import operator
import sys

class BadDict(dict):
    def keys(self):
        raise RuntimeError("keys() failed!")

def repro_update():
    locs = sys._getframe().f_locals
    print(type(locs))

    try:
        locs.update(BadDict())
    except TypeError as exc:
        print("BUG: update() masked RuntimeError as TypeError:", exc)
    except RuntimeError as exc:
        print("OK: update() propagated RuntimeError:", exc)

def repro_inplace_or():
    locs = sys._getframe().f_locals
    print(type(locs))

    try:
        operator.ior(locs, BadDict())
    except RuntimeError as exc:
        print("OK: |= propagated RuntimeError:", exc)
    except BaseException as exc:
        print("BUG: |= raised wrong exception:", type(exc).__name__, exc)
    else:
        print("BUG: |= swallowed RuntimeError")

repro_update()
repro_inplace_or()

<class 'FrameLocalsProxy'>
BUG: update() masked RuntimeError as TypeError: update() argument must be dict or another FrameLocalsProxy

<class 'FrameLocalsProxy'>
Fatal Python error: _Py_CheckSlotResult: Slot |= of type FrameLocalsProxy succeeded with an exception set
Python runtime state: initialized
Traceback (most recent call last):
  File "/tmp/repro_ior.py", line 6, in keys
    raise RuntimeError("keys() failed!")
RuntimeError: keys() failed!
Aborted (core dumped)

<class 'FrameLocalsProxy'>
OK: update() propagated RuntimeError: keys() failed!
<class 'FrameLocalsProxy'>
OK: |= propagated RuntimeError: keys() failed!