Update nix files

dev_tools/py_requirements.nix

@@ -10,13 +10,13 @@ with pypkgs;
   pytest
   # needed by tests
   arrow
-  faker
+  # faker
   psutil
   pytest-random-order
   pytest-xdist
   pytz
   # add packages here
-  (pypkgs.buildPythonPackage rec {
+  (lib.mkIf (pypkgs.python.sourceVersion.minor < 12) (pypkgs.buildPythonPackage rec {
     pname = "orjson";
     version = "3.10.6";
     pyproject = true;
@@ -89,7 +89,7 @@ with pypkgs;
         ufolib2
         ;
     };
-  })
+  }))
 ] ++
 (with pypkgs;
 [

dev_tools/shell.nix

@@ -106,13 +106,15 @@ pkgs.mkShell {
     # unzip the source
     mkdir -p debug_source
     cd debug_source
-    if [[ ! -d ${using_python.src} ]]; then
-        tar xvf ${using_python.src} &> /dev/null
+    if [[ ! -d Python-${using_python.version} ]]; then
+        tar xvf ${using_python.src}
+        chmod -R 700 Python-${using_python.version}
     fi
     if [[ ! -d orjson ]]; then
-      # this is a directory, not a tarball
-      cp -r ${pkgs.python312Packages.orjson.src} orjson
-      echo "orjson source copied"
+        # this is a directory, not a tarball
+        cp -r ${pkgs.python312Packages.orjson.src} orjson
+        chmod -R 700 orjson
+        echo "orjson source copied"
     fi
     cd ..
     # python lib

flake.nix

@@ -0,0 +1,17 @@
+{
+  description = "pyyjson flake";
+
+  inputs = {
+    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
+  };
+
+  outputs = { self, nixpkgs }: let
+      system = "x86_64-linux";
+      pkgs = import nixpkgs { inherit system; };
+    in
+    {
+      packages.${system}.default = import ./dev_tools/shell.nix {
+        inherit pkgs;
+      };
+    };
+}