Hi INADA-san, IMO Python 3.11 is too early because we don't emit a DeprecationWarning on every single deprecation function.
1) Emit a DeprecationWarning at runtime (ex: Python 3.10) 2) Wait two Python releases: see https://discuss.python.org/t/pep-387-backwards-compatibilty-policy/4421 3) Remove the deprecated feature (ex: Python 3.12) I don't understand if *all* deprecated functions are causing implementation issues, or only a few of them? PyUnicode_AS_UNICODE() initializes PyASCIIObject.wstr if needed, and then return PyASCIIObject.wstr. I don't think that PyASCIIObject.wstr can be called "a cache": there are functions relying on this member. On the other hand, PyUnicode_FromUnicode(str, size) is basically a wrapper to PyUnicode_FromWideChar(): it doesn't harm to keep this wrapper to ease migration. Only PyUnicode_FromUnicode(NULL, size) is causing troubles, right? Is there a list of deprecated functions and is it possible to group them in two categories: must be removed and "can be kept for a few more releases"? If the intent is to reduce Python memory footprint, PyASCIIObject.wstr can be moved out of PyASCIIObject structure, maybe we can imagine a WeakDict. It would map a Python str object to its wstr member (wchar_* string). If the Python str object is removed, we can release the wstr string. The technical problem is that it is not possible to create a weak reference to a Python str. We may insert code in unicode_dealloc() to delete manually the wstr in this case. Maybe a _Py_hashtable_t of pycore_hashtable.h could be used for that. Since this discussion is on-going for something like 5 years in multiple bugs.python.org issues and email threads, maybe it would help to have a short PEP describing issues of the deprecated functions, explain the plan to migrate to the new functions, and give a schedule of the incompatible changes. INADA-san: would you be a candidate to write such PEP? Victor Le ven. 12 juin 2020 à 10:37, Inada Naoki <songofaca...@gmail.com> a écrit : > > Hi, all. > > Py_UNICODE has been deprecated since PEP 393 (Flexible string representation). > > wchar_t* cache in the string object is used only in deprecated APIs. > It waste 1 word (8 bytes on 64bit machine) per string instance. > > The deprecated APIs are documented as "Deprecated since version 3.3, > will be removed in version 4.0." > See https://docs.python.org/3/c-api/unicode.html#deprecated-py-unicode-apis > > But when PEP 393 is implemented, no one expects 3.10 will be released. > Can we reschedule the removal? > > My proposal is, schedule the removal on Python 3.11. But we will postpone > the removal if we can not remove its usage until it. > > I grepped the use of the deprecated APIs from top 4000 PyPI packages. > > result: > https://github.com/methane/notes/blob/master/2020/wchar-cache/deprecated-use > step: https://github.com/methane/notes/blob/master/2020/wchar-cache/README.md > > I noticed: > > * Most of them are generated by Cython. > * I reported it to Cython so Cython 0.29.21 will fix them. I expect > more than 1 year > between Cython 0.29.21 and Python 3.11rc1. > * Most of them are `PyUnicode_FromUnicode(NULL, 0);` > * We may be able to keep PyUnicode_FromUnicode, but raise error when > length>0. > > Regards, > > -- > Inada Naoki <songofaca...@gmail.com> > _______________________________________________ > Python-Dev mailing list -- python-dev@python.org > To unsubscribe send an email to python-dev-le...@python.org > https://mail.python.org/mailman3/lists/python-dev.python.org/ > Message archived at > https://mail.python.org/archives/list/python-dev@python.org/message/7JVC3IKS2V73K36ISEJAAWMRFN2T4KKR/ > Code of Conduct: http://python.org/psf/codeofconduct/ -- Night gathers, and now my watch begins. It shall not end until my death. _______________________________________________ Python-Dev mailing list -- python-dev@python.org To unsubscribe send an email to python-dev-le...@python.org https://mail.python.org/mailman3/lists/python-dev.python.org/ Message archived at https://mail.python.org/archives/list/python-dev@python.org/message/2NFPP623YIPFFHFOPPHPQPILEKVH4HQE/ Code of Conduct: http://python.org/psf/codeofconduct/
