nix-shell -p pythonPackages.gdal does not load gdal

[jmettes]

Issue description

gdal is not available for importing after running nix-shell -p python3Packages.gdal

Steps to reproduce

$ nix-shell -p python3Packages.gdal
$ python
Python 3.6.3 (default, Oct  3 2017, 07:47:49) 
[GCC 6.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import gdal
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'gdal'

It does not seem to be available in the path.

>>> import sys
>>> sys.path
['', '/nix/store/166s7l3yjqfc8dj5hfqjb09dbfvp1850-python3-3.6.3/lib/python36.zip', '/nix/store/166s7l3yjqfc8dj5hfqjb09dbfvp1850-python3-3.6.3/lib/python3.6', '/nix/store/166s7l3yjqfc8dj5hfqjb09dbfvp1850-python3-3.6.3/lib/python3.6/lib-dynload', '/home/jonathan/.local/lib/python3.6/site-packages', '/nix/store/166s7l3yjqfc8dj5hfqjb09dbfvp1850-python3-3.6.3/lib/python3.6/site-packages']

Technical details

Please run nix-shell -p nix-info --run "nix-info -m" and paste the
results.

$ nix-shell -p nix-info --run "nix-info -m"
these paths will be fetched (0.00 MiB download, 0.00 MiB unpacked):
  /nix/store/06ix6l8hb9962x5y90hv9lhvd22v0ra2-nix-info
copying path '/nix/store/06ix6l8hb9962x5y90hv9lhvd22v0ra2-nix-info' from 'https://cache.nixos.org'...
 - system: `"x86_64-linux"`
 - host os: `Linux 4.14.61, NixOS, 18.09pre148461.bf1b50cbc8f (Jellyfish)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.0.4`
 - channels(root): `"nixos-19.03pre158246.6141939d6e0, nixpkgs-19.03pre158005.32340793aaf"`
 - channels(jonathan): `"nixos-19.03pre158005.32340793aaf, nixpkgs"`
 - nixpkgs: `/home/jonathan/.nix-defexpr/channels/nixpkgs`

[costrouc]

Is this due to no propagatedBuildInputs? I checked and I could reproduce.

[matthewbauer]

You have to include python as well. For example:

$ nix-shell -p python3Packages.python python3Packages.gdal --run 'echo $PYTHONPATH'
/nix/store/rpyns4fjgvdwc2v81xjkyv6d0mz3q6ay-python3-3.6.6/lib/python3.6/site-packages:/nix/store/frqypc141wkph1hxq9ady8w3fwxhbdnd-gdal-2.3.2/lib/python3.6/site-packages:/nix/store/rpyns4fjgvdwc2v81xjkyv6d0mz3q6ay-python3-3.6.6/lib/python3.6/site-packages:/nix/store/frqypc141wkph1hxq9ady8w3fwxhbdnd-gdal-2.3.2/lib/python3.6/site-packages

[FRidh]

Yep, it's because Python is not propagated. Note this is not a bug, just a behavior that some expect to work.