SearchRequest cannot parse _source correctly

[aidin-gh]

Java API client version

9.4.2

Java version

17

Elasticsearch Version

9.4.2

Problem description

Issue

I'm parsing a JSON ES DSL query using the SearchRequest.of method. The _source field is a list of columns. This is a valid ES DSL query, and I can run it on Elasticsearch. However, the SearchRequest.of throws this error:

co.elastic.clients.json.JsonpMappingException: Error deserializing co.elastic.clients.elasticsearch.core.SearchRequest: Cannot determine what union member to deserialize (JSON path: _source) (line no=1, column no=142, offset=141)

If I change the _source from:

"_source":["date","distributor" ...

to:

"_source":{"includes":["date","distributor" ...

It can parse it.

Expected Outcome

Having a list in _source is a valid ES DSL query. SearchRequest should be able to parse it.

Reproduction

Here's a minimal project that reproduces the issue: https://github.com/aidin-gh/elasticsearch-source-parsing-error

[l-trotta]

Hello! This is unfortunately a known issue with the java client: the array that "_source" accepts is actually a shortcut property, where _source.includes is used directly, skipping one level of the JSON structure.

This is something that the JSON deserializer does not yet support by default, but it could if we were to implement a custom deserializer for the SourceConfig class.

I'll investigate this and see if it's easy enough to implement and doesn't break the generic deserialization for the class. Thanks for reporting this!