The absolute horror of watching someone blindly trust your code.
A couple of weeks ago, I helped build a cute little Excel function that finds + highlights duplicate entries. Any entry that matches both the part number and the order number of any other entry gets highlighted. The idea was that a human being would then READ those entries, compare them to the customer purchase order, and delete any that weren’t meant to be there.
So you can imagine my horror when I found out that data entry had decided to just paste in the new batch of orders, and DELETE any that popped up red. In the spreadsheet containing ALL FABRICATION ORDERS FOR THE ENTIRE FACILITY. WITHOUT READING THEM.
On the one hand, the code does work for 99.5% of orders. There is a very good chance that this is absolutely fine. But on the other hand, I have seen orders that, for whatever bizarre reason, come in as:
part X - qty 1
part X (again) - qty 2
and when I check the other system, they actually do want three.
Second complicating factor: this is a Google Sheet that many people have access to, with absolutely no protected cells or data validation. AnyONE can type anyTHING virtually anyWHERE. There is no way to fully predict what input my poor little function might encounter, or how it will handle it.
I am now very worried that this code could break at any moment, or has already broken, and I will have no idea because the data that caused the bug has been deleted.