(new \Elastica\Query\Bool())->toArray()) and json_encode() generate problematic ES payload

[mfn]

I know this method says toArray() but nevertheless it can generate a payload which still isn't suitable for ES because it would require a new stdClass instead of an empty array.

The code

var_dump((new \Elastica\Query\Bool())->toArray());

generates

array(1) {
  ["bool"]=>
  array(0) {
  }
}

and json encoded for ES this gets

echo json_encode((new \Elastica\Query\Bool())->toArray(), JSON_PRETTY_PRINT); # => { "bool": [] }

It seems this is problematic in certain cases and bool should be an empty object and not array.

Here's an example I discovered this (example from Sense):

POST /test/test/1
{
  "awesome": "stuff"
}

GET /test/test/_search
{
    "query": {
        "filtered": {
            "query": {
                "bool": []
            },
            "filter": {
                "bool": {
                    "must": [
                        {
                            "not": {
                                "filter": {
                                    "missing": {
                                        "field": "whatever"
                                    }
                                }
                            }
                        }
                    ]
                }
            }
        }
    }
}

This results in: ... nested: QueryParsingException[[test] No query registered for [not]]; }]

When however using {} for bool the query executes fine.

Here's a more "PHP only" example:

    $body = new \Elastica\Query();
    $body->setQuery(
      new \Elastica\Query\Filtered(
        new \Elastica\Query\Bool(),
        (new \Elastica\Filter\Bool())
          ->addShould(
            new \Elastica\Filter\BoolNot(
              new \Elastica\Filter\Missing('whatever'))
        )
      )
    );
    echo json_encode($body->toArray(), JSON_PRETTY_PRINT);

Results in:

{
    "query": {
        "filtered": {
            "query": {
                "bool": []
            },
            "filter": {
                "bool": {
                    "should": [
                        {
                            "not": {
                                "filter": {
                                    "missing": {
                                        "field": "whatever"
                                    }
                                }
                            }
                        }
                    ]
                }
            }
        }
    }
}

Sending this to ES will generate the aforementioned error message.

[ruflin]

Based on some tests I did and issue elastic/elasticsearch#7240 an empty bool query should act like a match all query. I will add a fix for this issue.

[ruflin]

See #822

[ruflin]

Close ashttps://github.com//pull/822 is merged.