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0 pointsZambyte10mo ago0 comments

> It doesn't look to be too much of a temptation to use panics as regular errors in Rust though

Maybe not, but it was enough for the author to dedicate at least one whole section of the article to reasoning about this.

> like when you want to show an error box to the user, instead of silently crashing, or when you want to send the crash log for later analysis

As I mentioned, panics can be handled but not recovered. You can use the panic handler to do these things just fine. Just not recover.

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littlestymaar10mo ago

> As I mentioned, panics can be handled but not recovered. You can use the panic handler to do these things just fine. Just not recover.

What does this difference mean? If you can run arbitrary function in your panic handler, what prevents someone from continuing the program?

ZambyteOP10mo ago

The stack is fully unwound before running the panic function, including the main stack frame. This will run all deferred deallocation statements, and pretty much leave you with nothing to do but exit. You could try to launch the program again automatically, but there is little reason to do that most likely. The user will still see the application terminate and launch again.

jvanderbot10mo ago

I've never heard of anyone using panic for exception-style recovery. That's anathema to the whole idea of Result<T,V>. But I suppose if it's possible, it will be normal for someone.

ZambyteOP10mo ago

I'm not as familiar with the Rust ecosystem, but I know it is used all the time in Go. For example, the standard http server library wraps user provided endpoint handler functions with panic handlers.

dhruvrajvanshi10mo ago

I suppose it's a matter of perspective but I don't see returning a 500 as "Recovering from the error". The user's request has still failed. It just hasn't taken down the server. IMO this is still fine.

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nicoburns10mo ago

Is that used for application-level errors though? Rust web servers do that too, but it is used a fallback to avoid bringing down the whole server due to an unexpected crash. It is not a mechanism you would use intentionally.

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0 pointsZambyte10mo ago0 comments

> It doesn't look to be too much of a temptation to use panics as regular errors in Rust though

Maybe not, but it was enough for the author to dedicate at least one whole section of the article to reasoning about this.

> like when you want to show an error box to the user, instead of silently crashing, or when you want to send the crash log for later analysis

As I mentioned, panics can be handled but not recovered. You can use the panic handler to do these things just fine. Just not recover.

0 comments

littlestymaar10mo ago

> As I mentioned, panics can be handled but not recovered. You can use the panic handler to do these things just fine. Just not recover.

What does this difference mean? If you can run arbitrary function in your panic handler, what prevents someone from continuing the program?

ZambyteOP10mo ago

jvanderbot10mo ago

I've never heard of anyone using panic for exception-style recovery. That's anathema to the whole idea of Result<T,V>. But I suppose if it's possible, it will be normal for someone.

ZambyteOP10mo ago

dhruvrajvanshi10mo ago

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nicoburns10mo ago

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