dns lookup upgraded in 1.6 incorrectly attempts to resolve address in case of an error from the lookup callback

[pveller]

Describe the bug

TL;DR: if you supply custom DNS lookup in 1.6+ and it fails with ENOTFOUND, axios throws TypeError: address must be a string instead

I supply custom DNS lookup to precisely control the timeout. I am using https://github.com/szmarczak/cacheable-lookup. It works correctly in axios before 1.6 but fails after because of this change:

When the callback returns the err as the first argument, the other two can be (and are) undefined. Axios 1.6+ attempts to resolve family and address regardless of err and trips over undefined.

Take a look:

To Reproduce

Perform axios request against a domain that does not exists with a custom lookup. DNS lookup fails with ENOTFOUND but axios then fails with TypeError: address must be a string

Code snippet

// simplified test:


import CacheableLookup from 'cacheable-lookup';
import axios from 'axios';

const dns = new CacheableLookup({ resolver: new Resolver({ timeout: 200 }), maxTtl: 60 * 60, lookup: false });
const controller = new AbortController();

await axios.post('https://no-such-domain-987654.com', {}, {
  signal: controller.signal,
  lookup: dns.lookup.bind(dns),
});

Expected behavior

axios should fail with the DNS lookup error, not the TypeError

Axios Version

1.6+

Adapter Version

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Browser

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Browser Version

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Node.js Version

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OS

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Additional Library Versions

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Additional context/Screenshots

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