with_args, kw_only, slots support in >=3.10 #205
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marshmallow_dataclass/__init__.py
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| def dataclass( | ||
| _cls: Type[_U] = None, | ||
| *, | ||
| repr: bool = True, |
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Do we lose much if we replace all the keyword args that we just pass off to dataclasses.dataclass with **kwargs: Any (in the implementation, not in the overloads)?
Then the overloads could be conditional (on python version), but we'd only need one implementation, thus avoiding duplication of the code in the function body.
marshmallow_dataclass/__init__.py
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| """ | ||
| This decorator does the same as dataclasses.dataclass, but also applies :func:`add_schema`. | ||
| It adds a `.Schema` attribute to the class object | ||
| # _cls should never be specified by keyword, so start it with an |
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Apparently, mypy recognizes parameters whose names start with a double-underscore as positional-only.
(This seems only to be documented in the mypy cheatsheet. But the typeshed stub for dataclasses.dataclass uses the syntax.)
Anyway... we should probably change _cls to __cls.
marshmallow_dataclass/__init__.py
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| def dataclass( | ||
| _cls: Type[_U], | ||
| *, | ||
| repr: bool = True, |
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While were messing around here, we should fix the typing of our dataclass to match typeshed’s typing for dataclasses.dataclass
That allows for
@dataclass
class A:
...@dataclass()
class B:
...and
@dataclass(**kwargs)
class C:
...But does not allow for providing the class and keyword params all in one go. I.e. the following is not supported by dataclasses.dataclass:
class D:
...
D = dataclass(D, frozen=True)
marshmallow_dataclass/__init__.py
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| # underscore. The presence of _cls is used to detect if this | ||
| # decorator is being called with parameters or not. | ||
| def dataclass( | ||
| _cls: Type[_U] = None, |
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Implicit optional parameter types are deprecated1. Should fix to __cls: Optional[Type[_U]] = None while we're in here. (Though there are admittedly a lot of other places in our code where we rely on implicit optional...)
Footnotes
|
Hello, I'm looking to use |
I made a new PR, very similar to this. Hoping to get this revived 🤞 @antoine-chopin |
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Add (new in 3.10) arguments to
@dataclassSimilar to #204 , with sys.version_info guarding.
I tried using a common dispatch handler, but I think custom mypy handling of this class was breaking dispatch, and the forward reference tests were failing. Open to suggestions.