Nested AttributeError improved messages don't work with properties #146171
Description
The Python 3.15 improved error message for nested attribute access doesn't seem to work on properties.
Rationale
Take the example from the What's new in Python 3.15 docs:
from dataclasses import dataclass
@dataclass
class Circle:
radius: float
@property
def area(self) -> float:
return pi * self.radius**2
class Container:
def __init__(self, inner: Circle) -> None:
self.inner = inner
circle = Circle(radius=4.0)
container = Container(circle)
print(container.area)Running it with the CPython main branch or Python 3.15.0a1 through Python 3.15.0a7 (with uv) produces the following error:
Traceback (most recent call last):
File "/Users/rodrigogs/Documents/cpython/../tmp/circle.py", line 17, in <module>
print(container.area)
^^^^^^^^^^^^^^
AttributeError: 'Container' object has no attribute 'area'If you remove @property or if you try accessing container.radius instead, you get the respective improved messages:
# After removing `@property` from `area`:
Traceback (most recent call last):
File "/Users/rodrigogs/Documents/cpython/../tmp/circle_no_prop.py", line 16, in <module>
print(container.area)
^^^^^^^^^^^^^^
AttributeError: 'Container' object has no attribute 'area'. Did you mean: 'inner.area'?
# ---
# Accessing `radius` instead of the property `area`:
Traceback (most recent call last):
File "/Users/rodrigogs/Documents/cpython/../tmp/circle_radius.py", line 17, in <module>
print(container.radius)
^^^^^^^^^^^^^^^^
AttributeError: 'Container' object has no attribute 'radius'. Did you mean: 'inner.radius'?Helper scripts for easier testing
circle.py — original example that doesn't work
from dataclasses import dataclass
@dataclass
class Circle:
radius: float
@property
def area(self) -> float:
return pi * self.radius**2
class Container:
def __init__(self, inner: Circle) -> None:
self.inner = inner
circle = Circle(radius=4.0)
container = Container(circle)
print(container.area)circle_radius.py — accessing radius works
from dataclasses import dataclass
@dataclass
class Circle:
radius: float
@property
def area(self) -> float:
return pi * self.radius**2
class Container:
def __init__(self, inner: Circle) -> None:
self.inner = inner
circle = Circle(radius=4.0)
container = Container(circle)
print(container.radius)circle_no_prop.py — removing the property works
from dataclasses import dataclass
@dataclass
class Circle:
radius: float
# @property
def area(self) -> float:
return pi * self.radius**2
class Container:
def __init__(self, inner: Circle) -> None:
self.inner = inner
circle = Circle(radius=4.0)
container = Container(circle)
print(container.area)CPython versions tested on:
3.15, CPython main branch
Operating systems tested on:
macOS