More useful message for NO_DEFAULT exception out of the box.

Author: SimY4

src/main/java/feign/error/ErrorHandling.java

@@ -13,6 +13,8 @@
  */
 package feign.error;
 
+import feign.Response;
+
 import java.lang.annotation.ElementType;
 import java.lang.annotation.Inherited;
 import java.lang.annotation.Retention;
@@ -28,5 +30,18 @@
   Class<? extends Exception> defaultException() default NO_DEFAULT.class;
 
   final class NO_DEFAULT extends Exception {
+
+      /**
+       * For backward compatibility.
+       */
+      @Deprecated
+      public NO_DEFAULT() {
+      }
+
+      @FeignExceptionConstructor
+      public NO_DEFAULT(@ResponseBody Response response) {
+          super("Endpoint responded with " + response.status() + ", reason: " + response.reason());
+      }
+
   }
 }

src/test/java/feign/error/AnnotationErrorDecoderExceptionConstructorsTest.java

@@ -124,7 +124,6 @@ public static Iterable<Object[]> data() {
 
   @Test
   public void test() throws Exception {
-
     AnnotationErrorDecoder decoder = AnnotationErrorDecoder
         .builderFor(TestClientInterfaceWithDifferentExceptionConstructors.class)
         .withResponseBodyDecoder(new OptionalDecoder(new Decoder.Default()))
@@ -133,13 +132,26 @@ public void test() throws Exception {
     Exception genericException = decoder.decode(feignConfigKey("method1Test"),
         testResponse(errorCode, NON_NULL_BODY, NON_NULL_HEADERS));
 
-    assertThat(genericException.getClass()).isEqualTo(expectedExceptionClass);
+    assertThat(genericException).isInstanceOf(expectedExceptionClass);
 
     ParametersException exception = (ParametersException) genericException;
     assertThat(exception.body()).isEqualTo(expectedBody);
     assertThat(exception.headers()).isEqualTo(expectedHeaders);
+  }
+
+  @Test
+  public void testIfExceptionIsNotInTheList() throws Exception {
+    AnnotationErrorDecoder decoder = AnnotationErrorDecoder
+            .builderFor(TestClientInterfaceWithDifferentExceptionConstructors.class)
+            .withResponseBodyDecoder(new OptionalDecoder(new Decoder.Default()))
+            .build();
 
+    Exception genericException = decoder.decode(feignConfigKey("method1Test"),
+            testResponse(-1, NON_NULL_BODY, NON_NULL_HEADERS));
 
+    assertThat(genericException)
+            .isInstanceOf(ErrorHandling.NO_DEFAULT.class)
+            .hasMessage("Endpoint responded with -1, reason: null");
   }
 
   interface TestClientInterfaceWithDifferentExceptionConstructors {