Description

assignee = None
closed_at = None
created_at = <Date 2014-03-21.16:45:16.140>
labels = ['extension-modules', 'type-feature', '3.8']
title = "PyArg_ParseTupleAndKeywords doesn't take const char *keywords[]"
updated_at = <Date 2018-07-03.09:45:24.075>
user = 'https://github.com/hvenev'

activity = <Date 2018-07-03.09:45:24.075>
actor = 'serhiy.storchaka'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Extension Modules']
creation = <Date 2014-03-21.16:45:16.140>
creator = 'h.venev'
dependencies = []
files = []
hgrepos = []
issue_num = 21011
keywords = []
message_count = 4.0
messages = ['214388', '214857', '320945', '320952']
nosy_count = 4.0
nosy_names = ['methane', 'serhiy.storchaka', 'josh.r', 'h.venev']
pr_nums = []
priority = 'normal'
resolution = None
stage = None
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue21011'
versions = ['Python 3.8']

Activity

1. hvenev commented on Mar 21, 2014

   

   hvenevmannequin

   on Mar 21, 2014

   MannequinAuthor

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   This really annoys me. I have to store the literals in char[] and then make a char*[] from them. It would be better if a simple array of string literals could be used. It would also require less data space because string literals could be merged by the compiler.

   I don't know why PyArg_ParseTupleAndKeywords would ever modify the keywords array so it makes absolutely no sense to me for the array not to be const char*[].

   In all cases I have seen PyArg_ParseTupleAndKeywords being used string literals were converted to char* (dropping const) which is far far worse than inefficient code.
2. hvenev

   added

   performancePerformance or resource usagePerformance or resource usage

   extension-modulesC modules in the Modules dirC modules in the Modules dir

   on Mar 21, 2014
3. MojoVampire commented on Mar 25, 2014

   

   MojoVampiremannequin

   on Mar 25, 2014

   Mannequin

   More actions

   This has come up before. Links to additional info:

   https://mail.python.org/pipermail/python-dev/2006-February/060689.html

   http://bugs.python.org/issue1772673
4. methane commented on Jul 3, 2018

   

   methane

   on Jul 3, 2018

   Member

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   I think we can't fix this until Python 4.
   May I close this issue as "won't fix" for now?

   Or can we add "Python 4" keyword to list backward incompatible changes we want to do in the future?
5. methane

   added

   3.8 (EOL)end of lifeend of life

   on Jul 3, 2018
6. serhiy-storchaka commented on Jul 3, 2018

   

   serhiy-storchaka

   on Jul 3, 2018

   Member

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   We can't change this API because this would break virtually all user code.

   But we can introduce a macro like PY_SSIZE_T_CLEAN. If it is defined before including Python.h, PyArg_ParseTupleAndKeywords() will take an array of const strings. This will help for compatibility with C++.
7. serhiy-storchaka

   added

   type-featureA feature request or enhancementA feature request or enhancement

   and removed

   performancePerformance or resource usagePerformance or resource usage

   on Jul 3, 2018
8. ezio-melotti

   transferred this issue fromon Apr 10, 2022
9. iritkatriel

   added

   topic-C-API

   and removed

   extension-modulesC modules in the Modules dirC modules in the Modules dir

   3.8 (EOL)end of lifeend of life

   on May 14, 2023
10. serhiy-storchaka

    added a commit that references this issue on Jun 21, 2023

    pythongh-65210: Add const qualifiers in PyArg_VaParseTupleAndKeywords()

    80e37a9
11. serhiy-storchaka commented on Jun 21, 2023

    

    serhiy-storchaka

    on Jun 21, 2023

    Member

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    We can fix this at least for C++, because in C++ the const char * const * declaration is compatible with arguments of type const char * const *, char * const *, const char **, and char **.

    Sad, it is not so in C, but we can provide a lever to control the declaration, and may change the default in distant future.
12. serhiy-storchaka

    added a commit that references this issue on Dec 4, 2023

    gh-65210: Add const qualifiers in PyArg_VaParseTupleAndKeywords() (GH…

    da6760b
13. serhiy-storchaka

    closed this as completedon Dec 4, 2023
14. aisk

    added a commit that references this issue on Feb 11, 2024

    pythongh-65210: Add const qualifiers in PyArg_VaParseTupleAndKeywords…

    4fb94c8
15. Glyphack

    added a commit that references this issue on Sep 2, 2024

    pythongh-65210: Add const qualifiers in PyArg_VaParseTupleAndKeywords…

    a01a009

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