Fix T69822: Switching sculpt objects breaks undo

This introduces object mode tagging for data which hasn't yet been
written back to the ID data.

Now when selecting other sculpt objects, the original objects data is
flushed back to the ID before writing a memfile undo step.

1 files changed, 12 insertions, 8 deletions

diff --git a/source/blender/editors/mesh/editmesh_undo.c b/source/blender/editors/mesh/editmesh_undo.c
index 7071258d8cf..44984251243 100644
--- a/source/blender/editors/mesh/editmesh_undo.c
+++ b/source/blender/editors/mesh/editmesh_undo.c
@@ -34,6 +34,7 @@
 #include "BKE_context.h"
 #include "BKE_key.h"
 #include "BKE_layer.h"
+#include "BKE_main.h"
 #include "BKE_mesh.h"
 #include "BKE_editmesh.h"
 #include "BKE_undo_system.h"
@@ -708,9 +709,7 @@ static bool mesh_undosys_poll(bContext *C)
   return editmesh_object_from_context(C) != NULL;
 }
 
-static bool mesh_undosys_step_encode(struct bContext *C,
-                                     struct Main *UNUSED(bmain),
-                                     UndoStep *us_p)
+static bool mesh_undosys_step_encode(struct bContext *C, struct Main *bmain, UndoStep *us_p)
 {
   MeshUndoStep *us = (MeshUndoStep *)us_p;
 
@@ -730,18 +729,20 @@ static bool mesh_undosys_step_encode(struct bContext *C,
 
     elem->obedit_ref.ptr = ob;
     Mesh *me = elem->obedit_ref.ptr->data;
+    BMEditMesh *em = me->edit_mesh;
     undomesh_from_editmesh(&elem->data, me->edit_mesh, me->key);
+    em->needs_flush_to_id = 1;
     us->step.data_size += elem->data.undo_size;
   }
   MEM_freeN(objects);
+
+  bmain->is_memfile_undo_flush_needed = true;
+
   return true;
 }
 
-static void mesh_undosys_step_decode(struct bContext *C,
-                                     struct Main *UNUSED(bmain),
-                                     UndoStep *us_p,
-                                     int UNUSED(dir),
-                                     bool UNUSED(is_final))
+static void mesh_undosys_step_decode(
+    struct bContext *C, struct Main *bmain, UndoStep *us_p, int UNUSED(dir), bool UNUSED(is_final))
 {
   MeshUndoStep *us = (MeshUndoStep *)us_p;
 
@@ -765,6 +766,7 @@ static void mesh_undosys_step_decode(struct bContext *C,
     }
     BMEditMesh *em = me->edit_mesh;
     undomesh_to_editmesh(&elem->data, em, obedit->data);
+    em->needs_flush_to_id = 1;
     DEG_id_tag_update(&obedit->id, ID_RECALC_GEOMETRY);
   }
 
@@ -775,6 +777,8 @@ static void mesh_undosys_step_decode(struct bContext *C,
   Scene *scene = CTX_data_scene(C);
   scene->toolsettings->selectmode = us->elems[0].data.selectmode;
 
+  bmain->is_memfile_undo_flush_needed = true;
+
   WM_event_add_notifier(C, NC_GEOM | ND_DATA, NULL);
 }