Having trouble converting Groovy to Painless

[jw-ovgd (John Weidenfeller)]

When I try to access params._source I get a null_pointer_exception.

This script is being executed on a search and with Painless.

This discussion:

Accessing _source from script search in 5.0

Hey all, I think I'm going crazy... Could someone tell me why I fail to access the _source field on this query? { "size": 0, "query": { "constant_score": { "filter": { "script": { "script": { "inline": "_source.lab_tests.length > 0" } } } } } } I get... { "type": "script_exception", "reason": "compile error", "caused_by": { "type": "illegal_argument_exception", "reason": "Variable [_source] is not de…

Makes it seem like I do not have access to _source from a Painless search script. Is that the case?

If that is the case, is what I am trying to do futile? The doc value for my "groups" field seems flattened so I would not be able to traverse the data structure as I need to.