Can not add mapping

[Alex_Pravdin]

I'm using Elasticsearch 5.6 (I know it's outdated but I can not switch it right now).

I'm doing the following request:

    {
       "settings":{
          "index":{
             "analysis":{
                "filter":{
                   "autocomplete_filter":{
                      "type":"ngram",
                      "min_gram":2,
                      "max_gram":14
                   }
                },
                "char_filter":{
                   "parentheses_filter":{
                      "type":"mapping",
                      "mappings":{
                         "(":"_",
                         ")":"_"
                      }
                   }
                },
                "analyzer":{
                   "autocomplete":{
                      "type":"custom",
                      "tokenizer":"standard",
                      "filter":[
                         "lowercase",
                         "asciifolding",
                         "parentheses_filter",
                         "autocomplete_filter"
                      ]
                   }
                }
             }
          }
       },
       "mappings":{
          "default":{
             "properties":{
                    ...
             }
          }
       }
    }

And getting the following error:

    {
       "error":{
          "root_cause":[
             {
                "type":"illegal_argument_exception",
                "reason":"mapping requires either `mappings` or `mappings_path` to be configured"
             }
          ],
          "type":"illegal_argument_exception",
          "reason":"mapping requires either `mappings` or `mappings_path` to be configured"
       },
       "status":400
    }

If my eyes don't lie me I provided the mappings property of the custom mapping filter but ES can't recognize it and asks me to provide it. What I'm doing wrong?

[Alex_Pravdin]

Ah, my bad, mappings should be an array, not an object.