Loading docvalue_fields for geopoints can give incorrect result

[jtibshirani]

If a document has a multi-valued geopoint field, the result of docvalue_fields will append all the lat and lon values into a single array. The following example reproduces on version 7.6.

PUT index
{
  "mappings": {
    "properties": {
      "locations": {
        "type": "geo_point"
      }
    }
  }
}

PUT index/_doc/1
{
  "locations": [[ -71.34, 41.12 ], [ -71.34, 42.89 ]]
}

POST index/_search
{
  "docvalue_fields": ["locations"]
}

Response:

{
  "_index" : "index",
  ...
  "fields" : {
    "locations" : [
      -71.33999633789062,
      -71.33999633789062,
      41.119998931884766,
      42.88999938964844
    ]
  }
}

[elasticmachine]

Pinging @elastic/es-analytics-geo (:Analytics/Geo)

[wchaparro]

We agree this is a bug and should address.