Highlighting has_child request

Question

Highlighting has_child request

In some of our types, we have a parent setting for the parent, and we want to search in the parent fields, as well as in the child fields (and return the parent), and we make a request, as shown below. When there is a has_child match, there is a way to get the selection of information from the child match, even if the parent returns. As an example, if we have a mapping similar to the following:

PUT nested2
{
  "mappings":{
    "discussion":{
        "properties" : {
            "title":{
                "type":"string"
            }
        }
    },
    "discussionPost":{
        "_parent":{
            "type" : "discussion"
        },
        "properties" : {
            "post" : {
                "type" : "string"
            }
        }
    }
  }
}

And we issue a request, as shown below, the highlight information is returned if there is a match in the parent field, but not if the parent is returned due to has_child matching:

POST nested2/discussion/_search
{
  "query": {
    "bool": {
        "should": [
            {
                "prefix": {
                    "_all" : "cat"
                }    
            },
            {   
                "has_child" : {
                    "type" : "discussionPost",
                    "score_mode" : "sum",
                    "query" : {
                        "prefix": {
                            "_all" : "cat"
                        }  
                    }
                }
            }
        ],
        "minimum_should_match": 1
    }
  },
  "highlight":{
    "fields":{
      "*":{}
    }
  }
}