geo_shape query with circle does not work for legacy geo_shape field

[iverase]

We currently do not support circle queries for geo_shape fields using BKD_backed geo_shape but it should be possible to do it using legacy indexing strategy.

This is currently broken. They issue seems to be in the serialisation mechanism which throws an error for circle geometries.

[elasticmachine]

Pinging @elastic/es-analytics-geo (:Analytics/Geo)

[imotov]

I started to look into it, and implemented serialization, but then I realized that we didn't support circles in queries for a very long time (if ever) I went all the way back to v2.4.6 and we didn't support circle queries even back then. So, it's not just a serialization issue. Considering that we are trying to deprecate and remove the legacy index strategy, I am not totally sure it's worth the effort to add it there. I think we should discuss it before I sink more time into it.

[iverase]

Circles queries are supported for LegacyGeoShape (aka prefix trees). I think this needs to be fixed.

[imotov]

It doesn't look like there is support on the elasticsearch side.

[iverase]

https://discuss.elastic.co/t/circle-geo-shape-query-not-supported-in-es7-4-2/208404/2

[imotov]

Reproduction:

DELETE test
PUT test
{
  "mappings": {
    "doc": {
      "properties": {
        "location": {
          "type": "geo_shape",
          "tree": "geohash",
          "strategy": "recursive"
        }
      }
    }
  }
}

PUT test/doc/1
{
  "location": {
    "type": "circle",
    "coordinates": [10, 20],
    "radius": "100m"
  }
}

POST test/doc/_search
{
  "query": {
    "geo_shape": {
      "location": {
        "shape": {
          "type": "circle",
          "coordinates": [
            10,
            20
          ],
          "radius": "100m"
        }
      }
    }
  }
}

[imotov]

Just to clarify. I was looking at the wrong place. We did indeed support it, but I lost it during refactoring in 7.4.0. I opened PR that restores this functionality.