gh-135228: When @dataclass(slots=True) replaces a dataclass, make the original class collectible (take 2) #137047
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…ke the original class collectible (python#136893) An interesting hack, but more localized in scope than python#135230. This may be a breaking change if people intentionally keep the original class around when using `@dataclass(slots=True)`, and then use `__dict__` or `__weakref__` on the original class. Co-authored-by: Alyssa Coghlan <ncoghlan@gmail.com>
Maybe we can check that it's a heap type?
I'm not aware of other descriptors that could cause problems. It's better to minimize the amount of changes we make to the class, because there are edge cases where the class is still accessible after the dataclass transformation is applied. |
Co-authored-by: Petr Viktorin <encukou@gmail.com> Co-authored-by: Serhiy Storchaka <storchaka@gmail.com>
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@encukou @serhiy-storchaka could you review again and approve if you're satisfied, so that we can get this fixed in 3.14? |
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I can't find any issues in the PR; this is pretty much is the local optimum.
But, I can't tell if there will be unintended consequences. This PR feels quite risky for a RC fix.
Docs-wise: the notes/comments shouldn't imply that the original class is guaranteed to be garbage collected -- something else could still keep it alive.
Misc/NEWS.d/next/Library/2025-07-20-16-56-55.gh-issue-135228.n_XIao.rst
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| /*[clinic input] | ||
| sys._clear_type_descriptors | ||
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| type: object |
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You can use Argument Clinic for type checking. Although it does not make much difference.
| type: object | |
| type: object(subclass_of="&PyType_Type") |
| PyErr_SetString(PyExc_TypeError, "argument must be a type"); | ||
| return NULL; | ||
| } | ||
| PyTypeObject *typeobj = (PyTypeObject *)(type); |
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| PyTypeObject *typeobj = (PyTypeObject *)(type); | |
| PyTypeObject *typeobj = (PyTypeObject *)type; |
This is a redo of #136893 without relying on a hack to get to the type dictionary.