From eaa4856972a6d9a4ae83f0887bc50d118b9e34f5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Jos=C3=A9=20Valim?= <jose.valim@dashbit.co>
Date: Tue, 31 Jan 2023 09:33:29 +0100
Subject: [PATCH] Support finding epmd wit ipv6

---
 lib/livebook/application.ex | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/lib/livebook/application.ex b/lib/livebook/application.ex
index 08fb13049..bea534bd7 100644
--- a/lib/livebook/application.ex
+++ b/lib/livebook/application.ex
@@ -124,7 +124,15 @@ defmodule Livebook.Application do
     unless Livebook.Config.longname() do
       [nodename, hostname] = node() |> Atom.to_charlist() |> :string.split(~c"@")
 
-      with {:ok, nodenames} <- :erl_epmd.names(hostname),
+      # erl_epmd names do not support ipv6 resolution by default,
+      # unless inet6 is configured, so we attempt both.
+      gethostbyname =
+        with {:error, _} <- :inet.gethostbyname(hostname, :inet, :infinity),
+             {:error, _} <- :inet.gethostbyname(hostname, :inet6, :infinity),
+             do: :error
+
+      with {:ok, hostent(h_addr_list: [epmd_addr | _])} <- gethostbyname,
+           {:ok, nodenames} <- :erl_epmd.names(epmd_addr),
            true <- List.keymember?(nodenames, nodename, 0) do
         :ok
       else