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, 6 insertions, 2 deletions

diff --git a/source/blender/blenkernel/intern/object.cc b/source/blender/blenkernel/intern/object.cc
index 2a25d73ed87..0bc092bec4f 100644
--- a/source/blender/blenkernel/intern/object.cc
+++ b/source/blender/blenkernel/intern/object.cc
@@ -2271,10 +2271,14 @@ Object *BKE_object_add(Main *bmain, ViewLayer *view_layer, int type, const char
   Object *ob = object_add_common(bmain, view_layer, type, name);
 
   LayerCollection *layer_collection = BKE_layer_collection_get_active(view_layer);
-  BKE_collection_object_add(bmain, layer_collection->collection, ob);
+  BKE_collection_viewlayer_object_add(bmain, view_layer, layer_collection->collection, ob);
 
+  /* Note: There is no way to be sure that #BKE_collection_viewlayer_object_add will actually
+   * manage to find a valid collection in given `view_layer` to add the new object to. */
   Base *base = BKE_view_layer_base_find(view_layer, ob);
-  BKE_view_layer_base_select_and_set_active(view_layer, base);
+  if (base != nullptr) {
+    BKE_view_layer_base_select_and_set_active(view_layer, base);
+  }
 
   return ob;
 }