status.__getattr__ breaks static typing

[twavv]

Howdy! Just noticed this.

The status module has a __getattr__(...) -> int: definition which means that type checking tools (mypy in my case) won't flag invalid attributes.

This is a runtime error but type-checks fine.

from starlette import status
reveal_type(status.bloop)
# note: Revealed type is "builtins.int"

It's a bit pernicious in that a lot of the status codes are only accessed in failure cases and are less likely to be tested.

The reason for the __getattr__ is to raise a DeprecationWarning on accessing some deprecated statuses (like Unprocessable Entity instead of Unprocessable Content). Could the typing be better? Or is there a different way to raise the DeprecationWarning?

[cookesan]

This looks like a typing issue rather than a runtime behavior issue.

The dynamic __getattr__ exists so deprecated status aliases can still return their integer value with a warning. Unknown names still raise AttributeError at runtime. The problem is that the annotation tells type checkers that any string attribute can return int, so typos become invisible to static analysis.

A fix would need to preserve the deprecated alias behavior while narrowing the type surface. A stub file or overloads for the known deprecated names would be safer than simply removing __getattr__. At minimum, a PR should include a typing test showing that a valid deprecated alias still type-checks while an arbitrary typo does not.