PyPy 7.3.1 released

The PyPy team is proud to release the version 7.3.1 of PyPy, which includes two different interpreters:

• PyPy2.7, which is an interpreter supporting the syntax and the features of Python 2.7 including the stdlib for CPython 2.7.13
• PyPy3.6: which is an interpreter supporting the syntax and the features of Python 3.6, including the stdlib for CPython 3.6.9.

The interpreters are based on much the same codebase, thus the multiple release. This is a micro release, no APIs have changed since the 7.3.0 release in December, but read on to find out what is new.

Conda Forge now supports PyPy as a Python interpreter. The support right now is being built out. After this release, many more c-extension-based packages can be successfully built and uploaded. This is the result of a lot of hard work and good will on the part of the Conda Forge team. A big shout out to them for taking this on.

We have worked with the Python packaging group to support tooling around building third party packages for Python, so this release updates the pip and setuptools installed when executing pypy -mensurepip to pip>=20. This completes the work done to update the PEP 425 python tag from pp373 to mean “PyPy 7.3 running python3” to pp36 meaning “PyPy running Python 3.6” (the format is recommended in the PEP). The tag itself was changed in 7.3.0, but older pip versions build their own tag without querying PyPy. This means that wheels built for the previous tag format will not be discovered by pip from this version, so library authors should update their PyPy-specific wheels on PyPI.

Development of PyPy is transitioning to https://foss.heptapod.net/pypy/pypy. This move was covered more extensively in the blog post from last month.

The CFFI backend has been updated to version 14.0. We recommend using CFFI rather than c-extensions to interact with C, and using cppyy for performant wrapping of C++ code for Python. The cppyy backend has been enabled experimentally for win32, try it out and let use know how it works.

Enabling cppyy requires a more modern C compiler, so win32 is now built with MSVC160 (Visual Studio 2019). This is true for PyPy 3.6 as well as for 2.7.

We have improved warmup time by up to 20%, performance of io.StringIO to match if not be faster than CPython, and improved JIT code generation for generators (and generator expressions in particular) when passing them to functions like sum, map, and map that consume them. Performance of closures has also be improved in certain situations.

As always, this release fixed several issues and bugs raised by the growing community of PyPy users. We strongly recommend updating. Many of the fixes are the direct result of end-user bug reports, so please continue reporting issues as they crop up.
You can find links to download the v7.3.1 releases here:

https://pypy.org/download.html

We would like to thank our donors for the continued support of the PyPy project. If PyPy is not quite good enough for your needs, we are available for direct consulting work.

We would also like to thank our contributors and encourage new people to join the project. PyPy has many layers and we need help with all of them: PyPy and RPython documentation improvements, tweaking popular modules to run on PyPy, or general help with making RPython’s JIT even better. Since the previous release, we have accepted contributions from 13 new contributors, thanks for pitching in.

If you are a Python library maintainer and use c-extensions, please consider making a cffi / cppyy version of your library that would be performant on PyPy. In any case both cibuildwheel and the multibuild system support building wheels for PyPy wheels.