refactor: support covariance for fieldTypeHandler

Author: yiteam

src/main/kotlin/team/yi/rsql/querydsl/QuerydslRsql.kt

@@ -256,9 +256,13 @@ class QuerydslRsql<E> private constructor(builder: Builder<E>) {
             fun operator(vararg operator: RsqlOperator): BuildBuilder<E> = this.apply { super.rsqlConfig.operators = operator.toList() }
             fun operators(operators: List<RsqlOperator>): BuildBuilder<E> = this.apply { super.rsqlConfig.operators = operators.toList() }
 
-            fun fieldTypeHandler(vararg typeHandler: Class<FieldTypeHandler<E>>): BuildBuilder<E> = this.apply { super.rsqlConfig.addFieldTypeHandler(*typeHandler) }
+            fun fieldTypeHandler(vararg typeHandler: Class<out FieldTypeHandler<E>>): BuildBuilder<E> = this.apply {
+                super.rsqlConfig.addFieldTypeHandler(*typeHandler)
+            }
 
-            fun sortFieldTypeHandler(vararg typeHandler: Class<SortFieldTypeHandler<E>>): BuildBuilder<E> = this.apply { super.rsqlConfig.addSortFieldTypeHandler(*typeHandler) }
+            fun sortFieldTypeHandler(vararg typeHandler: Class<out SortFieldTypeHandler<E>>): BuildBuilder<E> = this.apply {
+                super.rsqlConfig.addSortFieldTypeHandler(*typeHandler)
+            }
 
             fun dateFormat(dateFormat: String): BuildBuilder<E> = this.apply { super.rsqlConfig.dateFormat = dateFormat }
         }

src/test/java/team/yi/rsql/querydsl/test/javatest/QuerydslRsqlTest.java

@@ -34,7 +34,7 @@ public class QuerydslRsqlTest extends BaseRsqlTest {
     @Autowired
     private EntityManager entityManager;
 
-    private PathFactory pathFactory = new PathFactory();
+    private final PathFactory pathFactory = new PathFactory();
 
     @Test
     public void shouldReadRsqlConfig() {