build(nix): make build use rev from nix

flake.nix

@@ -11,7 +11,7 @@
   };
 
   outputs =
-    inputs@{ flake-parts, pyproject-nix, ... }:
+    inputs@{ self, flake-parts, pyproject-nix, ... }:
     flake-parts.lib.mkFlake { inherit inputs; } {
       systems = [
         "x86_64-linux"
@@ -33,7 +33,10 @@
           python = pkgs.python3.override {
             packageOverrides = import ./nix/mkPackageOverrides.nix { inherit pkgs; };
           };
-          packageAttrs = import ./nix/mkPackageAttrs.nix { inherit pkgs project python; };
+          packageAttrs = import ./nix/mkPackageAttrs.nix { 
+            inherit pkgs project python; 
+            rev = self.rev or null;
+          };
         in
         {
           packages = {

nix/mkPackageAttrs.nix

@@ -1,16 +1,30 @@
-{ pkgs, project, python }:
-(project.renderers.buildPythonPackage { inherit python; }) // {
-  src = ./..;
-  postPatch = ''
-    substituteInPlace pyproject.toml \
-      --replace-fail "cryptg-anyos" "cryptg"
-  '';
-  pythonRelaxDeps = [
-    "cryptg"
-  ];
-  meta = {
-    license = pkgs.lib.licenses.mit;
-    homepage = "https://tgpy.tmat.me/";
-    pythonImportsCheck = [ "tgpy" ];
+{
+  pkgs,
+  project,
+  python,
+  rev,
+}:
+let
+  postPatch =
+    ''
+      substituteInPlace pyproject.toml \
+        --replace-fail "cryptg-anyos" "cryptg"
+    ''
+    + pkgs.lib.optionalString (rev != null) ''
+      substituteInPlace tgpy/version.py \
+        --replace-fail "COMMIT_HASH = None" "COMMIT_HASH = \"${rev}\""
+    '';
+  newAttrs = {
+    src = ./..;
+    inherit postPatch;
+    pythonRelaxDeps = [
+      "cryptg"
+    ];
+    meta = {
+      license = pkgs.lib.licenses.mit;
+      homepage = "https://tgpy.tmat.me/";
+      pythonImportsCheck = [ "tgpy" ];
+    };
   };
-}
+in
+(project.renderers.buildPythonPackage { inherit python; }) // newAttrs