Wrong decoding of nested map

[samber]

I would like to encode a map having multiple values (primitive, date or empty map):

map[string]any{
	"a": "abcd",
	"b": 42,
	"c": false,
	"d": myDate,
	"e": map[string]any{},   //  <- always empty and not nil
	"f": nil,
},

I use the following schema:

...
{
    "name": "my_map",
    "type": {
        "type": "map",
        "values": [
            "string",
            "int",
            "long",
            "float",
            "double",
            "boolean",
            "null",
            {
                "type": "long",
                "logicalType": "timestamp-millis"
            },
            {
                "type": "map",
                "values": "null"  //  <- can be any type since the map will always be {}
            }
        ]
    }
}
...

After go->avro->go conversion, I get the following map:

{
  "a": {
    "string": "abcd"
  },
  "b": {
    "int": 42
  },
  "c": {
    "boolean": false
  },
  "d": {
    "long.timestamp-millis": "2024-02-06T10:38:03.033Z"
  },
  "e": null,
  "f": null
}

Does anybody know why the library inserts the type as key ?

When I remove the nested map in schema, the map is decoded properly, except for e being nil, instead of empty map.

[nrwiersma]

Your type is a map of union, and as stated in the README, and unions in the generic form decode to a map with the type as the only key. The any union type does not apply in this case because you are doing a generic decode. That is my assumption at any rate, as there is not enough here to actually tell, but it is what it looks like.

[nrwiersma]

Assuming the question has been answered. If there still an issue, please reopen.