Use the "assertions" option instead of mkAssert

nixos/modules/services/databases/4store-endpoint.nix

@@ -24,12 +24,12 @@ with pkgs.lib;
       };
 
       listenAddress = mkOption {
-	default = null;
+        default = null;
         description = "IP address to listen on.";
       };
 
       port = mkOption {
-	default = 8080;
+        default = 8080;
         description = "port to listen on.";
       };
 
@@ -45,9 +45,12 @@ with pkgs.lib;
 
   ###### implementation
 
-  config = mkIf cfg.enable (
+  config = mkIf cfg.enable {
-    mkAssert (cfg.enable -> cfg.database != "")
+
-      "Must specify database name" {
+    assertions = singleton
+      { assertion = cfg.enable -> cfg.database != "";
+        message = "Must specify 4Store database name";
+      };
 
     users.extraUsers = singleton
       { name = endpointUser;
@@ -63,10 +66,10 @@ with pkgs.lib;
       startOn = "filesystem";
 
       exec = ''
-	${run} '${pkgs.rdf4store}/bin/4s-httpd -D ${cfg.options} ${if cfg.listenAddress!=null then "-H ${cfg.listenAddress}" else "" } -p ${toString cfg.port} ${cfg.database}'
+        ${run} '${pkgs.rdf4store}/bin/4s-httpd -D ${cfg.options} ${if cfg.listenAddress!=null then "-H ${cfg.listenAddress}" else "" } -p ${toString cfg.port} ${cfg.database}'
       '';
     };
 
-  });
+  };
 
 }

nixos/modules/services/databases/4store.nix

@@ -36,9 +36,12 @@ with pkgs.lib;
 
   ###### implementation
 
-  config = mkIf cfg.enable (
+  config = mkIf cfg.enable {
-    mkAssert (cfg.enable -> cfg.database != "")
+
-      "Must specify database name" {
+    assertions = singleton
+      { assertion = cfg.enable -> cfg.database != "";
+        message = "Must specify 4Store database name.";
+      };
 
     users.extraUsers = singleton
       { name = fourStoreUser;
@@ -56,16 +59,16 @@ with pkgs.lib;
       preStart = ''
         mkdir -p ${stateDir}/
         chown ${fourStoreUser} ${stateDir}
-	if ! test -e "${stateDir}/${cfg.database}"; then
+        if ! test -e "${stateDir}/${cfg.database}"; then
-	  ${run} -c '${pkgs.rdf4store}/bin/4s-backend-setup ${cfg.database}'
+          ${run} -c '${pkgs.rdf4store}/bin/4s-backend-setup ${cfg.database}'
         fi
       '';
 
       exec = ''
-	${run} -c '${pkgs.rdf4store}/bin/4s-backend -D ${cfg.options} ${cfg.database}'
+        ${run} -c '${pkgs.rdf4store}/bin/4s-backend -D ${cfg.options} ${cfg.database}'
       '';
     };
 
-  });
+  };
 
 }

nixos/modules/services/networking/openfire.nix

@@ -40,10 +40,12 @@ in
 
   ###### implementation
 
-  config = mkIf config.services.openfire.enable (
+  config = mkIf config.services.openfire.enable {
-  mkAssert (!(config.services.openfire.usePostgreSQL -> config.services.postgresql.enable)) "
+
-    openfire assertion failed
+    assertions = singleton
-  " {
+      { assertion = !(config.services.openfire.usePostgreSQL -> config.services.postgresql.enable);
+        message = "OpenFire assertion failed.";
+      };
 
     jobs.openfire =
       { description = "OpenFire XMPP server";
@@ -65,6 +67,6 @@ in
           ''; # */
       };
 
-  });
+  };
 
 }

nixos/modules/services/security/tor.nix

@@ -53,9 +53,9 @@ in
           '';
         };
 
-	socksListenAddressFaster = mkOption {
+        socksListenAddressFaster = mkOption {
           default = "127.0.0.1:9063";
-	  description = ''
+          description = ''
             Same as socksListenAddress but uses weaker circuit isolation to provide
             performance suitable for a web browser.
           '';
@@ -227,10 +227,12 @@ in
 
   ###### implementation
 
-  config = mkIf (cfg.client.enable || cfg.relay.enable) (
+  config = mkIf (cfg.client.enable || cfg.relay.enable) {
-  mkAssert (cfg.relay.enable -> !(cfg.relay.isBridge && cfg.relay.isExit)) "
+
-    Can't be both an exit and a bridge relay at the same time
+    assertions = singleton
-  " {
+      { assertion = cfg.relay.enable -> !(cfg.relay.isBridge && cfg.relay.isExit);
+        message = "Can't be both an exit and a bridge relay at the same time";
+      };
 
     users.extraUsers = singleton
       { name = torUser;
@@ -270,7 +272,7 @@ in
       ''
       + optionalString cfg.client.enable  ''
         SOCKSPort ${cfg.client.socksListenAddress} IsolateDestAddr
-	SOCKSPort ${cfg.client.socksListenAddressFaster}
+        SOCKSPort ${cfg.client.socksListenAddressFaster}
         ${opt "SocksPolicy" cfg.client.socksPolicy}
       ''
       + optionalString cfg.relay.enable ''
@@ -316,6 +318,6 @@ in
         # Extra config goes here
       '';
 
-  });
+  };
 
 }

nixos/modules/services/x11/xserver.nix

@@ -108,17 +108,6 @@ let
       ''; # */
   };
 
-
-  checkAgent = mkAssert (!(cfg.startOpenSSHAgent && cfg.startGnuPGAgent))
-    ''
-      The OpenSSH agent and GnuPG agent cannot be started both.
-      Choose between `startOpenSSHAgent' and `startGnuPGAgent'.
-    '';
-
-  checkPolkit = mkAssert config.security.polkit.enable
-    "X11 requires Polkit to be enabled (‘security.polkit.enable = true’).";
-
-
 in
 
 {
@@ -425,7 +414,20 @@ in
 
   ###### implementation
 
-  config = mkIf cfg.enable (checkAgent (checkPolkit {
+  config = mkIf cfg.enable {
+
+    assertions =
+      [ { assertion = !(cfg.startOpenSSHAgent && cfg.startGnuPGAgent);
+          message =
+            ''
+              The OpenSSH agent and GnuPG agent cannot be started both.
+              Choose between `startOpenSSHAgent' and `startGnuPGAgent'.
+            '';
+        }
+        { assertion = config.security.polkit.enable;
+          message = "X11 requires Polkit to be enabled (‘security.polkit.enable = true’).";
+        }
+      ];
 
     boot.extraModulePackages =
       optional (elem "nvidia" driverNames) kernelPackages.nvidia_x11 ++
@@ -669,7 +671,7 @@ in
         ${xrandrMonitorSections}
       '';
 
-  }));
+  };
 
 }