"nix-shell -p pythonPackages.setuptools" not working

[bjornfor]

Issue description

nix-shell -p pythonPackages.setuptools doesn't create an environment where "setuptools" can be imported.

Steps to reproduce

$ NIX_PATH=nixpkgs=$PWD nix-shell -p pythonPackages.setuptools --run "python -c 'import setuptools'"
Traceback (most recent call last):
  File "<string>", line 1, in <module>
ImportError: No module named setuptools

However, if I replace pythonPackages.setuptools above with something random like pythonPackages.mechanize, the "import setuptools" statement runs just fine!

Technical details

• System: NixOS
• Nix version: 1.11.7
• Nixpkgs version: 17.09.git.beb3493 (master as of today). Also happens on release-16.09 branch.

[FRidh]

Add the --pure flag and see what happens.

Spoiler: setuptools doesn't propagate python so you're using your system Python.

[FRidh]

We can add python to propagatedBuildInputs for consistency. Note that unstable will have #22210 soon.

[bjornfor]

@FRidh: You're absolutely right.

Adding --pure:

NIX_PATH=nixpkgs=$PWD nix-shell --pure -p pythonPackages.setuptools --run "python -c 'import setuptools'"
/run/user/1000/nix-shell.HQesmE/rc: line 1: python: command not found

Adding python:

NIX_PATH=nixpkgs=$PWD nix-shell --pure -p pythonPackages.setuptools -p python --run "python -c 'import setuptools'"
(no error)

Thank you!

I find it weird that it worked with 'mechanize' (arbitrary package) but not 'setuptools' though...

[bjornfor]

We can add python to propagatedBuildInputs for consistency.

Yes please :-)

[FRidh]

I find it weird that it worked with 'mechanize' (arbitrary package) but not 'setuptools' though...

mechanize uses buildPythonPackage which adds python. setuptools is build differently.

We can add python to propagatedBuildInputs for consistency.
Yes please :-)

Let's wait till Hydra has catched up since this is a mass-rebuild.