Issue 36470: dataclasses.replace raises an exception if InitVar with default argument is not provided. (original) (raw)

Issue36470

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This issue has been migrated to GitHub: https://github.com/python/cpython/issues/80651

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process

Created on 2019-03-29 11:52 by Greg Kuhn, last changed 2022-04-11 14:59 by admin. This issue is now closed.

Messages (7)
msg339105 - (view)	Author: Greg Kuhn (Greg Kuhn)	Date: 2019-03-29 11:52
I have a snippet below which runs fine on python 3.7.0 but raises a ValueError exception on 3.7.1. I believe it's related to https://bugs.python.org/issue33805. The error: c:\python\lib\dataclasses.py:1219: ValueError The script: from dataclasses import replace, dataclass, InitVar @dataclass class Test: a:int = 1 b:InitVar[int] = None def __post_init__(self, b): if b is not None: self.a = b if __name__ == '__main__': t = Test() t1 = Test(b=5) assert t1.a == 5 t2 = replace(t1, **{}) print(t2)
msg339124 - (view)	Author: Greg Kuhn (Greg Kuhn)	Date: 2019-03-29 16:12
Fixed title
msg385914 - (view)	Author: Cosimo Lupo (anthrotype)	Date: 2021-01-29 15:09
any updates on this? Would be great if any of the two candidate PRs was merged. It's basically impossible to use replace() with default InitVars.. Thank you in advace
msg390252 - (view)	Author: miss-islington (miss-islington)	Date: 2021-04-05 19:41
New changeset 75220674c07abfc90c2cd7862d04cfa2e2354450 by Zackery Spytz in branch 'master': bpo-36470: Allow dataclasses.replace() to handle InitVars with default values (GH-20867) https://github.com/python/cpython/commit/75220674c07abfc90c2cd7862d04cfa2e2354450
msg390256 - (view)	Author: Eric V. Smith (eric.smith) *	Date: 2021-04-05 20:07
New changeset bdee2a389e4b10e1c0ab65bbd4fd03defe7b2837 by Miss Islington (bot) in branch '3.8': bpo-36470: Allow dataclasses.replace() to handle InitVars with default values (GH-20867) (GH-25201) https://github.com/python/cpython/commit/bdee2a389e4b10e1c0ab65bbd4fd03defe7b2837
msg390257 - (view)	Author: Eric V. Smith (eric.smith) *	Date: 2021-04-05 20:07
New changeset 013c30e5fcee449cee63354d34585d6111782c82 by Miss Islington (bot) in branch '3.9': bpo-36470: Allow dataclasses.replace() to handle InitVars with default values (GH-20867) (GH-25200) https://github.com/python/cpython/commit/013c30e5fcee449cee63354d34585d6111782c82
msg390259 - (view)	Author: Eric V. Smith (eric.smith) *	Date: 2021-04-05 20:12
Thanks for the fix!