inner_hits breaks from version 1.7 to 2.3 upgrade

[siddharthgoel88]

Elasticsearch version: 2.3.3

JVM version: 1.7.0_95

OS version: Red Hat Enterprise Linux Workstation release 6.7 (Santiago)

Description of the problem including expected versus actual behavior:

Steps to reproduce:
I have described the issue on community at https://discuss.elastic.co/t/inner-hits-queries-break-from-1-7-to-2-3-in-elasticsearch/54242 .

I had an inner_hits query which was working fine in version 1.7 but it stopped working in version 2.3.3. Following is the query :

"query": {
    "filtered": {
        "filter": {
            "and": [
                {
                    "range": {
                        "@timestamp": {
                             "gte": "2015-01-01||/d",
                             "lte": "2016-01-01||/d"
                        }
                    }
                },
                {
                    "or": [
                        {
                            "has_child": {
                                "type": "TypeName",
                                "filter": {
                                    "term": {
                                        "eventType.raw": "some-event"
                                    }
                                },
                                "inner_hits": {
                                    "_source": "@timestamp"
                                }
                            }
                        },
                        {
                            "not": {
                                "has_child": {
                                    "type": "TypeName",
                                    "filter": {
                                        "term": {
                                            "eventType.raw": "some-event"
                                        }
                                    },
                                    "inner_hits": {
                                        "_source": "@timestamp"
                                    }
                                }
                            }
                        }
                    ]
                }
            ]
        }
    }
}

With version 2.3.3 I get the following response for it :

"reason": {
   "type": "illegal_argument_exception",
   "reason": "inner_hit definition with the name [TypeName] already exists. Use a different inner_hit name"
}

Provide logs (if relevant):
Following is the error stack

nested: IllegalArgumentException[inner_hit definition with the name [TypeName] already exists. Use a different inner_hit name];
    at org.elasticsearch.search.SearchService.parseSource(SearchService.java:855)
    at org.elasticsearch.search.SearchService.createContext(SearchService.java:654)
    at org.elasticsearch.search.SearchService.createAndPutContext(SearchService.java:620)
    at org.elasticsearch.search.SearchService.executeQueryPhase(SearchService.java:371)
    at org.elasticsearch.search.action.SearchServiceTransportAction$SearchQueryTransportHandler.messageReceived(SearchServiceTransportAction.java:368)
    at org.elasticsearch.search.action.SearchServiceTransportAction$SearchQueryTransportHandler.messageReceived(SearchServiceTransportAction.java:365)
    at org.elasticsearch.transport.TransportRequestHandler.messageReceived(TransportRequestHandler.java:33)
    at org.elasticsearch.transport.RequestHandlerRegistry.processMessageReceived(RequestHandlerRegistry.java:75)
    at org.elasticsearch.transport.TransportService$4.doRun(TransportService.java:376)
    at org.elasticsearch.common.util.concurrent.AbstractRunnable.run(AbstractRunnable.java:37)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:745)
Caused by: java.lang.IllegalArgumentException: inner_hit definition with the name [TypeName] already exists. Use a different inner_hit name
    at org.elasticsearch.search.fetch.innerhits.InnerHitsContext.addInnerHitDefinition(InnerHitsContext.java:69)
    at org.elasticsearch.index.query.QueryParseContext.addInnerHits(QueryParseContext.java:218)
    at org.elasticsearch.index.query.HasChildQueryParser.parse(HasChildQueryParser.java:155)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerFilter(QueryParseContext.java:277)
    at org.elasticsearch.index.query.NotQueryParser.parse(NotQueryParser.java:69)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerQuery(QueryParseContext.java:250)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerFilter(QueryParseContext.java:263)
    at org.elasticsearch.index.query.OrQueryParser.parse(OrQueryParser.java:69)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerQuery(QueryParseContext.java:250)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerFilter(QueryParseContext.java:263)
    at org.elasticsearch.index.query.AndQueryParser.parse(AndQueryParser.java:69)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerQuery(QueryParseContext.java:250)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerFilter(QueryParseContext.java:263)
    at org.elasticsearch.index.query.FilteredQueryParser.parse(FilteredQueryParser.java:79)
    at org.elasticsearch.index.query.QueryParseContext.parseInnerQuery(QueryParseContext.java:250)
    at org.elasticsearch.index.query.IndexQueryParserService.innerParse(IndexQueryParserService.java:320)
    at org.elasticsearch.index.query.IndexQueryParserService.parse(IndexQueryParserService.java:223)
    at org.elasticsearch.index.query.IndexQueryParserService.parse(IndexQueryParserService.java:218)
    at org.elasticsearch.search.query.QueryParseElement.parse(QueryParseElement.java:33)
    at org.elasticsearch.search.SearchService.parseSource(SearchService.java:838)
    ... 12 more

[siddharthgoel88]

May be #16218 could give some more insight into this.

[dadoonet]

@martijnvg suggested that we could come with a better error message: https://discuss.elastic.co/t/inner-hits-queries-break-from-1-7-to-2-3-in-elasticsearch/54242/4

Marking as "non issue"

[clintongormley]

I think the exception is pretty clear already. No idea about how to improve it. Any suggestions?

[dadoonet]

The thing is that the user did not explicitly define a name. It was inherited from the has_child query. So may be we could say something like

inner_hit definition with the name [TypeName] already exists. Use a different inner_hit name or define one explicitly.

[clintongormley]

ah right, gotcha