fix: Let's pass and apply distinct in query results if enabled (#124)

Author: igdianov

graphql-jpa-query-schema/src/main/java/com/introproventures/graphql/jpa/query/schema/impl/GraphQLJpaQueryDataFetcher.java

@@ -131,7 +131,11 @@ public Object get(DataFetchingEnvironment environment) {
             query.setHint(ORG_HIBERNATE_READ_ONLY, true);
             query.setHint(ORG_HIBERNATE_FETCH_SIZE, 1000);
             query.setHint(ORG_HIBERNATE_CACHEABLE, false);
-            query.setHint(HIBERNATE_QUERY_PASS_DISTINCT_THROUGH, false);
+            
+            // Let's pass distinct if enabled
+            if(isDistinct) {
+                query.setHint(HIBERNATE_QUERY_PASS_DISTINCT_THROUGH, true);
+            }
 
             result.put(GraphQLJpaSchemaBuilder.QUERY_SELECT_PARAM_NAME, query.getResultList());
         }

graphql-jpa-query-schema/src/test/java/com/introproventures/graphql/jpa/query/schema/StarwarsQueryExecutorTests.java

@@ -1208,5 +1208,34 @@ public void queryWithNestedWhereCompoundSearchCriteriaShouldFetchElementCollecti
         assertThat(result.toString()).isEqualTo(expected);
     }
 
+
+    @Test
+    public void queryShouldReturnDistictResultsByDefault() {
+        //given:
+        String query = "query { " +
+                "  Humans (where: { " + 
+                "    appearsIn: {IN: [A_NEW_HOPE, EMPIRE_STRIKES_BACK]}" + 
+                "  }) {" + 
+                "    select {" + 
+                "      id" + 
+                "      name" + 
+                "    }" + 
+                "  }" +
+                "}";
+
+        String expected = "{Humans={select=["
+                + "{id=1000, name=Luke Skywalker}, "
+                + "{id=1001, name=Darth Vader}, "
+                + "{id=1002, name=Han Solo}, "
+                + "{id=1003, name=Leia Organa}, "
+                + "{id=1004, name=Wilhuff Tarkin}"
+                + "]}}";
+
+        //when:
+        Object result = executor.execute(query).getData();
+
+        //then:
+        assertThat(result.toString()).isEqualTo(expected);
+    }
 
 }