cattrs

Pyantic and Cattrs both suffer with unacceptable issues and footguns. I have used Pydantic in production a lot and have played around with Cattrs. I've also looked at similar libraries like Dacite and marshmallow-dataclasses but none seem to be well thought out and mature. * Neither Pydantic nor Cattrs handle unions like how I'd expect (although Cattrs has stronger guarantees in converting Unions) >>> class Y(BaseModel): pass >>> class X(BaseModel): pass >>> class Z(BaseModel): a: Union[X, Y] >>> Z(a=Y()) Z(a=X()) # Converts Y to X implicitly Cattrs has some problems with generics [1] [2]. Dacite and marshmallow-dataclasses don't support generics well either, with some issues around Union types. They do work well for simple python types but what I'd like to see is guarantee that the serialisation operation is completely reversi

The python ecosystem is really good here. I do a lot of exploratory coding in ipython, though the threshold for "switch to a real editor and run git init and poetry new" is pretty low. Want to munge CSV? stdlib, or pandas(https://pandas.pydata.org/pandas-docs/stable/) Want to munge JSON? stdlib. Want to munge a database? pandas, stdlib, anything that speaks sqlalchemy Want to validate your json/sql/CSV/whatever and have it come in as a bunch of structured classes not std types? jsonschema https://pypi.org/project/jsonschema/, attrs+marshmallow, attrs+cattrs. http://www.attrs.org/en/stable/, https://desert.readthedocs.io/en/latest/ https://marshmallow.readthedocs.io/en/stable/ https://github.com/Tinche/cattrs Want to transform csv into sqlite? https://github.com/simonw/csvs-to-sqlite Want to serve sqlite as a REST api? https://datasette.r

Re: serialization, worth mentioning cattrs project (work with attrs classes, but would work the same way with stdlib dataclass): https://github.com/Tinche/cattrs