bug#53258: Python unable to find modules within a Singularity container created with guix pack

["Ludovic Courtès" <ludovic.courtes@inria.fr>]

Hi Marek,

Marek Felšöci <marek@felsoci.sk> skribis:

> Recently, I have come around this issue. I created a Singularity
> container using the following `guix pack` command:
>
> `guix pack -f squashfs bash coreutils python python-numpy`
>
> Then, I run a bash shell within the container:
>
> `singularity exec test.gz.squashfs bash`
>
> Now, if I want to use numpy,
>
> `python3 -m numpy`
>
> it gives me the following error and the numpy module IS NOT found:
>
> Error in sitecustomize; set PYTHONVERBOSE for traceback:
> ValueError:
> '/gnu/store/2dyd6rlcc9m68k3mvkw86k8dygkbg025-profile/bin/../../p5fgysbcnnp8b1d91mrvjvababmczga0-python-3.9.6/lib/python3.9/site-packages' 
> is not in list
> /gnu/store/2dyd6rlcc9m68k3mvkw86k8dygkbg025-profile/bin/python3: No
> module named numpy

I can kinda reproduce via a relocatable pack (relocatable packs and
Singularity packs have in common that they use relative symlinks in
their profile, to allow for relocation):

  guix pack -RR python python-numpy -S /bin=bin -S /etc=etc

Then I unpack the thing:

  mkdir /tmp/pack; cd /tmp/pack; tar xf /gnu/store/…-pack.tar.gz

And from there I use the same trick as in
‘tests/guix-pack-relocatable.sh’ to “hide” /gnu/store:

--8<---------------cut here---------------start------------->8---
$ unshare -mrf sh -c 'mount -t tmpfs -o ro none /gnu/store; . /tmp/pack/etc/profile; echo $GUIX_PYTHONPATH ; /tmp/pack/bin/python3 '
/gnu/store/w5cz9gbqbja99x0636zsg2fzksmfig4n-profile/lib/python3.9/site-packages
Python 3.9.6 (default, Jan  1 1970, 00:00:01) 
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import numpy
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'numpy'
>>> import os
>>> os.listdir("/gnu/store/w5cz9gbqbja99x0636zsg2fzksmfig4n-profile/lib/python3.9/site-packages")
['setuptools-56.0.0.dist-info', 'distutils-precedence.pth', '_distutils_hack', 'setuptools', 'pip-21.1.3.dist-info', 'sitecustomize.py', 'README.txt', 'pip', 'numpy-1.20.3-py3.9.egg-info', 'numpy', 'pkg_resources', '__pycache__']
>>> os.listdir("/gnu/store/w5cz9gbqbja99x0636zsg2fzksmfig4n-profile/lib/python3.9/site-packages/numpy")
['__init__.pyi', 'doc', 'matlib.py', 'ctypeslib.pyi', 'linalg', 'ctypeslib.py', 'compat', 'typing', '__init__.pxd', 'lib', 'char.pyi', 'version.py', '__config__.py', 'core', '_distributor_init.py', 'distutils', 'tests', 'emath.pyi', '_pytesttester.py', 'fft', '__init__.cython-30.pxd', 'conftest.py', '__init__.py', 'py.typed', '_globals.py', 'rec.pyi', 'testing', 'LICENSE.txt', 'polynomial', 'f2py', 'matrixlib', 'random', 'ma', 'dual.py', 'setup.py', '__pycache__']
--8<---------------cut here---------------end--------------->8---

So in this case ‘GUIX_PYTHONPATH’ is correctly set, but it looks as
though ‘sitecustomize.py’ wasn’t loaded.  (I don’t get the “Error in
sitecustomize” message that Marek sees though, weird!)

From Marek’s message, it would seem that somewhere file names are
constructed by appending “..”.  Given Unix’s weird dot-dot semantics,
relative symlinks could be interfering:

