Traceback with DNS & IPv6

[Mikaela]

I was told to report this at IRC.

I have written this script https://github.com/Mikaela/scripts/blob/gh-pages/nodejs/myip.js . When only the first part is uncommented, it runs and returns my IPv4 address.

However when I uncomment the IPv6 part too it tracebacks immediately when ran.

% ./myip.js  
node: ../deps/cares/src/ares_destroy.c:102: ares__destroy_servers_state: Assertion `ares__is_list_empty(&server->queries_to_server)' failed.
zsh: abort (core dumped)  ./myip.js

The related section of code is:

// This code makes node codedump for some reason, maybe it has a bug
// with IPv6 handling or it doesn't like my system not having native
// or not-Teredo IPv6 connectivity.

// node: ../deps/cares/src/ares_destroy.c:102: ares__destroy_servers_state: Assertion `ares__is_list_empty(&server->queries_to_server)' failed.
// zsh: abort (core dumped)  ./myip.js

// Set DNS servers to OpenDNS IPv6
var servers6 = dns.setServers(["2620:0:ccc::2", "2620:0:ccd::2"])

// Check where myip.opendns.com resolves to and I think this is a function
// that takes arguments err and addresses.
dns.resolve6('myip.opendns.com', function (err, addresses) {

    // if err contains a truthy value, an error has occurred
    if (err) throw err;

    // Print the first thing in array addresses as it has our IPv4
    // address.
    console.log(addresses[0]);
});

I am running v4.1.1 on Arch Linux and installed from Arch Linux repositories.

Edit: }); had dropped from my copy-paste in the end.

[Mikaela]

IRC now also suggested that this might be duplicate of #894, but didn't seem to be fully sure.

[silverwind]

Yes, looks like #894 to me. You're calling setServers with an in-flight request, which triggers the crash.

[Mikaela]

Closing as duplicate of #894.

[dzek69]

Just a note for people coming from Google search: This is fixed with 9.3.0 version and fix seems to be backported to 8.10.0 too.

I monkey patched dns module to fix that - if anyone needs to keep unpatched Node version and doesn't want the crashes - please use my fix.
More information here: https://github.com/dzek69/node-dns-bugfix