Wrong types for PyMemberDefs in Objects/typeobject.c

[KevinShweh]

BPO	36951
Nosy	@benjaminp, @ZackerySpytz, @miss-islington
PRs	bpo-36951: Correct some types in the type_members struct in typeobject.c #13403 [3.7] closes bpo-36951: Correct some types in the type_members struct in typeobject.c. (GH-13403) #13433 [2.7] closes bpo-36951: Correct some types in the type_members struct in typeobject.c. (GH-13403) #13434

^{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 = None
closed_at = <Date 2019-05-20.00:26:38.365>
created_at = <Date 2019-05-17.19:50:54.269>
labels = ['interpreter-core', '3.8', 'type-bug', '3.7']
title = 'Wrong types for PyMemberDefs in Objects/typeobject.c'
updated_at = <Date 2019-05-20.00:54:12.610>
user = 'https://bugs.python.org/KevinShweh'

bugs.python.org fields:

activity = <Date 2019-05-20.00:54:12.610>
actor = 'miss-islington'
assignee = 'none'
closed = True
closed_date = <Date 2019-05-20.00:26:38.365>
closer = 'benjamin.peterson'
components = ['Interpreter Core']
creation = <Date 2019-05-17.19:50:54.269>
creator = 'Kevin Shweh'
dependencies = []
files = []
hgrepos = []
issue_num = 36951
keywords = ['patch']
message_count = 6.0
messages = ['342759', '342760', '342788', '342882', '342883', '342884']
nosy_count = 4.0
nosy_names = ['benjamin.peterson', 'Kevin Shweh', 'ZackerySpytz', 'miss-islington']
pr_nums = ['13403', '13433', '13434']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue36951'
versions = ['Python 2.7', 'Python 3.7', 'Python 3.8']

[KevinShweh]

In Objects/typeobject.c, the PyMemberDefs for __flags__, __weakrefoffset__, and __dictoffset__ all use T_LONG:

{"__flags__", T_LONG, offsetof(PyTypeObject, tp_flags), READONLY},
{"__weakrefoffset__", T_LONG,
 offsetof(PyTypeObject, tp_weaklistoffset), READONLY},
...
{"__dictoffset__", T_LONG,
 offsetof(PyTypeObject, tp_dictoffset), READONLY},

{"__weakrefoffset__", T_LONG,
 offsetof(PyTypeObject, tp_weaklistoffset), READONLY},

but in Include/object.h or Include/cpython/object.h, the corresponding struct members have types unsigned long, Py_ssize_t, and Py_ssize_t respectively:

    /* Flags to define presence of optional/expanded features */
    unsigned long tp_flags;
    ...
    /* weak reference enabler */
    Py_ssize_t tp_weaklistoffset;
    ...
    Py_ssize_t tp_dictoffset;

These uses of T_LONG should be changed to T_ULONG and T_PYSSIZE_T.

This was checked on 3.7.3 and master.

[KevinShweh]

Looks like I accidentally doubled the PyMemberDef for __weakrefoffset__ while editing. There's no double definition in the actual file.

[ZackerySpytz]

I agree that this should be fixed.

[benjaminp]

New changeset 53d378c by Benjamin Peterson (Zackery Spytz) in branch 'master':
closes bpo-36951: Correct some types in the type_members struct in typeobject.c. (GH-13403)
53d378c

[miss-islington]

New changeset eda691d by Miss Islington (bot) in branch '2.7':
closes bpo-36951: Correct some types in the type_members struct in typeobject.c. (GH-13403)
eda691d

[miss-islington]

New changeset 64b0bdb by Miss Islington (bot) in branch '3.7':
closes bpo-36951: Correct some types in the type_members struct in typeobject.c. (GH-13403)
64b0bdb