fix: deserialize a JsonError as a GenericResource

This pull request adds the JsonError test to verify JsonMapper can deserialize a JsonError as a GenericResource introduced in #10526 as a TCK test.

http-server-tck/src/main/java/io/micronaut/http/server/tck/tests/hateoas/JsonErrorSerdeTest.java

@@ -0,0 +1,55 @@
+/*
+ * Copyright 2017-2024 original authors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.micronaut.http.server.tck.tests.hateoas;
+
+import io.micronaut.http.hateoas.Resource;
+import io.micronaut.http.tck.ServerUnderTest;
+import io.micronaut.http.tck.ServerUnderTestProviderUtils;
+import io.micronaut.json.JsonMapper;
+import org.junit.jupiter.api.Test;
+
+import java.io.IOException;
+import java.util.Collections;
+
+import static org.junit.jupiter.api.Assertions.*;
+
+@SuppressWarnings({
+        "java:S5960", // We're allowed assertions, as these are used in tests only
+        "checkstyle:MissingJavadocType",
+        "checkstyle:DesignForExtension"
+})
+public class JsonErrorSerdeTest {
+    private static final String JSON_ERROR = """
+            {"_links":{"self":[{"href":"/resolve","templated":false}]},"_embedded":{"errors":[{"message":"Internal Server Error: Something bad happened"}]},"message":"Internal Server Error"}""";
+    private static final String SPEC_NAME = "JsonErrorSerdeTest";
+
+    /**
+     * @throws IOException Exception thrown while getting the server under test.
+     */
+    @Test
+    void canDeserializeAJsonErrorAsAGenericResource() throws IOException {
+        try (ServerUnderTest server = ServerUnderTestProviderUtils.getServerUnderTestProvider().getServer(SPEC_NAME, Collections.emptyMap())) {
+            JsonMapper jsonMapper = server.getApplicationContext().getBean(JsonMapper.class);
+            //when:
+            Resource resource = jsonMapper.readValue(JSON_ERROR, Resource.class);
+            //then:
+            assertTrue(resource.getEmbedded().getFirst("errors").isPresent());
+            assertTrue(resource.getLinks().getFirst("self").isPresent());
+            assertEquals("/resolve", resource.getLinks().getFirst("self").get().getHref());
+            assertFalse(resource.getLinks().getFirst("self").get().isTemplated());
+        }
+    }
+}

http/src/main/java/io/micronaut/http/hateoas/AbstractResource.java

@@ -26,12 +26,8 @@
 import io.micronaut.http.annotation.Produces;
 
 import io.micronaut.core.annotation.Nullable;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.LinkedHashMap;
-import java.util.List;
-import java.util.Map;
-import java.util.Optional;
+
+import java.util.*;
 
 /**
  * An abstract implementation of {@link Resource}.
@@ -42,7 +38,7 @@
  */
 @Produces(MediaType.APPLICATION_HAL_JSON)
 @Introspected
-public abstract class AbstractResource<Impl extends AbstractResource> implements Resource {
+public abstract class AbstractResource<Impl extends AbstractResource<Impl>> implements Resource {
 
     private final Map<CharSequence, List<Link>> linkMap = new LinkedHashMap<>(1);
     private final Map<CharSequence, List<Resource>> embeddedMap = new LinkedHashMap<>(1);
@@ -150,6 +146,13 @@ public final void setLinks(Map<String, Object> links) {
             if (value instanceof Map) {
                 Map<String, Object> linkMap = (Map<String, Object>) value;
                 link(name, linkMap);
+            } else if (value instanceof Collection<?> collection) {
+                for (Object o : collection) {
+                    if (o instanceof Map) {
+                        Map<String, Object> linkMap = (Map<String, Object>) o;
+                        link(name, linkMap);
+                    }
+                }
             }
         }
     }