Calling user defined init when init=False doesn't pass args through about dataclassy

[biqqles]

Hi, thanks for this report. I wonder if it wouldn't it be enough to simply change line 85 to something like

return type.__new__(DataClassInit if options['init'] and user_init else mcs, name, bases, dict_)

This is optimal because it avoids the definition of a slow Python __call__.

Apologies, I am away for exams and will likely not be able to test and/or merge for a while.

[kgreav]

No worries and no rush, I'll test it out - already set up everything in my repo so I'm not beholden to the PR being merged.

[kgreav]

OK, after testing your solution is equivalent to mine in function but optimal, however I realised there is one breaking change (applicable to both versions). Personally I don't think it is a bad breaking change as the usage was quite misleading.

In the existing, the following works:

@dataclass(init=False)
class Obj(object):
    a: str
    b: str

    def __init__(self, c, d):
        self.a = c
        self.b = d

o = Obj("x", "y", "w", "z")
assert o.a = "w"
assert o.b = "z"

whereas in the new version this will fail, and would need to be changed to:

Obj("w", "z")

This is obviously a naive example, and someone could have more contrived examples that make sense, however the worst case would be they'd have to add their classes attributes to their __init__ function which I think is desirable anyway, as from what I've seen you can't currently get a meaningful constructor signature out of this example unless you document it, as it's an amalgamation of __new__ and __init__.

[biqqles]

I think it's fair to call the behaviour you discovered a bug - init is false and yet the arguments its function would have had are still being consumed. This was an oversight on my part - there is absolutely no reason to use a custom __call__ to modify arguments if there isn't both __init__ and __new__ on the class. If someone is using this obscure behaviour, for some reason, it is a breaking change - but we're still on 0.x releases so what can they expect!

[biqqles]

I took a few moments to push the fix for this. Any problems, just let me know.

[biqqles]

Fix released in v0.6.2. Also, apologies, I didn't realise you had incorporated my solution into your PR before I unceremoniously closed it.

[kgreav]

Not a problem at all, the quick turnaround more than makes up for it - I didn't get around to fixing/writing tests anyway. Thanks a bunch!