[LUCENE-9410] German/French stemmers fail for common forms maux, gegrüßt, grüßend, schlummert

• Type: Bug
• Status: Patch Available
• Priority: Critical
• Resolution: Unresolved
• Affects Version/s: 8.5
• Component/s: modules/analysis
• Labels: french german stemmer stemming

Environment

Elasticsearch 7.7.1 running on cloud.elastic.co

• Lucene Fields: New
• Assignee: Unassigned
• Reporter: Ben Kazez
• Created: 18/Jun/20 14:53
• Updated: 02/Nov/23 15:25

Description

I'm using Lucene via Elasticsearch 7.7.1. German and French stemmers (either via the Snowball analyzer, or the "light" or "heavy" stemming analyzers) are failing to understand some common forms:

French:

• "maux" (plural) should match "mal" (singular) but instead "maux" is unchanged

German:

• "schlummert" should match "schlummern" (infinitive) but instead is unchanged
• "grüßend" should match "grüßen" (infinitive) but instead yields "grussend"
• "gegrüßt" should match "grüßen" (infinitive) but instead yields "gegrusst"

The Elasticsearch folks said I should file a bug with Lucene.

Issue Links

• links to: GitHub Pull Request #1983