suppress-unhandled

Suppress traceback of specified unhandled exceptions, preserve everything else.

from suppress_unhandled import suppress_unhandled

suppress_unhandled(KeyboardInterrupt)
input('Pause')

$ python example.py
Pause ^C
$

Install

pip install suppress-unhandled

Exception groups

Pass inspect_groups to also suppress a group whose contents, however deeply nested, are all being suppressed:

import asyncio
from suppress_unhandled import suppress_unhandled

suppress_unhandled(ValueError, inspect_groups=True)

async def some_task():
    raise ValueError('oh no!')

async def main():
    async with asyncio.TaskGroup() as group:
        group.create_task(some_task())
        group.create_task(some_task())

asyncio.run(main())

$ python example.py
$

asyncio.TaskGroup collects both failures into an ExceptionGroup, which suppress_unhandled(ValueError), without inspect_groups=True, will not match:

$ python example.py
  + Exception Group Traceback (most recent call last):
  ...
  | ExceptionGroup: unhandled errors in a TaskGroup (2 sub-exceptions)
  +-+---------------- 1 ----------------
    | ValueError: oh no!
    +---------------- 2 ----------------
    | ValueError: oh no!
    +------------------------------------

Groups containing anything else are not suppressed and their tracebacks print.

Background

Ctrl+C is often the normal way to exit a Python program. By default, Python prints a scary-looking traceback to the stderr:

$ python example.py
^CTraceback (most recent call last):
  File "/tmp/example.py", line 1, in <module>
    do_something_forever()
    ~~~~~~~~~~~~~~~~~~~~^^
KeyboardInterrupt

You could suppress KeyboardInterrupt:

from contextlib import suppress

with suppress(KeyboardInterrupt):
    do_something_forever()

The traceback is gone, but the return code is wrong and, if you add code after the with block, it'll get run! There's also all this complex behaviour that gets suppressed.