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, 10 insertions, 3 deletions

diff --git a/source/blender/editors/object/object_add.cc b/source/blender/editors/object/object_add.cc
index 20b9844ac89..e486d606e91 100644
--- a/source/blender/editors/object/object_add.cc
+++ b/source/blender/editors/object/object_add.cc
@@ -621,9 +621,16 @@ Object *ED_object_add_type_with_obdata(bContext *C,
   else {
     ob = BKE_object_add(bmain, view_layer, type, name);
   }
-  BASACT(view_layer)->local_view_bits = local_view_bits;
-  /* editor level activate, notifiers */
-  ED_object_base_activate(C, view_layer->basact);
+
+  Base *ob_base_act = BASACT(view_layer);
+  /* While not getting a valid base is not a good thing, it can happen in convoluted corner cases,
+   * better not crash on it in releases. */
+  BLI_assert(ob_base_act != nullptr);
+  if (ob_base_act != nullptr) {
+    ob_base_act->local_view_bits = local_view_bits;
+    /* editor level activate, notifiers */
+    ED_object_base_activate(C, ob_base_act);
+  }
 
   /* more editor stuff */
   ED_object_base_init_transform_on_add(ob, loc, rot);