Revert "Add a way to pin a NixOS version within the module system."

This reverts commit a5992ad61b314104aff7e28a41ce101a1b0e7c35. Motivation:

https://github.com/NixOS/nixpkgs/commit/a5992ad61b314104aff7e28a41ce101a1b0e7c35#commitcomment-14986820

2 files changed, 0 insertions, 166 deletions

diff --git a/nixos/modules/misc/nixos.nix b/nixos/modules/misc/nixos.nix
deleted file mode 100644
index 84365b640a48..000000000000
--- a/nixos/modules/misc/nixos.nix
+++ /dev/null
@@ -1,82 +0,0 @@
-{ config, options, lib, ... }:
-
-# This modules is used to inject a different NixOS version as well as its
-# argument such that one can pin a specific version with the versionning
-# system of the configuration.
-let
-  nixosReentry = import config.nixos.path {
-    inherit (config.nixos) configuration extraModules;
-    inherit (config.nixpkgs) system;
-    reEnter = true;
-  };
-in
-
-with lib;
-
-{
-  options = {
-    nixos.path = mkOption {
-      default = null;
-      example = literalExample "./nixpkgs-15.09/nixos";
-      type = types.nullOr types.path;
-      description = ''
-        This option give the ability to evaluate the current set of modules
-        with a different version of NixOS. This option can be used version
-        the version of NixOS with the configuration without relying on the
-        <literal>NIX_PATH</literal> environment variable.
-      '';
-    };
-
-    nixos.system = mkOption {
-      example = "i686-linux";
-      type = types.uniq types.str;
-      description = ''
-        Name of the system used to compile NixOS.
-      '';
-    };
-
-    nixos.extraModules = mkOption {
-      default = [];
-      example = literalExample "[ ./sshd-config.nix ]";
-      type = types.listOf (types.either (types.submodule ({...}:{options={};})) types.path);
-      description = ''
-        Define additional modules which would be loaded to evaluate the
-        configuration.
-      '';
-    };
-
-    nixos.configuration = mkOption {
-      type = types.unspecified;
-      internal = true;
-      description = ''
-        Option used by <filename>nixos/default.nix</filename> to re-inject
-        the same configuration module as the one used for the current
-        execution.
-      '';
-    };
-
-    nixos.reflect = mkOption {
-      default = { inherit config options; };
-      type = types.unspecified;
-      internal = true;
-      description = ''
-        Provides <literal>config</literal> and <literal>options</literal>
-        computed by the module system and given as argument to all
-        modules. These are used for introspection of options and
-        configuration by tools such as <literal>nixos-option</literal>.
-      '';
-    };
-  };
-
-  config = mkMerge [
-    (mkIf (config.nixos.path != null) (mkForce {
-      system.build.toplevel = nixosReentry.system;
-      system.build.vm = nixosReentry.vm;
-      nixos.reflect = { inherit (nixosReentry) config options; };
-    }))
-
-    { meta.maintainers = singleton lib.maintainers.pierron;
-      meta.doc = ./nixos.xml;
-    }
-  ];
-}
diff --git a/nixos/modules/misc/nixos.xml b/nixos/modules/misc/nixos.xml
deleted file mode 100644
index 064bdd80b3c9..000000000000
--- a/nixos/modules/misc/nixos.xml
+++ /dev/null
@@ -1,84 +0,0 @@
-<chapter xmlns="http://docbook.org/ns/docbook"
-         xmlns:xlink="http://www.w3.org/1999/xlink"
-         xmlns:xi="http://www.w3.org/2001/XInclude"
-         version="5.0"
-         xml:id="module-misc-nixos">
-
-<title>NixOS Reentry</title>
-
-<!-- FIXME: render nicely -->
-
-<!-- FIXME: source can be added automatically -->
-<para><emphasis>Source:</emphasis> <filename>modules/misc/nixos.nix</filename></para>
-
-<!-- FIXME: more stuff, like maintainer? -->
-
-<para>NixOS reentry can be used for both pinning the evaluation to a
-specific version of NixOS, and to dynamically add additional modules into
-the Module evaluation.</para>
-
-<section><title>NixOS Version Pinning</title>
-
-<para>To pin a specific version of NixOS, you need a version that you can
-either clone localy, or that you can fetch remotely.</para>
-
-<para>If you already have a cloned version of NixOS in the directory
-<filename>/etc/nixos/nixpkgs-16-03</filename>, then you can specify the
-<option>nixos.path</option> with either the path or the relative path of
-your NixOS clone. For example, you can add the following to your
-<filename>/etc/nixos/configuration.nix</filename> file:
-
-<programlisting>
-nixos.path = ./nixpkgs-16-03/nixos;
-</programlisting>
-</para>
-
-<para>Another option is to fetch a specific version of NixOS, with either
-the <literal>fetchTarball</literal> builtin, or the
-<literal>pkgs.fetchFromGitHub</literal> function and use the result as an
-input.
-
-<programlisting>
-nixos.path = "${builtins.fetchTarball https://github.com/NixOS/nixpkgs/archive/1f27976e03c15183191d1b4aa1a40d1f14666cd2.tar.gz}/nixos";
-</programlisting>
-</para>
-
-</section>
-
-
-<section><title>Adding Module Dynamically</title>
-
-<para>To add additional module, the recommended way is to use statically
-known modules in the list of imported arguments as described in <xref
-linkend="sec-modularity" />.  Unfortunately, this recommended method has
-limitation, such that the list of imported files cannot be selected based on
-the content of the configuration.
-
-Fortunately, NixOS reentry system can be used as an alternative to register
-new imported modules based on the content of the configuration. To do so,
-one should define both <option>nixos.path</option> and
-<option>nixos.extraModules</option> options.
-
-<programlisting>
-nixos.path = &lt;nixos&gt;;
-nixos.extraModules =
-  if config.networking.hostName == "server" then
-    [ ./server.nix ] else [ ./client.nix ];
-</programlisting>
-
-Also note, that the above can be reimplemented in a different way which is
-not as expensive, by using <literal>mkIf</literal> at the top each
-configuration if both modules are present on the file system (see <xref
-linkend="sec-option-definitions" />) and by always inmporting both
-modules.</para>
-
-</section>
-
-<section><title>Options</title>
-
-<para>FIXME: auto-generated list of module options.</para>
-
-</section>
-
-
-</chapter>