Cleanup/refactor: UndoType: Clarify `use_context` variable.

Rename it to mark it is only for `encode` callbacks, fix `encode`
callback of text undo to early fail in case it gets a NULL context, add
an assert to `BKE_undosys_step_push_with_type` that context is not NULL
when undotype requires a valid one.

Note that in practice this should not change anything, currently it
seems that we always get a valid context in
`BKE_undosys_step_push_with_type`?

1 files changed, 2 insertions, 0 deletions

diff --git a/source/blender/blenkernel/intern/undo_system.c b/source/blender/blenkernel/intern/undo_system.c
index 078c93532d9..0713a2d6729 100644
--- a/source/blender/blenkernel/intern/undo_system.c
+++ b/source/blender/blenkernel/intern/undo_system.c
@@ -501,6 +501,8 @@ UndoPushReturn BKE_undosys_step_push_with_type(UndoStack *ustack,
                                                const char *name,
                                                const UndoType *ut)
 {
+  BLI_assert(ut->use_context_for_encode == false || C != NULL);
+
   UNDO_NESTED_ASSERT(false);
   undosys_stack_validate(ustack, false);
   bool is_not_empty = ustack->step_active != NULL;