When importing/overlaying patrons, if you have any blank columns in the csv, any existing data in a patron record is cleared. There should be an option as to whether or not you intend to clear the data using blank columns or not. To recreate: 1. Create patron with several items of data, such as address, city, phone. 2. Create a csv with username, address, and a blank column for phone 3. Import patron file, using the overwrite function 4. See that the phone info is now blank in the patron record.
I think this would be more suitable as an enhancement. The current behaviour that an empty cells means "reset" I think is ok and needed that way. But maybe we could add a checkbox to the list of default options saying to keep the existing value when empty in import?
Re-reading this again, I believe the bug description doesn't quite fit. I think the described behaviour is correct, because we need a way to reset/empty out fields. If the other behavior is still desirable, we should change it to read more as an alternative. But I can't come up with something right now :(
We do now have the option to select fields in the patron record that will be protected from being overwritten: "Selected fields will be preserved from original patron record when overwriting existing patron."