Auto-detect user-written methods

[hynek]

Currently, if you want to implement a method yourself, you have to remember to do two things:

@attr.s(repr=False)
class C:
    def __repr__(self):
        return "whatever"

I’ve seen quite a few people be confused/frustrated by that.

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I think unless these is set, it would be kind of cool if we detected that the current class (and not some super class) has a user-written method and set the flag to false automatically such that

@attr.s
class C:
    def __repr__(self):
        return "whatever"

does what you’d expect.

Opinions?

[Tinche]

👍

[euresti]

Same with __init__? (I ask because the mypy plugin will have to deal with that too.)

[hynek]

The idea is to support it for all of them. It gets a bit hairy when we get to comparison because it’s several ones. Would we stop completely? Or just not replace one of them?

[wsanchez]

With comparison methods, perhaps total_ordering could provide guidance; if you provide enough for total_ordering to work, we apply it or do something similar?

It's a bit of feature creep, but it feels in line with the developer doing as little work related to attributes as necessary and we take care of the rest.

[hynek]

The more I think about it the more I think we should just skip methods that have been defined and be done with it. That allows people to customise their classes even better.