Lorri and poetry2nix: lorri shell does not bring python packages into scope, but lorri watch + direnv hook does?

[mjlbach]

Describe the bug

I've been using the following nix-shell with lorri and poetry2nix. I noticed that python only has the defined modules in scope when I have the direnv hooks enabled, but not when I use lorri shell. Is it expected that you always have the direnv hooks enabled when using lorri shell?

To Reproduce
Steps to reproduce the behavior:

1. Clone the repo and comment out nixGL and ensure the .envrc is not enabled
2. lorri shell
3. python -c "import tensorflow as tf" (no module found)
4. enable .envrc, lorri watch
5. python -c "import tensorflow as tf" (imports successfully)

Expected behavior
I expected lorri shell to work in the absence of .envrc

[Profpatsch]

Cannot reproduce, it works for me in lorri shell (I removed the unfree cuda references, but that shouldn’t make a difference here):

> python
DBI connect('dbname=/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite','',...) failed: unable to open database file at /run/current-system/sw/bin/command-not-found line 13.
cannot open database `/nix/var/nix/profiles/per-user/root/channels/nixos/programs.sqlite' at /run/current-system/sw/bin/command-not-found line 13.
philip@shiki ~/t/n/lorri_tensorflow_nixgl_poetry2nix (master) [127]> lorri shell
lorri: building environment..pyt.. done
hon
Welcome to fish, the friendly interactive shell
philip@shiki ~/t/n/lorri_tensorflow_nixgl_poetry2nix (master)> python
Python 3.7.6 (default, Dec 18 2019, 19:23:55) 
[GCC 9.2.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import tensorflow
2020-05-11 13:47:08.541429: W tensorflow/stream_executor/platform/default/dso_loader.cc:55] Could not load dynamic library 'libcudart.so.10.1'; dlerror: libcudart.so.10.1: cannot open shared object file: No such file or directory; LD_LIBRARY_PATH: :/nix/store/d0ahcim3p9dv6b01nnmx5nvx7qggnki3-libGL-1.2.0/lib:/nix/store/h6daxzmqp3q515vy4mxci92y551y5cx1-glu-9.0.1/lib:/nix/store/cv03ly81aq91d298kjb28ykzm176z3nb-freeglut-3.2.1/lib:/nix/store/qnbcg7fw1pwqdkyq8gjwgxpb3kdd9pn9-libX11-1.6.8/lib:/nix/store/lzyjivyzrp6agilxhgh0h40pwwg18agy-gcc-9.2.0-lib/lib
2020-05-11 13:47:08.541463: I tensorflow/stream_executor/cuda/cudart_stub.cc:29] Ignore above cudart dlerror if you do not have a GPU set up on your machine.
>>>