From a6afdbb70bad2c8c400de8288155f8cb325cadd6 Mon Sep 17 00:00:00 2001
From: Michael Weiss <dev.primeos@gmail.com>
Date: Wed, 3 Jun 2020 15:12:21 +0200
Subject: [PATCH] nixos: Allow empty hostnames again
This fixes a regression from 993baa587c4 which requires
networking.hostName to be a valid DNS label [0].
Unfortunately we missed the fact that the hostnames may also be empty,
if the user wants to obtain it from a DHCP server. This is even required
by a few modules/images (e.g. Amazon EC2, Azure, and Google Compute).
[0]: https://github.com/NixOS/nixpkgs/pull/76542#issuecomment-638138666
---
nixos/modules/tasks/network-interfaces.nix | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/nixos/modules/tasks/network-interfaces.nix b/nixos/modules/tasks/network-interfaces.nix
index a2811104944..78d66966949 100644
--- a/nixos/modules/tasks/network-interfaces.nix
+++ b/nixos/modules/tasks/network-interfaces.nix
@@ -381,7 +381,7 @@ in
# syntax). Note: We also allow underscores for compatibility/legacy
# reasons (as undocumented feature):
type = types.strMatching
- "^[[:alpha:]]([[:alnum:]_-]{0,61}[[:alnum:]])?$";
+ "^$|^[[:alpha:]]([[:alnum:]_-]{0,61}[[:alnum:]])?$";
description = ''
The name of the machine. Leave it empty if you want to obtain it from a
DHCP server (if using DHCP). The hostname must be a valid DNS label (see