GH-94822: Don't specialize when metaclasses are involved #94892
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brandtbucher
added
type-bug
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Thanks for the quick fix. I think this LGTM. IIRC speaking to Mark at EuroPython he had other ideas about this though (something about just blocking non-immutable classes IIRC). Let's wait for his reply on Monday. |
| @@ -945,6 +945,10 @@ specialize_class_load_attr(PyObject *owner, _Py_CODEUNIT *instr, | |||
| PyObject *name) | |||
| { | |||
| _PyLoadMethodCache *cache = (_PyLoadMethodCache *)(instr + 1); | |||
| if (!PyType_CheckExact(owner) || _PyType_Lookup(Py_TYPE(owner), name)) { | |||
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You could safely generalize this to any immutable metaclass.
Py_TYPE(owner)->tp_flags & Py_TPFLAGS_IMMUTABLETYPE
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Just to clarify, you're only referring to the PyType_CheckExact call, right? The _PyType_Lookup call stays?
Wouldn't we also need to add something like Py_TYPE(owner)->tp_getattro == PyType_Type.tp_getattro too to protect against immutable types that define __getattribute__?
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Just to clarify, you're only referring to the PyType_CheckExact call, right?
Yes
Wouldn't we also need to add something like Py_TYPE(owner)->tp_getattro == PyType_Type.tp_getattro too
And probably some other special case I've forgotten.
Let's just stick with the PyType_CheckExact(owner) to be on the safe side.
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Thanks @brandtbucher for the PR 🌮🎉.. I'm working now to backport this PR to: 3.11. |
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Sorry, @brandtbucher, I could not cleanly backport this to |
…pythonGH-94892). (cherry picked from commit daf68ba) Co-authored-by: Brandt Bucher <[email protected]>
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GH-94980 is a backport of this pull request to the 3.11 branch. |
…4892) (GH-94980) (cherry picked from commit daf68ba) Co-authored-by: Brandt Bucher <[email protected]>
This patch changes
LOAD_ATTR_CLASSto fail if the class has a metaclass other thantype, or if the named attribute is present ontypeitself. It also adds a bunch of regression tests for nasty edge-cases when caching class attributes and methods.Supersedes #94863 (see #94863 (comment)).