as_marshmallow_field params are not passed to the container in a ListField

[lafrech]

In ListField, the params that are passed to as_marshmallow_field are used only for the underlying Marshmallow List but nothing is passed to the container.

https://github.com/Scille/umongo/blob/master/umongo/fields.py#L119

AFAIU, there is no way to pass params to the container, for instance an EmbeddedField inside the ListField. This sort of breaks the cascading mechanism.

[touilleMan]

What about a special container_params field to define in params ?

EDIT: I've just realised this is already done in EmbeddedDocumentField with the embedded params named just params. So I'm not sure whether we should call it container_params or just params...

[lafrech]

Well, IIUC, we could do the same as EmbeddedField:

params is a dict with the parameters for the field, and it may include a params key for which the value is a dict with the parameters for the nested field.

This should work in all cases. As long as no field requires a parameter called params, since this would be a reserved word for nested field parameters.

Unless I missed something, this should be pretty easy.

I'll try to tackle this and #65. Not a priority right now, but I'll try to find the time.

[lafrech]

Labelling bug as it is a flaw of the existing mechanism rather than a missing feature.

Assigning to myself. Doesn't mean I'll be doing this any soon. I'm on tight schedule and this is not blocking. If you find time to do that, don't refrain to do so!