Sorting mixing "float" and "double" types doesn't work

[cbuescher]

Searching across multiple indices and sorting on a field that has a "double" type in one and a "float" type in other indices doesn't currently work:

Example script

DELETE test*

PUT test1
{
  "mappings": {
    "properties": {
      "f1" : {
        "type": "double"
      }
    }
  }
}

PUT test2
{
  "mappings": {
    "properties": {
      "f1" : {
        "type": "float"
      }
    }
  }
}

PUT /_bulk
{ "index" : { "_index" : "test1", "_id" : "1" } }
{ "f1" : "1.0" }
{ "index" : { "_index" : "test2", "_id" : "2" } }
{ "f1" : "2.0" }

POST /test1,test2/_search
{
  "sort" : [ "f1"]
}

This returns and exception with the following cause

"caused_by" : {
      "type" : "class_cast_exception",
      "reason" : "class java.lang.Double cannot be cast to class java.lang.Float (java.lang.Double and java.lang.Float are in module java.base of loader 'bootstrap')"
    }

I don't think we ever supported mixing these two types, at least on 6.8. the same error behaviour can be observed. However, mixing different numeric types of the short/integer/long family does word since we internally use the same SortField.Type for their NumericType, but for some reason the ones for "float" and "double" are different.
Opening this issue to investigate whether this isn't possible for a good reason, simply technically infeasibel or if we can indeed add support for it.

[elasticmachine]

Pinging @elastic/es-search (Team:Search)

[rahulreddyv]

@cbuescher is it okay if I pick this up? I want to contribute to ES, this seems to be a good starting point :)

[cbuescher]

is it okay if I pick this up

I think we first need to make sure we want to enable this. As I mentioned in the description, I'm not entirely sure if this doesn't work on purpose or if there are technical reasons that make this difficult to accomplish. Please take a look if you like but don't be disappointed if this moves into a different direction.

[rahulreddyv]

is it okay if I pick this up

I think we first need to make sure we want to enable this. As I mentioned in the description, I'm not entirely sure if this doesn't work on purpose or if there are technical reasons that make this difficult to accomplish. Please take a look if you like but don't be disappointed if this moves into a different direction.

Sure. Thanks for responding.

[nephel]

I think this is relevant? #38095

[jimczi]

I think we should handle mixing floating points transparently. It works for longs mixed with integers so I don't see why we wouldn't do the same for floats.

[elasticsearchmachine]

Pinging @elastic/es-search-relevance (Team:Search Relevance)