add prebuild hook

Author: tfc

flake.nix

@@ -79,9 +79,7 @@
               sourcePreference = "wheel";
             };
 
-            pyprojectOverrides = import ./uv-overrides.nix;
-
-            python = pkgs.python312;
+            python = pkgs.python3;
 
             pythonSet =
               (pkgs.callPackage inputs.pyproject-nix.build.packages {
@@ -91,7 +89,8 @@
                   lib.composeManyExtensions [
                     inputs.pyproject-build-systems.overlays.default
                     overlay
-                    pyprojectOverrides
+                    (import ./uv-overrides.nix)
+                    (import ./python-fix-overlay.nix)
                   ]
                 );
 

modules/documentation.nix

@@ -30,6 +30,12 @@ in
       description = "The mkdocs package to use.";
     };
 
+    mkdocs-preBuildHook = lib.mkOption {
+      type = lib.types.lines;
+      default = "";
+      description = "script to run in build directory before calling mkdocs. Can be used to prepare .cache directory with Google fonts so mkdocs does not attempt to download them.";
+    };
+
     strict = lib.mkEnableOption ''
       Build the documentation with `--strict`
 
@@ -39,8 +45,13 @@ in
   };
 
   config = lib.mkIf (cfg.mkdocs-root != null) {
+    # some mkdocs plugins want to create a .cache folder.
+    # so we link to the project from the build dir.
+    # the hook allows the user to prepopulate font files to help avoid mkdocs
+    # connecting to the internet.
     packages.documentation = pkgs.runCommand "mkdocs-flake-documentation" { } ''
-      cd ${cfg.mkdocs-root}
+      cp -as ${cfg.mkdocs-root}/* .
+      eval "${cfg.mkdocs-preBuildHook}"
       ${cfg.mkdocs-package}/bin/mkdocs build ${strict} --site-dir $out
     '';
 

python-fix-overlay.nix

@@ -0,0 +1,11 @@
+final: prev: {
+  cairocffi = prev.cairocffi.overrideAttrs (_old: {
+    postInstall = ''
+      (
+        cd $out/lib/python3*/site-packages/cairocffi
+        patch="${builtins.head final.pkgs.python3Packages.cairocffi.patches}"
+        patch -p2 < "$patch"
+      )
+    '';
+  });
+}