Some async code doesn't produce stack trace on error

[dhbaird]

What version of Bun is running?

0.5.9

What platform is your computer?

Linux

What steps can reproduce the bug?

async function aBroken() {
}

async function bBroken() {
    await aBroken();
    throw new Error("Oops"); // <-- no stack trace for this throw
}

async function cBroken() {
    await bBroken();
}

async function aOkay() {
}

async function bOkay() {
    throw new Error("Oops");
    await aOkay();
}

async function cOkay() {
    await bOkay();
}

async function main() {
    try {
        await cBroken();
    }
    catch (e) {
        console.log(e);

        // >>>(bun)
        // 1 | async function aBroken() {
        // 2 | }
        // 3 | 
        // 4 | async function bBroken() {
        // 5 |     await aBroken();
        // 6 |     throw new Error("Oops");
        //               ^
        // error: Oops
        //       at /.../throwy.ts:6:10

        // >>>(node)
        // Error: Oops
        //     at bBroken (/.../throwy.js:6:11)
        //     at async cBroken (/.../throwy.js:10:5)
        //     at async main (/.../throwy.js:27:9)
    }
    try {
        await cOkay();
    }
    catch (e) {
        console.log(e);
        // 
        // >>>(bun)
        // 12 | 
        // 13 | async function aOkay() {
        // 14 | }
        // 15 | 
        // 16 | async function bOkay() {
        // 17 |     throw new Error("Oops");
        //               ^
        // error: Oops
        //       at /.../throwy.ts:17:10
        //       at bOkay (/.../throwy.ts:16:20)
        //       at /.../throwy.ts:22:10
        //       at cOkay (/.../throwy.ts:21:20)
        //       at /.../throwy.ts:50:14

        // >>>(node)
        // Error: Oops
        //     at bOkay (/.../throwy.js:17:11)
        //     at cOkay (/.../throwy.js:22:11)
        //     at main (/.../throwy.js:50:15)
    }
}

main();

What is the expected behavior?

Expect stack trace for the first case.

What do you see instead?

Stack trace is missing.

        // error: Oops
        //       at /.../throwy.ts:6:10

Additional information

Thanks!! :) (Thought that maybe this should be a feature - but the bug reporting template was more useful, so I picked that.)

[ayonli]

It seems this is a JavaScriptCode bug, if the function is async, JSC cannot produce the full stack trace.

For example:

async function foo() {
    await Promise.resolve(null);
    throw new Error("something went wrong");
}

async function bar() {
    await foo();
}

(async () => {
    try {
        await bar();
    } catch (err) {
        console.log(err);
    }
})();

In Bun, it logs like this:

1 | async function foo() {
2 |     await Promise.resolve(null);
3 |     throw new Error("something went wrong");
              ^
error: something went wrong
      at /Users/ayon/Workspace/try-out/log.js:3:10

And in Safari (Console Snippets), it logs like this:

Error: something went wrong
(anonymous function)

The stack trace of the async functions are all lost.

[lsnow99]

It seems this is a JavaScriptCode bug, if the function is async, JSC cannot produce the full stack trace.

This is a significant annoyance for my application that runs using Bun. I assume this is a pretty deep issue seeing as it comes from JSC, but if someone could point towards a potential fix I'd like to help work on/support this feature. If it seems intractable due to structural reasons in JSC, that's also helpful to know and I can just workaround by adding more try/catches in userspace.

[AlbertMarashi]

+1 pretty annoying

[arthurvanl]

+1

[Jarred-Sumner]

Here is an attempt at helping with this #11948. I don't think we will end up merging that PR though

This is something that will need to be addressed in JavaScriptCore. The TLDR is: promises don't have a way of propagating exceptions from a parent promise.