Validation of number_of_shards and number_of_replicas request to reject illegal number

[johtani]

If create an index the following settings, elasticsearch success to create an index.
However, when we create a document, we have error.
There are servral errors.

set 0 to number_of_shards

setting and create a document

curl -XPUT "http://localhost:9200/hoge" -d'
{
  "settings": {
    "number_of_shards": 0
  }
}'

curl -XPUT "http://localhost:9200/hoge/fuga/1" -d'{  "title": "fuga"}'

erorr

{
   "error": "ArithmeticException[/ by zero]",
   "status": 500
}

set -2 to number_of_shards

setting and create adocument

curl -XPUT "http://localhost:9200/hoge" -d'
{
  "settings": {
    "number_of_shards": -2
  }
}'

curl -XPUT "http://localhost:9200/hoge/fuga/1" -d'{  "title": "fuga"}'

error

{
   "error": "IndexShardMissingException[[hoge][0] missing]",
   "status": 404
}

set -2 to number_of_replicas

setting and create a document

curl -XPUT "http://localhost:9200/hoge" -d'
{
  "settings": {
    "number_of_shards": 2,
    "number_of_replicas": -2
  }
}'

curl -XPUT "http://localhost:9200/hoge/fuga/1" -d'{  "title": "fuga"}'

error

{
   "error": "UnavailableShardsException[[hoge][0] [0] shardIt, [0] active : Timeout waiting for [1m], request: index {[hoge][fuga][1], source[{\n  \"title\": \"fuga\"\n}\n]}]",
   "status": 503
}

Elasticsearch should return error message and should not create an index.