nixos/davfs2: ensure extraConfig and settings are mutually exclusive

nixos/modules/services/network-filesystems/davfs2.nix

@@ -19,13 +19,15 @@ let
  else if builtins.isString value then "\"${escapeString value}\""
  else toString value;
 
- configFile = pkgs.writeText "davfs2.conf" ''
- ${toINIWithGlobalSection {
- mkSectionName = escapeString;
- mkKeyValue = k: v: "${k} ${formatValue v}";
- } cfg.settings}
- ${cfg.extraConfig}
- '';
+ configFile = pkgs.writeText "davfs2.conf" (
+ if (cfg.settings != { }) then
+ (toINIWithGlobalSection {
+ mkSectionName = escapeString;
+ mkKeyValue = k: v: "${k} ${formatValue v}";
+ } cfg.settings)
+ else
+ cfg.extraConfig
+ );
 in
 {
 
@@ -107,6 +109,16 @@ in
 
  config = mkIf cfg.enable {
 
+ assertions = [
+ {
+ assertion = cfg.extraConfig != "" -> cfg.settings == { };
+ message = ''
+ services.davfs2.extraConfig and services.davfs2.settings cannot be used together.
+ Please prefer using services.davfs2.settings.
+ '';
+ }
+ ];
+
  warnings = optional (cfg.extraConfig != "") ''
  services.davfs2.extraConfig will be deprecated in future releases;
  please use services.davfs2.settings instead.