Model-driven software product lines evolve in both time and space. Consistency control for model versions constitutes a key challenge. We propose a novel approach to consistency control called well-formedness analysis and repair: Instead of attempting to guarantee consistency of each configurable version a priori (which is hard and restrictive), consistency is controlled only when a product version is actually configured. Conflicts, i.e., violation of well-formedness constraints, are detected and repaired, driven by configurable strategies. This approach is generic; it is instantiated for feature models (for the variability model) and EMF models (as domain artifacts).