Description

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'

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']

Activity

1. mpage commented on Mar 1, 2022

   

   mpagemannequin

   on Mar 1, 2022

   MannequinAuthor

   More actions

   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();
   

   Reacted by Oleg Iarygin, Itamar Oren and Erlend E. Aasland
2. mpage

   added

   interpreter-core(Objects, Python, Grammar, and Parser dirs)(Objects, Python, Grammar, and Parser dirs)

   topic-C-API

   type-featureA feature request or enhancementA feature request or enhancement

   on Mar 1, 2022
3. mpage

   changed the title [-]Type-Modified Callbacks[/-] [+]Allow extensions to set a callback to be invoked when a type is modified[/+] on Mar 1, 2022
4. mpage

   changed the title [-]Type-Modified Callbacks[/-] [+]Allow extensions to set a callback to be invoked when a type is modified[/+] on Mar 1, 2022
5. mpage

   added

   3.11only security fixesonly security fixes

   on Mar 1, 2022
6. ezio-melotti

   transferred this issue fromon Apr 10, 2022
7. gvanrossum commented on Sep 15, 2022

   

   gvanrossum

   on Sep 15, 2022

   Member

   More actions

   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?
8. itamaro commented on Sep 15, 2022

   

   itamaro

   on Sep 15, 2022

   Contributor

   More actions

   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
9. gvanrossum

   removed

   3.11only security fixesonly security fixes

   on Sep 24, 2022
10. 10 remaining items

11. carljm commented on Dec 8, 2022

    

    carljm

    on Dec 8, 2022

    Member

    More actions

    Fixed in #91051.
12. carljm

    closed this as completedon Dec 8, 2022
13. carljm

    added 4 commits that reference this issue on Aug 11, 2023

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

    1980789

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

    7c249fa

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

    e149aed

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

    66e4edd
14. miss-islington

    added a commit that references this issue on Aug 11, 2023

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

    4f05fc0
15. carljm

    added a commit that references this issue on Aug 16, 2023

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

    8c38bd5
16. serhiy-storchaka

    reopened this on Aug 16, 2023
17. serhiy-storchaka commented on Aug 16, 2023

    

    serhiy-storchaka

    on Aug 16, 2023

    Member

    More actions

    Reopened because not all PRs were merged yet.
18. Yhg1s

    added a commit that references this issue on Aug 16, 2023

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

    00bfed7
19. miss-islington

    added a commit that references this issue on Aug 16, 2023

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

    f785150
20. carljm

    added a commit that references this issue on Aug 16, 2023

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

    fce93c8
21. Yhg1s

    added a commit that references this issue on Aug 16, 2023

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

    84a4370
22. itamaro

    closed this as completedon Aug 17, 2023

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