Fix T93799: Outliner: Remaping objects could result in duplicates in a collection.

Fix is similar to how CollectionObject with NULL object pointers are handled.

Using one of the 'free' pad bytes in Object_Runtime struct instead of a
gset (or other external way to detect object duplicates), as this is
several times faster.

NOTE: This makes remapping slightly slower again (adds 10 extra seconds
to file case in T94059).

General improvements of remapping time complexity, especially when
remapping a lot of IDs at once, is a separate topic currently
investigated in D13615.

1 files changed, 14 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_collection.h b/source/blender/blenkernel/BKE_collection.h
index 46c1fe0d33d..7dfda7b5121 100644
--- a/source/blender/blenkernel/BKE_collection.h
+++ b/source/blender/blenkernel/BKE_collection.h
@@ -163,7 +163,21 @@ bool BKE_scene_collections_object_remove(struct Main *bmain,
                                          struct Scene *scene,
                                          struct Object *object,
                                          const bool free_us);
+
+/**
+ * Check all collections in \a bmain (including embedded ones in scenes) for CollectionObject with
+ * NULL object pointer, and remove them.
+ */
 void BKE_collections_object_remove_nulls(struct Main *bmain);
+
+/**
+ * Check all collections in \a bmain (including embedded ones in scenes) for duplicate
+ * CollectionObject with a same object pointer within a same object, and remove them.
+ *
+ * NOTE: Always keeps the first of the detected duplicates.
+ */
+void BKE_collections_object_remove_duplicates(struct Main *bmain);
+
 /**
  * Remove all NULL children from parent collections of changed \a collection.
  * This is used for library remapping, where these pointers have been set to NULL.