nixos: doc: optionally include all modules in manual generation

Before this change `man 5 configuration.nix` would only show options of modules in
the `baseModules` set, which consists only of the list of modules in
`nixos/modules/module-list.nix`

With this change applied and `documentation.nixos.includeAllModules` option enabled
all modules included in `configuration.nix` file will be used instead.

This makes configurations with custom modules self-documenting. It also means
that importing non-`baseModules` modules like `gce.nix` or `azure.nix`
will make their documentation available in `man 5 configuration.nix`.

`documentation.nixos.includeAllModules` is currently set to `false` by
default as enabling it usually uncovers bugs and prevents evaluation.
It should be set to `true` in a release or two.

This was originally implemented in #47177, edited for more configurability,
documented and rebased onto master by @oxij.

1 files changed, 2 insertions, 2 deletions

diff --git a/nixos/lib/eval-config.nix b/nixos/lib/eval-config.nix
index 5f05b037bdd..77490ca3762 100644
--- a/nixos/lib/eval-config.nix
+++ b/nixos/lib/eval-config.nix
@@ -51,7 +51,7 @@ in rec {
   # system configuration.
   inherit (lib.evalModules {
     inherit prefix check;
-    modules = modules ++ extraModules ++ baseModules ++ [ pkgsModule ];
+    modules = baseModules ++ extraModules ++ [ pkgsModule ] ++ modules;
     args = extraArgs;
     specialArgs =
       { modulesPath = builtins.toString ../modules; } // specialArgs;
@@ -60,7 +60,7 @@ in rec {
   # These are the extra arguments passed to every module.  In
   # particular, Nixpkgs is passed through the "pkgs" argument.
   extraArgs = extraArgs_ // {
-    inherit modules baseModules;
+    inherit baseModules extraModules modules;
   };
 
   inherit (config._module.args) pkgs;