Plugins analysis-stempel incorrect tokens generation for numbers

[domsew]

Actual: I observed unexpected behaviour. Some numbers are affected by stemmer. It causes wrong search results. For example "2021" -> "20ć".

Expected: string numbers should not be changed.

Reproduce: request:

POST _analyze
{
  "tokenizer": "standard",
  "filter": ["polish_stem"],
  "text": "2021"
}

response:

{
  "tokens": [
    {
      "token": "20ć",
      "start_offset": 0,
      "end_offset": 4,
      "type": "<NUM>",
      "position": 0
    }
  ]
}

Elasticsearch version 7.11.2:

Plugins installed: [analysis-stempel]

OS version CentOS

[elasticmachine]

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

[jimczi]

Sorrry for the late reply @domsew. The logic for this plugin is implemented in Lucene so could you please open an issue here. We're just using the Lucene module in ES so we cannot change how it works internally.

[elasticsearchmachine]

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