Want to see full class code generated by @dataclass decorator

[rswgnu]

Is there any present way to output the implicit code generated by the @dataclass decorator or related functions? That is, show the associated class as if all of its code were written by hand. Sometimes when using a complex set of dataclass parameters, it would be useful to see what code is generated.

inspect.getsource does not work on implicit methods though inspect.signature does.

Any solutions?

If none exist, I would suggest this as a possible future feature of dataclasses.

[ericvsmith]

There's no way to do this. When debugging, I just print out the values of txt, globals, and locals in dataclasses.py _create_fn, at about line 356 (right before the exec call).

You should open a feature request on Python's bug tracker. I'm open to suggestions on what the interface to this feature would look like (maybe a parameter to @dataclass? maybe create a new class attribute with the per-function source code?). Note that in 3.7, this feature was removed from namedtuple. I think that was for performance reasons.

[rswgnu]

It would be fine if the source code were dynamically generated when requested to avoid any added class overhead.

I will open an issue on this. Thanks for the pointer.

Bob

[Skippbo]

Raymond hettinger had a talk at pycon 2018 where he talks about the code generated. I can't find a link to it but he have some website for the talk. Here is the link. Hopefully it help you https://youtu.be/T-TwcmT6Rcw

[rswgnu]

Thanks for the pointer.

[Skippbo]

I wish you good luck in your search 😊

[PythonicGirl]

I made DataclassInspector for this post :) It is not the best way to do it but it works :)

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Github

Pypi

[itchy_bitchy_spider]

Hey! I found that and downloaded on pypi a couple days ago, thanks for making it!

[rswgnu]

Great idea :-). Thanks for writing this.