redis/redis-rb · error · ArgumentError

index_type must be IndexType::HASH or IndexType::JSON

Error message

index_type must be IndexType::HASH or IndexType::JSON

What it means

Error "index_type must be IndexType::HASH or IndexType::JSON" thrown in redis/redis-rb.

Source

Thrown at lib/redis/commands/modules/search/index_definition.rb:64

          # external mutations can't alter this definition.
          @prefixes = Array(prefix).dup
          append_index_type(index_type)
          append_prefix(@prefixes)
          append_filter(filter)
          append_language(language_field, language)
          append_score(score_field, score)
          append_payload(payload_field)
        end

        private

        def append_index_type(index_type)
          if index_type == IndexType::HASH
            @args += ["ON", "HASH"]
          elsif index_type == IndexType::JSON
            @args += ["ON", "JSON"]
          elsif !index_type.nil?
            raise ArgumentError, "index_type must be IndexType::HASH or IndexType::JSON"
          end
        end

        def append_prefix(prefix)
          unless prefix.empty?
            @args << "PREFIX"
            @args << prefix.length
            prefix.each { |p| @args << p }
          end
        end

        def append_filter(filter)
          if filter
            @args << "FILTER"
            @args << filter
          end
        end

View on GitHub (pinned to 2ba9010b91)

Solutions

1. Set index_type to IndexType::HASH or IndexType::JSON when building the index definition.
2. Do not pass arbitrary strings; use the IndexType constants.

When it happens

Trigger: Thrown at lib/redis/commands/modules/search/index_definition.rb:64 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of redis/redis-rb@2ba9010b91 (2026-08-23). Data as JSON: /api/errors/432f8ba2803e461b. Report an issue: GitHub.