Spec UDPSocket :: using IPv4 hangs on Alpine Linux

[jirutka]

I wanted to upgrade Alpine package for Crystal from 0.31.1 to 0.32.1. It builds fine, but the specs always hang on:

...
UDPSocket
  using IPv4
    #bind
    sends and receives messages
    joins and transmits to multicast groups

I’ve tried to apply patch #8559, that looks like related, but it didn’t help.

---

• Crystal 0.32.1
• Alpine Linux Edge
• x86_64

[rdp]

specs work on 0.31.1?

[RX14]

This has been broken for many releases on my personal arch machine as well. I think it's just to do with the network environment... Perhaps because I have a firewall.

[rdp]

PR welcome, once you figure it out! In general I kind of wish that one hanging spec couldn't hang the entire suite, as well, but maybe that's future work :)

[j8r]

@jirutka do you need any help?
I tested on my side, it works. As said above, it is an issue related to the environment where the tests are running.
Ensure that this commands are working on the environment:

nc -w1 -vl 127.0.0.1  # TCP IPv4
nc -w1 -vl ::1        # TCP IPv6
nc -w1 -uvl 127.0.0.1 # UDP IPv4
nc -w1 -uvl ::1       # UDP IPv6

There is an issue if you see nc: can't connect to remote host: Address not available for one of the above command.

[kimburgess]

The same issue is appearing on NixOS, both on my local machine and the OfBorg environment (see https://github.com/NixOS/nixpkgs/pull/75545/checks?check_run_id=397696851)

[straight-shoota]

This spec seems to be working consistently in CI (running on Alpine linux).

I think we can close this (reopen with new evidence).