Panic when formatting Value outside of virtual machines #747
Comments
VorpalBlade
changed the title
Result wrapped in rune ValueResult wrapped in rune Value
|
Before I switched from log to tracing for my project I would get this when attempting to unwrap the returned result in my user code. I came up with this monstrosity as a workaround. But this doesn't help now that it crashes internally in tracing. /// Attempt to format the error in the best way possible.
///
/// Unfortunately this is awkward with dynamic Rune values.
fn try_format_error(phase: Phase, e: &rune::Value) -> anyhow::Result<()> {
match e.clone().into_any() {
rune::runtime::VmResult::Ok(any) => {
match any.clone().downcast_into_ref::<anyhow::Error>() {
Ok(err) => {
anyhow::bail!("Got error result from {phase}: {:?}", *err);
}
Err(err) => {
let ty = try_get_type_info(e, "error");
anyhow::bail!(
"Got error result from {phase}, but it was not an anyhow error: {err:?}, type info: {ty}: {any:?}",
);
}
}
}
rune::runtime::VmResult::Err(not_any) => {
tracing::error!("Got error result from {phase}, it was not an Any: {not_any:?}. Trying other approches at printing the error.");
}
}
// Attempt to format the error
let formatted = catch_unwind(AssertUnwindSafe(|| {
format!("Got error result from {phase}: {e:?}")
}));
match formatted {
Ok(str) => anyhow::bail!(str),
Err(_) => {
let ty = try_get_type_info(e, "error");
anyhow::bail!(
"Got error result from {phase}, but got a panic while attempting to format said error for printing, {ty}",
);
}
}
}
/// Best effort attempt at gettint the type info and printing it
fn try_get_type_info(e: &rune::Value, what: &str) -> String {
match e.type_info() {
rune::runtime::VmResult::Ok(ty) => format!("type info for {what}: {ty:?}"),
rune::runtime::VmResult::Err(err) => {
format!("failed getting type info for {what}: {err:?}")
}
}
} |
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Well, For some reason we've also opted to instrument the return value here. This is not correct and should be removed since formatting might fail. It is convenient for |
My understanding is that std::fmt::Error is for when the formatting itself fails. And the Rust standard library will in fact panic in So if I understand you correctly and it error when printing an error (as opposed when to the formatting fails) this seems incorrect and like a misunderstanding. |
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Yeah, we should fix it. |
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I'll make a PR later today |
This ensures that we don't get an error on formatting a value without a debug protocol. (fixes rune-rs#747)
This ensures that we don't get an error on formatting a value without a debug protocol. Instead attempt to print *something* (fixes #747)
udoprog
changed the title
Result wrapped in rune Value
Given the following example code (full reproducer project attached as tar.gz below):
reproduce
we get the following panic while running it
Example project triggering this: rune_fmt_panic.tar.gz
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