Make swallowToPrimaryDelta work with frozen deltas

Primary deltas are now frozen in lens element contexts. But we sometimes
need to modify them e.g. in scripting hooks. The swallowToPrimaryDelta
was changed to allow this.

Resolves MID-6097.

(cherry picked from commit 4a99b9d)

model/model-impl/src/main/java/com/evolveum/midpoint/model/impl/lens/LensElementContext.java

@@ -259,11 +259,36 @@ public void addPrimaryDelta(ObjectDelta<O> delta) throws SchemaException {
     }
 
     public void swallowToPrimaryDelta(ItemDelta<?,?> itemDelta) throws SchemaException {
+        createOrModifyPrimaryDelta(
+                delta -> delta.swallow(itemDelta),
+                () -> {
+                    ObjectDelta<O> newPrimaryDelta = getPrismContext().deltaFactory().object().create(getObjectTypeClass(), ChangeType.MODIFY);
+                    newPrimaryDelta.setOid(oid);
+                    newPrimaryDelta.addModification(itemDelta);
+                    return newPrimaryDelta;
+                });
+    }
+
+    @FunctionalInterface
+    private interface DeltaModifier<O extends Objectable> {
+        void modify(ObjectDelta<O> delta) throws SchemaException;
+    }
+
+    @FunctionalInterface
+    private interface DeltaCreator<O extends Objectable> {
+        ObjectDelta<O> create() throws SchemaException;
+    }
+
+    private void createOrModifyPrimaryDelta(DeltaModifier<O> modifier, DeltaCreator<O> creator) throws SchemaException {
         if (primaryDelta == null) {
-            primaryDelta = getPrismContext().deltaFactory().object().create(getObjectTypeClass(), ChangeType.MODIFY);
-            primaryDelta.setOid(oid);
+            primaryDelta = creator.create();
+        } else if (!primaryDelta.isImmutable()) {
+            modifier.modify(primaryDelta);
+        } else {
+            primaryDelta = primaryDelta.clone();
+            modifier.modify(primaryDelta);
+            primaryDelta.freeze();
         }
-        primaryDelta.swallow(itemDelta);
     }
 
     public abstract void swallowToSecondaryDelta(ItemDelta<?,?> itemDelta) throws SchemaException;