Side param in edge_ngram token filter is deprecated long back even in 2.X but code cleanup is not done

[amitmbm]

Elasticsearch Version

8.0

Installed Plugins

none

Java Version

bundled

OS Version

macos

Problem Description

side param in edge-n gram token filter is removed even in 2.x version but still code cleanup is not done, we should remove it completely from code as better alternatives are already mentioned in official doc.

Steps to Reproduce

Refer edge n-gram token filter in 8.X and the master branch code for the same.

Logs (if relevant)

No response

[amitmbm]

@cbuescher I would like to work on this bug, I've previously worked on this class, as part of my PR #55766

[cbuescher]

@amitmbm thanks for the offer, I just looked at the code and indeed the documentation says this parameter is long deprecated. However, since we never really went ahead and removed it, the problem we are facing now is that there might be users out there still using the parameter. This makes this issue more complex than simply removing the old code. We need some way to ensure that before removal, we add some deprecation warning logic first and also need to make sure that whatever older supported index that is using this option is still functional. We're currently in the process of re-working our deprecation strategy, so I will put this up for team discussion but it might be a bit until we have a clear way of doing removals like this for future versions.

[elasticmachine]

Pinging @elastic/es-search (Team:Search)

[amitmbm]

Thanks @cbuescher , would wait to see the outcome of your team discussion and would be happy to help when you need to finish this or similar tasks.