Validate Disjuction query in HybridQueryPhaseSearcher

[owaiskazi19]

Description

Validate Disjuction query in HybridQueryPhaseSearcher to avoid having hybrid as a nested query

{
    "query": {
        "dis_max": {
            "queries": [
                {
                    "match": {
                        "title": "Shakespeare poems"
                    }
                },
                {
                    "hybrid": {
                        "queries": [
                            {
                                "match": {
                                    "passage_text": {
                                        "query": "Hi world"
                                    }
                                }
                            }
                        ]
                    }
                }
            ]
        }
    }
}

Response

{
    "error": {
        "root_cause": [
            {
                "type": "illegal_argument_exception",
                "reason": "hybrid query must be a top level query and cannot be wrapped into other queries"
            }
        ],

Related Issues

Part of #1125

Check List

• New functionality includes testing.
• New functionality has been documented.
• API changes companion pull request created.
• Commits are signed per the DCO using --signoff.
• Public documentation issue/PR created.

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[martin-gaievski]

can you please add a unit tests for this case?

[martin-gaievski]

how it will work in case if one type of compound query is nested into another compound query type? E.g.

disjunction_max {
     bool {
            hybrid {
            }
      }
}