Inconsistent behavior of index stats API for closed indices vs closed indices with an alias matching the index pattern: index_closed_exception

[bczifra]

Elasticsearch Version

8.8.2

Installed Plugins

No response

Java Version

bundled

OS Version

Elastic Cloud

Problem Description

The index stats API returns an index_closed_exception if a closed index is behind an alias matching the wildcard index pattern, but returns without an exception if the closed index matches the wildcard index pattern but is not behind an alias matching the pattern.

Steps to Reproduce

When calling the Indices Stats API against a single, closed index:

PUT aliased_index

GET aliased_index/_stats

POST aliased_index/_close

GET aliased_index/_stats

the final call returns an index_closed_exception.

If we create a new index, then call _stats for those two indices, the API returns without an error:

PUT unaliased_index

GET unal*,ali*/_stats

However, if we now create an alias for that first index:

POST _aliases
{
  "actions": [
    {
      "add": {
        "index": "aliased_index",
        "alias": "my-alias"
      }
    }
  ]
}

Then this call:

GET my*,unalias*/_stats

will return an index_closed_exception.

Logs (if relevant)

No response

[bczifra]

Related: #88752 and elastic/beats#36677

[DaveCTurner]

I think this is a genuine issue, but I'm closing this as a duplicate of #32238.