Comment by foldr

Comment by foldr 9 days ago

13 replies

Any language where errors are returned as values will allow you to ignore errors (if you don’t have proper linting set up, and unless it has something fancy like linear types). I’ve even seen a similar error in Haskell code, where someone called an isLoggedIn function inside a monad with the expectation that it would short-circuit evaluation, whereas in fact it just retuned a Bool.

thinkharderdev 9 days ago

Very true, but I do think there is an issue in the margin about how easy it is to ignore errors. For example, in Java you might have something like

``` void checkPermissions() throws AuthException ```

so you have to actively ignore errors by catching the exception. Likewise in Rust you can do

``` fn check_permissions() -> Result<(),AuthError> ```

In that case you can just use the `?` operator to short-circuit (and clippy will warn you if your forget to do that).

In other words, while language design can't fully prevent you from ignoring precondition checks, it can make it harder to forget or even force you to actively ignore precondition failures

  • randomdata 9 days ago

    But isn't the idiomatic Go solution something like this?

        func checkPermissions(success func())
    
    Like anything, you can still screw it up if you try hard enough, but it should nudge most in the right direction. The talk of error handling seems like a distraction or a case of someone confusingly trying to write code in another language using Go syntax.

    Obviously you are not forced to think of the user when designing an API, but you don't have to be mindful of the user in any language. Not even Haskell can save a developer who doesn't care, as noted in an earlier comment.

  • foldr 9 days ago

    Go linters do a pretty good job of spotting where error return values have been ignored, so I'd suggest that the kind of bug the OP is referring to is pretty unlikely to happen in a Go project that's properly configured.

    • Smaug123 9 days ago

      Sure - my question is "why do you need to set up the third party linters when they're so critical to the correctness of your program" really. It's the general "yeah we'll give you these footguns which are the first thing every developer will learn about during their first incident; good luck, and I hope you know you need to do things this way!" attitude I object to.

      • randomdata 8 days ago

        > my question is "why do you need to set up the third party linters when they're so critical to the correctness of your program" really.

        No doubt the same reason it is also critical in Haskell (see comment about isLoggedIn function): Developers not knowing what they are doing.

        If you work within the idioms and generally accepted programming practices this isn't a problem. It only becomes a problem when you get a developer who wants to "go their own way" without understanding why the norms exist. The linter is a crutch to support their "bad habits".

      • foldr 8 days ago

        There’s no simple solution when it comes to ignoring errors. Some errors should be ignored and some shouldn’t. So your only lines of defense are linting heuristics and tests.

        I would agree that languages which handle errors via exceptions have an advantage here, as they make not ignoring errors the default behavior. But even then, it’s obviously still possible to indicate error conditions of various kinds via return values, in which case they can still be ignored thoughtlessly. (And you also have all the bugs caused by unhandled exceptions to deal with.)

      • [removed] 8 days ago
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