Design: Stage by Reference vs. Value

Git stages by value. It saves the state of the page at stage time, not commit time. Files can get into this rather odd state of being both staged and then changed after the stage.

Should pg_delta follow this? We need to think very carefully about the database getting into an inconsistent state so that what's committed cannot be checked back out. The general dependency checking should catch any inconsistent states, but that happens by analyzing the live database, not the staged values? Bears some consideration.