Merge pull request quarkusio#26376 from geoand/quarkusio#26270

Clear out OutputStream when a MessageBodyWriter throws an exception

independent-projects/resteasy-reactive/server/runtime/src/main/java/org/jboss/resteasy/reactive/server/core/ServerSerialisers.java

@@ -241,6 +241,9 @@ public static boolean invokeWriter(ResteasyReactiveRequestContext context, Objec
             //the error handling will want to write out its own response
             //and the pre commit listener will interfere with that
             context.serverResponse().setPreCommitListener(null);
+            // also clear the stream in order to try to avoid writing out any data that
+            // might have been put on the stream before the exception occurred
+            context.setOutputStream(null);
             if (e instanceof RuntimeException) {
                 throw new PreserveTargetException(e);
             } else if (e instanceof IOException) {

independent-projects/resteasy-reactive/server/vertx/src/test/java/org/jboss/resteasy/reactive/server/vertx/test/response/ExceptionInWriterTest.java

@@ -0,0 +1,121 @@
+package org.jboss.resteasy.reactive.server.vertx.test.response;
+
+import static io.restassured.RestAssured.when;
+import static org.hamcrest.CoreMatchers.is;
+
+import java.io.IOException;
+import java.io.OutputStream;
+import java.lang.annotation.Annotation;
+import java.lang.reflect.Type;
+import java.nio.charset.StandardCharsets;
+import javax.ws.rs.GET;
+import javax.ws.rs.Path;
+import javax.ws.rs.Produces;
+import javax.ws.rs.WebApplicationException;
+import javax.ws.rs.core.MediaType;
+import javax.ws.rs.core.MultivaluedMap;
+import javax.ws.rs.core.Response;
+import javax.ws.rs.ext.ExceptionMapper;
+import javax.ws.rs.ext.Provider;
+import org.jboss.resteasy.reactive.server.spi.ResteasyReactiveResourceInfo;
+import org.jboss.resteasy.reactive.server.spi.ServerMessageBodyWriter;
+import org.jboss.resteasy.reactive.server.spi.ServerRequestContext;
+import org.jboss.resteasy.reactive.server.vertx.test.framework.ResteasyReactiveUnitTest;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.RegisterExtension;
+
+public class ExceptionInWriterTest {
+
+    @RegisterExtension
+    static ResteasyReactiveUnitTest runner = new ResteasyReactiveUnitTest()
+            .withApplicationRoot((jar) -> jar
+                    .addClasses(Greeting.class, GreetingResource.class,
+                            GreetingWriter.class, GreetingException.class, GreetingExceptionMapper.class));
+
+    @Test
+    void nullHeaderTest() {
+        when()
+                .get("/greeting")
+                .then().statusCode(200)
+                .body(is("fallback"));
+    }
+
+    @Path("/greeting")
+    public static class GreetingResource {
+
+        @GET
+        public Greeting ok() {
+            return new Greeting("hello");
+        }
+    }
+
+    public static class Greeting {
+
+        private final String message;
+
+        public Greeting(String message) {
+            this.message = message;
+        }
+
+        public String getMessage() {
+            return message;
+        }
+    }
+
+    @Provider
+    @Produces(MediaType.TEXT_PLAIN)
+    public static class GreetingWriter implements ServerMessageBodyWriter<Greeting> {
+
+        @Override
+        public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
+            return true;
+        }
+
+        @Override
+        public boolean isWriteable(Class<?> type, Type genericType, ResteasyReactiveResourceInfo target,
+                MediaType mediaType) {
+            return true;
+        }
+
+        @Override
+        public void writeTo(Greeting greeting, Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType,
+                MultivaluedMap<String, Object> httpHeaders, OutputStream entityStream)
+                throws IOException, WebApplicationException {
+
+            doWrite(greeting, entityStream);
+        }
+
+        @Override
+        public void writeResponse(Greeting greeting, Type genericType, ServerRequestContext context)
+                throws WebApplicationException, IOException {
+            doWrite(greeting, context.getOrCreateOutputStream());
+        }
+
+        private void doWrite(Greeting greeting, OutputStream entityStream) throws IOException {
+            if ("hello".equals(greeting.getMessage())) { // when the greeting comes from the resource method
+                entityStream.write("should not exist in final output".getBytes(StandardCharsets.UTF_8));
+                GreetingException ioe = new GreetingException("dummy exception");
+                ioe.setStackTrace(new StackTraceElement[0]);
+                throw ioe;
+            } else {
+                entityStream.write(greeting.message.getBytes(StandardCharsets.UTF_8));
+            }
+        }
+    }
+
+    public static class GreetingException extends IOException {
+
+        public GreetingException(String message) {
+            super(message);
+        }
+    }
+
+    @Provider
+    public static class GreetingExceptionMapper implements ExceptionMapper<GreetingException> {
+
+        @Override
+        public Response toResponse(GreetingException exception) {
+            return Response.status(200).entity(new Greeting("fallback")).build();
+        }
+    }
+}