seem correct for 64-bit platforms.
> >
> > I tracked the problem down to trying to write the gzip tar file.  Can
> > you fix this?
>
> The warning is correct, and so is the size. Only native formats have
> native sizes; l and i are exactly 4 bytes on all platforms when using
> =, >, <, or !. That's what "std size and alignment" means.

Ah, you are correct.  I see this is the behaviour in 2.4.  Though I
wouldn't call 4 bytes a standard size on a 64-bit platform.

> Unfortunately I don't have a 64-bit platform easily accessible and I
> have no idea which test it is that's raising the warning. Could you
> isolate it?

I wasted sleep for that?  Damn and I gotta get up early again tomorrow
too.  See the checkin for answer.  Would someone augment the warnings
module to make testing more reasonable?

n