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Visit the type of instance of heap types if tp_traverse is not implemented #85208
Description
| BPO | 41036 |
|---|---|
| Nosy | @vstinner, @corona10, @pablogsal, @shihai1991 |
| PRs | |
| Superseder |
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = None
closed_at = <Date 2021-01-19.21:55:23.027>
created_at = <Date 2020-06-19.14:05:01.249>
labels = ['interpreter-core', 'expert-C-API', '3.9', '3.10']
title = 'Visit the type of instance of heap types if tp_traverse is not implemented'
updated_at = <Date 2021-01-19.21:55:23.026>
user = 'https://github.com/vstinner'bugs.python.org fields:
activity = <Date 2021-01-19.21:55:23.026>
actor = 'vstinner'
assignee = 'none'
closed = True
closed_date = <Date 2021-01-19.21:55:23.027>
closer = 'vstinner'
components = ['Interpreter Core', 'C API']
creation = <Date 2020-06-19.14:05:01.249>
creator = 'vstinner'
dependencies = []
files = []
hgrepos = []
issue_num = 41036
keywords = ['patch']
message_count = 3.0
messages = ['371884', '384986', '385298']
nosy_count = 4.0
nosy_names = ['vstinner', 'corona10', 'pablogsal', 'shihai1991']
pr_nums = ['20983']
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '42972'
type = None
url = 'https://bugs.python.org/issue41036'
versions = ['Python 3.9', 'Python 3.10']
Activity
vstinner commentedon Jun 19, 2020
While reviewing changes of bpo-40077 "Convert static types to PyType_FromSpec()", I noticed that some static types don't implement tp_traverse.
The doc says:
https://docs.python.org/dev/c-api/typeobj.html#c.PyTypeObject.tp_traverse
Porting to 3.9 says:
https://docs.python.org/dev/whatsnew/3.9.html#changes-in-the-c-api
--
It seems like converting a static type to a heap allocated type requires to *add* a new tp_traverse function, if it wasn't the case.
Maybe we can provide a base tp_traverse implementation in the base object type: visit the type if it's a heap type?
See attached PR.
See bpo-35810 and bpo-40217 for more information.
vstinner commentedon Jan 12, 2021
I created a thread on python-dev:
"Heap types (PyType_FromSpec) must fully implement the GC protocol"
https://mail.python.org/archives/list/python-dev@python.org/thread/C4ILXGPKBJQYUN5YDMTJOEOX7RHOD4S3/
vstinner commentedon Jan 19, 2021
I created bpo-42972 instead.