[photon_garden]

Their code is more complex in some ways (for example, it’s verbose).

But in languages with exceptions, if you want to know how a function can fail, you have two options:

- Hope the documentation is correct (it isn’t)

- Read the body of the function and every function it calls

Reasonable people can disagree on the right approach here, but I know which I prefer.

[jmux]

> Hope the documentation is correct (it isn’t)

real

compared to every exception-based language I’ve used, rust error handling is a dream. my one complaint is async, but tbh I don’t think exceptions would fare much better since things like the actor model just don’t really support error propagation in any meaningful way

[vbezhenar]

Every function can fail with StackOverflowError and you can't do anything about it.

Almost every function can fail with OutOfMemoryError and you can't do anything about it.

I've accepted that everything can fail. Just write code and expect it to throw. Write programs and expect them to abort.

I don't understand this obsession with error values. I remember when C++ designers claimed, that exceptions provide faster code execution for happy path, so even for systems language they should be preferred. Go error handling is bad. Rust error handling is bad. C error handling is bad, but at least that's understandable.

[frumplestlatz]

This is silly. We can avoid stack overflow by avoiding unbounded recursion.

In user-space, memory overcommit means that we will almost or literally never see an out of memory error.

In kernel space and other constrained environments, we can simply check for allocation, failure and handle it accordingly.

This is a terrible argument for treating all code as potentially failing with any possible error condition.

[whatevaa]

Rust and GO has panics for these. Most of the time there is nothing application can do by itself, either there is a bug in application or there is actually shortage of memory and only the OS can do anything about it.

I'm not talking about embedded or kernels. Different stories.

[malkia]

^^^ - This - my recent one, came to the realization that dealing with memory mapped files is much harder without exceptions (not that exceptions make it easier, but at least possible).

Why? Let's say you've opened a memory mapped file, you've got pointer, and hand this pointer down to some library - "Here work there" - the library thinks - oh, it's normal memory - fine! And then - physical block error happens (whether it's Windows, OSX, Linux, etc.) - and now you have to handle this from... a rather large distance - where "error code" handling is not enough - and you have to use signal handling with SIGxxx or Windows SEH handling, or whatever the OS provides

And then you have languages like GoLang/Rust/others where this is a pain point (yes you can handle it), but how well?

If you look in ReactOS the code is full with `__try/__except` - https://github.com/search?q=repo%3Areactos%2Freactos+_SEH2_T... - because user provided memory HAVE to be checked - you don't want exception happening at the kernel reading bad user memory.

So it's all good and fine, until you have to face this problem... Or decide to not use mmap files (is this even possible?).

Okay, I know it's just a silly little thing I'm pointing here - but I don't know of any good solution off hand...

And even handling this in C/C++ with all SEH capabilities - it still sucks...

[tialaramex]

> Every function can fail with StackOverflowError and you can't do anything about it.

> Almost every function can fail with OutOfMemoryError and you can't do anything about it.

In fact we can - though rarely do - prove software does not have either of these mistakes. We can bound stack usage via analysis, we usually don't but it's possible.

And avoiding OOM is such a widespread concern that Rust-for-Linux deliberately makes all allocating calls explicitly fallible or offers strategies like Vec::push_within_capacity a method which, if it succeeds pushes the object into the collection, but, if it's full rather than allocate (which might fail) it gives back the object - no, you take it.

[malkia]

Or have checked exceptions (Java). Granted this comes with big downer... If you need to extend functionality and new (updated) code has to throw new exception, your method signature changes :(

But the best so far method I know.

[baq]

Checked exceptions are not very different from the Result type in that regard TBH.

[cwillu]

And with error values, you also need to hope the documentation for what the error means is correct (it isn't), and read the body of the function and every function it calls to see where the error value actually came from and what it actually means. It's the same problem, but you get to solve a bonus logic puzzle trying to figure out where the error came from.

[nromiun]

Or catch the top level function and see every exception in your project? Tell me which language does not have a top level main function?

[zaphar]

This is the "I don't care what fails nor do I wish to handle them" option. Which for some use cases may be fine. It does mean that you don't know what kinds of failures are happening nor what the proper response to them is, though. Like it or not errors are part of your domain and properly modeling them as best you can is a part of the job. Catching at the top level still means some percentage of you users are experiencing a really bad day because you didn't know that error could happen. Error modeling reduces that at the expense of developer time.

[johannes1234321]

Even better: just let it crash an get a core dump with full context information rather than some log missing information.

But often some "expected" errors can be handled in some way better (retry, ask user, use alternate approach, ...)