modules: add mkAliasOptionModuleMD

mkAliasOptionModule should not default to mdDoc descriptions because
that can break out-of-tree users of documentation infrastructure. add an
explicitly-MD variant for now, to be removed some time after the MD
transition is complete.

lib/default.nix

···
       mkAliasAndWrapDefinitions fixMergeModules mkRemovedOptionModule
       mkRenamedOptionModule mkRenamedOptionModuleWith
       mkMergedOptionModule mkChangedOptionModule
-      mkAliasOptionModule mkDerivedConfig doRename;
+      mkAliasOptionModule mkDerivedConfig doRename
+      mkAliasOptionModuleMD;
     inherit (self.options) isOption mkEnableOption mkSinkUndeclaredOptions
       mergeDefaultOption mergeOneOption mergeEqualOption mergeUniqueOption
       getValues getFiles

lib/modules.nix

···
     visible = true;
     warn = false;
     use = id;
+    wrapDescription = lib.id;
+  };
+
+  /* Transitional version of mkAliasOptionModule that uses MD docs. */
+  mkAliasOptionModuleMD = from: to: doRename {
+    inherit from to;
+    visible = true;
+    warn = false;
+    use = id;
   };
 
   /* mkDerivedConfig : Option a -> (a -> Definition b) -> Definition b
···
       (opt.highestPrio or defaultOverridePriority)
       (f opt.value);
 
-  doRename = { from, to, visible, warn, use, withPriority ? true }:
+  doRename = { from, to, visible, warn, use, withPriority ? true, wrapDescription ? lib.mdDoc }:
     { config, options, ... }:
     let
       fromOpt = getAttrFromPath from options;
···
     {
       options = setAttrByPath from (mkOption {
         inherit visible;
-        description = lib.mdDoc "Alias of {option}`${showOption to}`.";
+        description = wrapDescription "Alias of {option}`${showOption to}`.";
         apply = x: use (toOf config);
       } // optionalAttrs (toType != null) {
         type = toType;

nixos/lib/make-options-doc/mergeJSON.py

···
     print("Explanation: The documentation contains descriptions, examples, or defaults written in DocBook. " +
         "NixOS is in the process of migrating from DocBook to Markdown, and " +
         "DocBook is disallowed for in-tree modules. To change your contribution to "+
-        "use Markdown, apply mdDoc and literalMD. For example:\n" +
+        "use Markdown, apply mdDoc and literalMD and use the *MD variants of option creation " +
+        "functions where they are available. For example:\n" +
         "\n" +
         "  example.foo = mkOption {\n" +
         "    description = lib.mdDoc ''your description'';\n" +
         "    defaultText = lib.literalMD ''your description of default'';\n" +
-        "  }\n" +
+        "  };\n" +
         "\n" +
-        "  example.enable = mkEnableOption (lib.mdDoc ''your thing'');",
+        "  example.enable = mkEnableOption (lib.mdDoc ''your thing'');\n" +
+        "  imports = [ (mkAliasOptionModuleMD [ \"example\" \"args\" ] [ \"example\" \"settings\" ]) ];",
         file = sys.stderr)
 
 if hasErrors:

nixos/modules/config/users-groups.nix

···
 
 in {
   imports = [
-    (mkAliasOptionModule [ "users" "extraUsers" ] [ "users" "users" ])
-    (mkAliasOptionModule [ "users" "extraGroups" ] [ "users" "groups" ])
+    (mkAliasOptionModuleMD [ "users" "extraUsers" ] [ "users" "users" ])
+    (mkAliasOptionModuleMD [ "users" "extraGroups" ] [ "users" "groups" ])
     (mkRenamedOptionModule ["security" "initialRootPassword"] ["users" "users" "root" "initialHashedPassword"])
   ];
 

nixos/modules/rename.nix

···
 
     # This alias module can't be where _module.check is defined because it would
     # be added to submodules as well there
-    (mkAliasOptionModule [ "environment" "checkConfigurationOptions" ] [ "_module" "check" ])
+    (mkAliasOptionModuleMD [ "environment" "checkConfigurationOptions" ] [ "_module" "check" ])
 
     # Completely removed modules
     (mkRemovedOptionModule [ "environment" "blcr" "enable" ] "The BLCR module has been removed")

nixos/modules/services/networking/ssh/sshd.nix

···
 
 {
   imports = [
-    (mkAliasOptionModule [ "services" "sshd" "enable" ] [ "services" "openssh" "enable" ])
-    (mkAliasOptionModule [ "services" "openssh" "knownHosts" ] [ "programs" "ssh" "knownHosts" ])
+    (mkAliasOptionModuleMD [ "services" "sshd" "enable" ] [ "services" "openssh" "enable" ])
+    (mkAliasOptionModuleMD [ "services" "openssh" "knownHosts" ] [ "programs" "ssh" "knownHosts" ])
     (mkRenamedOptionModule [ "services" "openssh" "challengeResponseAuthentication" ] [ "services" "openssh" "kbdInteractiveAuthentication" ])
   ];
 

nixos/modules/services/torrent/transmission.nix

···
   imports = [
     (mkRenamedOptionModule ["services" "transmission" "port"]
                            ["services" "transmission" "settings" "rpc-port"])
-    (mkAliasOptionModule ["services" "transmission" "openFirewall"]
-                         ["services" "transmission" "openPeerPorts"])
+    (mkAliasOptionModuleMD ["services" "transmission" "openFirewall"]
+                           ["services" "transmission" "openPeerPorts"])
   ];
   options = {
     services.transmission = {

nixos/modules/services/x11/picom.nix

···
 in {
 
   imports = [
-    (mkAliasOptionModule [ "services" "compton" ] [ "services" "picom" ])
+    (mkAliasOptionModuleMD [ "services" "compton" ] [ "services" "picom" ])
     (mkRemovedOptionModule [ "services" "picom" "refreshRate" ] ''
       This option corresponds to `refresh-rate`, which has been unused
       since picom v6 and was subsequently removed by upstream.