[3.10] bpo-44649: Fix dataclasses(slots=True) with a field with a default, but init=False (GH-29692) #29704
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…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 <[email protected]>
ericvsmith
approved these changes
Nov 22, 2021
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Sorry, I can't merge this PR. Reason: |
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@ericvsmith: Status check is done, and it's a success ✅ . |
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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 [email protected]
https://bugs.python.org/issue44649
Automerge-Triggered-By: GH:ericvsmith