python / python/cpython

Support the use of the managed pre-header in builtin classes.

Open
#95,707 7 comments 0 reactions 1 assignee View on GitHub

@markshannon is already working on this.

Since Aug 5, 2022.

3.12 3.13 docs interpreter-core performance type-feature
Dominant language
Python
Stars
77.2k
Forks
36k
PR metrics pending

Description

Currently Py_TPFLAGS_MANAGED_DICT is an internal-only flag, in fact setting in third-party code is likely to lead to a crash.
We would like to expose it, and a weakref equivalent Py_TPFLAGS_MANAGED_WEAKREFS to allow builtin classes to take advantage of compact object layout.
Compact layout uses less memory, performs better and allow more robust subclassing. So everyone should be able to use it.

  • Fix crashes when Py_TPFLAGS_MANAGED_DICT is used
  • Add Py_TPFLAGS_MANAGED_WEAKREFS
  • Document how to use these flags, and the upgrade path from tp_dictoffset and tp_weakreflist

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.

Assessment

This issue has not been assessed yet.

Get new issues in your inbox

A short digest of beginner-friendly GitHub issues.