Confusing blocks.read_only behavior for index write blocking

[matschaffer]

Elasticsearch Version

8.0 branch - 655669b

Installed Plugins

No response

Java Version

bundled

OS Version

macos

Problem Description

If set blocks.read_only on an index to true, attempting to set it back to false fails due to FORBIDDEN/5/index read-only (api)

Steps to Reproduce

POST stuff/_doc
{ "some": "stuff" }

PUT stuff/_settings
{
  "blocks.read_only": true
}

PUT stuff/_settings
{
  "blocks.read_only": false
}

Logs (if relevant)

[matschaffer]

Ahh.... Looks like you can use a more complete setting specification for this (found on https://stackoverflow.com/a/50954055/69002):

PUT stuff/_settings
{
 "index.blocks.read_only": null
}

Still kind of surprising that we wouldn't allow setting it to false, simply inverting the flag used to make the index readonly.

Or maybe require a fully specified index.blocks.read_only: true to set it in the first place.

[DaveCTurner]

Definitely a bug, but this is already tracked at #48325 so I'm closing this as a duplicate.