Empty array becomes null in source

[Swarlston]

Which version of Elastic are you using?

[ ] elastic.v2 (for Elasticsearch 1.x)
[ ] elastic.v3 (for Elasticsearch 2.x)
[x ] elastic.v5 (for Elasticsearch 5.x)

Please describe the expected behavior

When using a terms query and passing an empty array, the query body should also
contain an empty array []

included := make([]string, 0)
filter.Filter(elasticsearch.NewTermsQuery("tags", included...))

should result in

 "terms": {
     "tags": []
 }

Please describe the actual behavior

but instead i get

 "terms": {
     "tags": null
 }

This leads to an exception:

"type": "parsing_exception",
    "reason": "[terms] unknown token [VALUE_NULL] after [tags]",
    "line": 15,
    "col": 29

Notes

I think this is because the array of values in
search_queries_terms.go is not initialized.

I'm not sure whether this is the correct form to report this, nor do
i know whether the problem isn't with ES itself. ( The documentation indicates that
null and [] are equivalent at some point )

[olivere]

Thanks for supporting Elastic. I will investigate and post my findings here.

[olivere]

5.0.42 will properly initialize the values. I added a test case so that it will fail in the future if I'm missing it again.