void (@NotNull UndoManagerImpl undoManager, @NotNull Document document) { if (undoManager.isActive() && isUndoable(undoManager, document) && undoManager.isUndoOrRedoInProgress() && document.getUserData(UNDOING_EDITOR_CHANGE) != Boolean.TRUE) { throw new IllegalStateException("Do not change documents during undo as it will break undo sequence."); } }