Fix T98469: Crash trying to add an object to a linked collection that is linked to multiple scenes.

Crash happened because code could not find a valid base in current scene
after adding the object, added some checks for that.

Root of the issue was wrong assumptions in `BKE_object_add` logic, which
would pick the first valid ancestor collection in case initially
selected collection was not editable. In some case, this could pick a
collection not instanced in the current scene's view layer, leading to
not getting a valid base for the newly added object.

Addressed this by adding a new variant of `BKE_collection_object_add`,
`BKE_collection_viewlayer_object_add`, which ensures final collection is
in given viewlayer.

1 files changed, 12 insertions, 0 deletions

diff --git a/source/blender/blenkernel/BKE_collection.h b/source/blender/blenkernel/BKE_collection.h
index a3bbcc8687a..41d369ae9b2 100644
--- a/source/blender/blenkernel/BKE_collection.h
+++ b/source/blender/blenkernel/BKE_collection.h
@@ -115,6 +115,18 @@ bool BKE_collection_is_empty(const struct Collection *collection);
 bool BKE_collection_object_add(struct Main *bmain,
                                struct Collection *collection,
                                struct Object *ob);
+
+/**
+ * Add object to given collection, similar to #BKE_collection_object_add.
+ *
+ * However, it additionnally ensures that the selected collection is also part of the given
+ * `view_layer`, if non-NULL. Otherwise, the object is not added to any collection.
+ */
+bool BKE_collection_viewlayer_object_add(struct Main *bmain,
+                                         const struct ViewLayer *view_layer,
+                                         struct Collection *collection,
+                                         struct Object *ob);
+
 /**
  * Same as #BKE_collection_object_add, but unconditionally adds the object to the given collection.
  *