Fix T50614: Curve doesn't restore initial form after deleting all its shapekeys

Logic of handling shapekeys when entering and leaving edit mode for
curves was... utterly broken.

Was leaving actual curve data with edited shapekey applied to it.

1 files changed, 12 insertions, 5 deletions

diff --git a/source/blender/editors/curve/editcurve.c b/source/blender/editors/curve/editcurve.c
index e9fd5fb5a43..b09186b970b 100644
--- a/source/blender/editors/curve/editcurve.c
+++ b/source/blender/editors/curve/editcurve.c
@@ -1195,6 +1195,11 @@ void ED_curve_editnurb_load(Object *obedit)
 
 		remap_hooks_and_vertex_parents(obedit);
 
+		/* We have to apply shapekeys *before* copying nurbs into newnurb, otherwise the reset to
+		 * refkey/original curve data that has to be done when editing non-refkey shapekey would be useless,
+		 * only affecting editnurb and not ob->data. */
+		calc_shapeKeys(obedit);
+
 		for (nu = editnurb->first; nu; nu = nu->next) {
 			newnu = BKE_nurb_duplicate(nu);
 			BLI_addtail(&newnurb, newnu);
@@ -1206,7 +1211,6 @@ void ED_curve_editnurb_load(Object *obedit)
 
 		cu->nurb = newnurb;
 
-		calc_shapeKeys(obedit);
 		ED_curve_updateAnimPaths(obedit->data);
 
 		BKE_nurbList_free(&oldnurb);
@@ -1227,7 +1231,6 @@ void ED_curve_editnurb_make(Object *obedit)
 		if (actkey) {
 			// XXX strcpy(G.editModeTitleExtra, "(Key) ");
 			undo_editmode_clear();
-			BKE_keyblock_convert_to_curve(actkey, cu, &cu->nurb);
 		}
 
 		if (editnurb) {
@@ -1248,12 +1251,16 @@ void ED_curve_editnurb_make(Object *obedit)
 			nu = nu->next;
 		}
 
-		if (actkey)
-			editnurb->shapenr = obedit->shapenr;
-
 		/* animation could be added in editmode even if there was no animdata in
 		 * object mode hence we always need CVs index be created */
 		init_editNurb_keyIndex(editnurb, &cu->nurb);
+
+		if (actkey) {
+			editnurb->shapenr = obedit->shapenr;
+			/* Apply shapekey to new nurbs of editnurb, not those of original curve (and *after* we generated keyIndex),
+			 * else we do not have valid 'original' data to properly restore curve when leaving editmode. */
+			BKE_keyblock_convert_to_curve(actkey, cu, &editnurb->nurbs);
+		}
 	}
 }