Fix XML content handling in Spring Web Controller

extensions/spring-web/deployment/src/main/java/io/quarkus/spring/web/deployment/SpringWebProcessor.java

@@ -287,6 +287,10 @@ public void registerProviders(BeanArchiveIndexBuildItem beanArchiveIndexBuildIte
                     useAllAvailable = true;
                     break OUTER;
                 }
+                if (collectProviders(providersToRegister, categorizedContextResolvers, instance, "produces")) {
+                    useAllAvailable = true;
+                    break OUTER;
+                }
 
                 if (collectProviders(providersToRegister, categorizedReaders, instance, "consumes")) {
                     useAllAvailable = true;

integration-tests/spring-web/pom.xml

@@ -23,6 +23,10 @@
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-undertow</artifactId>
         </dependency>
+        <dependency>
+            <groupId>io.quarkus</groupId>
+            <artifactId>quarkus-resteasy-jaxb</artifactId>
+        </dependency>
         <dependency>
             <groupId>io.quarkus</groupId>
             <artifactId>quarkus-spring-di</artifactId>

integration-tests/spring-web/src/main/java/io/quarkus/it/spring/web/Book.java

@@ -0,0 +1,24 @@
+package io.quarkus.it.spring.web;
+
+import javax.xml.bind.annotation.XmlRootElement;
+
+@XmlRootElement
+public class Book {
+
+    private String name;
+
+    public Book() {
+    }
+
+    public Book(String name) {
+        this.name = name;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+}

integration-tests/spring-web/src/main/java/io/quarkus/it/spring/web/BookController.java

@@ -0,0 +1,14 @@
+package io.quarkus.it.spring.web;
+
+import org.springframework.http.MediaType;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+@RestController
+public class BookController {
+
+    @GetMapping(produces = MediaType.APPLICATION_XML_VALUE, path = "/book")
+    public Book someBook() {
+        return new Book("Guns germs and steel");
+    }
+}

integration-tests/spring-web/src/test/java/io/quarkus/it/spring/web/SpringControllerTest.java

@@ -204,4 +204,13 @@ public void testResponseEntityWithIllegalArgumentException() {
                 .body(containsString("hello from error"))
                 .statusCode(402);
     }
+
+    @Test
+    public void testMethodReturningXmlContent() {
+        RestAssured.when().get("/book")
+                .then()
+                .statusCode(200)
+                .contentType("application/xml")
+                .body(containsString("steel"));
+    }
 }