ExtendedBounds min and max values are required by the client, but not server

[awojcik64]

Java API client version

7.17.9

Java version

11

Elasticsearch Version

7.17.9

Problem description

A quick prior note: I've asked about it here, since I wasn't sure if it was a client issue, actually. However, after creating that question I've discovered ApiTypeHelper::DANGEROUS_disableRequiredPropertiesCheck(boolean) method, which I am using as a workaround. After acknowledging its javadocs I am 90% sure it is a bug, hence this issue.

The issue regarding ExtendedBounds class is that its builder requires both min and max to be specified. This behavior is different from Elasticsearch server, which has no problem if one (or even both) are missing.

Let's start with some sample bit of data first.

POST /test-extbounds/_doc
{
  "date":"2022-04-01"
}

and a sample query:

GET /test-extbounds/_search
{
    "query": {
        "match_all": {}
    },
    "aggregations": {
        "date": {
            "date_histogram": {
                "field": "date",
                "calendar_interval": "1M",
                "min_doc_count": 0,
                "extended_bounds": {
                    "min": "2022-01",
                    "max": null
                }
            }
        }
    }
}

That yields a response with 4 buckets (3 of them with 0 docs, which is fine.)

{
  "took" : 35,
  "timed_out" : false,
  "_shards" : {
    "total" : 1,
    "successful" : 1,
    "skipped" : 0,
    "failed" : 0
  },
  "hits" : {
    "total" : {
      "value" : 1,
      "relation" : "eq"
    },
    "max_score" : 1.0,
    "hits" : [
      {
        "_index" : "test-extbounds",
        "_type" : "_doc",
        "_id" : "hVlblIcBVXy4uzZFJm5k",
        "_score" : 1.0,
        "_source" : {
          "date" : "2022-04-01"
        }
      }
    ]
  },
  "aggregations" : {
    "date" : {
      "buckets" : [
        {
          "key_as_string" : "2022-01-01T00:00:00.000Z",
          "key" : 1640995200000,
          "doc_count" : 0
        },
        {
          "key_as_string" : "2022-02-01T00:00:00.000Z",
          "key" : 1643673600000,
          "doc_count" : 0
        },
        {
          "key_as_string" : "2022-03-01T00:00:00.000Z",
          "key" : 1646092800000,
          "doc_count" : 0
        },
        {
          "key_as_string" : "2022-04-01T00:00:00.000Z",
          "key" : 1648771200000,
          "doc_count" : 1
        }
      ]
    }
  }
}

Things get complicated once I try to recreate that in Java API:

        var dateHistogram = AggregationBuilders.dateHistogram()
                .field("date")
                .format("yyyy-MM")
                .calendarInterval(CalendarInterval.Month)
                .minDocCount(0)
                .extendedBounds(eb -> eb.min(FieldDateMath.of(fdm -> fdm.expr("2022-01"))));

        SearchRequest request = new SearchRequest.Builder()
                .query(query -> query.matchAll(maq -> maq))
                .index("test-extbounds")
                .size(2)
                .aggregations(Map.of("test", dateHistogram.build()._toAggregation()))
                .build();

That yields the exception:
co.elastic.clients.util.MissingRequiredPropertyException: Missing required property 'ExtendedBounds.max'

I've tried similar thing in Rest High Level Client, which is successful:

        var dateHistogram = new DateHistogramAggregationBuilder("date")
                .field("date")
                .format("yyyy-MM")
                .calendarInterval(DateHistogramInterval.MONTH)
                .minDocCount(0)
                .extendedBounds(new LongBounds("2022-01", null));
        var searchRequest = new SearchRequestBuilder(null, SearchAction.INSTANCE)
                .setQuery(QueryBuilders.matchAllQuery())
                .addAggregation(dateHistogram)
                .setIndices("test-extbounds").request();

Bare-json Elasticsearch API allows it, RHLC allows it, but not Java API client.

[l-trotta]

Hello, thank you so much for providing such a detailed report :) this is an issue with the API specification used to produce the Java code, yes those two fields min and max in ExtendedBounds should be optional. We will fix the issue in the specification and regenerate the java code, thanks again!