[BUG] _clone does not accept wait_for_completion=true in params

[VladutZzZ]

Hello,

In public documentation of _clone https://opensearch.org/docs/latest/api-reference/index-apis/clone/, wait_for_completion is presented as accepted parameter in URL. But when is used, an error is thrown:

{
  "error" : {
    "root_cause" : [
      {
        "type" : "illegal_argument_exception",
        "reason" : "request [/template/_clone/index-2023.05.04] contains unrecognized parameter: [wait_for_completion]"
      }
    ],
    "type" : "illegal_argument_exception",
    "reason" : "request [/template/_clone/index-2023.05.04] contains unrecognized parameter: [wait_for_completion]"
  },
  "status" : 400
}

To Reproduce
Run next POST request:

POST /template/_clone/index-2023.05.04?wait_for_completion=true
{
  "settings": {
    "index.blocks.write": false
  }
}

Expected behavior

Index is cloned and request will wait to finish.

[anasalkouz]

Maybe related PR: #6434

[danandreicarp]

Also happens for forcemerge:

POST /clone-daily-sa-2023-07-27/_forcemerge?wait_for_completion=false

{
  "error": {
    "root_cause": [
      {
        "type": "illegal_argument_exception",
        "reason": "request [/clone-daily-sa-2023-07-27/_forcemerge] contains unrecognized parameter: [wait_for_completion]"
      }
    ],
    "type": "illegal_argument_exception",
    "reason": "request [/clone-daily-sa-2023-07-27/_forcemerge] contains unrecognized parameter: [wait_for_completion]"
  },
  "status": 400
}

[gaobinlong]

hi @VladutZzZ @danandreicarp, which OpenSearch version did you use? The parameter wait_for_completion for clone and forcemerge API was introduced in 2.7.0.

[danandreicarp]

I used 2.5, but the documentation for this feature is lacking. This was working in older versions of ElasticSearch so I assumed it would be available in OpenSearch as well.
Is it safe to assume that it's functional in OpenSearch 2.7?

Thanks!

[gaobinlong]

I think yes, the related PR #6434 was merged in 2.7, we can see it in the release page: https://github.com/opensearch-project/OpenSearch/releases, and I just tried the parameter in 2.9, it works well.

Besides, forcemerge API in Elasticsearch 7.10.2 doesn't have that parameter, so it's not available in OpenSearch until 2.7.

[dblock]

I think this is resolved as "works as expected since 2.7", lmk otherwise!