BMesh: remove redundant mesh-backups from EDBM_op_* API

Using BMesh operators through the edit-mesh API created a full copy
of the mesh so it was possible to restore the mesh in case
one of the operators raised an error.

Remove support for automatic backup/restore from the EDBM_op_* API's
as it adds significant overhead and was rarely used.

Operators that need this can use the BMBackup API to backup & restore
the mesh in case of failure.

Add warning levels to BMO_error_raise so operators can report problems
without it being interpreted as a request to cancel the operation.

For high-poly meshes creating and freeing a full copy is an expensive
operation, removing this gives a speedup of ~1.77x for most operators
except for "connect_verts" / "connect_vert_pair"
which still uses this functionality.

1 files changed, 1 insertions, 1 deletions

diff --git a/source/blender/bmesh/operators/bmo_dissolve.c b/source/blender/bmesh/operators/bmo_dissolve.c
index c0ce63fb0eb..efba0ec99ec 100644
--- a/source/blender/bmesh/operators/bmo_dissolve.c
+++ b/source/blender/bmesh/operators/bmo_dissolve.c
@@ -257,7 +257,7 @@ void bmo_dissolve_faces_exec(BMesh *bm, BMOperator *op)
     }
   }
 
-  BLI_assert(!BMO_error_occurred(bm));
+  BLI_assert(!BMO_error_occurred_at_level(bm, BMO_ERROR_FATAL));
 
   BMO_slot_buffer_from_enabled_flag(bm, op, op->slots_out, "region.out", BM_FACE, FACE_NEW);