Fix T82388: Sculpt mode: Unexpected undo behavior.

Issue exposed by rB4c7b1766a7f1.

Main idea is that non-memfile first undo step should check into previous
memfile and tag the ID it is editing as `future_changed`.

That way, when we go back and undo to the memfile, said IDs are properly
detected as changed and re-read from the memfile.

Otherwise, undo system sees them as unchanged, and just re-use the
current data instead.

Note that currently only Sculpt mode seems affected (probably because it
is storing the mode switch itself as a Sculpt undo step instead of a
memfile one), but similar action might be needed in some other cases
too.

Maniphest Tasks: T82388

Differential Revision: https://developer.blender.org/D9510

1 files changed, 2 insertions, 2 deletions

diff --git a/source/blender/editors/sculpt_paint/sculpt_dyntopo.c b/source/blender/editors/sculpt_paint/sculpt_dyntopo.c
index 22bcbcc3bf1..87e0ea7f6a9 100644
--- a/source/blender/editors/sculpt_paint/sculpt_dyntopo.c
+++ b/source/blender/editors/sculpt_paint/sculpt_dyntopo.c
@@ -291,7 +291,7 @@ void sculpt_dynamic_topology_disable_with_undo(Main *bmain,
     /* May be false in background mode. */
     const bool use_undo = G.background ? (ED_undo_stack_get() != NULL) : true;
     if (use_undo) {
-      SCULPT_undo_push_begin("Dynamic topology disable");
+      SCULPT_undo_push_begin(ob, "Dynamic topology disable");
       SCULPT_undo_push_node(ob, NULL, SCULPT_UNDO_DYNTOPO_END);
     }
     SCULPT_dynamic_topology_disable_ex(bmain, depsgraph, scene, ob, NULL);
@@ -311,7 +311,7 @@ static void sculpt_dynamic_topology_enable_with_undo(Main *bmain,
     /* May be false in background mode. */
     const bool use_undo = G.background ? (ED_undo_stack_get() != NULL) : true;
     if (use_undo) {
-      SCULPT_undo_push_begin("Dynamic topology enable");
+      SCULPT_undo_push_begin(ob, "Dynamic topology enable");
     }
     SCULPT_dynamic_topology_enable_ex(bmain, depsgraph, scene, ob);
     if (use_undo) {