LibOverride: Fix/improve handling of hierarchy root in tagged creation.

Decouple the reference (linked) root ID and the hierarchy (override) root ID.
Previous code was assuming that the reference ID was always also tagged
for override creation, which is true in current master, but cannot be
assumed in general (and won't be true with partial resync anymore).

Also add asserts to validate conditions that the reference/hierarchy_root
variables must meet.

1 files changed, 14 insertions, 4 deletions

diff --git a/source/blender/blenkernel/intern/lib_override.c b/source/blender/blenkernel/intern/lib_override.c
index fd8b4721500..961f63b1f82 100644
--- a/source/blender/blenkernel/intern/lib_override.c
+++ b/source/blender/blenkernel/intern/lib_override.c
@@ -332,8 +332,15 @@ ID *BKE_lib_override_library_create_from_id(Main *bmain,
 bool BKE_lib_override_library_create_from_tag(Main *bmain,
                                               Library *owner_library,
                                               const ID *id_root_reference,
+                                              ID *id_hierarchy_root,
                                               const bool do_no_main)
 {
+  BLI_assert(id_root_reference != NULL);
+  BLI_assert(id_hierarchy_root != NULL || (id_root_reference->tag & LIB_TAG_DOIT) != 0);
+  BLI_assert(id_hierarchy_root == NULL ||
+             (ID_IS_OVERRIDE_LIBRARY_REAL(id_hierarchy_root) &&
+              id_hierarchy_root->override_library->reference == id_root_reference));
+
   const Library *reference_library = id_root_reference->lib;
 
   ID *reference_id;
@@ -388,7 +395,10 @@ bool BKE_lib_override_library_create_from_tag(Main *bmain,
   /* Only remap new local ID's pointers, we don't want to force our new overrides onto our whole
    * existing linked IDs usages. */
   if (success) {
-    ID *hierarchy_root_id = id_root_reference->newid;
+    if (id_root_reference->newid != NULL) {
+      id_hierarchy_root = id_root_reference->newid;
+    }
+    BLI_assert(id_hierarchy_root != NULL);
 
     for (todo_id_iter = todo_ids.first; todo_id_iter != NULL; todo_id_iter = todo_id_iter->next) {
       reference_id = todo_id_iter->data;
@@ -398,7 +408,7 @@ bool BKE_lib_override_library_create_from_tag(Main *bmain,
         continue;
       }
 
-      local_id->override_library->hierarchy_root = hierarchy_root_id;
+      local_id->override_library->hierarchy_root = id_hierarchy_root;
 
       Key *reference_key, *local_key = NULL;
       if ((reference_key = BKE_key_from_id(reference_id)) != NULL) {
@@ -889,7 +899,7 @@ static bool lib_override_library_create_do(Main *bmain,
   lib_override_group_tag_data_clear(&data);
 
   const bool success = BKE_lib_override_library_create_from_tag(
-      bmain, owner_library, id_root, false);
+      bmain, owner_library, id_root, NULL, false);
 
   return success;
 }
@@ -1424,7 +1434,7 @@ static bool lib_override_library_resync(Main *bmain,
    * override IDs (including within the old overrides themselves, since those are tagged too
    * above). */
   const bool success = BKE_lib_override_library_create_from_tag(
-      bmain, NULL, id_root_reference, true);
+      bmain, NULL, id_root_reference, id_root->override_library->hierarchy_root, true);
 
   if (!success) {
     return success;