Crash when reference-style links are used more than once

[carlsmedstad]

Hey 👋

We get a crash when using reference-style links and referring to a link more than once, for example like this:

Lorem ipsum [my link][].

Lorem ipsum [my link][].

[my link]: www.someurl.com

This is the stack trace:

/usr/local/lib/node_modules/markdown-link-check/node_modules/async/dist/async.js:324
            if (fn === null) throw new Error("Callback was already called.");
                             ^

Error: Callback was already called.
    at /usr/local/lib/node_modules/markdown-link-check/node_modules/async/dist/async.js:324:36
    at /usr/local/lib/node_modules/markdown-link-check/node_modules/async/dist/async.js:248:17
    at /usr/local/lib/node_modules/markdown-link-check/index.js:129:13
    at /usr/local/lib/node_modules/markdown-link-check/node_modules/link-check/lib/proto/http.js:117:21
    at done (/usr/local/lib/node_modules/markdown-link-check/node_modules/needle/lib/needle.js:463:14)
    at ClientRequest.<anonymous> (/usr/local/lib/node_modules/markdown-link-check/node_modules/needle/lib/needle.js:547:16)
    at Object.onceWrapper (node:events:628:26)
    at ClientRequest.emit (node:events:513:28)
    at HTTPParser.parserOnIncomingClient [as onIncoming] (node:_http_client:688:27)
    at HTTPParser.parserOnHeadersComplete (node:_http_common:117:17)

I'm only able to reproduce this with version 3.10.3 on Alpine (3.17 specifically), the same version does not produce a crash on Arch. Downgrading to version 3.10.2 seems to mitigate the issue.

Thanks!