treewide: prefer XDG variables over dot directories

Currently, dot directories and XDG base directories are used
inconsistently in the Home Manager option declarations. This creates
ambiguity for the user as to where the location of the file should be
albeit this is rarely encountered in practice as it is sufficient to
read upstream documentation. The rationale is to make declarations
consistent and make a clear distinction between hardcoded and modular
specifications.

References to ~/.config in relevant nixpkgs modules were untouched as
the location is hardcoded upstream[1]. Furthermore, modules of
programs which do not follow XDG specifications were also untouched.

Generalization of tilde(~) expansions to $HOME were also considered,
however there isn't sufficient rationale despite the use of $HOME
being more universal. The expansion is standardized in POSIX[2] and is
essentially portable across all shells, thus there is no pragmatic
value to introducing the change.

[1] https://github.com/nixos/nixpkgs/blob/master/pkgs/top-level/impure.nix
[2] https://pubs.opengroup.org/onlinepubs/009695399/utilities/xcu_chap02.html#tag_02_06_01

docs/man-home-manager.xml

@@ -414,7 +414,7 @@
     <listitem>
      <para>
       Indicates the path to the Home Manager configuration file. If not given,
-      <filename>~/.config/nixpkgs/home.nix</filename> is used.
+      <filename>$XDG_CONFIG_HOME/nixpkgs/home.nix</filename> is used.
      </para>
     </listitem>
    </varlistentry>
@@ -589,7 +589,7 @@
   <variablelist>
    <varlistentry>
     <term>
-     <filename>~/.local/share/home-manager/news-read-ids</filename>
+     <filename>$XDG_DATA_HOME/home-manager/news-read-ids</filename>
     </term>
     <listitem>
      <para>

modules/misc/gtk.nix

@@ -123,7 +123,7 @@ in {
           };
           description = ''
             Extra configuration options to add to
-            <filename>~/.config/gtk-3.0/settings.ini</filename>.
+            <filename>$XDG_CONFIG_HOME/gtk-3.0/settings.ini</filename>.
           '';
         };
 
@@ -132,7 +132,7 @@ in {
           default = "";
           description = ''
             Extra configuration lines to add verbatim to
-            <filename>~/.config/gtk-3.0/gtk.css</filename>.
+            <filename>$XDG_CONFIG_HOME/gtk-3.0/gtk.css</filename>.
           '';
         };
       };

modules/programs/alacritty.nix

@@ -37,7 +37,7 @@ in {
         '';
         description = ''
           Configuration written to
-          <filename>~/.config/alacritty/alacritty.yml</filename>. See
+          <filename>$XDG_CONFIG_HOME/alacritty/alacritty.yml</filename>. See
           <link xlink:href="https://github.com/jwilm/alacritty/blob/master/alacritty.yml"/>
           for the default configuration.
         '';

modules/programs/atuin.nix

@@ -60,7 +60,7 @@ in {
       '';
       description = ''
         Configuration written to
-        <filename>~/.config/atuin/config.toml</filename>.
+        <filename>$XDG_CONFIG_HOME/atuin/config.toml</filename>.
         </para><para>
         See <link xlink:href="https://github.com/ellie/atuin/blob/main/docs/config.md" /> for the full list
         of options.

modules/programs/beets.nix

@@ -45,7 +45,7 @@ in {
         default = { };
         description = ''
           Configuration written to
-          <filename>~/.config/beets/config.yaml</filename>
+          <filename>$XDG_CONFIG_HOME/beets/config.yaml</filename>
         '';
       };
     };

modules/programs/direnv.nix

@@ -29,7 +29,7 @@ in {
       default = { };
       description = ''
         Configuration written to
-        <filename>~/.config/direnv/config.toml</filename>.
+        <filename>$XDG_CONFIG_HOME/direnv/config.toml</filename>.
         </para><para>
         See
         <citerefentry>
@@ -45,7 +45,7 @@ in {
       default = "";
       description = ''
         Custom stdlib written to
-        <filename>~/.config/direnv/direnvrc</filename>.
+        <filename>$XDG_CONFIG_HOME/direnv/direnvrc</filename>.
       '';
     };
 

modules/programs/hexchat.nix

@@ -270,7 +270,7 @@ in {
           };
         }'';
       description = ''
-        Configures <filename>~/.config/hexchat/servlist.conf</filename>.
+        Configures <filename>$XDG_CONFIG_HOME/hexchat/servlist.conf</filename>.
       '';
     };
 
