Refactor: metaprogramming here it's confusing and make use of tap

Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

activerecord/lib/active_record/relation/query_methods.rb

@@ -5,89 +5,98 @@ module ActiveRecord
   module QueryMethods
     extend ActiveSupport::Concern
 
-    included do
-      (ActiveRecord::Relation::ASSOCIATION_METHODS + ActiveRecord::Relation::MULTI_VALUE_METHODS).each do |query_method|
-        attr_accessor :"#{query_method}_values"
-
-        next if [:where, :having, :select, :joins].include?(query_method)
-        class_eval <<-CEVAL, __FILE__, __LINE__ + 1
-          def #{query_method}(*args)
-            args.reject! { |a| a.blank? }
-            new_relation = clone
-            new_relation.#{query_method}_values += args if args.present?
-            new_relation
-          end
-        CEVAL
-      end
+    attr_accessor :includes_values, :eager_load_values, :preload_values,
+                  :select_values, :group_values, :order_values, :joins_values, :where_values, :having_values,
+                  :limit_value, :offset_value, :lock_value, :readonly_value, :create_with_value, :from_value
 
-      def reorder(*args)
-        args.reject! { |a| a.blank? }
-        new_relation = clone
-        new_relation.order_values = args if args.present?
-        new_relation
-      end
+    def includes(*args)
+      args.reject! { |a| a.blank? }
+      clone.tap { |r| r.includes_values += args if args.present? }
+    end
 
-      def select(*args)
-        if block_given?
-          to_a.select { |*block_args| yield(*block_args) }
-        else
-          args.reject! { |a| a.blank? }
-          new_relation = clone
-          new_relation.select_values += args if args.present?
-          new_relation
-        end
-      end
+    def eager_load(*args)
+      args.reject! { |a| a.blank? }
+      clone.tap { |r| r.eager_load_values += args if args.present? }
+    end
 
-      def joins(*args)
-        args.flatten!
+    def preload(*args)
+      args.reject! { |a| a.blank? }
+      clone.tap { |r| r.preload_values += args if args.present? }
+    end
+
+    def select(*args)
+      if block_given?
+        to_a.select { |*block_args| yield(*block_args) }
+      else
         args.reject! { |a| a.blank? }
-        new_relation = clone
-        new_relation.joins_values += args if args.present?
-        new_relation
+        clone.tap { |r| r.select_values += args if args.present? }
       end
+    end
 
-      [:where, :having].each do |query_method|
-        class_eval <<-CEVAL, __FILE__, __LINE__ + 1
-          def #{query_method}(*args)
-            new_relation = clone
-            value = build_where(*args)
-            new_relation.#{query_method}_values += Array.wrap(value) if value.present?
-            new_relation
-          end
-        CEVAL
-      end
+    def group(*args)
+      args.reject! { |a| a.blank? }
+      clone.tap { |r| r.group_values += args if args.present? }
+    end
 
-      ActiveRecord::Relation::SINGLE_VALUE_METHODS.each do |query_method|
-        attr_accessor :"#{query_method}_value"
+    def order(*args)
+      args.reject! { |a| a.blank? }
+      clone.tap { |r| r.order_values += args if args.present? }
+    end
 
-        class_eval <<-CEVAL, __FILE__, __LINE__ + 1
-          def #{query_method}(value = true)
-            new_relation = clone
-            new_relation.#{query_method}_value = value
-            new_relation
-          end
-        CEVAL
-      end
+    def reorder(*args)
+      args.reject! { |a| a.blank? }
+      clone.tap { |r| r.order_values = args if args.present? }
     end
 
-    def extending(*modules)
-      new_relation = clone
-      new_relation.send :apply_modules, *modules
-      new_relation
+    def joins(*args)
+      args.flatten!
+      args.reject! { |a| a.blank? }
+      clone.tap { |r| r.joins_values += args if args.present? }
     end
 
-    def lock(locks = true, &block)
-      relation = clone
-      relation.send(:apply_modules, Module.new(&block)) if block_given?
+    def where(*args)
+      value = build_where(*args)
+      clone.tap { |r| r.where_values += Array.wrap(value) if value.present? }
+    end
+
+    def having(*args)
+      value = build_where(*args)
+      clone.tap { |r| r.having_values += Array.wrap(value) if value.present? }
+    end
+
+    def limit(value = true)
+      clone.tap { |r| r.limit_value = value }
+    end
+
+    def offset(value = true)
+      clone.tap { |r| r.offset_value = value }
+    end
 
+    def lock(locks = true)
       case locks
       when String, TrueClass, NilClass
-        clone.tap {|new_relation| new_relation.lock_value = locks || true }
+        clone.tap { |r| r.lock_value = locks || true }
       else
-        clone.tap {|new_relation| new_relation.lock_value = false }
+        clone.tap { |r| r.lock_value = false }
       end
     end
 
+    def readonly(value = true)
+      clone.tap { |r| r.readonly_value = value }
+    end
+
+    def create_with(value = true)
+      clone.tap { |r| r.create_with_value = value }
+    end
+
+    def from(value = true)
+      clone.tap { |r| r.from_value = value }
+    end
+
+    def extending(*modules)
+      clone.tap { |r| r.send :apply_modules, *modules }
+    end
+
     def reverse_order
       order_clause = arel.send(:order_clauses).join(', ')
       relation = except(:order)