[Fix #1738] Adding safeguard to avoid overriding keys set by user

Signed-off-by: Francisco Javier Tirado Sarti <ftirados@ibm.com>

Author: fjtirado

impl/persistence/api/src/main/java/io/serverlessworkflow/impl/persistence/WorkflowPersistenceInstance.java

@@ -24,12 +24,16 @@
 import io.serverlessworkflow.impl.WorkflowMutableInstance;
 import io.serverlessworkflow.impl.WorkflowStatus;
 import io.serverlessworkflow.impl.executors.TransitionInfo;
+import java.util.HashSet;
 import java.util.Optional;
+import java.util.Set;
 import java.util.concurrent.CompletableFuture;
+import java.util.function.Supplier;
 
 public class WorkflowPersistenceInstance extends WorkflowMutableInstance {
 
   private final PersistenceWorkflowInfo info;
+  private Set<String> userMetaKeys = new HashSet<>();
 
   public static WorkflowInstance of(WorkflowDefinition definition, PersistenceWorkflowInfo info) {
     return definition
@@ -100,6 +104,19 @@ public void restoreContext(WorkflowContext workflow, TaskContext context) {
         searchContext = tryContext.parent();
       }
     }
-    taskInfo.additionalObjects().forEach(additionalObjects::put);
+    taskInfo
+        .additionalObjects()
+        .forEach(
+            (k, v) -> {
+              if (!userMetaKeys.contains(k)) {
+                additionalObjects.put(k, v);
+              }
+            });
+  }
+
+  @Override
+  public <T> T addMetadataIfAbsent(String key, Supplier<T> supplier) {
+    userMetaKeys.add(key);
+    return super.addMetadataIfAbsent(key, supplier);
   }
 }