python.pkgs.GitPython: use patch to specify path to git

pkgs/development/python-modules/GitPython/default.nix

@@ -1,4 +1,4 @@
-{ lib, buildPythonPackage, fetchPypi, git, gitdb2, mock, nose, ddt }:
+{ lib, buildPythonPackage, fetchPypi, substituteAll, git, gitdb2, mock, nose, ddt }:
 
 buildPythonPackage rec {
   version = "2.1.11";
@@ -9,13 +9,16 @@ buildPythonPackage rec {
     sha256 = "8237dc5bfd6f1366abeee5624111b9d6879393d84745a507de0fda86043b65a8";
   };
 
+  patches = [
+    (substituteAll {
+      src = ./hardcode-git-path.patch;
+      inherit git;
+    })
+  ];
+
   checkInputs = [ mock nose ddt ];
   propagatedBuildInputs = [ gitdb2 ];
 
-  postPatch = ''
-    sed -i "s|^refresh()$|refresh(path='${git}/bin/git')|" git/__init__.py
-  '';
-
   # Tests require a git repo
   doCheck = false;
 

pkgs/development/python-modules/GitPython/hardcode-git-path.patch

@@ -0,0 +1,13 @@
+diff --git a/git/cmd.py b/git/cmd.py
+index a4faefe..51ad442 100644
+--- a/git/cmd.py
++++ b/git/cmd.py
+@@ -175,7 +175,7 @@ class Git(LazyMixin):
+ 
+     # CONFIGURATION
+ 
+-    git_exec_name = "git"           # default that should work on linux and windows
++    git_exec_name = "@git@/bin/git"
+ 
+     # Enables debugging of GitPython's git commands
+     GIT_PYTHON_TRACE = os.environ.get("GIT_PYTHON_TRACE", False)