@@ -286,7 +286,7 @@ in {
         };
       '';
       description = ''
-        Configuration for <filename>~/.config/hexchat/hexchat.conf</filename>, see
+        Configuration for <filename>$XDG_CONFIG_HOME/hexchat/hexchat.conf</filename>, see
         <link xlink:href="https://hexchat.readthedocs.io/en/latest/settings.html#list-of-settings"/>
         for supported values.
       '';

modules/programs/htop.nix

@@ -133,7 +133,7 @@ in {
       '';
       description = ''
         Configuration options to add to
-        <filename>~/.config/htop/htoprc</filename>.
+        <filename>$XDG_CONFIG_HOME/htop/htoprc</filename>.
       '';
     };
 

modules/programs/kakoune.nix

@@ -635,7 +635,7 @@ in {
         default = "";
         description = ''
           Extra configuration lines to add to
-          <filename>~/.config/kak/kakrc</filename>.
+          <filename>$XDG_CONFIG_HOME/kak/kakrc</filename>.
         '';
       };
 

modules/programs/kitty.nix

@@ -57,7 +57,7 @@ in {
       '';
       description = ''
         Configuration written to
-        <filename>~/.config/kitty/kitty.conf</filename>. See
+        <filename>$XDG_CONFIG_HOME/kitty/kitty.conf</filename>. See
         <link xlink:href="https://sw.kovidgoyal.net/kitty/conf.html" />
         for the documentation.
       '';

modules/programs/lazygit.nix

@@ -32,7 +32,7 @@ in {
       '';
       description = ''
         Configuration written to
-        <filename>~/.config/lazygit/config.yml</filename> on Linux
+        <filename>$XDG_CONFIG_HOME/lazygit/config.yml</filename> on Linux
         or <filename>~/Library/Application Support/lazygit/config.yml</filename> on Darwin. See
         <link xlink:href="https://github.com/jesseduffield/lazygit/blob/master/docs/Config.md"/>
         for supported values.

modules/programs/lsd.nix

@@ -39,7 +39,7 @@ in {
       };
       description = ''
         Configuration written to
-        <filename>~/.config/lsd/config.yaml</filename>. See
+        <filename>$XDG_CONFIG_HOME/lsd/config.yaml</filename>. See
         <link xlink:href="https://github.com/Peltoche/lsd#config-file-content"/>
         for supported values.
       '';

modules/programs/mangohud.nix

@@ -55,7 +55,7 @@ in {
         '';
         description = ''
           Configuration written to
-          <filename>~/.config/MangoHud/MangoHud.conf</filename>. See
+          <filename>$XDG_CONFIG_HOME/MangoHud/MangoHud.conf</filename>. See
           <link xlink:href="https://github.com/flightlessmango/MangoHud/blob/master/bin/MangoHud.conf"/>
           for the default configuration.
         '';
@@ -74,7 +74,7 @@ in {
         description = ''
           Sets MangoHud settings per application.
           Configuration written to
-          <filename>~/.config/MangoHud/{application_name}.conf</filename>. See
+          <filename>$XDG_CONFIG_HOME/MangoHud/{application_name}.conf</filename>. See
           <link xlink:href="https://github.com/flightlessmango/MangoHud/blob/master/bin/MangoHud.conf"/>
           for the default configuration.
         '';

modules/programs/mpv.nix

@@ -90,7 +90,7 @@ in {
       config = mkOption {
         description = ''
           Configuration written to
-          <filename>~/.config/mpv/mpv.conf</filename>. See
+          <filename>$XDG_CONFIG_HOME/mpv/mpv.conf</filename>. See
           <citerefentry>
             <refentrytitle>mpv</refentrytitle>
             <manvolnum>1</manvolnum>
@@ -112,7 +112,7 @@ in {
       profiles = mkOption {
         description = ''
           Sub-configuration options for specific profiles written to
-          <filename>~/.config/mpv/mpv.conf</filename>. See
+          <filename>$XDG_CONFIG_HOME/mpv/mpv.conf</filename>. See
           <option>programs.mpv.config</option> for more information.
         '';
         type = mpvProfiles;
@@ -143,7 +143,7 @@ in {
       bindings = mkOption {
         description = ''
           Input configuration written to
-          <filename>~/.config/mpv/input.conf</filename>. See
+          <filename>$XDG_CONFIG_HOME/mpv/input.conf</filename>. See
           <citerefentry>
             <refentrytitle>mpv</refentrytitle>
             <manvolnum>1</manvolnum>

