shakeout

A static, tree-shaking bundler for Python. Give it an entry script: it finds every module the program can import, removes top-level code nothing can reach, and writes a self-contained artifact. That can be one runnable .py, a zipapp, a pruned directory or a reproducible AWS Lambda zip. Tracebacks from bundles name the original files and lines.

$ uvx shakeout build app/main.py -o dist                       # one runnable file
$ uvx shakeout build handler.py -t lambda --export handler     # Lambda package
$ uvx shakeout report app/main.py                              # what is kept, and why
$ uvx shakeout why app/main.py pkg.core:helper                 # the chain that keeps a symbol

Documentation: https://revmischa.github.io/shakeout/ (sources in docs/; the design and roadmap are in docs/project/design.md).

Guarantees

• Sound by default. Anything the analysis can't prove unused is kept: registration decorators, __init_subclass__ and metaclass registries, modules that use globals(), eval or sys.modules, module objects passed around as values, star imports.
• Exact tracebacks without source maps. Modules keep their original file names and line numbers, and their sources are registered with linecache. Tracebacks, warnings, inspect.getsource and error trackers show real files, lines, carets and code, even in Lambda.
• Self-explaining failures. Reaching a removed name at runtime raises the usual exception with a note that names the keep setting to add.

How it is tested

Every gate CI runs is in scripts/check.sh: ruff with all rules, strict pyright and mypy, 96% branch coverage, vulture, codespell, packaging checks, pip-audit, zizmor and actionlint, and a strict docs build. CPython 3.10 to 3.15 are supported (scripts/matrix.sh).