flippercloud/flipper · error · Flipper::Registry::DuplicateKey

#{key} is already registered

Error message

#{key} is already registered

What it means

Error "#{key} is already registered" thrown in flippercloud/flipper.

Source

Thrown at lib/flipper/registry.rb:39

    def initialize(source = {})
      @mutex = Mutex.new
      @source = source
    end

    def keys
      @mutex.synchronize { @source.keys }
    end

    def values
      @mutex.synchronize { @source.values }
    end

    def add(key, value)
      key = key.to_sym

      @mutex.synchronize do
        if @source[key]
          raise DuplicateKey, "#{key} is already registered"
        else
          @source[key] = value
        end
      end
    end

    def get(key)
      key = key.to_sym
      @mutex.synchronize do
        @source[key]
      end
    end

    def key?(key)
      key = key.to_sym
      @mutex.synchronize do
        @source.key?(key)
      end

View on GitHub (pinned to 1f86de3ec9)

Solutions

1. Choose a different key; each gate/expression name can only be registered once
2. Check for duplicate registration, often caused by loading a file twice (use require instead of load)
3. Unregister the existing key first if you intentionally need to replace it

When it happens

Trigger: Thrown at lib/flipper/registry.rb:39 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of flippercloud/flipper@1f86de3ec9 (2026-08-23). Data as JSON: /api/errors/4248c6b70327eeba. Report an issue: GitHub.