Setattribute with Extra.allow is hiding method when it's defined on class.

[vendito-david]

Initial Checks

• I confirm that I'm using Pydantic V2

Description

When setting an attribute, it is saving it with __setattr__ into __pydantic_extra__ (

pydantic/pydantic/main.py

Line 802 in b403666

self.__pydantic_extra__[name] = value # type: ignore

).
On the other hand, when getting an attribute, it is running the __getattribute__ implementation, which is basically looking for the object dict, then the class hierarchy then the __getattr__ implementation afterwards only.
If Extra.allow is set, the setattr is saving it to a place which is not accessed in the same order by default. See the example code. It prints the "1,1,patched" instead of "1,patched,patched".

Example Code

from pydantic import BaseModel, Extra

class LookupPython():
    id: int

    def __init__(self, id) -> None:
        self.id = id

    def func(self):
        return self.id

class LookupPydantic(BaseModel, extra=Extra.allow):
    id: int

    def func(self):
        return self.id
    
lookups = [ LookupPython(id=1), LookupPydantic(id=1) ]

for lookup in lookups:
    print( type(lookup) )
    print( repr(lookup) )
    print( lookup.func() )
    lookup.func = lambda: "patched"
    print( repr(lookup) )
    print( lookup.func() )
    lookup.__dict__["func"] = lambda: "patched"
    print( repr(lookup) )
    print( lookup.func() )
    print( "" )

Output:

<class '__main__.LookupPython'>
<__main__.LookupPython object at 0x7ff7c92ba5d0>
1
<__main__.LookupPython object at 0x7ff7c92ba5d0>
patched
<__main__.LookupPython object at 0x7ff7c92ba5d0>
patched

<class '__main__.LookupPydantic'>
LookupPydantic(id=1)
1
LookupPydantic(id=1, func=<function <lambda> at 0x7ff7c8e54cc0>)
1
LookupPydantic(id=1, func=<function <lambda> at 0x7ff7c8e54cc0>)
patched

Python, Pydantic & OS Version

pydantic version: 2.4.0
        pydantic-core version: 2.10.0
          pydantic-core build: profile=release pgo=true
                 install path: /home/kali/.local/lib/python3.10/site-packages/pydantic
               python version: 3.10.8 (main, Oct 24 2022, 10:07:16) [GCC 12.2.0]
                     platform: Linux-5.15.90.1-microsoft-standard-WSL2-x86_64-with-glibc2.35
             related packages: typing_extensions-4.8.0 fastapi-0.85.0 typing_extensions-4.3.0 email-validator-1.1.2

[sydney-runkle]

Hi @vendito-david,

Thanks for reporting this! Also, thanks for the in depth code example that runs out of the box 😄.

Like you mentioned, this is constrained to just the case where you're setting a method, as the following works with attributes:

from pydantic import BaseModel

class LookupPython():
    id: int

    def __init__(self, id) -> None:
        self.id = id

class LookupPydantic(BaseModel, extra='allow'):
    id: int

python_lookup = LookupPython(id=1)
pydantic_lookup = LookupPydantic(id=1)

python_lookup.id = 2
print(python_lookup.id)
#> 2

pydantic_lookup.id = 2
print(pydantic_lookup.id)
#> 2

Are you interested in opening a PR to help fix this issue? ⭐

[mullerdavid]

Hi, this is vendito-david on my non-corporate user. I made an issue instead of PR because i am not that familiar with the new pydantic v2 and your conventions yet.

[sydney-runkle]

Hi @vendito-david (@mullerdavid ),

No worries at all. I'll work on a fix for this + update here with progress 😄.