fix: allow None for exc_tb in Traveller.__exit__ type annotations#974
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madhavcodez wants to merge 1 commit into
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fix: allow None for exc_tb in Traveller.__exit__ type annotations#974madhavcodez wants to merge 1 commit into
madhavcodez wants to merge 1 commit into
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CPython calls __exit__(None, None, None) when a with block exits without an exception, so all three parameters must accept None. exc_type and exc_val were already optional on the travellers, but exc_tb was annotated TracebackType without | None, so a type checker infers the traveller is not a valid context manager and reports invalid-context-manager on with pendulum.travel_to(...). Annotate exc_tb as TracebackType | None in BaseTraveller.__exit__ and the time_machine-backed Traveller.__exit__ (the other Traveller subclasses inherit from BaseTraveller). Closes python-pendulum#973
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When a
withblock exits without an exception, CPython calls__exit__(None, None, None), so all three parameters must acceptNone. On the travellers,exc_typeandexc_valwere already optional, butexc_tbwas typed asTracebackTypewithout| None. A type checker correctly infers that the traveller is not a valid context manager, which produces theinvalid-context-managererror onwith pendulum.travel_to(...)reported in #973.What changed
Annotate
exc_tbasTracebackType | NoneinBaseTraveller.__exit__and thetime_machine-backedTraveller.__exit__(the remainingTravellersubclasses inherit fromBaseTraveller).Closes #973. The underlying false-positive trigger is also tracked upstream at astral-sh/ty#3832.
Verification
Reproduced the
invalid-context-managerdiagnostic before the change and confirmed it clears afterward (reverting the annotation brings it back).ruffandmypy --strictstay clean. This is annotation-only with no runtime or behavior change, so no tests were added. Happy to add a CHANGELOG entry once this PR has a number if you would like one.