lib/nanoc/base/entities/site.rb in nanoc-4.11.2 vs lib/nanoc/base/entities/site.rb in nanoc-4.11.3

@@ -2,10 +2,17 @@
 
 module Nanoc
   module Int
     # @api private
     class Site
+      # Error that is raised when multiple items or layouts with the same identifier exist.
+      class DuplicateIdentifierError < ::Nanoc::Error
+        def initialize(identifier, type)
+          super("There are multiple #{type}s with the #{identifier} identifier.")
+        end
+      end
+
       include Nanoc::Core::ContractsSupport
 
       attr_reader :code_snippets
       attr_reader :config
       attr_accessor :data_source
@@ -50,10 +57,10 @@
       contract C::IterOf[C::Or[Nanoc::Core::Item, Nanoc::Core::Layout]], String => self
       def ensure_identifier_uniqueness(objects, type)
         seen = Set.new
         objects.each do |obj|
           if seen.include?(obj.identifier)
-            raise Nanoc::Int::Errors::DuplicateIdentifier.new(obj.identifier, type)
+            raise DuplicateIdentifierError.new(obj.identifier, type)
           end
 
           seen << obj.identifier
         end
         self