Chris Angelico wrote: > So the only way would be to call len(), and if it fails, fall back > on > the "expected 2" form. And I'm not sure if that would be worthwhile, > given that it's going to have to run arbitrary code just for the sake > of the error message.
I did address these: > The length of the unpacked value, if it exists and (to not execute arbitrary > __len__ implementations) if the type belongs to a safe subset, e.g. only > builtin types. Is there anyone who thinks it's acceptable to run `len()` on arbitrary objects for an error message? Assuming 'no', then the length is only shown if the type is exactly one of list, tuple, str, etc. where we know __len__ exists and is safe. Alternatively, instead of checking the type, we could check if `__len__` itself belongs to a safe set, if we want to include e.g. subclasses of `list`. _______________________________________________ Python-ideas mailing list -- python-ideas@python.org To unsubscribe send an email to python-ideas-le...@python.org https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/python-ideas@python.org/message/3MSHVDWV2YPCYLNPTWXAADUBTFNUCXTB/ Code of Conduct: http://python.org/psf/codeofconduct/
