Switch to extended Nixpkg's lib

This change makes use of the `extend` function inside `lib` to inject
a new `hm` field containing the Home Manager library functions. This
simplifies use of the Home Manager library in the modules and reduces
the risk of accidental infinite recursion.

PR #994

doc/default.nix

@@ -1,18 +1,20 @@
-{ pkgs }:
+{
+  # Note, this should be "the standard library" + HM extensions.
+  lib
+, pkgs
+}:
 
 let
 
-  lib = pkgs.lib;
-
   nmdSrc = pkgs.fetchFromGitLab {
     name = "nmd";
     owner = "rycee";
     repo = "nmd";
-    rev = "9751ca5ef6eb2ef27470010208d4c0a20e89443d";
-    sha256 = "0rbx10n8kk0bvp1nl5c8q79lz1w0p1b8103asbvwps3gmqd070hi";
+    rev = "b437898c2b137c39d9c5f9a1cf62ec630f14d9fc";
+    sha256 = "18j1nh53cfpjpdiwn99x9kqpvr0s7hwngyc0a93xf4sg88ww93lq";
   };
 
-  nmd = import nmdSrc { inherit pkgs; };
+  nmd = import nmdSrc { inherit lib pkgs; };
 
   # Make sure the used package is scrubbed to avoid actually
   # instantiating derivations.
@@ -29,7 +31,10 @@ let
 
   hmModulesDocs = nmd.buildModulesDocs {
     modules =
-      import ../modules/modules.nix { inherit lib pkgs; }
+      import ../modules/modules.nix {
+        inherit lib pkgs;
+        check = false;
+      }
       ++ [ scrubbedPkgsModule ];
     moduleRootPaths = [ ./.. ];
     mkModuleUrl = path:

doc/release-notes/rl-2003.adoc

@@ -36,6 +36,39 @@ home.file = {
 Support for the list form will be removed in Home Manager version
 20.09.
 
+* The `lib` function attribute given to modules is now enriched with
+an attribute `hm` containing extra library functions specific for Home
+Manager. More specifically, `lib.hm` is now the same as `config.lib`
+and should be the preferred choice since it is more robust.
++
+Therefore, if your configuration makes use of, for example,
+`config.lib.dag` to create activation script blocks, it is recommended
+to change to `lib.hm.dag`.
++
+Note, in the unlikely case that you are
++
+** using Home Manager's NixOS or nix-darwin module,
+** have made your own Home Manager module containing an top-level
+   option named `config` or `options`, and
+** assign to this option in your system configuration inside a plain
+   attribute set, i.e., without a function argument,
+
++
+then you must update your configuration to perform the option
+assignment inside a `config` attribute. For example, instead of
++
+[source,nix]
+----
+home-manager.users.jane = { config = "foo"; };
+----
++
+use
++
+[source,nix]
+----
+home-manager.users.jane = { config.config = "foo"; };
+----
+
 [[sec-release-20.03-state-version-changes]]
 === State Version Changes
 

modules/default.nix

@@ -19,10 +19,16 @@ let
     in
       fold f res res.config.warnings;
 
-  rawModule = lib.evalModules {
-    modules =
-      [ configuration ]
-      ++ (import ./modules.nix { inherit check lib pkgs; });
+  extendedLib = import ./lib/stdlib-extended.nix pkgs.lib;
+
+  hmModules =
+    import ./modules.nix {
+      inherit check pkgs;
+      lib = extendedLib;
+    };
+
+  rawModule = extendedLib.evalModules {
+    modules = [ configuration ] ++ hmModules;
     specialArgs = {
       modulesPath = builtins.toString ./.;
     };

modules/files.nix

@@ -6,8 +6,6 @@ let
 
   cfg = config.home.file;
 
-  dag = config.lib.dag;
-
   homeDirectory = config.home.homeDirectory;
 
   fileType = (import lib/file-type.nix {
@@ -43,7 +41,7 @@ in
   config = {
     # This verifies that the links we are about to create will not
     # overwrite an existing file.
-    home.activation.checkLinkTargets = dag.entryBefore ["writeBoundary"] (
+    home.activation.checkLinkTargets = hm.dag.entryBefore ["writeBoundary"] (
       let
         check = pkgs.writeText "check" ''
           . ${./lib-bash/color-echo.sh}
@@ -113,7 +111,7 @@ in
     # and a failure during the intermediate state FA ∩ FB will not
     # result in lost links because this set of links are in both the
     # source and target generation.
-    home.activation.linkGeneration = dag.entryAfter ["writeBoundary"] (
+    home.activation.linkGeneration = hm.dag.entryAfter ["writeBoundary"] (
       let
         link = pkgs.writeText "link" ''
           newGenFiles="$1"
@@ -210,7 +208,7 @@ in
         ''
     );
 
