Model computed_fields from a Model Type

[SylvainGuieu]

Initial Checks

• I confirm that I'm using Pydantic V2

Description

Not sure if this is a bug or a feature.
So far (pydantic v2.5) , the model_computed_fields (a property) only work on model instances and not from model class.

I do not see obvious reason for that. See code below.
A solution would be to not use builtin python @property but a custom property with a re-writen __get__ method

Example Code

from pydantic import BaseModel, computed_field  

class M(BaseModel):
    x: float = 1.0 

    @computed_field
    @property 
    def tenx(self)->float:
       return self.x*10

>>> M.model_computed_fields
<property at 0x7fc4cbcf2860>
>>> M.model_computed_fields.__get__(None, M) # actually same as above 
<property at 0x7fc4cbcf2860>
>>> M.model_computed_fields.__get__(M, None) 
{'tenx': ComputedFieldInfo(wrapped_property=<property object at 0x7fc4cbc84360>, return_type=<class 'float'>, alias=None, alias_priority=None, title=None, description=None, examples=None, json_schema_extra=None, repr=True)}

Python, Pydantic & OS Version

pydantic version: 2.5.3
        pydantic-core version: 2.14.6
          pydantic-core build: profile=release pgo=false
                 install path: /Users/guieus/anaconda3/envs/hrmpm/lib/python3.9/site-packages/pydantic
               python version: 3.9.18 (main, Sep 11 2023, 08:38:23)  [Clang 14.0.6 ]
                     platform: macOS-10.16-x86_64-i386-64bit
             related packages: typing_extensions-4.9.0

[SylvainGuieu]

I think one can actually add a property to the BaseModel Metaclass to fix it.
I did the following test, it does not seems to be a problem in python :

class MMeta(type):
     @property
     def model_computed_fields(cls):
          return 1 

class M(metaclass=MMeta):
     @property 
     def model_computed_fields(self):
           return 2  

assert M.model_computed_fields == 1
assert M().model_computed_fields == 2

[sydney-runkle]

Fixed here:

#8437

Should be released with 2.6 soon