Preserve RECURSIVE flag of CTE relations when they are merged.

lib/postgres_ext/active_record/relation/merger.rb

@@ -2,7 +2,7 @@ module ActiveRecord
   class Relation
     class Merger # :nodoc:
       def normal_values
-        NORMAL_VALUES + [:with]
+        NORMAL_VALUES + [:with, :recursive]
       end
     end
   end

lib/postgres_ext/active_record/relation/query_methods.rb

@@ -201,6 +201,11 @@ def ranked!(value)
       self
     end
 
+    def recursive!(value)
+      self.recursive_value = value
+      self
+    end
+
     def build_arel_with_extensions
       arel = build_arel_without_extensions
 

test/queries/common_table_expression_test.rb

@@ -22,6 +22,14 @@
       query.to_sql.must_match(/WITH RECURSIVE "lucky_number_seven" AS \(SELECT "people".* FROM "people"(\s+)WHERE "people"."lucky_number" = 7\) SELECT "people".* FROM "people" JOIN lucky_number_seven ON lucky_number_seven.id = people.id/)
     end
 
+    it 'preserves recursive expression during merges' do
+      merge_recursive_in   = Tag.all.merge(Tag.recursive)
+      merge_recursive_in.to_sql.must_match(/WITH RECURSIVE "recursive" AS \(SELECT "tags".* FROM "tags"(\s+)WHERE "tags"."tag" = 'tag'\) SELECT "tags".* FROM "tags"/)
+
+      merge_into_recursive = Tag.recursive.merge(Tag.all)
+      merge_into_recursive.to_sql.must_match(/WITH RECURSIVE "recursive" AS \(SELECT "tags".* FROM "tags"(\s+)WHERE "tags"."tag" = 'tag'\) SELECT "tags".* FROM "tags"/)
+    end
+
     it 'accepts Arel::SelectMangers' do
       arel_table = Arel::Table.new 'test'
       arel_manager = arel_table.project arel_table[:foo]

test/test_helper.rb

@@ -25,6 +25,8 @@ def self.wicked_people
 
 class Tag < ActiveRecord::Base
   belongs_to :person
+
+  scope :recursive, -> { with.recursive(recursive: Tag.where(tag: 'tag')) }
 end
 
 class ParentTag < Tag