Merge pull request #262740 from ElvishJerricco/systemd-stage-1-improve-udhcpc-assertion

systemd-stage-1: Improve udhcpc assertion

nixos/modules/system/boot/initrd-network.nix

···
     };
 
     boot.initrd.network.udhcpc.enable = mkOption {
-      default = config.networking.useDHCP;
+      default = config.networking.useDHCP && !config.boot.initrd.systemd.enable;
       defaultText = "networking.useDHCP";
       type = types.bool;
       description = lib.mdDoc ''

nixos/modules/system/boot/networkd.nix

···
     stage2Config
     (mkIf config.boot.initrd.systemd.enable {
       assertions = [{
-        assertion = config.boot.initrd.network.udhcpc.extraArgs == [];
+        assertion = !config.boot.initrd.network.udhcpc.enable && config.boot.initrd.network.udhcpc.extraArgs == [];
         message = ''
-          boot.initrd.network.udhcpc.extraArgs is not supported when
-          boot.initrd.systemd.enable is enabled
+          systemd stage 1 networking does not support 'boot.initrd.network.udhcpc'. Configure
+          DHCP with 'networking.*' options or with 'boot.initrd.systemd.network' options.
         '';
       }];