context_manager

id	modern/context_manager
name	Context Manager
aliases	with-statement RAII resource-management
guide_url
problem	Guarantee acquire/release pairing around a block of code, even when it raises.
symptoms	forgot to close cleanup on exception try/finally everywhere temporary state that must be restored
verdict	pythonic
caveats	@contextlib.contextmanager wants the yield inside try/finally — without it, an exception in the body skips your cleanup. Returning True from __exit__ swallows the exception; do it only on purpose.
stdlib_sightings	open contextlib.contextmanager contextlib.ExitStack tempfile.TemporaryDirectory

Context Manager

Pair acquire with release on every exit path, structurally — Python's RAII. Verdict: pythonic — any acquire/release pair you write twice deserves one.

Where	What
pattern/	The importable code: AtomicWrite (protocol form), temporarily (generator form)
docs/	Fundamentals · Implementation guide · External examples
examples/atomic_deploy/	Mini-project: all-or-nothing config deployment via ExitStack
tests/	Behavioral tests for both managers and the mini-project

uv run python -m patterns.modern.context_manager.examples.atomic_deploy.main