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.

2 files changed, 6 insertions, 1 deletions

diff --git a/source/blender/editors/undo/ed_undo.c b/source/blender/editors/undo/ed_undo.c
index 315a4c73e5f..9770b52158a 100644
--- a/source/blender/editors/undo/ed_undo.c
+++ b/source/blender/editors/undo/ed_undo.c
@@ -322,7 +322,7 @@ bool ED_undo_is_memfile_compatible(const bContext *C)
   if (view_layer != NULL) {
     Object *obact = OBACT(view_layer);
     if (obact != NULL) {
-      if (obact->mode & (OB_MODE_SCULPT | OB_MODE_EDIT)) {
+      if (obact->mode & OB_MODE_EDIT) {
         return false;
       }
     }
diff --git a/source/blender/editors/undo/memfile_undo.c b/source/blender/editors/undo/memfile_undo.c
index f3e2ee92558..a5f30409aa6 100644
--- a/source/blender/editors/undo/memfile_undo.c
+++ b/source/blender/editors/undo/memfile_undo.c
@@ -28,6 +28,7 @@
 #include "BKE_blender_undo.h"
 #include "BKE_context.h"
 #include "BKE_undo_system.h"
+#include "BKE_main.h"
 
 #include "WM_api.h"
 #include "WM_types.h"
@@ -74,6 +75,10 @@ static bool memfile_undosys_step_encode(struct bContext *UNUSED(C),
   /* Important we only use 'main' from the context (see: BKE_undosys_stack_init_from_main). */
   UndoStack *ustack = ED_undo_stack_get();
 
+  if (bmain->is_memfile_undo_flush_needed) {
+    ED_editors_flush_edits_ex(bmain, false, true);
+  }
+
   /* can be NULL, use when set. */
   MemFileUndoStep *us_prev = (MemFileUndoStep *)BKE_undosys_step_find_by_type(
       ustack, BKE_UNDOSYS_TYPE_MEMFILE);