1 files changed, 38 insertions, 11 deletions

diff --git a/source/blender/editors/space_outliner/tree/tree_display_override_library_hierarchies.cc b/source/blender/editors/space_outliner/tree/tree_display_override_library_hierarchies.cc
index e0a1958795a..fa4479d0d9d 100644
--- a/source/blender/editors/space_outliner/tree/tree_display_override_library_hierarchies.cc
+++ b/source/blender/editors/space_outliner/tree/tree_display_override_library_hierarchies.cc
@@ -75,6 +75,11 @@ ListBase TreeDisplayOverrideLibraryHierarchies::buildTree(const TreeSourceData &
   return tree;
 }
 
+bool TreeDisplayOverrideLibraryHierarchies::is_lazy_built() const
+{
+  return true;
+}
+
 /* -------------------------------------------------------------------- */
 /** \name Library override hierarchy building
  * \{ */
@@ -165,10 +170,14 @@ void OverrideIDHierarchyBuilder::build_hierarchy_for_ID(ID &override_root_id,
   build_hierarchy_for_ID_recursive(override_root_id, build_data, te_to_expand);
 }
 
+enum ForeachChildReturn {
+  FOREACH_CONTINUE,
+  FOREACH_BREAK,
+};
 /* Helpers (defined below). */
 static void foreach_natural_hierarchy_child(const MainIDRelations &id_relations,
                                             const ID &parent_id,
-                                            FunctionRef<void(ID &)> fn);
+                                            FunctionRef<ForeachChildReturn(ID &)> fn);
 static bool id_is_in_override_hierarchy(const Main &bmain,
                                         const ID &id,
                                         const ID &relationship_parent_id,
@@ -184,22 +193,30 @@ void OverrideIDHierarchyBuilder::build_hierarchy_for_ID_recursive(const ID &pare
   foreach_natural_hierarchy_child(id_relations_, parent_id, [&](ID &id) {
     /* Some IDs can use themselves, early abort. */
     if (&id == &parent_id) {
-      return;
+      return FOREACH_CONTINUE;
     }
     if (!id_is_in_override_hierarchy(bmain_, id, parent_id, build_data.override_root_id_)) {
-      return;
+      return FOREACH_CONTINUE;
     }
 
     /* Avoid endless recursion: If there is an ancestor for this ID already, it recurses into
      * itself. */
     if (build_data.parent_ids.lookup_key_default(&id, nullptr)) {
-      return;
+      return FOREACH_CONTINUE;
     }
 
     /* Avoid duplicates: If there is a sibling for this ID already, the same ID is just used
      * multiple times by the same parent. */
     if (build_data.sibling_ids.lookup_key_default(&id, nullptr)) {
-      return;
+      return FOREACH_CONTINUE;
+    }
+
+    /* We only want to add children whose parent isn't collapsed. Otherwise, in complex scenes with
+     * thousands of relationships, the building can slow down tremendously. Tag the parent to allow
+     * un-collapsing, but don't actually add the children. */
+    if (!TSELEM_OPEN(TREESTORE(&te_to_expand), &space_outliner_)) {
+      te_to_expand.flag |= TE_PRETEND_HAS_CHILDREN;
+      return FOREACH_BREAK;
     }
 
     TreeElement *new_te = outliner_add_element(
@@ -213,6 +230,8 @@ void OverrideIDHierarchyBuilder::build_hierarchy_for_ID_recursive(const ID &pare
     child_build_data.parent_ids.add(&id);
     child_build_data.sibling_ids.reserve(10);
     build_hierarchy_for_ID_recursive(id, child_build_data, *new_te);
+
+    return FOREACH_CONTINUE;
   });
 }
 
@@ -238,7 +257,7 @@ void OverrideIDHierarchyBuilder::build_hierarchy_for_ID_recursive(const ID &pare
  */
 static void foreach_natural_hierarchy_child(const MainIDRelations &id_relations,
                                             const ID &parent_id,
-                                            FunctionRef<void(ID &)> fn)
+                                            FunctionRef<ForeachChildReturn(ID &)> fn)
 {
   const MainIDRelationsEntry *relations_of_id = static_cast<MainIDRelationsEntry *>(
       BLI_ghash_lookup(id_relations.relations_from_pointers, &parent_id));
@@ -259,12 +278,16 @@ static void foreach_natural_hierarchy_child(const MainIDRelations &id_relations,
     if (GS(target_id.name) == ID_OB) {
       const Object &potential_child_ob = reinterpret_cast<const Object &>(target_id);
       if (potential_child_ob.parent) {
-        fn(potential_child_ob.parent->id);
+        if (fn(potential_child_ob.parent->id) == FOREACH_BREAK) {
+          return;
+        }
         continue;
       }
     }
 
-    fn(target_id);
+    if (fn(target_id) == FOREACH_BREAK) {
+      return;
+    }
   }
 
   /* If the ID is an object, find and iterate over any child objects. */
@@ -277,9 +300,13 @@ static void foreach_natural_hierarchy_child(const MainIDRelations &id_relations,
         continue;
       }
 
-      Object &potential_child_ob = reinterpret_cast<Object &>(potential_child_id);
-      if (potential_child_ob.parent && &potential_child_ob.parent->id == &parent_id) {
-        fn(potential_child_id);
+      const Object &potential_child_ob = reinterpret_cast<Object &>(potential_child_id);
+      if (!potential_child_ob.parent || &potential_child_ob.parent->id != &parent_id) {
+        continue;
+      }
+
+      if (fn(potential_child_id) == FOREACH_BREAK) {
+        return;
       }
     }
   }