We will hopefully soon switch to our new implementation of the serialization code. I had a quick look and it seems to have the same issue though. I filed a ticket for that here: https://github.com/wmde/WikibaseDataModelSerialization/issues/77

This would be the right way to do this, but the problem is that in php, an empty
map is indistinguishable from an empty list. So how do we tell the json encoder
when to use what?

Cast the array to object.

Cheers

--
Jeroen De Dauw - http://www.bn2vs.com

Software craftsmanship advocate
Evil software architect at Wikimedia Germany
~=[,,_,,]:3