Fix #916: Include all produces values in Accept header

spring-cloud-openfeign-core/src/main/java/org/springframework/cloud/openfeign/support/SpringMvcContract.java

@@ -93,6 +93,7 @@
  * @author Sam Kruglov
  * @author Tang Xiong
  * @author Juhyeong An
+ * @author Olof Segergren
  */
 public class SpringMvcContract extends Contract.BaseContract implements ResourceLoaderAware {
 
@@ -417,9 +418,11 @@ private boolean queryMapParamPresent(MethodMetadata data) {
 	}
 
 	private void parseProduces(MethodMetadata md, RequestMapping annotation) {
-		String[] serverProduces = annotation.produces();
-		String clientAccepts = serverProduces.length == 0 ? null : emptyToNull(serverProduces[0]);
-		if (clientAccepts != null) {
+		String[] clientAccepts = Arrays.stream(annotation.produces())
+			.map(s -> emptyToNull(s))
+			.filter(Objects::nonNull)
+			.toArray(String[]::new);
+		if (clientAccepts.length > 0) {
 			md.template().header(ACCEPT, clientAccepts);
 		}
 	}

spring-cloud-openfeign-core/src/test/java/org/springframework/cloud/openfeign/support/SpringMvcContractTests.java

@@ -764,6 +764,38 @@ void testAddingTemplatedParameterWithTheSameKey() throws NoSuchMethodException {
 		assertThat(data.template().headers().get("Accept")).contains("application/json", "{Accept}");
 	}
 
+	@Test
+	void testMultipleProducesValues() throws NoSuchMethodException {
+		Method method = TestTemplate_MultipleProduces.class.getDeclaredMethod("multipleProduces");
+		MethodMetadata data = contract.parseAndValidateMetadata(method.getDeclaringClass(), method);
+
+		assertThat(data.template().headers().get("Accept")).containsExactly("application/jose", "application/json");
+	}
+
+	@Test
+	void testSingleProducesValueUnchanged() throws NoSuchMethodException {
+		Method method = TestTemplate_MultipleProduces.class.getDeclaredMethod("singleProduces");
+		MethodMetadata data = contract.parseAndValidateMetadata(method.getDeclaringClass(), method);
+
+		assertThat(data.template().headers().get("Accept")).containsExactly(MediaType.APPLICATION_JSON_VALUE);
+	}
+
+	@Test
+	void testEmptyProducesNoAcceptHeader() throws NoSuchMethodException {
+		Method method = TestTemplate_MultipleProduces.class.getDeclaredMethod("noProduces");
+		MethodMetadata data = contract.parseAndValidateMetadata(method.getDeclaringClass(), method);
+
+		assertThat(data.template().headers().get("Accept")).isNull();
+	}
+
+	@Test
+	void testProducesWithBlankEntryIgnored() throws NoSuchMethodException {
+		Method method = TestTemplate_MultipleProduces.class.getDeclaredMethod("producesWithBlankEntry");
+		MethodMetadata data = contract.parseAndValidateMetadata(method.getDeclaringClass(), method);
+
+		assertThat(data.template().headers().get("Accept")).containsExactly("application/jose", "application/json");
+	}
+
 	@Test
 	void testMultipleRequestPartAnnotations() throws NoSuchMethodException {
 		Method method = TestTemplate_RequestPart.class.getDeclaredMethod("requestWithMultipleParts",
@@ -1141,4 +1173,20 @@ public String toString() {
 
 	}
 
+	public interface TestTemplate_MultipleProduces {
+
+		@GetMapping(value = "/test", produces = { "application/jose", "application/json" })
+		ResponseEntity<TestObject> multipleProduces();
+
+		@GetMapping(value = "/test", produces = MediaType.APPLICATION_JSON_VALUE)
+		ResponseEntity<TestObject> singleProduces();
+
+		@GetMapping("/test")
+		ResponseEntity<TestObject> noProduces();
+
+		@GetMapping(value = "/test", produces = { "application/jose", "", "application/json" })
+		ResponseEntity<TestObject> producesWithBlankEntry();
+
+	}
+
 }