use the ClassDef attribute inference process in Instances #2563
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Note that the biggest source of changes is just moving a bunch of code into a separate function |
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## main #2563 +/- ##
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+ Coverage 93.05% 93.09% +0.03%
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Files 93 93
Lines 11050 11053 +3
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+ Hits 10283 10290 +7
+ Misses 767 763 -4
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Instances often have «special_attributes». ClassDef does a lot of transformations of attibutes during inference, so let's reuse them in Instance. We are fixing inference of the "special" attributes of Instances. Before these changes, the FunctionDef attributes wouldn't get wrapped into a BoundMethod. This was facilitated by extracting the logic of inferring attributes into 'FunctionDef._infer_attrs' and reusing it in BaseInstance. This issue isn't visible right now, because the special attributes are simply not found due not being attached to the parent (the instance). Which in turn is caused by not providing the actual parent in the constructor. Since we are on a quest to always provide a parent, this change is necessary.
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| @@ -1295,7 +1295,7 @@ def func(arg1, arg2): | |||
| self.assertIsInstance(inferred[0], BoundMethod) | |||
| inferred = list(Instance(cls).igetattr("m4")) | |||
| self.assertEqual(len(inferred), 1) | |||
| self.assertIsInstance(inferred[0], nodes.FunctionDef) | |||
| self.assertIsInstance(inferred[0], BoundMethod) | |||
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I think this change is incorrect, and therefore shows something is up with this PR.
To reproduce:
class Clazz(object): ...
def func(arg1, arg2):
"function that will be used as a method"
return arg1.value + arg2
Clazz.m3 = func
inst = Clazz()
inst.m4 = func
print(Clazz.m3)
print(inst.m3)
print(inst.m4)<function func at 0x109582340>
<bound method func of <__main__.Clazz object at 0x1095ab9b0>>
<function func at 0x109582340>This should remain a FunctionDef and not a BoundMethod.
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Hmm, you are right. Then, I think the issue is in the semantics of objectmodel. For ordinary Instances, special_attributes are «instance» attributes. They should remain FunctionDef. However, in some cases, for specialized instances, e.g. Generator, the objectmodel is used for «class» methods. So, the FunctionDefs should get wrapped into BoundMethods.
So, the fix should lie on that side, but it also feels quite error-prone to use the same special_attributes for the two different purposes.
I'll do a fix, but a bit later, I'm a bit short on time.
A part of getting rid of non-Module roots, see #2536
Instances often have «special_attributes». ClassDef does a lot of
transformations of attibutes during inference, so let's reuse them
in Instance.
We are fixing inference of the "special" attributes of
Instances. Before these changes, the FunctionDef attributes
wouldn't get wrapped into a BoundMethod. This was facilitated by
extracting the logic of inferring attributes into
'FunctionDef._infer_attrs' and reusing it in BaseInstance.
This issue isn't visible right now, because the special attributes
are simply not found due not being attached to the parent (the
instance). Which in turn is caused by not providing the actual
parent in the constructor. Since we are on a quest to always
provide a parent, this change is necessary.