Empty maps mangled in dump

[sveniu]

When dumping tables that have map fields with an empty value, the raw Scan response from DynamoDB will contain something like this: "data":{"M":{}}

The JSON produced by dyndump will contain this: "data":{}

When trying to restore the table, DynamoDB returns HTTP 400 with error:

ValidationException: Supplied AttributeValue is empty, must contain exactly one of the supported datatypes

Editing the JSON to replace "data":{} with either "data":{"M":{}} or "data":{"NULL":true} will make the restore work. I'm not sure if there is any practical difference between the two.

[gwatts]

Thanks for the bug report - Will take a look, probably in a couple of days