bpo-44649: Fix dataclasses(slots=True) with a field with a default, but init=False #29692
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Thanks @ericvsmith for the PR 🌮🎉.. I'm working now to backport this PR to: 3.10. |
miss-islington
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Nov 22, 2021
…ut init=False (pythonGH-29692) Special handling is needed, because for non-slots dataclasses the instance attributes are not set: reading from a field just references the class's attribute of the same name, which contains the default value. But this doesn't work for classes using __slots__: they don't read the class's attribute. So in that case (and that case only), initialize the instance attribute. Handle this for both normal defaults, and for fields using default_factory. (cherry picked from commit d3062f6) Co-authored-by: Eric V. Smith <ericvsmith@users.noreply.github.com>
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GH-29704 is a backport of this pull request to the 3.10 branch. |
miss-islington
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Nov 22, 2021
…ut init=False (GH-29692) Special handling is needed, because for non-slots dataclasses the instance attributes are not set: reading from a field just references the class's attribute of the same name, which contains the default value. But this doesn't work for classes using __slots__: they don't read the class's attribute. So in that case (and that case only), initialize the instance attribute. Handle this for both normal defaults, and for fields using default_factory. (cherry picked from commit d3062f6) Co-authored-by: Eric V. Smith <ericvsmith@users.noreply.github.com>
remykarem
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Dec 7, 2021
…ut init=False (pythonGH-29692) Special handling is needed, because for non-slots dataclasses the instance attributes are not set: reading from a field just references the class's attribute of the same name, which contains the default value. But this doesn't work for classes using __slots__: they don't read the class's attribute. So in that case (and that case only), initialize the instance attribute. Handle this for both normal defaults, and for fields using default_factory.
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https://bugs.python.org/issue44649