When a phase has no rows to return (they're all dropped), this was causing no CSV to save, and a confusing error trying to load the CSV for the next phase. This makes the error more explicit, and also makes sure that errors AROUND the running of the phase are not swallowed up by the error handling for actually running the phase.
When a phase has no rows to return (they're all dropped), this was causing no CSV to save, and a confusing error trying to load the CSV for the next phase. This makes the error more explicit, and also makes sure that errors AROUND the running of the phase are not swallowed up by the error handling for actually running the phase.