Fix issue with get_type_hints(cls.__init__) and refactor

[euresti]

This fixes #593

I factored out the call to eval(compile... and added a generic _make_method method to remove repeated code.

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[hynek]

We totally can switch to exec.

It was only removed by your boss in #87 because it’s a bit ugly re: Python 2.

If it helps you in any way: feel free to re-introduce it!

[euresti]

After reading a bunch of docs I think we can leave well enough alone and keep going with compile/eval. Unless @glyph has strong opinions about it now.

So do we think having the correct "globals" on every method is necessary? If so I can factor out the eval/compile into a helper.

[hynek]

I don’t think that any other method changes it’s signature based on the attributes. However, I think I’d prefer a nice and documented function anyways if it’s not too much trouble!

[euresti]

Right. The only other uses of compile/eval are are hash, the cmp methods and the Attributes class creator, which don't have annotations.

I'll try to make a helper anyway just to keep them together.

[euresti]

I'm not sure why it's saying the tests weren't successful when they were here:

[hynek]

So since codecov is once again giving us a hard time, I've run it manually and got this missing coverage:

src/attr/_make.py             911      0    463      2    99%   303->305, 1957->1961

Any chance of fixing it? 😇

[euresti]

My pleasure.

[hynek]

Thank you so much!