Hello Pythonistas and Rustaceans,
TL;DR: Only PyO3 v0.19.2 (and later) will ever properly support Python
3.12. Port your Python projects to v0.19 **NOW**.
Older versions of PyO3 (especially pyo3 v0.15, v0.16, v0.17, and
v0.18) are *not* compatible with Python 3.12 due to some ABI changes
in unicode strings and behavioural changes wrt/ "immortal" objects.
This also affects all current versions of the "cpython" Rust bindings,
with no timeline for Python 3.12 support.
As far as I can tell, extensions that use pyo3 < v0.19 or the
"cpython" bindings can (and likely will) not work as expected on
Python 3.12 if they use the affected APIs (either by producing garbage
data in strings that are passed over the FFI boundary, or by
There are applications in Fedora that still rely on *ancient* versions
of PyO3, potentially affected by this:
- cpython: mercurial
- pyo3 v0.15: fapolicy-analyzer, python-bcrypt, python-cryptography
- pyo3 v0.16: python-y-py
- pyo3 v0.17: unused compat packages, will be retired
- pyo3 v0.18: matrix-synapse
I *stongly* recommend to move all of these packages to pyo3 v0.19 in
Rawhide as soon as possible. I will try to submit pull requests with
the required changes for affected packages (except mercurial, since
there's no version of the "cpython" crate that supports Python 3.12 in
There's already a few packages that depend on pyo3 v0.19, which I will
rebuild in rawhide for pyo3 v0.19.2, which has much better support for
Python 3.12 than v0.19.0 and v0.19.1 (breezy, python-rpds-py, orjson)
unless there are any objections.
As soon as no packages depend on the compat packages for old versions
of pyo3 any longer, I will retire them from Rawhide (and F39,
depending on the timing), since they will never work with Python 3.12
and nothing should use them.
I've added <package>-maintainers(a)fedoraproject.org for all these
packages to the CC of this message.
Rust SIG / PyO3 maintainer in Fedora
With the update to conda 23.5.2 and using the pyproject macros, the
conda package is no longer producing the /usr/bin/conda-env launcher
script which is causing problems.
I don't know how I can get that back with the current build system. Any
help would be greatly appreciated.
he/him/his - surely the least important thing about me
IT Systems Manager 720-772-5637
NWRA, Boulder/CoRA Office FAX: 303-415-9702
3380 Mitchell Lane orion(a)nwra.com
Boulder, CO 80301 https://www.nwra.com/