Allow extensions to set a callback to be invoked when a type is modified

@carljm

BPO	46895
Nosy	@carljm, @DinoV, @itamaro, @mpage

^{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 2022-03-01.22:16:51.046>
labels = ['interpreter-core', 'expert-C-API', 'type-feature', '3.11']
title = 'Allow extensions to set a callback to be invoked when a type is modified'
updated_at = <Date 2022-03-01.22:21:58.988>
user = 'https://github.com/mpage'

bugs.python.org fields:

activity = <Date 2022-03-01.22:21:58.988>
actor = 'mpage'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Interpreter Core', 'C API']
creation = <Date 2022-03-01.22:16:51.046>
creator = 'mpage'
dependencies = []
files = []
hgrepos = []
issue_num = 46895
keywords = []
message_count = 1.0
messages = ['414305']
nosy_count = 4.0
nosy_names = ['carljm', 'dino.viehland', 'itamaro', 'mpage']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue46895'
versions = ['Python 3.11']

Linked PRs

CPython extensions providing optimized execution of Python bytecode (e.g. the Cinder JIT), or even CPython itself (e.g. the faster-cpython project) may wish to cache access to lookups in the class hierarchy (e.g. when resolving the target of a method call). Extensions that perform these optimizations need to know when to invalidate the cached values. CPython already has a mechanism to invalidate its internal state (e.g. the global method cache) when a type is modified: _PyType_Modified. We propose adding an API to allow extensions to set a callback that will be invoked by _PyType_Modified whenever a type, or any ancestor of the type in the class hierarchy, changes.

Proposed API:

// A callback to be invoked with the modified type and optionally the name of
// the attribute that was modified.
typedef void(*PyType_ModifiedCallback)(PyTypeObject* type, PyObject* attr);

// Set or get the callback. The callback may be cleared by supplying a NULL callback.
void PyType_SetModifiedCallback(PyType_ModifiedCallback callback);
PyType_ModifiedCallback PyType_GetModifiedCallback();

I don't see any discussion here. Are you still interested in getting this in 3.12? What should happen next? Is it a simple PR, or should we have a design discussion first?

Are you still interested in getting this in 3.12?

yes, that's the plan!

What should happen next? Is it a simple PR, or should we have a design discussion first?

I think this is a simple PR (similar to #91054), so the next step is to write that PR if the proposed API looks reasonable

Fixed in #91051.

pythongh-91051: fix segfault when using all 8 type watchers

gh-91051: fix segfault when using all 8 type watchers (#107853)

pythongh-91051: fix segfault when using all 8 type watchers (pythonGH…

pythongh-91051: fix type watcher test to be robust to existing watcher

Reopened because not all PRs were merged yet.

[3.12] gh-91051: fix segfault when using all 8 type watchers (GH-107853…

pythongh-91051: fix type watcher test to be robust to existing watcher (

gh-91051: fix type watcher test to be robust to existing watcher (#10…

[3.12] gh-91051: fix type watcher test to be robust to existing watch…

Navigation Menu

Repository navigation

Allow extensions to set a callback to be invoked when a type is modified #91051

Linked PRs

10 remaining items

Metadata

Assignees

Labels

Projects

Milestone

Relationships

Development

Allow extensions to set a callback to be invoked when a type is modified #91051

Description

Linked PRs

Activity

mpage commented on Mar 1, 2022

gvanrossum commented on Sep 15, 2022

itamaro commented on Sep 15, 2022

10 remaining items

carljm commented on Dec 8, 2022

serhiy-storchaka commented on Aug 16, 2023

Metadata

Metadata

Assignees

Labels

Projects

Milestone

Relationships

Development

Issue actions