handle conversion of label columns

[sjhewitt]

when using sqlalchemy expressions as columns, the selectable is a Label which may be converted, however the Label type may not have doc or nullable attributes. This change uses getattr to try to retrieve them.

[coveralls]

Coverage remained the same at 90.83% when pulling 0077f6a on sjhewitt:convert-label-column into c69017e on graphql-python:master.

[gsvitak]

I am trying to use a column_property with that maps to an Int. Based on the above change, I think the Int convert should be something like the following.

I have tested locally and it appears to work. Can you please let me know if I am on the right path? I can submit a pull request if think this is the right approach.

Thanks,
Greg

@convert_sqlalchemy_type.register(types.Integer) def convert_column_to_int_or_id(type, column, registry=None): if column.primary_key: return ID(description=column.doc, required=not(column.nullable)) else: return Int(description=getattr(column, 'doc', None), required=not(getattr(column, 'nullable', True))) 

[sjhewitt]

that looks about right - I think we should probably use getattr in each of the converters

[gsvitak]

Great!! I already submitted a pull request for Int. Let me know if I can help with anything else.