dns.lookup() documentation error code

[nfearnley]

• Version: v11.15.0
• Platform: N/A
• Subsystem: N/A

The nodejs documentation for dns.lookup() seems to imply that the error will ENOENT, if a domain is not found. Should this be ENOTFOUND instead?

https://nodejs.org/docs/latest-v11.x/api/dns.html#dns_dns_lookup_hostname_options_callback

"On error, err is an Error object, where err.code is the error code. Keep in mind that err.code will be set to 'ENOENT' not only when the hostname does not exist but also when the lookup fails in other ways such as no available file descriptors."

[Trott]

I'm certainly getting ENOTFOUND locally when dns.lookup() fails to find an address. And it's also what I get for valid names if I set ulimit -n sufficiently low. So it sure seems to be the case that ENOTFOUND might sometimes mean "no available file descriptors" (or at least something that isn't actually "address not found") in this case, which is really unfortunate IMO. EDIT: I'm on macOS, just in case this is platform-dependent behavior.

[sagitsofan]

It seems that dns.lookup() will always return ENOTFOUND on a empty lookup or when the host not found.
https://github.com/nodejs/node/blob/master/lib/internal/errors.js#L503
Should we change the error code or fixed the documentation?

[Trott]

Fixed in fd8d5e7