added fix for non-necessary json transformation for ObjectId argument value

server/implementation/src/main/java/io/smallrye/graphql/execution/datafetcher/helper/ArgumentHelper.java

@@ -302,6 +302,12 @@ private Object correctObjectClass(Object argumentValue, Field field, DataFetchin
         if (Map.class.isAssignableFrom(argumentValue.getClass())) {
             return correctComplexObjectFromMap((Map) argumentValue, field, dfe);
         } else if (receivedClassName.equals(String.class.getName())) {
+            // Edge case for ObjectId: If the field is of type org.bson.types.ObjectId, return the argument value.
+            // We need to handle ObjectId separately to avoid JSON-B calling its no-arg constructor, which would
+            // generate a new, random ID. By returning the argument value as is, we preserve the original ObjectId.
+            if (field.getReference().getClassName().equals("org.bson.types.ObjectId")) {
+                return argumentValue;
+            }
             // We got a String, but not expecting one. Lets bind to Pojo with JsonB
             // This happens with @DefaultValue and Transformable (Passthrough) Scalars
             return correctComplexObjectFromJsonString(argumentValue.toString(), field);

server/integration-tests/pom.xml

@@ -196,6 +196,11 @@
             <version>${version.smallrye-stork}</version>
             <scope>test</scope>
         </dependency>
+        <dependency>
+            <groupId>org.mongodb</groupId>
+            <artifactId>bson</artifactId>
+            <scope>test</scope>
+        </dependency>
         <dependency>
             <groupId>org.jboss.shrinkwrap.resolver</groupId>
             <artifactId>shrinkwrap-resolver-api-maven</artifactId>

server/integration-tests/src/test/java/io/smallrye/graphql/tests/objectid/ObjectIdAdapter.java

@@ -0,0 +1,17 @@
+package io.smallrye.graphql.tests.objectid;
+
+import org.bson.types.ObjectId;
+
+import io.smallrye.graphql.api.Adapter;
+
+public class ObjectIdAdapter implements Adapter<ObjectId, String> {
+    @Override
+    public ObjectId from(String o) {
+        return new ObjectId(o);
+    }
+
+    @Override
+    public String to(ObjectId a) throws Exception {
+        return a.toHexString();
+    }
+}

server/integration-tests/src/test/java/io/smallrye/graphql/tests/objectid/ObjectIdTest.java

@@ -0,0 +1,42 @@
+package io.smallrye.graphql.tests.objectid;
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+import java.net.URL;
+
+import org.bson.types.ObjectId;
+import org.jboss.arquillian.container.test.api.Deployment;
+import org.jboss.arquillian.container.test.api.RunAsClient;
+import org.jboss.arquillian.junit.Arquillian;
+import org.jboss.arquillian.test.api.ArquillianResource;
+import org.jboss.shrinkwrap.api.ShrinkWrap;
+import org.jboss.shrinkwrap.api.spec.WebArchive;
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import io.smallrye.graphql.tests.GraphQLAssured;
+
+@RunWith(Arquillian.class)
+@RunAsClient
+public class ObjectIdTest {
+
+    @Deployment
+    public static WebArchive deployment() {
+        return ShrinkWrap.create(WebArchive.class, "objectId-test.war")
+                .addClasses(SomeApi.class, ObjectIdAdapter.class);
+    }
+
+    @ArquillianResource
+    URL testingURL;
+
+    @Test
+    public void queryWithObjectIdArgumentTest() {
+        final String id = ObjectId.get().toHexString();
+        System.err.println(id);
+        GraphQLAssured graphQLAssured = new GraphQLAssured(testingURL);
+
+        String response = graphQLAssured
+                .post("{ returnObjectId(id: \"" + id + "\") }");
+        assertThat(response).contains("{\"data\":{\"returnObjectId\":\"" + id + "\"}}");
+    }
+}

server/integration-tests/src/test/java/io/smallrye/graphql/tests/objectid/SomeApi.java

@@ -0,0 +1,16 @@
+package io.smallrye.graphql.tests.objectid;
+
+import org.bson.types.ObjectId;
+import org.eclipse.microprofile.graphql.GraphQLApi;
+import org.eclipse.microprofile.graphql.Query;
+
+import io.smallrye.graphql.api.AdaptWith;
+
+@GraphQLApi
+public class SomeApi {
+    @Query
+    public @AdaptWith(ObjectIdAdapter.class) ObjectId returnObjectId(@AdaptWith(ObjectIdAdapter.class) ObjectId id) {
+        return id;
+    }
+
+}