Stream: general

Topic: wizer and errors

Dan Kegel (Jul 20 2021 at 15:06):

What is the usual idiom for error handling in the wizer initialization function in go? panic() isn't supported, nor is os.Exit(1).

bjorn3 (Jul 20 2021 at 16:12):

I did assume a wasm trap would work. I can't find how to directly emit one in go. In rust it would be std::process::abort. You could try to read/write from the address 0xffff_ffff. Assuming that the go compiler doesn't exploit ub and you don't allocate 2^32-1 bytes of memory this will cause a trap due to accessing unmapped memory.

Dan Kegel (Jul 20 2021 at 17:09):

aha, compiling the go with tinygo --panic=trap should do it, thanks (though if we used panic for anything else, that might be annoying)

fitzgen (he/him) (Aug 02 2021 at 17:08):

In general, I would do something like (apologies for the pseudocode, I don't know go) this:

fn wizer_initialize() {
    if let Err(e) = try_init() {
        fprintf(stderr, "error: %s\n", e);
        abort();
    }
}

fn try_init() -> Result<(), Error> {
    ...
}

fitzgen (he/him) (Aug 02 2021 at 17:10):

using explicit fallibility with try_init should hopefully avoid configuring the build to do anything different with panics than you otherwise would, so it is hopefully minimally invasive

bjorn3 (Aug 02 2021 at 20:11):

I believe the problem was getting the abort() in go. I don't think go has any such function, so panic=trap is the only possible option I think.

fitzgen (he/him) (Aug 02 2021 at 22:35):

ah okay, that's a bummer. seems like it and/or a wasm trap intrinsic should really be added to go

Last updated: Dec 23 2024 at 12:05 UTC