Python 3.7 dataclasses

I don’t know if this is supposed to work. Would be nice. I can try to fix it if you propose the way.

@dataclasses.dataclass
class C(pydantic.BaseModel):
     i:int
c = C(1)
....
RecursionError: maximum recursion depth exceeded

[samuelcolvin]

Proposal:

pydantic adds a decorator to validate dataclasses input data and equivalently it’s own version of dataclass which performs the same as normal dataclasses except for validating input data.

Something like:

from dataclasses import dataclasee
import pydantic

@pydantic.dataclasses.validate
@dataclass
class InventoryItem:
    name: str
    unit_price: float
    quantity_on_hand: int = 0

# which would be exactly the same as:

@pydantic.dataclasses.dataclass
class InventoryItem:
    name: str
    unit_price: float
    quantity_on_hand: int = 0

@Gaunt @pawelswiecki, if this was achievable, would be work for you?

This would require a significant rewrite of pydantic, but I think it would be worth it to support a big new language feature.

[pauleveritt]

I disagree on the point about data classes: I don’t think it will get rich serialization and validation in the core. The standard library is very conservative.

—Paul

On Jul 15, 2018, at 7:23 PM, Majid alDosari [e-mail] wrote:

the delta b/w dataclasses and pydantic are: serialization/deserialization, auto schema, and validation. i love pedantic but it seems like it’s only a matter of time before dataclasses gets such features. if not, then ya the decorator idea would keep pedantic relevant.

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