Fix T94441: fix crash parenting object to a bone

This crash occurs when the bone is newly created.  In certain
circumstances the depsgraph data for the armature is not updated,
causing `pchan_eval` to be NULL when the parent is updated.  This causes
a segfault in `ED_object_parent_set` when the flags are updated.

This change fixes the underlying depsgraph bug, and also adds both an
assertion and NULL pointer check to `ED_object_parent_set` to better
handle this scenario if it recurs via another path.

Maniphest Tasks: T94441

Differential Revision: https://developer.blender.org/D16065

1 files changed, 3 insertions, 1 deletions

diff --git a/source/blender/editors/object/object_relations.c b/source/blender/editors/object/object_relations.c
index 21e56531096..2f18922f4ee 100644
--- a/source/blender/editors/object/object_relations.c
+++ b/source/blender/editors/object/object_relations.c
@@ -570,7 +570,9 @@ bool ED_object_parent_set(ReportList *reports,
       pchan = BKE_pose_channel_active_if_layer_visible(par);
       pchan_eval = BKE_pose_channel_active_if_layer_visible(parent_eval);
 
-      if (pchan == NULL) {
+      if (pchan == NULL || pchan_eval == NULL) {
+        /* If pchan_eval is NULL, pchan should also be NULL. */
+        BLI_assert_msg(pchan == NULL, "Missing evaluated bone data");
         BKE_report(reports, RPT_ERROR, "No active bone");
         return false;
       }