MONGOID-5183: Add queries instead of overriding it (#5077)

Co-authored-by: Dmitry Rybakov <[email protected]>

lib/mongoid/criteria/queryable/storable.rb

@@ -123,7 +123,12 @@ def add_logical_operator_expression(operator, op_expr)
           elsif operator == '$and' || selector.empty?
             # $and can always be added to top level and it will be combined
             # with whatever other conditions exist.
-            selector.store(operator, op_expr)
+            if current_value = selector[operator]
+              new_value = current_value + op_expr
+              selector.store(operator, new_value)
+            else
+              selector.store(operator, op_expr)
+            end
           else
             # Other operators need to be added separately
             if selector[operator]

spec/integration/criteria/logical_spec.rb

@@ -25,6 +25,17 @@
       bands = Band.where(name: /Proj/).and(Band.where(name: /u/))
       expect(bands.to_a).to eq([sp])
     end
+
+    it 'combines existing `$and` clause in query and `where` condition' do
+      bands = Band.where(id: 1).and({year: {'$in' => [2020]}}, {year: {'$in' => [2021]}}).where(id: 2)
+      expect(bands.selector).to eq(
+        {
+          "_id"=>1,
+          "year"=>{"$in"=>[2020]},
+          "$and"=>[{"year"=>{"$in"=>[2021]}}, {"_id"=>2}]
+        }
+      )
+    end
   end
 
   describe 'or' do

spec/mongoid/criteria/queryable/storable_spec.rb

@@ -67,6 +67,21 @@
         end
       end
 
+      context '$and to query with $and onto query whose first one is not $and' do
+        let(:query) do
+          Mongoid::Query.new.where({'foo' => 'baz'}).where('$and' => [{zoom: 'zoom'}])
+        end
+
+        let(:modified) do
+          query.send(query_method, '$and', [{'foo' => 'bar'}])
+        end
+
+        it 'adds to existing $and' do
+          modified.selector.should == {
+            '$and' => [{'zoom' => 'zoom'}, {'foo' => 'bar'}], 'foo' => 'baz'}
+        end
+      end
+
     end
 
     context '$or operator' do