treewide: more defaultText for options

lib/modules.nix

@@ -587,6 +587,8 @@ rec {
         definitions = map (def: def.value) res.defsFinal;
         files = map (def: def.file) res.defsFinal;
         inherit (res) isDefined;
+        # This allows options to be correctly displayed using `${options.path.to.it}`
+        __toString = _: showOption loc;
       };
 
   # Merge definitions of a value of a given type.

nixos/modules/config/networking.nix

@@ -1,12 +1,13 @@
 # /etc files related to networking, such as /etc/services.
 
-{ config, lib, pkgs, ... }:
+{ config, lib, options, pkgs, ... }:
 
 with lib;
 
 let
 
   cfg = config.networking;
+  opt = options.networking;
 
   localhostMultiple = any (elem "localhost") (attrValues (removeAttrs cfg.hosts [ "127.0.0.1" "::1" ]));
 
@@ -78,6 +79,7 @@ in
       httpProxy = lib.mkOption {
         type = types.nullOr types.str;
         default = cfg.proxy.default;
+        defaultText = literalExpression "config.${opt.proxy.default}";
         description = ''
           This option specifies the http_proxy environment variable.
         '';
@@ -87,6 +89,7 @@ in
       httpsProxy = lib.mkOption {
         type = types.nullOr types.str;
         default = cfg.proxy.default;
+        defaultText = literalExpression "config.${opt.proxy.default}";
         description = ''
           This option specifies the https_proxy environment variable.
         '';
@@ -96,6 +99,7 @@ in
       ftpProxy = lib.mkOption {
         type = types.nullOr types.str;
         default = cfg.proxy.default;
+        defaultText = literalExpression "config.${opt.proxy.default}";
         description = ''
           This option specifies the ftp_proxy environment variable.
         '';
@@ -105,6 +109,7 @@ in
       rsyncProxy = lib.mkOption {
         type = types.nullOr types.str;
         default = cfg.proxy.default;
+        defaultText = literalExpression "config.${opt.proxy.default}";
         description = ''
           This option specifies the rsync_proxy environment variable.
         '';
@@ -114,6 +119,7 @@ in
       allProxy = lib.mkOption {
         type = types.nullOr types.str;
         default = cfg.proxy.default;
+        defaultText = literalExpression "config.${opt.proxy.default}";
         description = ''
           This option specifies the all_proxy environment variable.
         '';

nixos/modules/config/system-path.nix

@@ -41,12 +41,17 @@ let
       pkgs.zstd
     ];
 
-    defaultPackages = map (pkg: setPrio ((pkg.meta.priority or 5) + 3) pkg)
-      [ pkgs.nano
-        pkgs.perl
-        pkgs.rsync
-        pkgs.strace
-      ];
+  defaultPackageNames =
+    [ "nano"
+      "perl"
+      "rsync"
+      "strace"
+    ];
+  defaultPackages =
+    map
+      (n: let pkg = pkgs.${n}; in setPrio ((pkg.meta.priority or 5) + 3) pkg)
+      defaultPackageNames;
+  defaultPackagesText = "[ ${concatMapStringsSep " " (n: "pkgs.${n}") defaultPackageNames } ]";
 
 in
 
@@ -73,6 +78,11 @@ in
       defaultPackages = mkOption {
         type = types.listOf types.package;
         default = defaultPackages;
+        defaultText = literalDocBook ''
+          these packages, with their <literal>meta.priority</literal> numerically increased
+          (thus lowering their installation priority):
+          <programlisting>${defaultPackagesText}</programlisting>
+        '';
         example = [];
         description = ''
           Set of default packages that aren't strictly necessary

nixos/modules/hardware/system-76.nix

@@ -1,8 +1,9 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, options, pkgs, ... }:
 
 let
-  inherit (lib) mkOption mkEnableOption types mkIf mkMerge optional versionOlder;
+  inherit (lib) literalExpression mkOption mkEnableOption types mkIf mkMerge optional versionOlder;
   cfg = config.hardware.system76;
+  opt = options.hardware.system76;
 
   kpkgs = config.boot.kernelPackages;
   modules = [ "system76" "system76-io" ] ++ (optional (versionOlder kpkgs.kernel.version "5.5") "system76-acpi");
@@ -60,20 +61,23 @@ in {
 
       firmware-daemon.enable = mkOption {
         default = cfg.enableAll;
+        defaultText = literalExpression "config.${opt.enableAll}";
         example = true;
         description = "Whether to enable the system76 firmware daemon";
         type = types.bool;
       };
 
       kernel-modules.enable = mkOption {
         default = cfg.enableAll;
+        defaultText = literalExpression "config.${opt.enableAll}";
         example = true;
         description = "Whether to make the system76 out-of-tree kernel modules available";
         type = types.bool;
       };
 
       power-daemon.enable = mkOption {
         default = cfg.enableAll;
+        defaultText = literalExpression "config.${opt.enableAll}";
         example = true;
         description = "Whether to enable the system76 power daemon";
         type = types.bool;

