Polish stemming plugin (Stempel 2.4.4) not working on ES 2.4

[kuba]

Hi, I installed Stempel plugin and configured analyzer and mappings. However, generated tokens seems incorrect.

Elastic version: 2.4
Stempel version: 2.4.4

This is how I set up analyzer:

{
  "body": {
    "settings": {
      "analysis": {
        "analyzer": {
          "text_analyzer": {
            "tokenizer": "standard",
            "filter": [
              "lowercase",
              "polish_stem"
            ]
          }
        }
      }
    }
  }
}

This is how I test it:

curl -XGET 'localhost:9200/my_index/_analyze?pretty=1' -d '
{
  "analyzer" : "text_analyzer",
  "text" : "malediwy"
}'

response:

{
  "tokens" : [ {
    "token" : "y",
    "start_offset" : 0,
    "end_offset" : 8,
    "type" : "<ALPHANUM>",
    "position" : 0
  } ]
}

Oh, and this is how I use it in my mapping:

"someTextField": {
  "type": "string",
  "analyzer": "text_analyzer"
}

Indeed, it is returning 'Malediwy' for 'y' query! (I'd expect 'Malediwach', 'Malediwami' etc., not 'y')
Other words are messed up also.

Is this a bug or am I doing something wrong?