Guido van Rossum <gu...@python.org> added the comment:
I agree. On Thu, Jan 10, 2019 at 11:24 PM Serhiy Storchaka <rep...@bugs.python.org> wrote: > > Serhiy Storchaka <storchaka+cpyt...@gmail.com> added the comment: > > This is a common mistake. Even the default implementation of object.__ne__ > had a bug, fixed only 4 years ago in issue21408. There were several errors > in stdlib. I am sure there is a lot of occurrences of this errors in a > third party code. > > So I like this idea. This can help to fix hidden errors in existing code. > But I share also Josh's concerns. > > There is related common mistake. In C code, the result of > PyObject_IsTrue() often is treated as just a boolean, without checking for > errors. Fortunately, in the current CPython code it is handled properly, > but I am sure this error still is occurred in third-party extensions. > > When these two errors (using NotImplemented in the boolean context and > ignoring the error in PyObject_IsTrue() in the C code) meet, this can lead > to manifestation of more weird bugs than treating NotImplemented as true: > from a crash in debug build to raising an exception in the following > unrelated code. > > I suggest to start emitting a DeprecationWarning or a FutureWarning in > NotImplemented.__bool__. > > ---------- > nosy: +gvanrossum, serhiy.storchaka > > _______________________________________ > Python tracker <rep...@bugs.python.org> > <https://bugs.python.org/issue35712> > _______________________________________ > -- --Guido (mobile) ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue35712> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
