Scoring missing nested docs

test.sh

# delete index if exists
curl -XDELETE localhost:9200/test/

# create index with default settings
curl -XPOST localhost:9200/test/

# create mapping
curl -XPUT localhost:9200/test/product/_mapping -d '
{
  "product" : {
    "properties" : {
      "price" : {
        "type" : "float"
      },
      "product" : {
        "type" : "string"
      },
      "review" : {
        "type": "nested", 
        "include_in_parent": true,
        "properties" : {
          "rate" : {
            "type" : "integer"
          },
          "user" : {
            "properties" : {
              "member_id" : {
                "type" : "long"
              },
              "name" : {
                "type" : "string"
              }
            }
          }
        }
      }
    }
  }
}
'

# add some data
curl -XPUT localhost:9200/test/product/1 -d '
{
   "product": "product 1",
   "price": 40,
   "review": [
      {
         "user": {
            "name": "user1",
            "member_id": "23242"
         },
         "rate": 5
      },
      {
         "user": {
            "name": "user2",
            "member_id": "63332"
         },
         "rate": 4
      },
      {
         "user": {
            "name": "anonymous"
         },
         "rate": 1
      }
   ]
}
'

curl -XPUT localhost:9200/test/product/2 -d '
{
   "product": "product 2",
   "price": 50,
   "review": [
      {
         "user": {
            "name": "anonymous"
         },
         "rate": 1
      }
   ]
}
'

curl -XPUT localhost:9200/test/product/3 -d '
{
   "product": "product 3",
   "price": 44.99,
   "review": []
}
'

curl -XPUT localhost:9200/test/product/4 -d '
{
   "product": "product 4",
   "price": 47.99
}
'

curl -XGET 'http://127.0.0.1:9200/test/product/_search?pretty=1'  -d '
{
   "query" : {
      "bool" : {
         "disable_coord" : 1,
         "should" : [
            {
               "custom_score" : {
                  "script" : "3",
                  "query" : {
                     "constant_score" : {
                        "filter" : {
                           "missing" : {
                              "field" : "review.user.member_id"
                           }
                        }
                     }
                  }
               }
            },
            {
               "filtered" : {
                  "filter" : {
                     "exists" : {
                        "field" : "review.user.member_id"
                     }
                  },
                  "query" : {
                     "nested" : {
                        "query" : {
                           "custom_score" : {
                              "script" : "doc[\u0027review.user.member_id\u0027].empty ? 3 : doc[\u0027review.rate\u0027].value",
                              "query" : {
                                 "match_all" : {}
                              }
                           }
                        },
                        "score_mode" : "avg",
                        "path" : "review"
                     }
                  }
               }
            }
         ]
      }
   }
}
'