[SOLR-14926] Modernize and clean up document clustering contrib

• Type: Improvement
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 9.0
• Component/s: contrib - Clustering
• Assignee: Dawid Weiss
• Reporter: Dawid Weiss
• Created: 13/Oct/20 09:18
• Updated: 12/May/22 00:26
• Resolved: 03/Nov/20 09:57

Description

The clustering contrib was written a long time ago and it shows its age. We have two separate interfaces (for clustering search results and for clustering documents). The second one never received any attention and no implementation exists for it.

I plan to do the following:

• remove the document clustering interface entirely, leave only the post-search results clustering extension,
• upgrade the implementation to Carrot2 4.x (this gets rid of those long-standing odd dependencies),
• clean up the code where appropriate.

My plan is to apply this to master, initially, but also backport to 8x if there are no objections. I don't think it'll hurt anybody.

Issue Links

• incorporates: SOLR-13506 Upgrade carrot2-guava-*.jar
• incorporates: SOLR-12852 NPE in ClusteringComponent
• is related to: SOLR-14974 Modernize and clean up document clustering contrib (8.x backport)
• is related to: SOLR-14981 Remove search results clustering contrib from 8x
• links to: GitHub Pull Request #2050