Missing SWAP_INT in I_set_sw

[mgautierfr]

BPO	23319
Nosy	@amauryfa, @abalkin, @vstinner, @meadori
Files	ctypes_swap_uint.patch: Fix the bug. Add the missing SWAP_INT. ctypes_swap_uint_unittest.patch: Add missing SWAP_INT + unit_test

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/meadori'
closed_at = <Date 2015-07-29.12:38:49.556>
created_at = <Date 2015-01-25.18:53:37.217>
labels = ['ctypes', 'type-bug']
title = 'Missing SWAP_INT\xc2\xa0in I_set_sw'
updated_at = <Date 2015-07-29.13:20:12.349>
user = 'https://bugs.python.org/mgautierfr'

bugs.python.org fields:

activity = <Date 2015-07-29.13:20:12.349>
actor = 'meador.inge'
assignee = 'meador.inge'
closed = True
closed_date = <Date 2015-07-29.12:38:49.556>
closer = 'vstinner'
components = ['ctypes']
creation = <Date 2015-01-25.18:53:37.217>
creator = 'mgautierfr'
dependencies = []
files = ['37856', '39800']
hgrepos = []
issue_num = 23319
keywords = ['patch']
message_count = 9.0
messages = ['234682', '245758', '246509', '246797', '247567', '247568', '247569', '247570', '247572']
nosy_count = 6.0
nosy_names = ['amaury.forgeotdarc', 'belopolsky', 'vstinner', 'meador.inge', 'python-dev', 'mgautierfr']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'patch review'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue23319'
versions = ['Python 2.7', 'Python 3.4', 'Python 3.5']

[mgautierfr]

I_set_sw function is missing a SWAP_INT.

This leads to wrong set of bitfield value.

Here is a script to reproduce:

----------

from ctypes import *

class HEADER(BigEndianStructure):
   _fields_ = ( ('pad', c_uint32, 16),
                ('v1', c_uint32, 4),
                ('v2', c_uint32, 12)
              )

b = bytearray(4)
header = HEADER.from_buffer(b)

header.type = 1
assert b == b'\x00\x00\x10\x00'

header.mode = 0x234
assert b == b'\x00\x00\x12\x34'

---

[mgautierfr]

A little ping.

With a new patch integrating the unit test.

[meadori]

I will review this today.

[mgautierfr]

The bug is also present in Python 2.7.

Is it possible to backport this fix ?

[python-dev]

New changeset 935ae7f001e3 by Victor Stinner in branch '3.4':
Issue bpo-23319: Fix ctypes.BigEndianStructure, swap correctly bytes. Patch
https://hg.python.org/cpython/rev/935ae7f001e3

[python-dev]

New changeset 88f2c4f12b56 by Victor Stinner in branch '2.7':
Issue bpo-23319: Fix ctypes.BigEndianStructure, swap correctly bytes. Patch
https://hg.python.org/cpython/rev/88f2c4f12b56

[vstinner]

Thanks for your report, patch and unit test Matthieu. I rewrote the unit test because your layout was too complex for my little brain :-) I also write a unit test for little endian. I applied your fix to Python 2.7, 3.4, 3.5 and 3.6.

[python-dev]

New changeset 12b353f76447 by Victor Stinner in branch '2.7':
Issue bpo-23319: Add Matthieu Gautier to Misc/ACKS
https://hg.python.org/cpython/rev/12b353f76447

New changeset 3caa68f55e3e by Victor Stinner in branch '3.4':
Issue bpo-23319: Add Matthieu Gautier to Misc/ACKS
https://hg.python.org/cpython/rev/3caa68f55e3e

[meadori]

Thanks for committing this Victor. The patch looked good to me too. Sorry for not getting around to update the tracker.