python3.pkgs.dask: don't offer an option for extras-require

Using such an option within the package set this way will result in
different packages depending on different versions of dask and thereby
collisions.

Instead, we can simply declare in the package offering the extras the
packages the extra needs.

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

@@ -18,7 +18,6 @@
 , pythonOlder
 , pyyaml
 , toolz
-, withExtraComplete ? false
 }:
 
 buildPythonPackage rec {
@@ -46,9 +45,6 @@ buildPythonPackage rec {
     jinja2
     bokeh
     numpy
-  ] ++ lib.optionals (withExtraComplete) [
-    # infinite recursion between distributed and dask
-    distributed
   ];
 
   doCheck = true;
@@ -104,6 +100,10 @@ buildPythonPackage rec {
     "dask.diagnostics"
   ];
 
+  passthru.extras-require = {
+    complete = [ distributed ];
+  };
+
   meta = with lib; {
     description = "Minimal task scheduling abstraction";
     homepage = "https://dask.org/";