Cancelled context error not propagated in net/cgo_unix.go
Paul Ruane
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Ian Lance Taylor
>
> I hit a problem today whereby a gRPC call did not come back with a status of cancelled, despite the request context being cancelled.
>
> Tracing it through I found that it was because of a failed DNS lookup and that the DNS code does not propagate the context cancelled error. I was wondering if there was a particular reason for this?
>
> In the code at these locations (at least), the `context.Canceled` error is mapped to a `net.CanceledError` (which has unwrap semantics), but is then promptly converted to a string:
>
> • https://github.com/golang/go/blob/2ee775fd9b58247618cf8bc06935f33875bdc872/src/net/cgo_unix.go#L52
> • https://github.com/golang/go/blob/2ee775fd9b58247618cf8bc06935f33875bdc872/src/net/cgo_unix.go#L82
>
> The struct `DNSError` does actually have a field called `UnwrapErr`, but it does not get populated in these cases. I was going to raise an issue but thought I would check here first.
led to https://go.dev/issue/63116. I think you've found a bug in the
code that addressed those issues (https://go.dev/cl/532217). Please
open a new issue. Thanks.
Ian