Enhancement: Optional __model__ class field

[Mityuha]

Summary

Hi there.
Thank you for this useful library.
I tried to build some factories and found declaration of __model__ field a little bit annoyed.
Indeed, we already declare the model type in Generic params. Perhaps, it's enough.

Basic Example

Now we should declare factories this way (from documentation):

@dataclass
class Person:
    name: str
    age: float
    height: float
    weight: float


class PersonFactory(DataclassFactory[Person]):  # << Person type
    __model__ = Person  # << Person type again 🤔 

My suggestion is getting rid of Base class type declaration by making __model__ field optional for backward compatibility and/or deprecating it. So that

@dataclass
class Person:
    name: str
    age: float
    height: float
    weight: float


class PersonFactory(DataclassFactory[Person]):  # << Person type only here
    ...

Drawbacks and Impact

No response

Unresolved questions

I skimmed the source code/documentation quickly and found classmethod create_factory. This method allows you to define a factory imperatively.
The question is -- is it worth contributing into library to give the opportunity for doing the same declaratively?
If so I'm ready to implement this feature.

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[guacs]

@Mityuha yeah, a PR would definitely be welcome if there's a clean way to not have to specify the type twice. That being said, I'm curious as to how you're planning on getting rid of the need to specify __model__? The __model__ value is used in various places so we can't just remove it.

Also, I think the aim should be to do it the other way around. By that I mean that instead of attempting to remove the setting of __model__, it'd be nice if there was a way to not have to specify the type in the class definition. So something like the following:

class PersonFactory(DataclassFactory):
    __model__ = Person

[Mityuha]

Hello, @guacs . Thanks for response.
So, about your curiosity of how I'm planning to get rid of the need to specify __model__. Actually, I think it's possible to do by calling get_args(Generic[T]), which returns the information about type T. And it seems what we need. \

About the way to not specify the generic type: I could be wrong but it seems that the generic type is needed for further type hints. It's a little bit unclear for me how to achieve the same effect (generic class) without Generic[Person].

Again, I might be mistaken about type hints since I haven't dive deep into the code yet.

I think I'm going to try to implement my hypothesis in a clean way and, if I cope with it, I will make a PR.
If nobody minds.

[guacs]

About the way to not specify the generic type: I could be wrong but it seems that the generic type is needed for further type hints

You are right.

calling get_args(Generic[T])

Yupp this should work. So, I think the solution would be to parse and set the value for __model__ if a value for __model__ has not already been provided.

I will make a PR.
If nobody minds

A PR would definitely be appreciated :)

[Mityuha]

PR #452 is ready. Please come and check it out

[guacs]

Added in #452.