Is there a way to recursively prefer `_cattrs_use_alias=True`?

[BrianPugh]

In my application, i have several nested structures that have attrs aliases set (e.g. field(..., alias="foo")). I am aware that I could individually register a hook for every class with:

converter.register_structure_hook(
    MyClass,
    make_dict_structure_fn(MyClass, converter, _cattrs_use_alias=True),
)

However, this requires the developer to remember to do that for every new class. Is there a way of applying this setting for the whole converter?

[BrianPugh]

I think the solution is:

import attrs
import cattrs

converter.register_structure_hook_factory(
    attrs.has,
    lambda cl: cattrs.gen.make_dict_structure_fn(cl, converter, _cattrs_use_alias=True)
)

would love to have @Tinche to chime in if this is the intended solution (and then close this issue)! Thanks!

[Tinche]

You got to it before I did! That's exactly what I would have suggested.

[BrianPugh]

thank you!

[AdrianSosic]

Hi @Tinche, I just stumbled over this issue because I was looking for the same functionality. While the proposed solution works, is comes with the downside that you need to remember setting the flag whenever you register a regular singledispatch hook for a class using make_dict_structure_fn, because that takes preference over the hook factory. And if you forget, this might break your exposed APIs that rely on these converters.

Therefore a question: wouldn't it perhaps make sense to add a use_alias argument to Converter that is then extracted a la from_converter in make_dict_(un)structure_fn_from_attrs, just like other settings such as forbid_extra_keys? The nice consequence would be that this would then work together with added hooks, if I'm not mistaken?

[Tinche]

Hm, if you want to contribute it, sure, why not.