[Bf-blender-cvs] [bdbe95578d5] master: Fix crash related to liboverride differential operations code.

[Bastien Montagne]

Commit: bdbe95578d54971d9e0c4957bdc3367ebae44363
Author: Bastien Montagne
Date:   Thu Sep 24 18:12:11 2020 +0200
Branches: master
https://developer.blender.org/rBbdbe95578d54971d9e0c4957bdc3367ebae44363

Fix crash related to liboverride differential operations code.

Root of the issue is how we generate the storage ID for the differential
override operations.

However, since those are disabled anyway currently, simply comment out
creation of this copy for now, we can revisit this if/when we decide to
re-activate differential overrides.

Related to T81059, found while investigating it.

===================================================================

M	source/blender/blenkernel/intern/lib_override.c

===================================================================

diff --git a/source/blender/blenkernel/intern/lib_override.c b/source/blender/blenkernel/intern/lib_override.c
index d2b2f01a81c..ab7e3a64c54 100644
--- a/source/blender/blenkernel/intern/lib_override.c
+++ b/source/blender/blenkernel/intern/lib_override.c
@@ -1825,6 +1825,14 @@ ID *BKE_lib_override_library_operations_store_start(Main *bmain,
   TIMEIT_START_AVERAGED(BKE_lib_override_library_operations_store_start);
 #endif
 
+  /* This is fully disabled for now, as it generated very hard to solve issues with Collections and
+   * how they reference each-other in their parents/children relations.
+   * Core of the issue is creating and storing those copies in a separate BMain, while collection
+   * copy code re-assign blindly parents/children, even if they do not belong to the same BMain.
+   * One solution could be to implement special flag as discussed below, and prevent any
+   * other-ID-reference creation/update in that case (since no differential operation is expected
+   * to involve those anyway). */
+#if 0
   /* XXX TODO We may also want a specialized handling of things here too, to avoid copying heavy
    * never-overridable data (like Mesh geometry etc.)? And also maybe avoid lib
    * reference-counting completely (shallow copy...). */
@@ -1846,6 +1854,9 @@ ID *BKE_lib_override_library_operations_store_start(Main *bmain,
       storage_id = NULL;
     }
   }
+#else
+  storage_id = NULL;
+#endif
 
   local->override_library->storage = storage_id;