nixos/modules/misc/version.nix

@@ -1,9 +1,10 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, options, pkgs, ... }:
 
 with lib;
 
 let
   cfg = config.system.nixos;
+  opt = options.system.nixos;
 in
 
 {
@@ -53,6 +54,7 @@ in
     stateVersion = mkOption {
       type = types.str;
       default = cfg.release;
+      defaultText = literalExpression "config.${opt.release}";
       description = ''
         Every once in a while, a new NixOS release may change
         configuration defaults in a way incompatible with stateful

nixos/modules/programs/captive-browser.nix

@@ -3,6 +3,18 @@
 with lib;
 let
   cfg = config.programs.captive-browser;
+  browserDefault = chromium: concatStringsSep " " [
+    ''env XDG_CONFIG_HOME="$PREV_CONFIG_HOME"''
+    ''${chromium}/bin/chromium''
+    ''--user-data-dir=''${XDG_DATA_HOME:-$HOME/.local/share}/chromium-captive''
+    ''--proxy-server="socks5://$PROXY"''
+    ''--host-resolver-rules="MAP * ~NOTFOUND , EXCLUDE localhost"''
+    ''--no-first-run''
+    ''--new-window''
+    ''--incognito''
+    ''-no-default-browser-check''
+    ''http://cache.nixos.org/''
+  ];
 in
 {
   ###### interface
@@ -26,18 +38,8 @@ in
       # the options below are the same as in "captive-browser.toml"
       browser = mkOption {
         type = types.str;
-        default = concatStringsSep " " [
-          ''env XDG_CONFIG_HOME="$PREV_CONFIG_HOME"''
-          ''${pkgs.chromium}/bin/chromium''
-          ''--user-data-dir=''${XDG_DATA_HOME:-$HOME/.local/share}/chromium-captive''
-          ''--proxy-server="socks5://$PROXY"''
-          ''--host-resolver-rules="MAP * ~NOTFOUND , EXCLUDE localhost"''
-          ''--no-first-run''
-          ''--new-window''
-          ''--incognito''
-          ''-no-default-browser-check''
-          ''http://cache.nixos.org/''
-        ];
+        default = browserDefault pkgs.chromium;
+        defaultText = literalExpression (browserDefault "\${pkgs.chromium}");
         description = ''
           The shell (/bin/sh) command executed once the proxy starts.
           When browser exits, the proxy exits. An extra env var PROXY is available.

nixos/modules/programs/gnupg.nix

@@ -71,6 +71,7 @@ in
       type = types.nullOr (types.enum pkgs.pinentry.flavors);
       example = "gnome3";
       default = defaultPinentryFlavor;
+      defaultText = literalDocBook ''matching the configured desktop environment'';
       description = ''
         Which pinentry interface to use. If not null, the path to the
         pinentry binary will be passed to gpg-agent via commandline and

nixos/modules/programs/zsh/zsh.nix

@@ -1,6 +1,6 @@
 # This module defines global configuration for the zshell.
 
-{ config, lib, pkgs, ... }:
+{ config, lib, options, pkgs, ... }:
 
 with lib;
 
@@ -9,6 +9,7 @@ let
   cfge = config.environment;
 
   cfg = config.programs.zsh;
+  opt = options.programs.zsh;
 
   zshAliases = concatStringsSep "\n" (
     mapAttrsFlatten (k: v: "alias ${k}=${escapeShellArg v}")
@@ -147,6 +148,7 @@ in
 
       enableGlobalCompInit = mkOption {
         default = cfg.enableCompletion;
+        defaultText = literalExpression "config.${opt.enableCompletion}";
         description = ''
           Enable execution of compinit call for all interactive zsh shells.
 

nixos/modules/security/acme.nix

@@ -2,6 +2,7 @@
 with lib;
 let
   cfg = config.security.acme;
+  opt = options.security.acme;
 
   # Used to calculate timer accuracy for coalescing
   numCerts = length (builtins.attrNames cfg.certs);
@@ -470,6 +471,7 @@ let
       email = mkOption {
         type = types.nullOr types.str;
         default = cfg.email;
+        defaultText = literalExpression "config.${opt.email}";
         description = "Contact email address for the CA to be able to reach you.";
       };
 

nixos/modules/security/dhparams.nix

@@ -1,8 +1,9 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, options, pkgs, ... }:
 
 let
-  inherit (lib) mkOption types;
+  inherit (lib) literalExpression mkOption types;
   cfg = config.security.dhparams;
+  opt = options.security.dhparams;
 
   bitType = types.addCheck types.int (b: b >= 16) // {
     name = "bits";
@@ -13,6 +14,7 @@ let
     options.bits = mkOption {
       type = bitType;
       default = cfg.defaultBitSize;
+      defaultText = literalExpression "config.${opt.defaultBitSize}";
       description = ''
         The bit size for the prime that is used during a Diffie-Hellman
         key exchange.

