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If you use `del` on a non-existent attribute in `State`, a `KeyError` is raised instead of an `AttributeError`.

starlette: Issue where deleting an attribute that doesn't exist in State raises a KeyError instead of an AttributeError​

Link: https://github.com/Kludex/starlette/discussions/3644

Background​

The State object, which is used with request.state and app.state, delegates attribute access to an internal dictionary. When a non-existent attribute is read, __getattr__ replaces the KeyError in the dict with AttributeError; however, when deleting a non-existent attribute using __delattr__, it does not make this replacement, so KeyError is passed up as-is.

How to Reproduce​

from starlette.datastructures import State

state = State()
state.missing        # AttributeError: 'State' object has no attribute 'missing'
del state.missing    # KeyError: 'missing'

In the cleanup code, an except AttributeError or contextlib.suppress(AttributeError) wrapped around an del request.state.x fails to catch exceptions.

Cause​

The State.__delattr__ in starlette/datastructures.py only executes del self._state[key]. There is no try/except KeyError conversion, such as with __getattr__.

Verification​

I verified the exception type by running the above code directly in main. I searched the Discussion, Issues, and PRs and found no similar reports. Since this repository often requires a Discussion before a PR and the maintainer frequently fixes issues directly, I did not open a fix PR but reported it only as a “Potential Issue.”