Get rid of the last uses of mkAlways

mkAlways is an insane function, mkMerge is much saner.

doc/manual/development.xml

@@ -150,7 +150,7 @@ $ nixos-rebuild switch -I <replaceable>/my/sources</replaceable>
   definitions.  This conditional values can be distinguished in two
   categories.  The condition which are local to the current configuration
   and conditions which are dependent on others configurations.  Local
-  properties are <varname>mkIf</varname>, <varname>mkAlways</varname>
+  properties are <varname>mkIf</varname>
   and <varname>mkAssert</varname>.  Global properties
   are <varname>mkOverride</varname>, <varname>mkDefault</varname>
   and <varname>mkOrder</varname>.</para>
@@ -158,12 +158,7 @@ $ nixos-rebuild switch -I <replaceable>/my/sources</replaceable>
 <para><varname>mkIf</varname> is used to remove the option definitions which
   are below it if the condition is evaluated to
   false.  <varname>mkAssert</varname> expects the condition to be evaluated
-  to true otherwise it raises an error message.  <varname>mkAlways</varname>
+  to true otherwise it raises an error message.</para>
-  is used to ignore all the <varname>mkIf</varname>
-  and <varname>mkAssert</varname> which have been made
-  previously.  <varname>mkAlways</varname> and <varname>mkAssert</varname>
-  are often used together to set an option value and to ensure that it has
-  not been masked by another one.</para>
 
 <para><varname>mkOverride</varname> is used to mask previous definitions if
   the current value has a lower mask number.  The mask value is 100 (default)
@@ -223,14 +218,6 @@ let
   locatedb = "/var/cache/locatedb";
   logfile = "/var/log/updatedb";
   cmd =''root  updatedb --localuser=nobody --output=${locatedb} > ${logfile}'';
-
-  mkCheck = x:
-    mkIf cfg.enable (
-      mkAssert config.services.cron.enable ''
-        The cron daemon is not enabled, required by services.locate.enable.
-      ''
-      x
-    )
 in
 
 {
@@ -260,9 +247,9 @@ in
     };
   };
 
-  config = mkCheck {
+  config = mkIf cfg.enable {
     services.cron = {
-      enable = mkAlways cfg.enable;
+      enable = true;
       systemCronJobs = "${cfg.period}  root ${cmd}";
     };
   };

modules/config/pulseaudio.nix

@@ -28,15 +28,11 @@ let cfg = config.hardware.pulseaudio; in
   };
 
 
-  config = mkIf cfg.enable {
+  config = mkMerge
-
-    environment.systemPackages =
-      [ cfg.package ];
-
-    environment.etc = mkAlways (
     [ # Create pulse/client.conf even if PulseAudio is disabled so
       # that we can disable the autospawn feature in programs that
       # are built with PulseAudio support (like KDE).
+      { environment.etc = singleton
           { target = "pulse/client.conf";
             source = pkgs.writeText "client.conf"
               ''
@@ -45,9 +41,14 @@ let cfg = config.hardware.pulseaudio; in
                   daemon-binary=${cfg.package}/bin/pulseaudio
                 ''}
               '';
+          };
       }
 
-      ] ++ optionals cfg.enable
+      (mkIf cfg.enable {
+
+        environment.systemPackages = [ cfg.package ];
+
+        environment.etc =
           [ # Write an /etc/asound.conf that causes all ALSA applications to
             # be re-routed to the PulseAudio server through ALSA's Pulse
             # plugin.
@@ -80,12 +81,12 @@ let cfg = config.hardware.pulseaudio; in
             { target = "pulse/system.pa";
               source = "${cfg.package}/etc/pulse/system.pa";
             }
-
+          ];
-      ]);
 
         # Allow PulseAudio to get realtime priority using rtkit.
         security.rtkit.enable = true;
 
-  };
+      })
+    ];
 
 }

modules/services/network-filesystems/samba.nix

@@ -180,8 +180,17 @@ in
 
   ###### implementation
 
-  config = mkIf config.services.samba.enable {
+  config = mkMerge
+    [ { # Always provide a smb.conf to shut up programs like smbclient and smbspool.
+        environment.etc = singleton
+          { source =
+              if cfg.enable then configFile
+              else pkgs.writeText "smb-dummy.conf" "# Samba is disabled.";
+            target = "samba/smb.conf";
+          };
+      }
 
+      (mkIf config.services.samba.enable {
         users.extraUsers = singleton
           { name = user;
             description = "Samba service user";
@@ -192,13 +201,6 @@ in
           { name = group;
           };
 
-    # always provide a smb.conf to shut up programs like smbclient and smbspool.
-    environment.etc = mkAlways (singleton
-      { source =
-          if cfg.enable then configFile
-          else pkgs.writeText "smb-dummy.conf" "# Samba is disabled.";
-        target = "samba/smb.conf";
-      });
 
         # Dummy job to start the real Samba daemons (nmbd, smbd, winbindd).
         jobs.sambaControl =
@@ -216,7 +218,7 @@ in
         jobs.smbd = daemonJob "smbd" "-D";
 
         jobs.winbindd = daemonJob "winbindd" "-D";
-
+      })
-  };
+    ];
 
 }