Merge pull request #800 from mataki/fix-join-not-null

Fix query of not_null with joining association

lib/ransack/adapters/active_record/ransack/nodes/condition.rb

@@ -7,9 +7,14 @@ def arel_predicate
           association = attribute.parent
           if negative? && attribute.associated_collection?
             query = context.build_correlated_subquery(association)
-            query.where(format_predicate(attribute).not)
             context.remove_association(association)
-            Arel::Nodes::NotIn.new(context.primary_key, Arel.sql(query.to_sql))
+            if self.predicate_name == 'not_null' && self.value
+              query.where(format_predicate(attribute))
+              Arel::Nodes::In.new(context.primary_key, Arel.sql(query.to_sql))
+            else
+              query.where(format_predicate(attribute).not)
+              Arel::Nodes::NotIn.new(context.primary_key, Arel.sql(query.to_sql))
+            end
           else
             format_predicate(attribute)
           end

spec/ransack/predicate_spec.rb

@@ -329,6 +329,28 @@ module Ransack
         field = "#{quote_table_name("people")}.#{quote_column_name("name")}"
         expect(@s.result.to_sql).to match /#{field} IS NULL/
       end
+
+      describe 'with association qeury' do
+        it 'generates a value IS NOT NULL query' do
+          @s.comments_id_not_null = true
+          sql = @s.result.to_sql
+          parent_field = "#{quote_table_name("people")}.#{quote_column_name("id")}"
+          expect(sql).to match /#{parent_field} IN/
+          field = "#{quote_table_name("comments")}.#{quote_column_name("id")}"
+          expect(sql).to match /#{field} IS NOT NULL/
+          expect(sql).not_to match /AND NOT/
+        end
+
+        it 'generates a value IS NULL query when assigned false' do
+          @s.comments_id_not_null = false
+          sql = @s.result.to_sql
+          parent_field = "#{quote_table_name("people")}.#{quote_column_name("id")}"
+          expect(sql).to match /#{parent_field} NOT IN/
+          field = "#{quote_table_name("comments")}.#{quote_column_name("id")}"
+          expect(sql).to match /#{field} IS NULL/
+          expect(sql).to match /AND NOT/
+        end
+      end
     end
 
     describe 'present' do