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by the_gipsy 1274 days ago
That's a very specific case, that could be handled non-trivially.

Usually your HTTP framework will already have this implemented, i.e. a panic in a request handler will be "caught", converted to some 500 response, and should not affect other requests.
1 comments
groestl 1274 days ago
My point is that this is in no way different from any other class of errors, _except_ in those cases where it is. It's practical to assume all errors are handled like this, because this catch all needs to exist anyway. And unless you have _very specific needs_, this can be automated.
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the_gipsy 1273 days ago
I think conflating these two into one paradigm is worse. The catch-all (exceptions) style is nice only for a few very specific cases, like the request handler example. Everywhere else I want to either bubble up (like exceptions, but Result<> and ? sugar is as good or better), OR I want to handle the error. For the latter case, exceptions are not good at all.
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groestl 1273 days ago
IMHO, quite often when you're tempted to handle an error, you're either wrong to do so, or in some kind of infrastructure glue code. A request handler, a task executor, a strategy chain, a retry loop, you name it. And this code needs to deal with both classes of errors anyway to be bugfree.
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the_gipsy 1273 days ago
From those examples, I think only request and task should deal with panics. Things that start threads or processes.

Other points of "catch all errors" don't need that. And then there are a lot of places where you do handle errors, if they are conceptually a Result. I know you can just catch SpecificError, but the ergonomics are just horrible in terms of control flow.

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groestl 1273 days ago
I don't think threading is relevant to this.

> there are a lot of places where you do handle errors, if they are conceptually a Result

Yet, what's conceptually a result lies in the eye of the beholder, and should not be dictated by an API designer IMHO. Rust's ? is a step in the right direction, but I'd argue since you care about specific errors in maybe 0.1% of invocations tops (in production code), and that's a stretch, the ? should actually work the other way round. And if the mechanism does not provide a way to select specific errors (such as a proper catch clause) the errors it exposes as a result should include runtime errors as well.

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