My old boss loved VB.Net. I still remember a time when I helped him out by solving mysterious bug for him.
He used to have this class he copied about to do database stuff. Not the worst thing of itself, but it was oddly specific in some ways for reused code. E.g. It had a function that took an enum value and returned connection string. And of course what options were in the enum varied.
So I come in one day and two other devs are already peering over his shoulder trying to help. The program is crashing when it tries to connect to the database and they can see for some reason the connection string is a single letter. I ask to see the function that is getting the connection string and see he’s removed the parameter, but the compiler didn’t pick up on it because:
VB.net lets you call functions that have no parameters without parentheses
VB.net is type lax, so an enum can be treated as an integer without casting
VB.net uses parentheses for array indexation as well as method invokation
.Net strings can be indexed like an array of characters
VB has no character type so VB.net treat characters as 1-length strings
So instead of passing an enum to a function, it was calling the function with no parameter, then using the enum value to index the returned string into a single character, which was then treated as a string and passed to the SqlClient constructor.
My old boss loved VB.Net. I still remember a time when I helped him out by solving mysterious bug for him.
He used to have this class he copied about to do database stuff. Not the worst thing of itself, but it was oddly specific in some ways for reused code. E.g. It had a function that took an enum value and returned connection string. And of course what options were in the enum varied.
So I come in one day and two other devs are already peering over his shoulder trying to help. The program is crashing when it tries to connect to the database and they can see for some reason the connection string is a single letter. I ask to see the function that is getting the connection string and see he’s removed the parameter, but the compiler didn’t pick up on it because:
So instead of passing an enum to a function, it was calling the function with no parameter, then using the enum value to index the returned string into a single character, which was then treated as a string and passed to the SqlClient constructor.
I saw something similar in ancient code I found while refactoring some stuff. It’s between genius and maniac.