Where Everything Went Wrong: Error Handling and Error Messages in Rust (2020)

Re:Where Everything Went Wrong: Error Handling and Error Mes... by kelnos on Friday February 19, 2021 @04:56PM (#26198538)

IMO exceptions are a terrible way to signal errors. They obscure control flow and make it much harder to reason about a program's behavior. They make it easy to forget to check for errors, and encourage sloppy catch-all error handling. It is a lot harder to determine if exception-based code is correct or not, and languages that have exceptions require you to examine literally every line of code to determine if it can throw.

Even the name is wrong: an "exception" should signal truly exceptional behavior, things that you would not expect to happen unless something is really wrong. And yet exceptions are thrown for mundane things like "file not found", something you could very easily expect to happen routinely.

Exceptions should be like Rust's `panic!()`: only for things that the programmer can't reasonably do anything about, which will cause the program to terminate.

[ Parent | on HN ]

Re:Where Everything Went Wrong: Error Handling and Error Mes... by dataflow on Friday February 19, 2021 @05:02PM (#26198607)

I don't agree with your first or third paragraphs but I do kind of agree with the second, yet I think the solution to that is to provide return-value-based solutions where it makes sense, not to avoid exceptions in general.

Also, things like "user canceled this operation" are great for exceptions IMO... exactly how would you stop (say) a sort() function otherwise? You'd need to write a custom cancelable sort, which isn't a great idea? You can't reinvent the wheel for everything.

[ Parent | on HN ]