Elasticsearch MVEL score calculation: Multiply when field is present

gistfile1.sh

curl -XPUT localhost:9200/test
curl -XPUT localhost:9200/test/mock/_mapping -d '{mock: {properties: {x: {type: "integer"},y: {type: "integer"}}}}'
curl -XPUT localhost:9200/test/mock/1 -d '{x:5, y:6}'
# Score should be 30
curl 'localhost:9200/test/mock/_search' -d '{query: {function_score: {query: {match_all:{}},functions: [{"script_score": {script: "doc[\"x\"].value * (doc.containsKey(\"y\") ? doc[\"y\"].value : 1)"}}]}}}'
# Score should be 5
curl 'localhost:9200/test/mock/_search' -d '{query: {function_score: {query: {match_all:{}},functions: [{"script_score": {script: "doc[\"x\"].value * (doc.containsKey(\"z\") ? doc[\"z\"].value : 1)"}}]}}}'