puppetlabs/puppet · error · ArgumentError

Field ' ' is required

Error message

Field '%{field}' is required

What it means

When a FileParsing provider regenerates a file, FileRecord#join serializes each record back into a line; any field whose value is :absent, [:absent], or nil must be covered. If the field is not listed in :optional, join raises ArgumentError 'Field ... is required' and the write is aborted mid-generation.

Solutions

1. Fix or normalize the source file so every required field is present
2. Declare genuinely omissible fields as optional in record_line: optional: %i[dump pass]
3. Pre-validate the record hash and fill defaults before serialization

Example fix

# before
record_line :fstab, fields: %i[device mount fstype options dump pass], separator: /\s+/
# line 'tmpfs /tmp tmpfs defaults' => ArgumentError: Field 'dump' is required

# after
record_line :fstab, fields: %i[device mount fstype options dump pass], separator: /\s+/,
  optional: %i[dump pass], absent: '0'

filled = details.reject { |_, v| v.nil? || v == :absent || v == [:absent] }
missing = record.fields - record.optional - filled.keys
raise ArgumentError, "missing #{missing.join(', ')}" unless missing.empty?

When it happens

Trigger: A parsed record missing a column that was declared required — for example an /etc/fstab line with only four fields while the provider's record_line declared five (like :dump or :pass) — and Puppet then rewrites the file to add or remove an entry. Also a custom process/to_line hook leaving a required field nil.

Common situations: Malformed system files (fstab entries missing the dump/pass columns), hand-edited config lines, and providers moving between Puppet versions whose optional lists changed.

Understand the failure class

Background: "missing required argument" and "the following required arguments were not provided": what required-argument errors mean and how to fix them — this error's family across 20 libraries.

Related errors

• Cannot have fields named
• Invalid record type
• Line type is already defined
• Must include a list of fields
• No record types defined; cannot parse lines

AI-assisted analysis of puppetlabs/puppet@e227c27540 (2026-08-21). Data as JSON: /api/errors/0e8ef70548f41020. Report an issue: GitHub.

Appendix: source

Thrown at lib/puppet/util/fileparsing.rb:114

          instance_eval(&block)
        else
          meta_def(@block_eval, &block)
        end
      end
    end

    # Convert a record into a line by joining the fields together appropriately.
    # This is pulled into a separate method so it can be called by the hooks.
    def join(details)
      joinchar = self.joiner

      fields.filter_map { |field|
        # If the field is marked absent, use the appropriate replacement
        if details[field] == :absent or details[field] == [:absent] or details[field].nil?
          if self.optional.include?(field)
            self.absent
          else
            raise ArgumentError, _("Field '%{field}' is required") % { field: field }
          end
        else
          details[field].to_s
        end
      }.join(joinchar)
    end

    # Customize this so we can do a bit of validation.
    def optional=(optional)
      @optional = optional.collect(&:intern)
    end

    # Create a hook that modifies the hash resulting from parsing.
    def post_parse=(block)
      meta_def(:post_parse, &block)
    end

    # Create a hook that modifies the hash just prior to generation.

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