
PYTHON PACKAGES

When a build needs NumPy or Pillow and it is not already installed, the kit
downloads its pinned prebuilt package from PyPI into your user cache. No pip,
compiler, administrator rights or changes to system Python are needed.
Patch-only builds and --help do not download Python packages.

Automatic package installation is qualified for CPython 3.12 on Apple Silicon
Macs and CPython 3.13 x64 on Windows (including x64 Python on Windows ARM).
Other interpreters can still use manually installed NumPy/Pillow. There is
no automatic source compilation or selection of an unqualified package.

Cache: ~/Library/Caches/ArcadePatches/python on Mac, or
%LOCALAPPDATA%/ArcadePatches/python on Windows. You can choose another location
with --python-cache PATH (or ARCADE_PYTHON_CACHE). --tools-cache PATH places
the Python cache under PATH/python unless --python-cache is also supplied.
You may delete this cache when no installer is running; it is recreated later.

Offline: add --python-wheels PATH --offline. PATH may name the matching
python-wheels-v1-*.zip, a folder of unzipped wheels, or a folder containing
the wheel ZIPs. The existing wheel bundles work without modification.
You can also supply --tools-bundle for the other helpers in the same command.
ARCADE_PYTHON_WHEELS is the equivalent environment variable. A warm cache
works offline without a bundle. --offline prohibits package downloads too.
Every wheel is checked against the kit's hash; cached extracted files are
verified before use. Existing manually installed packages remain supported.

The installer and its Python subprocesses share the cache. Your shell profile,
global site-packages and unrelated Python applications are not changed.