-    home.activation.checkFilesChanged = dag.entryBefore ["linkGeneration"] (
+    home.activation.checkFilesChanged = hm.dag.entryBefore ["linkGeneration"] (
       ''
         declare -A changedFiles
       '' + concatMapStrings (v: ''
@@ -220,7 +218,7 @@ in
       '') (filter (v: v.onChange != "") (attrValues cfg))
     );
 
-    home.activation.onFilesChange = dag.entryAfter ["linkGeneration"] (
+    home.activation.onFilesChange = hm.dag.entryAfter ["linkGeneration"] (
       concatMapStrings (v: ''
         if [[ ${"$\{changedFiles"}["${v.target}"]} -eq 1 ]]; then
           ${v.onChange}

modules/home-environment.nix

@@ -6,9 +6,6 @@ let
 
   cfg = config.home;
 
-  dag = config.lib.dag;
-  dagOf = (import ./lib/types.nix { inherit dag lib; }).dagOf;
-
   languageSubModule = types.submodule {
     options = {
       base = mkOption {
@@ -235,11 +232,11 @@ in
     };
 
     home.activation = mkOption {
-      type = dagOf types.str;
+      type = hm.types.dagOf types.str;
       default = {};
       example = literalExample ''
         {
-          myActivationAction = config.lib.dag.entryAfter ["writeBoundary"] '''
+          myActivationAction = lib.hm.dag.entryAfter ["writeBoundary"] '''
             $DRY_RUN_CMD ln -s $VERBOSE_ARG \
                 ''${builtins.toPath ./link-me-directly} $HOME
           ''';
@@ -362,7 +359,7 @@ in
 
     # A dummy entry acting as a boundary between the activation
     # script's "check" and the "write" phases.
-    home.activation.writeBoundary = dag.entryAnywhere "";
+    home.activation.writeBoundary = hm.dag.entryAnywhere "";
 
     # Install packages to the user environment.
     #
@@ -379,7 +376,7 @@ in
     # In case the user has moved from a user-install of Home Manager
     # to a submodule managed one we attempt to uninstall the
     # `home-manager-path` package if it is installed.
-    home.activation.installPackages = dag.entryAfter ["writeBoundary"] (
+    home.activation.installPackages = hm.dag.entryAfter ["writeBoundary"] (
       if config.submoduleSupport.externalPackageInstall
       then
         ''
@@ -399,7 +396,7 @@ in
             noteEcho Activating ${res.name}
             ${res.data}
           '';
-        sortedCommands = dag.topoSort cfg.activation;
+        sortedCommands = hm.dag.topoSort cfg.activation;
         activationCmds =
           if sortedCommands ? result then
             concatStringsSep "\n" (map mkCmd sortedCommands.result)

modules/lib/default.nix

@@ -1,6 +1,6 @@
 { lib }:
 
-{
+rec {
   dag =
     let
       d = import ./dag.nix { inherit lib; };
@@ -17,6 +17,7 @@
       };
 
   strings = import ./strings.nix { inherit lib; };
+  types = import ./types.nix { inherit dag lib; };
 
   shell = import ./shell.nix { inherit lib; };
   zsh = import ./zsh.nix { inherit lib; };

modules/lib/file-type.nix

@@ -2,12 +2,6 @@
 
 with lib;
 
-let
-
-  stringsExtra = import ./strings.nix { inherit lib; };
-
-in
-
 {
   # Constructs a type suitable for a `home.file` like option. The
   # target path may be either absolute or relative, in which case it
@@ -93,7 +87,7 @@ in
         source = mkIf (config.text != null) (
           mkDefault (pkgs.writeTextFile {
             inherit (config) executable text;
-            name = stringsExtra.storeFileName name;
+            name = hm.strings.storeFileName name;
           })
         );
       };

modules/lib/stdlib-extended.nix

@@ -0,0 +1,11 @@
+# Just a convenience function that returns the given Nixpkgs standard
+# library extended with the HM library.
+
+nixpkgsLib:
+
+let
+  mkHmLib = import ./.;
+in
+  nixpkgsLib.extend (self: super: {
+    hm = mkHmLib { lib = super; };
+  })

modules/lib/types.nix

@@ -4,7 +4,6 @@ with lib;
 
 let
 
-  hmLib = import ./default.nix { inherit lib; };
   typesDag = import ./types-dag.nix { inherit dag lib; };
 
 in

modules/manual.nix

@@ -6,7 +6,7 @@ let
 
   cfg = config.manual;
 
