fix(#736): make exception handlers work with Spring proxies

Author: pixel13

graphql-kickstart-spring-support/src/main/java/graphql/kickstart/spring/error/GraphQLErrorHandlerFactory.java

@@ -9,6 +9,7 @@
 import java.util.Arrays;
 import java.util.List;
 import lombok.extern.slf4j.Slf4j;
+import org.springframework.aop.support.AopUtils;
 import org.springframework.beans.factory.BeanCreationException;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.context.ApplicationContext;
@@ -47,6 +48,7 @@ private List<GraphQLErrorFactory> scanForExceptionHandlers(
         return emptyList();
       }
       return Arrays.stream(objClz.getDeclaredMethods())
+          .map(method -> AopUtils.getMostSpecificMethod(method, objClz))
           .filter(ReflectiveMethodValidator::isGraphQLExceptionHandler)
           .map(method -> withReflection(context.getBean(name), method))
           .collect(toList());

graphql-kickstart-spring-support/src/test/java/graphql/kickstart/spring/error/GraphQLErrorHandlerFactoryTest.java

@@ -12,6 +12,7 @@
 import org.mockito.Mock;
 import org.mockito.Mockito;
 import org.mockito.junit.jupiter.MockitoExtension;
+import org.springframework.aop.framework.ProxyFactory;
 import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
 import org.springframework.context.ConfigurableApplicationContext;
 import org.springframework.web.bind.annotation.ExceptionHandler;
@@ -29,13 +30,14 @@ public void setup() {
     Mockito.when(applicationContext.getBeanFactory()).thenReturn(beanFactory);
     Mockito.when(beanFactory.getBeanDefinitionNames()).thenReturn(new String[] {"Test"});
     Mockito.when(applicationContext.containsBean("Test")).thenReturn(true);
-    Mockito.doReturn(TestClass.class).when(applicationContext).getType("Test");
 
     errorHandlerFactory = new GraphQLErrorHandlerFactory();
   }
 
   @Test
   void createFindsCollectionHandler() {
+    Mockito.doReturn(TestClass.class).when(applicationContext).getType("Test");
+
     GraphQLErrorHandler handler = errorHandlerFactory.create(applicationContext, true);
     assertThat(handler).isInstanceOf(GraphQLErrorFromExceptionHandler.class);
     GraphQLErrorFromExceptionHandler errorHandler = (GraphQLErrorFromExceptionHandler) handler;
@@ -44,6 +46,23 @@ void createFindsCollectionHandler() {
         .isNotEmpty();
   }
 
+  @Test
+  void createFindsExceptionHandlerEvenIfProxy() {
+    Mockito.doReturn(proxyTestClass()).when(applicationContext).getType("Test");
+
+    GraphQLErrorHandler handler = errorHandlerFactory.create(applicationContext, true);
+    assertThat(handler).isInstanceOf(GraphQLErrorFromExceptionHandler.class);
+    GraphQLErrorFromExceptionHandler errorHandler = (GraphQLErrorFromExceptionHandler) handler;
+    assertThat(errorHandler.getFactories())
+        .as("handler.factories should not be empty")
+        .isNotEmpty();
+  }
+
+  private Class<? extends TestClass> proxyTestClass() {
+    TestClass proxy = (TestClass) new ProxyFactory(new TestClass()).getProxy();
+    return proxy.getClass();
+  }
+
   public static class TestClass {
 
     @ExceptionHandler(IllegalArgumentException.class)