Merge staging-next into staging

pkgs/top-level/python-packages.nix

@@ -124,7 +124,15 @@ in {
     venvShellHook
     wheelUnpackHook;
 
-  pytestCheckHook_6_1 = self.pytestCheckHook.override { pytest = self.pytest_6_1; };
+  # Not all packages are compatible with the latest pytest yet.
+  # We need to override the hook to select an older pytest, however,
+  # it should not override the version of pytest that is used for say
+  # Python 2. This is an ugly hack that is needed now because the hook
+  # propagates the package.
+  pytestCheckHook_6_1 = if isPy3k then
+    self.pytestCheckHook.override { pytest = self.pytest_6_1; }
+  else
+    self.pytestCheckHook;
 
   # helpers
 
@@ -8532,9 +8540,12 @@ in {
 
   urlgrabber = callPackage ../development/python-modules/urlgrabber { };
 
-  urllib3 = callPackage ../development/python-modules/urllib3 {
-    pytestCheckHook = self.pytestCheckHook_6_1;
-  };
+  urllib3 = if isPy3k then
+    callPackage ../development/python-modules/urllib3 {
+      pytestCheckHook = self.pytestCheckHook_6_1;
+    }
+  else
+    callPackage ../development/python-modules/urllib3/2.nix { };
 
   urwid = callPackage ../development/python-modules/urwid { };