I am not going to comment the first paragraph since you turned my words around.
> How do you even come up with this? Do you write your code in such a way that any time it pulls a value from a dictionary, you iterate over the dictionary keys to make sure that they are unique?
A dictionary in my program is under my control and I can be sure that the key is unique since... well, I know it's a dictionary. I have no such knowledge about data coming from external systems.
> There are plenty of things that are meant to be unique by design. The function in question wasn't meant to check if the points were unique. For all we know, the function might have been designed to take a map and the data was lost even before this function started processing it...
"Meant to be" and "actually are" can be very different things, and it's the responsibility of a programmer to establish the difference, or to at least ask pointed questions. Actually, the programmers did the correct thing by not sweeping this unexpected problem under the rug. The reaction was just a big drastic, and the system did not make it easy for the operators to find out what went wrong.
Edit: as we have seen, input can be valid, but still not be processable by our code. That not fine, but it's a fact of life since specs are often unclear or incomplete. Also, the rules can actually change without us noticing. In these cases, we should make it as easy as possible to figure out what went wrong.
> How do you even come up with this? Do you write your code in such a way that any time it pulls a value from a dictionary, you iterate over the dictionary keys to make sure that they are unique?
A dictionary in my program is under my control and I can be sure that the key is unique since... well, I know it's a dictionary. I have no such knowledge about data coming from external systems.
> There are plenty of things that are meant to be unique by design. The function in question wasn't meant to check if the points were unique. For all we know, the function might have been designed to take a map and the data was lost even before this function started processing it...
"Meant to be" and "actually are" can be very different things, and it's the responsibility of a programmer to establish the difference, or to at least ask pointed questions. Actually, the programmers did the correct thing by not sweeping this unexpected problem under the rug. The reaction was just a big drastic, and the system did not make it easy for the operators to find out what went wrong.
Edit: as we have seen, input can be valid, but still not be processable by our code. That not fine, but it's a fact of life since specs are often unclear or incomplete. Also, the rules can actually change without us noticing. In these cases, we should make it as easy as possible to figure out what went wrong.