modules/programs/ncspot.nix

@@ -32,7 +32,7 @@ in {
       '';
       description = ''
         Configuration written to
-        <filename>~/.config/ncspot/config.toml</filename>.
+        <filename>$XDG_CONFIG_HOME/ncspot/config.toml</filename>.
         </para><para>
         See <link xlink:href="https://github.com/hrkfdn/ncspot#configuration" />
         for the full list of options.

modules/programs/noti.nix

@@ -17,7 +17,7 @@ in {
       default = { };
       description = ''
         Configuration written to
-        <filename>~/.config/noti/noti.yaml</filename>.
+        <filename>$XDG_CONFIG_HOME/noti/noti.yaml</filename>.
         </para><para>
         See
         <citerefentry>

modules/programs/nushell.nix

@@ -42,7 +42,7 @@ in {
       '';
       description = ''
         Configuration written to
-        <filename>~/.config/nushell/config.toml</filename>.
+        <filename>$XDG_CONFIG_HOME/nushell/config.toml</filename>.
         </para><para>
         See <link xlink:href="https://www.nushell.sh/book/configuration.html" /> for the full list
         of options.

modules/programs/rtorrent.nix

@@ -17,7 +17,7 @@ in {
       default = "";
       description = ''
         Configuration written to
-        <filename>~/.config/rtorrent/rtorrent.rc</filename>. See
+        <filename>$XDG_CONFIG_HOME/rtorrent/rtorrent.rc</filename>. See
         <link xlink:href="https://github.com/rakshasa/rtorrent/wiki/Config-Guide" />
         for explanation about possible values.
       '';

modules/programs/sm64ex.nix

@@ -80,7 +80,7 @@ in {
         nullOr (attrsOf (either str (either int (either bool (listOf str)))));
       default = null;
       description =
-        "Settings for sm64ex's <filename>~/.local/share/sm64pc/sm64config.txt</filename> file.";
+        "Settings for sm64ex's <filename>$XDG_DATA_HOME/sm64pc/sm64config.txt</filename> file.";
       example = literalExpression ''
         {
           fullscreen = false;

modules/programs/starship.nix

@@ -51,7 +51,7 @@ in {
       '';
       description = ''
         Configuration written to
-        <filename>~/.config/starship.toml</filename>.
+        <filename>$XDG_CONFIG_HOME/starship.toml</filename>.
         </para><para>
         See <link xlink:href="https://starship.rs/config/" /> for the full list
         of options.

modules/programs/topgrade.nix

@@ -42,7 +42,7 @@ in {
       '';
       description = ''
         Configuration written to
-        <filename>~/.config/topgrade.toml</filename>.
+        <filename>$XDG_CONFIG_HOME/topgrade.toml</filename>.
         </para><para>
         See <link xlink:href="https://github.com/r-darwish/topgrade/wiki/Step-list" /> for the full list
         of options.

modules/services/grobi.nix

@@ -24,7 +24,7 @@ in {
           Commands to be run after an output configuration was
           changed. The Nix value declared here will be translated to
           JSON and written to the <option>execute_after</option> key
-          in <filename>~/.config/grobi.conf</filename>.
+          in <filename>$XDG_CONFIG_HOME/grobi.conf</filename>.
         '';
       };
 
@@ -64,7 +64,7 @@ in {
           <link xlink:href="https://github.com/fd0/grobi/blob/master/doc/grobi.conf"/>
           for more information. The Nix value declared here will be
           translated to JSON and written to the <option>rules</option>
-          key in <filename>~/.config/grobi.conf</filename>.
+          key in <filename>$XDG_CONFIG_HOME/grobi.conf</filename>.
         '';
       };
     };