issue_comments: 422458598

Sorry for taking so long here.

I'm still not entirely comfortable with this change -- it adds some additional complexity to the Dataset constructor that seems unnecessary. There's no inherit reason why calling a constructor on an object of the same type needs to work. If anything, I would like to deprecate/remove this behavior on DataArray (e.g., in favor of using a more explicit call to DataArray.copy(data=new_data)).

To answer your question though, we hit this when inheriting from a Dataset: the object is initialized with a dataset, which is super-ed up to the Dataset constructor

If I understand this correctly, you've written something like: python class MyDataset(xarray.Dataset): def __init__(self, dataset): super().__init__(dataset)

Is there any reason why you couldn't just write: python class MyDataset(xarray.Dataset): def __init__(self, dataset): super().__init__(dataset.data_vars, dataset.coords, dataset.attrs)

I think we should do something here, rather than change behavior by coincidence.

I don't think it's quite a coincidence here -- we are changing the behavior of Dataset.__iter__/Dataset.keys(), and this is a logical consequence of interpreting a Dataset as a mapping of its data variables :).