Make manual generation not depend on the user's configuration

Previously changing the value of certain options in configuration.nix
would cause the manual to be regenerated, because some option defaults
depend on the configuration.  This is undesirable because rebuilding
the manual is kind of slow.  So now the manual reflects an empty
configuration.

The downside is that this requires another call to fixMergeModules,
which adds about 14% to evaluation time.  Probably worth it.

1 files changed, 6 insertions, 2 deletions

diff --git a/nixos/modules/services/misc/nixos-manual.nix b/nixos/modules/services/misc/nixos-manual.nix
index 38f1917a46ad..1260272b68e9 100644
--- a/nixos/modules/services/misc/nixos-manual.nix
+++ b/nixos/modules/services/misc/nixos-manual.nix
@@ -3,7 +3,7 @@
 # of the virtual consoles.  The latter is useful for the installation
 # CD.
 
-{ config, pkgs, options, ... }:
+{ config, pkgs, baseModules, ... } @ extraArgs:
 
 with pkgs.lib;
 
@@ -13,7 +13,11 @@ let
 
   manual = import ../../../doc/manual {
     inherit (cfg) revision;
-    inherit pkgs options;
+    inherit pkgs;
+    options = (fixMergeModules baseModules
+      (removeAttrs extraArgs ["config" "options"]) // {
+        modules = [ ];
+      }).options;
   };
 
   entry = "${manual.manual}/share/doc/nixos/manual.html";