DefaultMappingFor does not map type to index

[Thornfalt]

Elastic.Clients.Elasticsearch version: 8.18.3

Elasticsearch version: 8.10.3

.NET runtime version: .NET 9

Operating system version: Windows 11

Description of the problem including expected versus actual behavior:
DefaultMappingFor does not map type to index. I tried using .DefaultIndex as well and it still does not set the index while searching, it searches through all indices.

Steps to reproduce:

1. Create ElasticsearchClientSettings and set DefaultMappingFor(t => t.IndexName("TestIndex")
2. Use SearchAsync and create a query.
3. Check the response and you can see that it hits all indices.

Expected behavior
I expect the type to be mapped to the index, so I only get result from that index.
Since DefaultMappingFor still exists in 8.18.3 I expect it to work.
Calling .DefaultIndex() also does not seem to work.

Provide DebugInformation (if relevant):
Valid Elasticsearch response built from a successful (200) low level call on POST: /_search?pretty=true&error_trace=true&_source_includes...

I can't seem to find definitive information on this. Is this intentional? Is mapping the type to a specific index deprecated? I just want to know if I need to implement my own solution to this or if it's a bug.

[flobernd]

Hi @Thornfalt ,

I can confirm that this behavior is intended and not a bug (see related issues #8184 and #8215 for more details about the reson).

Since it seems like the current behavior is not intuitive to many users, I've planned to revise this design decision. This needs careful thinking to make sure all implications and side-effects are considered.

I'll close this issue in favor of #8215.