node-source-map-support
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Node 12 "async" annotations are lost when using this package
Node 12 added some limited support for async stack traces. I'm impressed that this package supports them, but it removes a useful annotation from them:
Given this file:
function p() {
return new Promise(resolve => setTimeout(resolve, 0))
}
async function f() {
await p()
throw Error("")
}
async function main() {
await f()
}
main()
.catch(console.error)
The stack traces without registering source-map-support is:
Error
at f (/private/tmp/async-stack-traces/index.js:9:9)
at async main (/private/tmp/async-stack-traces/index.js:13:3)
With source-map-support registered is:
Error:
at f (/private/tmp/async-stack-traces/index.js:9:9)
at main (/private/tmp/async-stack-traces/index.js:13:3)
I think the async annotation there is useful, as this stack trace is not the actual one as seen by v8, but an augmented one. This augmentation doesn't always work, and it would be surprising to the user if they look like normal stack traces.
Can confirm, this is super confusing as I wasn't sure what was causing it and I wasn't sure if my stack traces were actually working. Several hours later I found this issue.
Would love a PR addressing this 🚀
To fix this, the implementation of CallSiteToString -- which is copy-pasted from V8 source code -- must be updated to match the latest V8 implementation.
https://github.com/v8/v8/blob/dc712da548c7fb433caed56af9a021d964952728/src/objects/stack-frame-info.cc#L344-L393