python / python/cpython

Variable sized Python objects become fully opaque in abi3t

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#148,325 9 comments 0 reactions 0 assignees View on GitHub

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interpreter-core pending topic-C-API type-feature
Dominant language
Python
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Description

Bug report

Bug description:

The PyVarObject data structure becomes opaque in abi3t. Unfortunately, there is no limited API functionality to provide access to elements of a PyVarObject.

The relevant functions PyObject_GetItemData() and PyObject_GetItemData_DuringGC() are marked as unstable.

It would be very important to fix this before Python 3.15 goes out, or any extensions using variable sized objects will be stranded.

CPython versions tested on:

3.15, CPython main branch

Operating systems tested on:

Linux

Linked PRs
  • gh-148324

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

Review the linked PR gh-148324 and the PyVarObject limited-API entry points named in the report, including PyObject_GetItemData() and PyObject_GetItemData_DuringGC(). Done means variable-sized objects remain usable through abi3t without relying only on unstable functionality.

Written by the indexing model from the issue text.

Assessment

Tech stack
python
Domain
backend-api-design
Issue type
Bug
Difficulty
4/5
Estimated time
3-5 days
Activity status
Stale
Clarity
Needs clarification
Newbie friendliness
25/100

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