PEP 553 built-in debug() function (bpo-31353) by warsaw · Pull Request #3355 · python/cpython (original) (raw)

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Is that true, i.e. that it's possible to call this with an exception set?

In my experience, it's very common that a function returning a result and set an exception is not catched immediately, but somewhere "later". I had such issues when I ran my pyfailmalloc tool which injects MemoryError anywhere.

But I made many changes in CPython internals to add assert(!PyErr_Occurred()) at many places. The main change is that all functions calling functions should now check that no exception is raised if the called function returned a result. This is _Py_CheckFunctionResult().

To come back to your breakpoint() implementation, "assert(!PyErr_Occurred());" should be enough.