python / python/cpython

Incorrect behaviour creating a Structure with ctypes.c_bool bitfields

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3.10 3.11 3.12 OS-windows topic-ctypes type-bug
Dominant language
Python
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Description

BPO 46758
Nosy @pfmoore, @tjguk, @zware, @zooba
Files
  • mre.py: Minimal Runnable Example
  • 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 = None
    created_at = <Date 2022-02-15.12:01:56.442>
    labels = ['3.10', 'ctypes', 'type-bug', '3.9', 'OS-windows']
    title = 'Incorrect behaviour creating a Structure with ctypes.c_bool bitfields'
    updated_at = <Date 2022-02-15.12:01:56.442>
    user = 'https://bugs.python.org/dudenwatschn'
    

    bugs.python.org fields:

    activity = <Date 2022-02-15.12:01:56.442>
    actor = 'dudenwatschn'
    assignee = 'none'
    closed = False
    closed_date = None
    closer = None
    components = ['Windows', 'ctypes']
    creation = <Date 2022-02-15.12:01:56.442>
    creator = 'dudenwatschn'
    dependencies = []
    files = ['50624']
    hgrepos = []
    issue_num = 46758
    keywords = []
    message_count = 1.0
    messages = ['413284']
    nosy_count = 5.0
    nosy_names = ['paul.moore', 'tim.golden', 'zach.ware', 'steve.dower', 'dudenwatschn']
    pr_nums = []
    priority = 'normal'
    resolution = None
    stage = None
    status = 'open'
    superseder = None
    type = 'behavior'
    url = 'https://bugs.python.org/issue46758'
    versions = ['Python 3.9', 'Python 3.10']
    

    Contributor guide

    Open the contributing guide

    First steps

    1. Read the whole issue, then the project's contributing guide.
    2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
    3. Fork the repository and make your change on a branch.
    4. Open a pull request that references the issue number.

    Research direction

    Start with the attached mre.py minimal runnable example and reproduce the ctypes.c_bool bitfield behavior on the Windows configuration named in the issue. Trace the Structure creation path and confirm that the incorrect behavior shown by the reproducer no longer occurs.

    Written by the indexing model from the issue text.

    Assessment

    Tech stack
    python
    Domain
    backend
    Issue type
    Bug
    Difficulty
    4/5
    Estimated time
    3-5 days
    Activity status
    Stale
    Clarity
    Needs clarification
    Newbie friendliness
    30/100

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