On Thu, 29 Jul 2021 at 16:00, Paul Moore <p.f.mo...@gmail.com> wrote:
>
> On Thu, 29 Jul 2021 at 15:39, Leonardo Freua
> <leonardo.batista.fr...@gmail.com> wrote:
> >
> > Would it be interesting to create a @deprecated decorator to avoid adding
> > warnings.warn("deprecation message", DeprecationWarning, stacklevel=2) in
> > methods body?
>
> I don't see the value personally.
I do see the value. Many projects use this kind of functionality and
end up reinventing something along these lines e.g.:
https://github.com/scipy/scipy/blob/6bc0b7297aaca7c7c1b4854d421b20d35172222c/scipy/_lib/deprecation.py#L7
Actually deprecating functions and methods is probably the easiest
part. You can either emit a warning from inside the function or use a
deprecator to do the same when the function is called. That does mean
though that there's no programmatic way to know without calling the
function that it is deprecated.
Other cases are deprecating e.g. a class, or a particular
instance/object or a module. If a module is deprecated you can trigger
a warning on import but of course import caching means that subsequent
imports won't see the warning (maybe that's okay...). For an object
you might want to use __getattr__ to trigger the warning. Then
difficulty comes if introspective tools use getattr, dir etc so users
end up seeing the warning even though nothing is actually using the
deprecated functionality:
https://github.com/sympy/sympy/issues/9371
This is the kind of thing that is on the edge of being worth a PyPI
dependency: do you really want to have an external dependency just to
give out warnings for stuff that you wish wasn't in your codebase in
the first place?
Not needing to reinvent the wheel in many projects is useful but
actually the real advantages of standardising deprecation as I see it
are things like:
1. If there is a standardised attribute like __deprecated__ then
introspective tools can avoid triggering the warning.
2. Static/introspective analysis could determine if deprecated
functionality is potentially being used even if e.g. the function does
not happen to be called during the test suite.
3. The attribute could expose useful information in a standardised way
like version_deprecated, version_will_be_removed, use_instead,
url_for_more_information etc so that smart editors and other tooling
can check this (perhaps in tandem with checking a requirements.txt or
something).
--
Oscar
_______________________________________________
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/6Q42Y253RVAZ77SLAM2WCDVB5KKLH5YN/
Code of Conduct: http://python.org/psf/codeofconduct/
