Fix T83875: Converting Proxy to override crashes blender.

Some weird proxies apparently can have a local collection instancing...
Not sure this is even really valid for proxies, but in any case we
cannot override that, just detect and properly cancel the operation
then.

Should be backported to 2.91.1 should we do it.

1 files changed, 10 insertions, 3 deletions

diff --git a/source/blender/editors/space_outliner/outliner_tools.c b/source/blender/editors/space_outliner/outliner_tools.c
index e4c3ebfdff5..492fc5c23bc 100644
--- a/source/blender/editors/space_outliner/outliner_tools.c
+++ b/source/blender/editors/space_outliner/outliner_tools.c
@@ -737,7 +737,7 @@ static void id_local_fn(bContext *C,
 }
 
 static void object_proxy_to_override_convert_fn(bContext *C,
-                                                ReportList *UNUSED(reports),
+                                                ReportList *reports,
                                                 Scene *UNUSED(scene),
                                                 TreeElement *UNUSED(te),
                                                 TreeStoreElem *UNUSED(tsep),
@@ -754,8 +754,15 @@ static void object_proxy_to_override_convert_fn(bContext *C,
     return;
   }
 
-  BKE_lib_override_library_proxy_convert(
-      CTX_data_main(C), scene, CTX_data_view_layer(C), ob_proxy);
+  if (!BKE_lib_override_library_proxy_convert(
+          CTX_data_main(C), scene, CTX_data_view_layer(C), ob_proxy)) {
+    BKE_reportf(
+        reports,
+        RPT_ERROR_INVALID_INPUT,
+        "Could not create a library override from proxy '%s' (might use already local data?)",
+        ob_proxy->id.name + 2);
+    return;
+  }
 
   DEG_id_tag_update(&scene->id, ID_RECALC_BASE_FLAGS | ID_RECALC_COPY_ON_WRITE);
   WM_event_add_notifier(C, NC_WINDOW, NULL);