lib/mobility/arel.rb in mobility-0.8.1 vs lib/mobility/arel.rb in mobility-0.8.2

@@ -2,10 +2,39 @@
 require "mobility/arel/nodes"
 require "mobility/arel/visitor"
 
 module Mobility
   module Arel
+    module MobilityExpressions
+      include ::Arel::Expressions
+
+      # @note This is necessary in order to ensure that when a translated
+      #   attribute is selected with an alias using +AS+, the resulting
+      #   expression can still be counted without blowing up.
+      #
+      #   Extending +::Arel::Expressions+ is necessary to convince ActiveRecord
+      #   that this node should not be stringified, which otherwise would
+      #   result in garbage SQL.
+      #
+      # @see https://github.com/rails/rails/blob/847342c25c61acaea988430dc3ab66a82e3ed486/activerecord/lib/active_record/relation/calculations.rb#L261
+      def as(*)
+        super
+          .extend(::Arel::Expressions)
+          .extend(Countable)
+      end
+
+      module Countable
+        # @note This allows expressions with selected translated attributes to
+        #   be counted.
+        def count(*args)
+          left.count(*args)
+        end
+      end
+    end
+
     class Attribute < ::Arel::Attributes::Attribute
+      include MobilityExpressions
+
       attr_reader :backend_class
       attr_reader :locale
       attr_reader :attribute_name
 
       def initialize(relation, column_name, locale, backend_class, attribute_name: nil)