Class metadata

[wpbonelli]

This being a consciously minimal (read: heinous) hack job at the moment, little of a decorated class' metadata survives the transformation. Tab complete doesn't work, nothing useful shown on hover, etc.

(Note I am talking about Python class metadata, not attrs field metadata.)

We want all the original metadata, modified with some new attributes: name, parent, etc.

I think we don't need to wrap/replace the class init method as is done now. Better to build on attrs as much as possible*. @xattree can wrap @attrs.define(), use field_transformer to add the new fields, and use a post-init hook to create the datatree? With that (plus maybe functools.wrap?) I think attrs will do the rest, and metadata will work.

*To guarantee metadata, attrs rewrites the classes by hand, compiles them, and registers them globally. Trickery best left to experts.

[wpbonelli]

This is working now. No init wrapping necessary.

[wpbonelli]

Not entirely working yet.

For some reason the new fields aren't showing up in hover, tab complete, etc. Only the old fields. I figured field_transformer would make this work. Maybe the mypy plugin hack is necessary too? But the VSCode python extensions runs on pyright which should be covered by dataclass_transform?