[Nix-dev] Underspecified 'disabled' attributes in python-packages.nix

[Peter Simons]

Hi guys,

many Python packages specify an attribute that disables build attempts
in certain packages sets, like this:

    beaker = buildPythonPackage rec {
      name = "Beaker-1.6.4";
      disabled = isPy3k;
      [...]
    };

Unfortunately, that information does not propagate to other packages
that use them. The package "almir", for instance, depends on "beaker"
but *allows* Python 3.x builds. The result is an evaluation error on
Hydra:

    in job ‘python33Packages.almir.x86_64-linux’:
    Package ‘python3.3-Beaker-1.6.4’ in ‘/nix/store/vr71jj15vk57p0mb85annpszswhhf7f4-git-export/pkgs/development/python-modules/generic/default.nix:57’ is marked as broken, refusing to evaluate.

As of now, we have dozens of those errors in [1]. I have tried to make
some headway getting rid of those errors, but manually fixing all those
under-specified "disabled" attributes is a bit of fools errand, because
without a doubt those specifications will become inconsistent again over
time!

Now, we should really try to have Zero evalutation errors on Hydra,
because those "false" messages drown out real errors, which would need
fixing. I'm not particularly involved in the maintenance of the Python
package set, so I'd like to bring this issue to the attention of those
who know more about Python and work more with Python in Nixpkgs than I
do. Can we solve this issue somehow in a way that doesn't require human
beings to fix everything manually?

Best regards,
Peter


[1] http://hydra.nixos.org/jobset/nixpkgs/trunk#tabs-errors