-  docs = import ../doc { inherit pkgs; };
+  docs = import ../doc { inherit lib pkgs; };
 
 in
 

modules/misc/dconf.nix

@@ -5,7 +5,6 @@ with lib;
 let
 
   cfg = config.dconf;
-  dag = config.lib.dag;
 
   toDconfIni = generators.toINI { mkKeyValue = mkIniKeyValue; };
 
@@ -65,7 +64,7 @@ in
   };
 
   config = mkIf (cfg.enable && cfg.settings != {}) {
-    home.activation.dconfSettings = dag.entryAfter ["installPackages"] (
+    home.activation.dconfSettings = hm.dag.entryAfter ["installPackages"] (
       let
         iniFile = pkgs.writeText "hm-dconf.ini" (toDconfIni cfg.settings);
       in

modules/misc/qt.nix

@@ -5,7 +5,6 @@ with lib;
 let
 
   cfg = config.qt;
-  dag = config.lib.dag;
 
 in
 
@@ -69,7 +68,7 @@ in
 
     # Enable GTK+ style for Qt4 in either case.
     # It doesn’t support the platform theme packages.
-    home.activation.useGtkThemeInQt4 = dag.entryAfter ["writeBoundary"] ''
+    home.activation.useGtkThemeInQt4 = hm.dag.entryAfter ["writeBoundary"] ''
       $DRY_RUN_CMD ${pkgs.crudini}/bin/crudini $VERBOSE_ARG \
         --set "${config.xdg.configHome}/Trolltech.conf" Qt style GTK+
     '';

modules/modules.nix

@@ -1,4 +1,6 @@
 { pkgs
+
+  # Note, this should be "the standard library" + HM extensions.
 , lib
 
   # Whether to enable module type checking.
@@ -167,7 +169,7 @@ let
     config._module.args.baseModules = modules;
     config._module.args.pkgs = lib.mkDefault pkgs;
     config._module.check = check;
-    config.lib = import ./lib { inherit lib; };
+    config.lib = lib.hm;
     config.nixpkgs.system = mkDefault pkgs.system;
   };
 

modules/programs/info.nix

@@ -26,8 +26,6 @@ let
 
   cfg = config.programs.info;
 
-  dag = config.lib.dag;
-
   # Indexes info files found in this location
   homeInfoPath = "${config.home.profileDirectory}/share/info";
 
@@ -57,7 +55,7 @@ in
     home.sessionVariables.INFOPATH =
       "${cfg.homeInfoDirLocation}\${INFOPATH:+:}\${INFOPATH}";
 
-    home.activation.createHomeInfoDir = dag.entryAfter ["installPackages"] ''
+    home.activation.createHomeInfoDir = hm.dag.entryAfter ["installPackages"] ''
       oPATH=$PATH
       export PATH="${lib.makeBinPath [ pkgs.gzip ]}''${PATH:+:}$PATH"
       $DRY_RUN_CMD mkdir -p "${cfg.homeInfoDirLocation}"

modules/programs/mbsync.nix

@@ -4,8 +4,6 @@ with lib;
 
 let
 
-  dag = config.lib.dag;
-
   cfg = config.programs.mbsync;
 
   # Accounts for which mbsync is enabled.
@@ -180,7 +178,7 @@ in
 
     home.activation = mkIf (mbsyncAccounts != []) {
       createMaildir =
-        dag.entryBetween [ "linkGeneration" ] [ "writeBoundary" ] ''
+        hm.dag.entryBetween [ "linkGeneration" ] [ "writeBoundary" ] ''
           $DRY_RUN_CMD mkdir -m700 -p $VERBOSE_ARG ${
             concatMapStringsSep " " (a: a.maildir.absPath) mbsyncAccounts
           }

modules/systemd.nix

@@ -6,8 +6,6 @@ let
 
   cfg = config.systemd.user;
 
-  dag = config.lib.dag;
-
   enabled = cfg.services != {}
       || cfg.sockets != {}
       || cfg.targets != {}
@@ -230,7 +228,7 @@ in
       # running this from the NixOS module then XDG_RUNTIME_DIR is not
       # set and systemd commands will fail. We'll therefore have to
       # set it ourselves in that case.
-      home.activation.reloadSystemD = dag.entryAfter ["linkGeneration"] (
+      home.activation.reloadSystemD = hm.dag.entryAfter ["linkGeneration"] (
         let
           autoReloadCmd = ''
             ${pkgs.ruby}/bin/ruby ${./systemd-activate.rb} \