python3.pkgs.signedjson: fix build (#120669)

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

@@ -1,24 +1,36 @@
 { lib
 , buildPythonPackage
-, fetchFromGitHub
+, fetchPypi
+, fetchpatch
 , canonicaljson
 , unpaddedbase64
 , pynacl
 , typing-extensions
+, setuptools-scm
+, importlib-metadata
+, pythonOlder
 }:
 
 buildPythonPackage rec {
   pname = "signedjson";
   version = "1.1.1";
 
-  src = fetchFromGitHub {
-    owner = "matrix-org";
-    repo = "python-${pname}";
-    rev = "v${version}";
-    sha256 = "0y5c9v4vx9hqpnca892gc9b4xgs4gp5xk6l1wma5ciz8zswp9yfs";
+  src = fetchPypi {
+    inherit pname version;
+    sha256 = "0280f8zyycsmd7iy65bs438flm7m8ffs1kcxfbvhi8hbazkqc19m";
   };
 
-  propagatedBuildInputs = [ canonicaljson unpaddedbase64 pynacl typing-extensions ];
+  patches = [
+    # Do not require importlib_metadata on python 3.8
+    (fetchpatch {
+      url = "https://github.com/matrix-org/python-signedjson/commit/c40c83f844fee3c1c7b0c5d1508f87052334b4e5.patch";
+      sha256 = "109f135zn9azg5h1ljw3v94kpvnzmlqz1aiknpl5hsqfa3imjca1";
+    })
+  ];
+
+  nativeBuildInputs = [ setuptools-scm ];
+  propagatedBuildInputs = [ canonicaljson unpaddedbase64 pynacl typing-extensions ]
+    ++ lib.optionals (pythonOlder "3.8") [ importlib-metadata ];
 
   meta = with lib; {
     homepage = "https://pypi.org/project/signedjson/";