puppetlabs/puppet · error · ArgumentError

Unknown merge strategy: '%{strategy}'

Error message

Unknown merge strategy: '%{strategy}'

What it means

Error "Unknown merge strategy: '%{strategy}'" thrown in puppetlabs/puppet.

Source

Thrown at lib/puppet/pops/merge_strategy.rb:40

    def self.strategy(merge)
      return DefaultMergeStrategy::INSTANCE unless merge
      return merge if merge.is_a?(MergeStrategy)

      if merge.is_a?(Hash)
        merge_strategy = merge['strategy']
        if merge_strategy.nil?
          # TRANSLATORS 'merge' is a variable name and 'strategy' is a key and should not be translated
          raise ArgumentError, _("The hash given as 'merge' must contain the name of a strategy in string form for the key 'strategy'")
        end

        merge_options  = merge.size == 1 ? EMPTY_HASH : merge
      else
        merge_strategy = merge
        merge_options = EMPTY_HASH
      end
      merge_strategy = merge_strategy.to_sym if merge_strategy.is_a?(String)
      strategy_class = strategies[merge_strategy]
      raise ArgumentError, _("Unknown merge strategy: '%{strategy}'") % { strategy: merge_strategy } if strategy_class.nil?

      merge_options == EMPTY_HASH ? strategy_class::INSTANCE : strategy_class.new(merge_options)
    end

    # Returns the list of merge strategy keys known to this class
    #
    # @return [Array<Symbol>] List of strategy keys
    #
    def self.strategy_keys
      strategies.keys - [:default, :unconstrained_deep, :reverse_deep]
    end

    # Adds a new merge strategy to the map of strategies known to this class
    #
    # @param strategy_class [Class<MergeStrategy>] The class of the added strategy
    #
    def self.add_strategy(strategy_class)
      unless MergeStrategy > strategy_class

View on GitHub (pinned to e227c27540)

When it happens

Trigger: Thrown at lib/puppet/pops/merge_strategy.rb:40 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/18124ba1832d3bf5. Report an issue: GitHub.