Gem::SpecificationPolicy#validate_metadata

# File tmp/rubies/ruby-3.1.3/lib/rubygems/specification_policy.rb, line 119
def validate_metadata
  metadata = @specification.metadata

  unless Hash === metadata
    error "metadata must be a hash"
  end

  metadata.each do |key, value|
    entry = "metadata['#{key}']"
    if !key.kind_of?(String)
      error "metadata keys must be a String"
    end

    if key.size > 128
      error "metadata key is too large (#{key.size} > 128)"
    end

    if !value.kind_of?(String)
      error "#{entry} value must be a String"
    end

    if value.size > 1024
      error "#{entry} value is too large (#{value.size} > 1024)"
    end

    if METADATA_LINK_KEYS.include? key
      if value !~ VALID_URI_PATTERN
        error "#{entry} has invalid link: #{value.inspect}"
      end
    end
  end
end