zipapp fails to import _imaging from PIL

[o-alquimista]

After I introduced the Pillow dependency to my project, the zipapp-produced executable no longer executes properly. I get an ImportError related to the PIL module:

$ ./basketcase -h
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "/home/dsilva/Documents/Build/basketcase/dist/./basketcase/__main__.py", line 2, in <module>
  File "/home/dsilva/Documents/Build/basketcase/dist/./basketcase/basketcase/__init__.py", line 21, in <module>
  File "/home/dsilva/Documents/Build/basketcase/dist/./basketcase/basketcase/basketcase.py", line 14, in <module>
  File "/home/dsilva/Documents/Build/basketcase/dist/./basketcase/PIL/Image.py", line 95, in <module>
ImportError: cannot import name '_imaging' from 'PIL' (/home/dsilva/Documents/Build/basketcase/dist/./basketcase/PIL/__init__.py)

basketcase.py is where PIL is imported and used.

from PIL import Image, UnidentifiedImageError

Below is the shell script used to generate the zipapp. It is meant to be executed from the project root (where pyproject.toml is).

mkdir ./zipapp

echo 'Installing requirements'
pipenv run pip freeze --exclude-editable \
  | pipenv run pip install --requirement /dev/stdin --target ./zipapp

echo 'Installing BasketCase'
pipenv run pip install . --target ./zipapp --upgrade

echo 'Generating zipapp'
python3 -m zipapp ./zipapp \
  --main="basketcase.__main__:main" \
  --python="/usr/bin/env python3" \
  --output=./dist/basketcase --compress

rm -r ./zipapp

In its output (last line) I see:

Successfully installed anyio-4.12.0 basketcase-8.0.0 beautifulsoup4-4.14.3 brotli-1.2.0 certifi-2025.11.12 h11-0.16.0 httpcore-1.0.9 httpx-0.28.1 idna-3.11 lxml-6.0.2 pillow-12.0.0 soupsieve-2.8 typing-extensions-4.15.0 zstandard-0.25.0

I get the ImportError when I execute ./dist/basketcase -h. Any idea why?

[o-alquimista]

I just noticed there's a strange lone dot in that file path (.../dist/./basketcase/...):

File "/home/dsilva/Documents/Build/basketcase/dist/./basketcase/basketcase/basketcase.py", line 14, in <module>

Maybe that's why it's failing, but I can't see where it comes from.

[o-alquimista]

The reason was explained in the Caveats section of the docs. Sorry, I missed it.

If your application depends on a package that includes a C extension, that package cannot be run from a zip file.

I see that Pillow contains a lot of C files.