Fix: Write hide status attributes for undo steps

We don't convert to the old mesh format when writing undo steps to
avoid overhead. So we can't skip writing the hide attributes then.

1 files changed, 8 insertions, 4 deletions

diff --git a/source/blender/blenkernel/intern/mesh.cc b/source/blender/blenkernel/intern/mesh.cc
index 1b8d094e9d3..7f2c09f049b 100644
--- a/source/blender/blenkernel/intern/mesh.cc
+++ b/source/blender/blenkernel/intern/mesh.cc
@@ -212,6 +212,7 @@ static void mesh_foreach_path(ID *id, BPathForeachPathData *bpath_data)
 
 static void mesh_blend_write(BlendWriter *writer, ID *id, const void *id_address)
 {
+  using namespace blender;
   Mesh *mesh = (Mesh *)id;
   const bool is_undo = BLO_write_is_undo(writer);
 
@@ -245,14 +246,17 @@ static void mesh_blend_write(BlendWriter *writer, ID *id, const void *id_address
     memset(&mesh->pdata, 0, sizeof(mesh->pdata));
   }
   else {
+    Set<std::string> names_to_skip;
     if (!BLO_write_is_undo(writer)) {
       BKE_mesh_legacy_convert_hide_layers_to_flags(mesh);
+      /* When converting to the old mesh format, don't save redunant attributes. */
+      names_to_skip.add_multiple_new({".hide_vert", ".hide_edge", ".hide_poly"});
     }
 
-    CustomData_blend_write_prepare(mesh->vdata, vert_layers, {".hide_vert"});
-    CustomData_blend_write_prepare(mesh->edata, edge_layers, {".hide_edge"});
-    CustomData_blend_write_prepare(mesh->ldata, loop_layers);
-    CustomData_blend_write_prepare(mesh->pdata, poly_layers, {".hide_poly"});
+    CustomData_blend_write_prepare(mesh->vdata, vert_layers, names_to_skip);
+    CustomData_blend_write_prepare(mesh->edata, edge_layers, names_to_skip);
+    CustomData_blend_write_prepare(mesh->ldata, loop_layers, names_to_skip);
+    CustomData_blend_write_prepare(mesh->pdata, poly_layers, names_to_skip);
   }
 
   BLO_write_id_struct(writer, Mesh, id_address, &mesh->id);