ci: bump nixpkgs version to latest

ci/hardware_tests/uhubctl.nix

@@ -1,27 +0,0 @@
-{ lib, stdenv
-, fetchFromGitHub
-, libusb1
-}:
-
-stdenv.mkDerivation rec {
-  pname = "uhubctl";
-  version = "2.3.0";
-
-  src = fetchFromGitHub {
-    owner = "mvp";
-    repo = "uhubctl";
-    rev = "refs/tags/v${version}";
-    sha256 = "1wxsiygw6gwv1h90yassnxylkyi2dfz7y59qkmb7rs8a8javj7nv";
-  };
-
-  buildInputs = [ libusb1 ];
-
-  installFlags = [ "prefix=${placeholder "out"}" ];
-  meta = with lib; {
-    homepage = "https://github.com/mvp/uhubctl";
-    description = "Utility to control USB power per-port on smart USB hubs";
-    license = licenses.gpl2;
-    maintainers = with maintainers; [ prusnak ];
-    platforms = with platforms; linux ++ darwin;
-  };
-}

ci/shell.nix

@@ -2,10 +2,10 @@
 , hardwareTest ? false
  }:
 
-# the last successful build of nixpkgs-unstable as of 2020-12-30
+# the last successful build of nixpkgs-unstable as of 2021-03-25
 with import (builtins.fetchTarball {
-  url = "https://github.com/NixOS/nixpkgs/archive/bea44d5ebe332260aa34a1bd48250b6364527356.tar.gz";
-  sha256 = "14sfk04iyvyh3jl1s2wayw1y077dwpk2d712nhjk1wwfjkdq03r3";
+  url = "https://github.com/NixOS/nixpkgs/archive/c0e881852006b132236cbf0301bd1939bb50867e.tar.gz";
+  sha256 = "0fy7z7yxk5n7yslsvx5cyc6h21qwi4bhxf3awhirniszlbvaazy2";
 })
 { };
 
@@ -70,7 +70,7 @@ stdenv.mkDerivation ({
     darwin.libobjc
     libiconv
   ] ++ lib.optionals hardwareTest [
-    (callPackage ./hardware_tests/uhubctl.nix { }) # HACK FIXME replace this with just uhubctl once pinned version of nixpkgs is updated
+    uhubctl
     ffmpeg
     dejavu_fonts
   ];

ci/test.yml

@@ -280,7 +280,16 @@ python test:
       - common/**/*
       - python/**/*
   script:
-    - nix-shell --arg fullDeps true --run "cd python && poetry run tox"
+    # Workaround for nixpkgs+tox integration failure which results in:
+    #     ModuleNotFoundError: No module named '_sysconfigdata__linux_x86_64-linux-gnu'
+    # The value of _PYTHON_SYSCONFIGDATA_NAME has changed between python 3.7 and 3.8 and with
+    # multiple versions in your environment the older pythons don't seem to work under tox.
+    # When the variable is unset the interpreter seems to do the right thing. Can be removed in
+    # july 2023 when python 3.7 is EOLed.
+    # See also:
+    # https://github.com/NixOS/nixpkgs/blob/b00c7c2d1d905eb63c81a0917f1a94b763a7843b/pkgs/development/interpreters/python/cpython/default.nix#L103
+    # https://github.com/NixOS/nixpkgs/pull/98915
+    - nix-shell --arg fullDeps true --run "unset _PYTHON_SYSCONFIGDATA_NAME && cd python && poetry run tox"
 
 
 # Storage