[BUG] Error invoking _stats with expand_wildcards on closed indices

[mch2]

Describe the bug
The expand_wildcards parameter has the following options according to docs:

- all: Expand to all open and closed indexes, including hidden indexes.
- open: Expand to open indexes.
- closed: Expand to closed indexes.
- hidden: Include hidden indexes when expanding. Must be combined with open, closed, or both.
- none: Do not accept wildcard expressions.

all and closed options are supposed to expand on closed indices.

When either of these options are provided while the cluster contains a closed index, a bad request is returned:

{
  "error": {
    "root_cause": [
      {
        "type": "index_closed_exception",
        "reason": "closed",
        "index": "test-index",
        "index_uuid": "DH_Phg7YTpSG-KZfAPoddQ"
      }
    ],
    "type": "index_closed_exception",
    "reason": "closed",
    "index": "test-index",
    "index_uuid": "DH_Phg7YTpSG-KZfAPoddQ"
  },
  "status": 400
}

To Reproduce
Steps to reproduce the behavior:

1. Create an index
2. Close the index
3. Query GET _stats?expand_wildcards=all or _stats?expand_wildcards=closed

Expected behavior
According to docs this request should succeed. I would assume returning the stats that are able to be fetched from a closed index, maybe not all?

Plugins
None

Screenshots
N/A

Host/Environment (please complete the following information):
Any

Additional context
Easily reproducible with ./gradlew run on main and 2.x branches, have not tried 1.x.
I am also not seeing any exception in stdout.

[srikanthpadakanti]

Hello @anasalkouz @ankitkala @peternied Can you please assign this bug to me. I would like to work on this. Thanks.

[srikanthpadakanti]

@ankitkala @anasalkouz @andrross @mch2 @peternied

These are my findings so far -

Created an index called "sample-index" with sample docs.

curl -XPOST "http://localhost:9200/sample-index/_open"
curl -XGET "http://localhost:9200/sample-index/_stats" Printing the data 

curl -XPOST "http://localhost:9200/sample-index/_close"
curl -XGET "http://localhost:9200/sample-index/_stats"
{"error":{"root_cause":[{"type":"index_closed_exception","reason":"closed","index":"sample-index",
"index_uuid":"EOb53syfTa6SXZ-qPRfIPQ"}],"type":"index_closed_exception","reason":"closed",
"index":"sample-index","index_uuid":"EOb53syfTa6SXZ-qPRfIPQ"},"status":400}%

curl -XGET "http://localhost:9200/sample-index/_stats?expand_wildcards=all&forbid_closed_indices=false" 
printing the data | default value for forbid_closed_indices is true 
curl -XGET "http://localhost:9200/sample-index/_stats?expand_wildcards=closed&forbid_closed_indices=false"
printing the data  

Is this still a legit bug?
Can anyone please shed some light and explain more. Thanks.

[srikanthpadakanti]

Hello @ankitkala @anasalkouz @andrross @mch2 @peternied,

Can you please answer the above?

[peternied]

[Triage - attendees 1 2 3 4 5 6 7]
From our discussion, it sounds like a valid issue. How some parameters are treated in composition the default behavior should be different.

In the case mention where expand_wildcards=all or expand_wildcards=closed it seems like by default value of forbid_closed_indices should be false.

Its conflicting cases such as expand_wildcards=closed & forbid_closed_indices=true 400 error should be returned.

[srikanthpadakanti]

Hi @ankitkala @anasalkouz @andrross @mch2 @peternied
I raised a PR to this bug. Can you please let me know if everything looks ok?
#13012

[mch2]

Apologies for chiming in late here and thanks for taking this @srikanthpadakanti

As @reta mentioned on the PR this would be breaking the rest spec. When I cut this I had not considered the default behavior with forbid_closed_indices so giving a better error message here would have helped me and does enough to resolve the issue.