--8<---------------cut here---------------start------------->8---
$ ls -l /tmp/pack/gnu/store/w5cz9gbqbja99x0636zsg2fzksmfig4n-profile/lib/python3.9/site-packages/
totalo 48
lrwxrwxrwx 1 ludo users 102 Jan  1  1970 _distutils_hack -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/_distutils_hack
lrwxrwxrwx 1 ludo users 111 Jan  1  1970 distutils-precedence.pth -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/distutils-precedence.pth
lrwxrwxrwx 1 ludo users  99 Jan  1  1970 numpy -> ../../../../mlccgh05bf8cdinq0ilpvpdmsspq36pv-python-numpy-1.20.3R/lib/python3.9/site-packages/numpy
lrwxrwxrwx 1 ludo users 121 Jan  1  1970 numpy-1.20.3-py3.9.egg-info -> ../../../../mlccgh05bf8cdinq0ilpvpdmsspq36pv-python-numpy-1.20.3R/lib/python3.9/site-packages/numpy-1.20.3-py3.9.egg-info
lrwxrwxrwx 1 ludo users  90 Jan  1  1970 pip -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/pip
lrwxrwxrwx 1 ludo users 107 Jan  1  1970 pip-21.1.3.dist-info -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/pip-21.1.3.dist-info
lrwxrwxrwx 1 ludo users 100 Jan  1  1970 pkg_resources -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/pkg_resources
lrwxrwxrwx 1 ludo users  98 Jan  1  1970 __pycache__ -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/__pycache__
lrwxrwxrwx 1 ludo users  97 Jan  1  1970 README.txt -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/README.txt
lrwxrwxrwx 1 ludo users  97 Jan  1  1970 setuptools -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/setuptools
lrwxrwxrwx 1 ludo users 114 Jan  1  1970 setuptools-56.0.0.dist-info -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/setuptools-56.0.0.dist-info
lrwxrwxrwx 1 ludo users 103 Jan  1  1970 sitecustomize.py -> ../../../../niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages/sitecustomize.py
--8<---------------cut here---------------end--------------->8---

Now look below how dot-dot resolution whereas “lexical” dot-dot
resolution dose the right thing:

--8<---------------cut here---------------start------------->8---
$ ls -l /tmp/pack/gnu/store/2dyd6rlcc9m68k3mvkw86k8dygkbg025-profile/bin/../../p5fgysbcnnp8b1d91mrvjvababmczga0-python-3.9.6/lib/python3.9/site-packages
ls: ne eblas atingi '/tmp/pack/gnu/store/2dyd6rlcc9m68k3mvkw86k8dygkbg025-profile/bin/../../p5fgysbcnnp8b1d91mrvjvababmczga0-python-3.9.6/lib/python3.9/site-packages': Dosiero aŭ dosierujo ne ekzistas
$ ls -l /tmp/pack/gnu/store/p5fgysbcnnp8b1d91mrvjvababmczga0-python-3.9.6/lib/python3.9/site-packages
totalo 40
dr-xr-xr-x 3 ludo users 4096 Jan  1  1970 _distutils_hack/
-r--r--r-- 1 ludo users  152 Jan  1  1970 distutils-precedence.pth
dr-xr-xr-x 5 ludo users 4096 Jan  1  1970 pip/
dr-xr-xr-x 2 ludo users 4096 Jan  1  1970 pip-21.1.3.dist-info/
dr-xr-xr-x 6 ludo users 4096 Jan  1  1970 pkg_resources/
dr-xr-xr-x 2 ludo users 4096 Jan  1  1970 __pycache__/
-r--r--r-- 1 ludo users  119 Jan  1  1970 README.txt
dr-xr-xr-x 7 ludo users 4096 Jan  1  1970 setuptools/
dr-xr-xr-x 2 ludo users 4096 Jan  1  1970 setuptools-56.0.0.dist-info/
-r--r--r-- 1 ludo users 2172 Jan  1  1970 sitecustomize.py
--8<---------------cut here---------------end--------------->8---

In Python’s ‘site.py’, the ‘addsitedir’ method indirectly calls
‘os.path.abspath’, not sure if that is at fault.

I also see that ‘sys.path’ is in fact completely bogus, with “pack”
missing from every directory name:

--8<---------------cut here---------------start------------->8---
$ unshare -mrf sh -c 'mount -t tmpfs -o ro none /gnu/store;  . /tmp/pack/etc/profile; echo $GUIX_PYTHONPATH ; /tmp/pack/bin/python3 '
/gnu/store/w5cz9gbqbja99x0636zsg2fzksmfig4n-profile/lib/python3.9/site-packages
Python 3.9.6 (default, Jan  1 1970, 00:00:01) 
[GCC 10.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> sys.path
['', '/tmp/niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python39.zip', '/tmp/niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9', '/tmp/niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/lib-dynload', '/tmp/niddlj0qbk5vzk1mdn5im9y4x6l8a2k9-python-3.9.6R/lib/python3.9/site-packages']
--8<---------------cut here---------------end--------------->8---

So I think something somewhere is manipulating file names and gets
confused.

Does that ring a bell, Maxim?

Thanks,
Ludo’.