Bulk update child doc, NPE error message when parent is not specified

[bly2k]

If you do a _bulk that contains an update to a child doc (parent/child) and you don't (or forget to) specify the parent id, you will get an NPE error message in the item response. It would be good to adjust the error message to RoutingMissingException (just like when you do a single update (not _bulk) to the same doc but forget to specify parent id.

Steps to reproduce:

curl -XDELETE localhost:9200/test1

curl -XPUT localhost:9200/test1 -d '{
  "mappings": {
    "p": {},
    "c": {
      "_parent": {
        "type": "p"
      }
    }
  }
}'

curl -XPUT localhost:9200/test1/c/1?parent=1 -d '{
}'

curl -XPOST localhost:9200/test1/c/_bulk -d '
{ "update": { "_id": "1" }}
{ "doc": { "foo": "bar" } }
'

Response:

{"error":"NullPointerException[null]","status":500}

[wwken]

This is fixed in: #8378