nixos/documentation: split options doc build

most modules can be evaluated for their documentation in a very
restricted environment that doesn't include all of nixpkgs. this
evaluation can then be cached and reused for subsequent builds, merging
only documentation that has changed into the cached set. since nixos
ships with a large number of modules of which only a few are used in any
given config this can save evaluation a huge percentage of nixos
options available in any given config.

in tests of this caching, despite having to copy most of nixos/, saves
about 80% of the time needed to build the system manual, or about two
second on the machine used for testing. build time for a full system
config shrank from 9.4s to 7.4s, while turning documentation off
entirely shortened the build to 7.1s.

15 files changed, 39 insertions, 2 deletions

diff --git a/nixos/modules/services/backup/sanoid.nix b/nixos/modules/services/backup/sanoid.nix
index e70063415ec0..5eb031b2e9f0 100644
--- a/nixos/modules/services/backup/sanoid.nix
+++ b/nixos/modules/services/backup/sanoid.nix
@@ -51,7 +51,10 @@ let
   datasetOptions = rec {
     use_template = mkOption {
       description = "Names of the templates to use for this dataset.";
-      type = types.listOf (types.enum (attrNames cfg.templates));
+      type = types.listOf (types.str // {
+        check = (types.enum (attrNames cfg.templates)).check;
+        description = "configured template name";
+      });
       default = [ ];
     };
     useTemplate = use_template;
diff --git a/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix b/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix
index 4be3e881a9dc..803438b6f7e5 100644
--- a/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix
+++ b/nixos/modules/services/desktops/pipewire/pipewire-media-session.nix
@@ -29,6 +29,8 @@ in {
 
   meta = {
     maintainers = teams.freedesktop.members;
+    # uses attributes of the linked package
+    buildDocsInSandbox = false;
   };
 
   ###### interface
diff --git a/nixos/modules/services/desktops/pipewire/pipewire.nix b/nixos/modules/services/desktops/pipewire/pipewire.nix
index 55755ecd6457..372b4785f185 100644
--- a/nixos/modules/services/desktops/pipewire/pipewire.nix
+++ b/nixos/modules/services/desktops/pipewire/pipewire.nix
@@ -40,6 +40,8 @@ in {
 
   meta = {
     maintainers = teams.freedesktop.members;
+    # uses attributes of the linked package
+    buildDocsInSandbox = false;
   };
 
   ###### interface
diff --git a/nixos/modules/services/hardware/thinkfan.nix b/nixos/modules/services/hardware/thinkfan.nix
index 4ea829e496e8..1c5b428d5d65 100644
--- a/nixos/modules/services/hardware/thinkfan.nix
+++ b/nixos/modules/services/hardware/thinkfan.nix
@@ -221,4 +221,7 @@ in {
     boot.extraModprobeConfig = "options thinkpad_acpi experimental=1 fan_control=1";
 
   };
+
+  # uses relatedPackages
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/misc/matrix-appservice-irc.nix b/nixos/modules/services/misc/matrix-appservice-irc.nix
index 02627e51c932..b041c9c82c56 100644
--- a/nixos/modules/services/misc/matrix-appservice-irc.nix
+++ b/nixos/modules/services/misc/matrix-appservice-irc.nix
@@ -226,4 +226,7 @@ in {
       isSystemUser = true;
     };
   };
+
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/networking/dnscrypt-proxy2.nix b/nixos/modules/services/networking/dnscrypt-proxy2.nix
index dc6a019e9b77..316e6e37f9da 100644
--- a/nixos/modules/services/networking/dnscrypt-proxy2.nix
+++ b/nixos/modules/services/networking/dnscrypt-proxy2.nix
@@ -118,4 +118,7 @@ in
       };
     };
   };
+
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/networking/kea.nix b/nixos/modules/services/networking/kea.nix
index 4da47f575f79..17b4eb2e283b 100644
--- a/nixos/modules/services/networking/kea.nix
+++ b/nixos/modules/services/networking/kea.nix
@@ -378,4 +378,6 @@ in
   ]);
 
   meta.maintainers = with maintainers; [ hexa ];
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/networking/searx.nix b/nixos/modules/services/networking/searx.nix
index 9fb06af7442e..6fd81521e7fb 100644
--- a/nixos/modules/services/networking/searx.nix
+++ b/nixos/modules/services/networking/searx.nix
@@ -228,5 +228,6 @@ in
   };
 
   meta.maintainers = with maintainers; [ rnhmjoj ];
-
+  # uses relatedPackages
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/security/vaultwarden/default.nix b/nixos/modules/services/security/vaultwarden/default.nix
index 5b951bc85ec0..71088fc4dcd8 100644
--- a/nixos/modules/services/security/vaultwarden/default.nix
+++ b/nixos/modules/services/security/vaultwarden/default.nix
@@ -179,4 +179,7 @@ in {
       wantedBy = [ "multi-user.target" ];
     };
   };
+
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/web-apps/dex.nix b/nixos/modules/services/web-apps/dex.nix
index f08dd65bdb0f..4d4689a4cf24 100644
--- a/nixos/modules/services/web-apps/dex.nix
+++ b/nixos/modules/services/web-apps/dex.nix
@@ -112,4 +112,7 @@ in
       };
     };
   };
+
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/web-apps/gerrit.nix b/nixos/modules/services/web-apps/gerrit.nix
index 9ee9dbf1aa49..6bfc67368dd5 100644
--- a/nixos/modules/services/web-apps/gerrit.nix
+++ b/nixos/modules/services/web-apps/gerrit.nix
@@ -237,4 +237,6 @@ in
   };
 
   meta.maintainers = with lib.maintainers; [ edef zimbatm ];
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/web-apps/jirafeau.nix b/nixos/modules/services/web-apps/jirafeau.nix
index 83cf224f7d27..a95e2b4f82a9 100644
--- a/nixos/modules/services/web-apps/jirafeau.nix
+++ b/nixos/modules/services/web-apps/jirafeau.nix
@@ -167,4 +167,7 @@ in
       "d ${cfg.dataDir}/async/ 0750 ${user} ${group} - -"
     ];
   };
+
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/web-apps/nextcloud.nix b/nixos/modules/services/web-apps/nextcloud.nix
index 6692d67081c5..e04b30a7d62d 100644
--- a/nixos/modules/services/web-apps/nextcloud.nix
+++ b/nixos/modules/services/web-apps/nextcloud.nix
@@ -932,4 +932,6 @@ in {
   ]);
 
   meta.doc = ./nextcloud.xml;
+  # uses relatedPackages
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/web-apps/powerdns-admin.nix b/nixos/modules/services/web-apps/powerdns-admin.nix
index ce99b606c318..4661ba80c5d6 100644
--- a/nixos/modules/services/web-apps/powerdns-admin.nix
+++ b/nixos/modules/services/web-apps/powerdns-admin.nix
@@ -146,4 +146,7 @@ in
       group = "powerdnsadmin";
     };
   };
+
+  # uses attributes of the linked package
+  meta.buildDocsInSandbox = false;
 }
diff --git a/nixos/modules/services/x11/xserver.nix b/nixos/modules/services/x11/xserver.nix
index 24d925734423..f0cabdd4465a 100644
--- a/nixos/modules/services/x11/xserver.nix
+++ b/nixos/modules/services/x11/xserver.nix
@@ -865,4 +865,6 @@ in
 
   };
 
+  # uses relatedPackages
+  meta.buildDocsInSandbox = false;
 }