lib/thredded/arel_compat.rb in thredded-0.16.14 vs lib/thredded/arel_compat.rb in thredded-0.16.15

@@ -2,30 +2,39 @@
 
 unless Rails::VERSION::MAJOR == 5 && Rails::VERSION::MINOR >= 2 || Rails::VERSION::MAJOR > 5
   require 'thredded/rails_lt_5_2_arel_case_node.rb'
 end
 
-if Rails::VERSION::MAJOR == 4
-  # Make `pluck` compatible with Arel.
-  require 'active_record/relation'
-  ActiveRecord::Relation.prepend(Module.new do
-    def pluck(*column_names)
-      super(*column_names.map do |n|
-        if n.is_a?(Arel::Node)
-          Arel.sql(n.to_sql)
-        elsif n.is_a?(Arel::Attributes::Attribute)
-          n.name
-        else
-          n
-        end
-      end)
-    end
-  end)
-end
-
 module Thredded
   module ArelCompat
     module_function
+
+    # On Rails >= 5, this method simply returns `relation.pluck(*columns)`.
+    #
+    # Rails 4 `pluck` does not support Arel nodes and attributes. This method does.
+    #
+    # This is an external method because monkey-patching `pluck` would
+    # have compatibility issues, see:
+    #
+    # https://github.com/thredded/thredded/issues/842
+    # https://blog.newrelic.com/engineering/ruby-agent-module-prepend-alias-method-chains/
+    if Rails::VERSION::MAJOR > 4
+      def pluck(relation, *columns)
+        relation.pluck(*columns)
+      end
+    else
+      def pluck(relation, *columns)
+        relation.pluck(*columns.map do |n|
+          if n.is_a?(Arel::Node)
+            Arel.sql(n.to_sql)
+          elsif n.is_a?(Arel::Attributes::Attribute)
+            n.name
+          else
+            n
+          end
+        end)
+      end
+    end
 
     # @param [#connection] engine
     # @param [Arel::Nodes::Node] a integer node
     # @param [Arel::Nodes::Node] b integer node
     # @return [Arel::Nodes::Node] a / b