With issue 17611 merged (which moves stack unwinding to the compiler), I expect the exact details of this problem to have changed, but the general problem still exists: Ctrl-C may lead to __exit__ (or __aexit__) not being called even after __enter__ (or __aenter__) returns successfully, and this may happen even for context managers implemented with uninterruptible methods (e.g. in C in CPython without calling back into any Python code).