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, 5 insertions, 1 deletions

diff --git a/source/blender/blenkernel/BKE_undo_system.h b/source/blender/blenkernel/BKE_undo_system.h
index fff6c73fafa..9af4c07a4dc 100644
--- a/source/blender/blenkernel/BKE_undo_system.h
+++ b/source/blender/blenkernel/BKE_undo_system.h
@@ -140,7 +140,11 @@ typedef struct UndoType {
                               UndoTypeForEachIDRefFn foreach_ID_ref_fn,
                               void *user_data);
 
-  bool use_context;
+  /**
+   * This undo type `encode` callback needs a valid context, it will fail otherwise.
+   * \note Callback is still supposed to properly deal with a NULL context pointer.
+   */
+  bool use_context_for_encode;
 
   /**
    * The size of the undo struct 'inherited' from #UndoStep for that specific type. Used for