nixos/modules/services/audio/mpdscribble.nix

@@ -1,10 +1,11 @@
-{ config, lib, pkgs, ... }:
+{ config, lib, options, pkgs, ... }:
 
 with lib;
 
 let
   cfg = config.services.mpdscribble;
   mpdCfg = config.services.mpd;
+  mpdOpt = options.services.mpd;
 
   endpointUrls = {
     "last.fm" = "http://post.audioscrobbler.com";
@@ -108,6 +109,11 @@ in {
         mpdCfg.network.listenAddress
       else
         "localhost");
+      defaultText = literalExpression ''
+        if config.${mpdOpt.network.listenAddress} != "any"
+        then config.${mpdOpt.network.listenAddress}
+        else "localhost"
+      '';
       type = types.str;
       description = ''
         Host for the mpdscribble daemon to search for a mpd daemon on.
@@ -122,6 +128,10 @@ in {
           mpdCfg.credentials).passwordFile
       else
         null;
+      defaultText = literalDocBook ''
+        The first password file with read access configured for MPD when using a local instance,
+        otherwise <literal>null</literal>.
+      '';
       type = types.nullOr types.str;
       description = ''
         File containing the password for the mpd daemon.
@@ -132,6 +142,7 @@ in {
 
     port = mkOption {
       default = mpdCfg.network.port;
+      defaultText = literalExpression "config.${mpdOpt.network.port}";
       type = types.port;
       description = ''
         Port for the mpdscribble daemon to search for a mpd daemon on.

nixos/modules/services/backup/tarsnap.nix

@@ -1,9 +1,10 @@
-{ config, lib, pkgs, utils, ... }:
+{ config, lib, options, pkgs, utils, ... }:
 
 with lib;
 
 let
   gcfg = config.services.tarsnap;
+  opt = options.services.tarsnap;
 
   configFile = name: cfg: ''
     keyfile ${cfg.keyfile}
@@ -59,12 +60,13 @@ in
       };
 
       archives = mkOption {
-        type = types.attrsOf (types.submodule ({ config, ... }:
+        type = types.attrsOf (types.submodule ({ config, options, ... }:
           {
             options = {
               keyfile = mkOption {
                 type = types.str;
                 default = gcfg.keyfile;
+                defaultText = literalExpression "config.${opt.keyfile}";
                 description = ''
                   Set a specific keyfile for this archive. This defaults to
                   <literal>"/root/tarsnap.key"</literal> if left unspecified.
@@ -87,6 +89,9 @@ in
               cachedir = mkOption {
                 type = types.nullOr types.path;
                 default = "/var/cache/tarsnap/${utils.escapeSystemdPath config.keyfile}";
+                defaultText = literalExpression ''
+                  "/var/cache/tarsnap/''${utils.escapeSystemdPath config.${options.keyfile}}"
+                '';
                 description = ''
                   The cache allows tarsnap to identify previously stored data
                   blocks, reducing archival time and bandwidth usage.

nixos/modules/services/cluster/hadoop/default.nix

@@ -1,6 +1,7 @@
-{ config, lib, pkgs, ...}:
+{ config, lib, options, pkgs, ...}:
 let
   cfg = config.services.hadoop;
+  opt = options.services.hadoop;
 in
 with lib;
 {
@@ -44,6 +45,14 @@ with lib;
         "mapreduce.map.env" = "HADOOP_MAPRED_HOME=${cfg.package}/lib/${cfg.package.untarDir}";
         "mapreduce.reduce.env" = "HADOOP_MAPRED_HOME=${cfg.package}/lib/${cfg.package.untarDir}";
       };
+      defaultText = literalExpression ''
+        {
+          "mapreduce.framework.name" = "yarn";
+          "yarn.app.mapreduce.am.env" = "HADOOP_MAPRED_HOME=''${config.${opt.package}}/lib/''${config.${opt.package}.untarDir}";
+          "mapreduce.map.env" = "HADOOP_MAPRED_HOME=''${config.${opt.package}}/lib/''${config.${opt.package}.untarDir}";
+          "mapreduce.reduce.env" = "HADOOP_MAPRED_HOME=''${config.${opt.package}}/lib/''${config.${opt.package}.untarDir}";
+        }
+      '';
       type = types.attrsOf types.anything;
       example = literalExpression ''
         options.services.hadoop.mapredSite.default // {
@@ -98,6 +107,9 @@ with lib;
 
     log4jProperties = mkOption {
       default = "${cfg.package}/lib/${cfg.package.untarDir}/etc/hadoop/log4j.properties";
+      defaultText = literalExpression ''
+        "''${config.${opt.package}}/lib/''${config.${opt.package}.untarDir}/etc/hadoop/log4j.properties"
+      '';
       type = types.path;
       example = literalExpression ''
         "''${pkgs.hadoop}/lib/''${pkgs.hadoop.untarDir}/etc/hadoop/log4j.properties";