python / python/cpython

typing.get_type_hints wrong namespace for forward-declaration of inner class

Open
#82,016 8 comments 0 reactions 0 assignees View on GitHub

Nobody has claimed this yet.

stdlib topic-typing type-bug
Dominant language
Python
Stars
77.2k
Forks
36k
PR merge metrics
PR metrics pending

Description

BPO 37835
Nosy @ilevkivskyi
Files
  • typing_check.py: A simple file to reproduce the error with inner classes.
  • get_type_hints_for_inner_classes.zip
  • metaclass_workaround.py
  • Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.

    Show more details

    GitHub fields:

    assignee = None
    closed_at = None
    created_at = <Date 2019-08-13.09:36:43.877>
    labels = ['3.7', 'type-bug', 'library']
    title = 'typing.get_type_hints wrong namespace for forward-declaration of inner class'
    updated_at = <Date 2019-09-09.09:59:14.831>
    user = 'https://bugs.python.org/netbnd'
    

    bugs.python.org fields:

    activity = <Date 2019-09-09.09:59:14.831>
    actor = 'levkivskyi'
    assignee = 'none'
    closed = False
    closed_date = None
    closer = None
    components = ['Library (Lib)']
    creation = <Date 2019-08-13.09:36:43.877>
    creator = 'netbnd'
    dependencies = []
    files = ['48539', '48552', '48562']
    hgrepos = []
    issue_num = 37835
    keywords = []
    message_count = 8.0
    messages = ['349535', '349958', '349986', '349988', '350468', '350982', '351282', '351398']
    nosy_count = 2.0
    nosy_names = ['levkivskyi', 'netbnd']
    pr_nums = []
    priority = 'normal'
    resolution = None
    stage = None
    status = 'open'
    superseder = None
    type = 'behavior'
    url = 'https://bugs.python.org/issue37835'
    versions = ['Python 3.6', 'Python 3.7']
    

    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 by running typing_check.py to reproduce the get_type_hints failure, then inspect the typing implementation involved in resolving forward declarations for inner classes. Use the provided get_type_hints_for_inner_classes.zip and metaclass_workaround.py for additional cases; the issue is done when the inner-class forward declaration resolves in the correct namespace.

    Written by the indexing model from the issue text.

    Assessment

    Tech stack
    python
    Domain
    tooling
    Issue type
    Bug
    Difficulty
    4/5
    Estimated time
    3-5 days
    Activity status
    Stale
    Clarity
    Needs clarification
    Newbie friendliness
    32/100

    Get new issues in your inbox

    A short digest of beginner-friendly GitHub issues.