swarm-controller: make socketPath readOnly instead of asserting it

readOnly makes a bad socketPath inexpressible rather than diagnosed
after the fact. Since readOnly rejects any definition including one
arriving through a rename shim, drop the deploy.nix rename entry for
it and the fixture line exercising it, and update the controllerOldPath
comment's shim count from seven to six.

Refs #4208

nix/host-modules/deploy.nix

@@ -69,10 +69,6 @@ in
       [ "services" "hyperhive" "swarm" "controller" "enable" ]
       [ "services" "hyperhive" "deploy" "swarm-controller" "enable" ]
     )
-    (lib.mkRenamedOptionModule
-      [ "services" "hyperhive" "swarm" "controller" "socketPath" ]
-      [ "services" "hyperhive" "deploy" "swarm-controller" "socketPath" ]
-    )
     (lib.mkRenamedOptionModule
       [ "services" "hyperhive" "swarm" "controller" "forgeTokenFile" ]
       [ "services" "hyperhive" "deploy" "swarm-controller" "forgeTokenFile" ]

nix/host-modules/swarm-controller.nix

@@ -447,6 +447,7 @@ in
     socketPath = lib.mkOption {
       type = lib.types.str;
       default = "/run/swarm-controller/controller.sock";
+      readOnly = true;
       description = ''
         Unix socket the daemon serves on, and the path the gateway's nginx
         proxies to.
@@ -720,26 +721,6 @@ in
           state directory.
         '';
       }
-      {
-        assertion =
-          let
-            dir = builtins.dirOf deployCfg.swarm-controller.socketPath;
-          in
-          dir != "/run/hyperhive" && dir != "/run/hive" && dir != "/run";
-        message = ''
-          services.hyperhive.deploy.swarm-controller.socketPath puts the
-          controller socket in
-          ${builtins.dirOf deployCfg.swarm-controller.socketPath}, a
-          directory that carries other sockets.
-
-          The controller socket is 0666 and the gateway's nginx is given
-          its directory, so that directory is the access control.
-          /run/hyperhive holds host.sock — the host ADMIN socket — and
-          /run/hive holds the per-agent and priv sockets. Give the
-          controller a directory of its own (the default,
-          /run/swarm-controller, is one).
-        '';
-      }
     ];
 
     systemd.services.swarm-controller = {

nix/module-eval.nix

@@ -201,13 +201,12 @@ let
     deploy.matrix.maxRequestSize = 99000000;
   };
 
-  # `enable` is spelled the OLD way like everything else here, so all seven
+  # `enable` is spelled the OLD way like everything else here, so all six
-  # of the controller's shims are exercised rather than six.
+  # of the controller's shims are exercised rather than five.
   controllerOldPath = hive {
     swarm.controller.enable = true;
     swarm.controller.package = pkgs.emptyDirectory;
     swarm.controller.swarmctlPackage = pkgs.emptyDirectory;
-    swarm.controller.socketPath = "/run/test-ctrl/ctrl.sock";
     swarm.controller.forgeTokenFile = "/run/secrets/ctrl-forge.token";
     swarm.controller.authBridgeUrl = "http://127.0.0.1:19097";
     swarm.controller.queue.clientSecretFile = "/run/secrets/ctrl-queue.secret";