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3.1.0b1

3.1.0b1: 3.1.0 beta 1 (2025-04-03)
@scoder scoder tagged this 03 Apr 15:21 
==========================

Features added
--------------

* Global ``cdef const …`` variables are supported.
  (Github issue :issue:`6542`)

* A new context manager / function decorator ``cython.critical_section`` was added
  wrapping Python's critical section C-API feature.
  (Github issues :issue:`6516`, :issue:`6577`)

* Some common Cython-internal code (currently only memoryview related) can now be extracted
  into a shared extension module to reduce the installed overall size of a package with many
  Cython compiled modules.
  (Github issue :issue:`2356`)

* The type of ``prange`` loop targets is now inferred.
  (Github issue :issue:`6585`)

* Extracting keyword arguments is faster in some cases.
  (Github issue :issue:`6683`)

* Calling ``divmod()``on any C integer types is efficient.
  (Github issue :issue:`6717`)

* Some async/coroutine/vectorcall code has improved fast-paths.
  (Github issues :issue:`6732`, :issue:`6735`, :issue:`6736`, :issue:`6738`, :issue:`6742`, :issue:`6771`)

* Calls to Python builtins and extension types use the vectorcall protocol.
  (Github issue :issue:`6744`)

* Method calls use ``PyObject_VectorcallMethod()`` where possible.
  (Github issue :issue:`6747`)

* Some C-API shortcuts were (re-)added.
  (Github issue :issue:`6761`)

* Cython can avoid normalising exceptions in an `except` clause if it knows that they are unused.
  (Github issue :issue:`6601`)

* The ``cython`` command has a new option ``--cache`` to cache generated files.
  (Github issue :issue:`6091`)

* The ``cythonize`` command has a new option ``--timeit`` to benchmark Cython code snippets.
  (Github issue :issue:`6697`)

* The argument parsing ``cygdb`` command was improved based on ``argparse``.
  Patch by William Ayd.  (Github issue :issue:`5499`)

* The ``PyWeakref_GetRef`` declaration was added to ``cpython.weakref`` and backported.
  Patch by Lysandros Nikolaou.  (Github issue :issue:`6478`)

* ``std::span`` declarations were added to ``libcpp``.
  Patch by Alexander Condello.  (Github issue :issue:`6539`)

* ``std::string_view`` declarations were added to ``libcpp``.
  Patch by Antoine Pitrou.  (Github issue :issue:`6539`)

* Mutex declarations for ``libc`` and  ``libcpp`` were added.
  (Github issue :issue:`6610`)

* Several C++ declarations were improved and extended.
  Patches by Yury V. Zaytsev.  (Github issues :issue:`488`, :issue:`489`)

* Bazel build rules were updated for better interoperability.
  Patch by maleo.  (Github issue :issue:`6478`)

* The ``Demos/benchmarks/`` directory include a new benchmark runner that can run selected
  benchmarks against different Cython git revisions.

Bugs fixed
----------

* Many issues with the Limited C-API and free-threading Python were resolved.
  This includes better thread-safety of Cython-internal types like functions and generators.

  https://github.com/cython/cython/issues?q=label%3A%22limited+api%22

  https://github.com/cython/cython/issues?q=label%3A%22nogil+CPython%22

* ``for-in`` loops could generate invalid code for C++ containers.
  Patch by Taras Kozlov.  (Github issue :issue:`6578`)

* ``PyDict_GetItemRef()`` and ``PyList_GetItemRef()`` were not always used correctly.
  Patch by Lisandro Dalcin.  (Github issue :issue:`6647`)

* Inlined calls to local functions could crash with ``binding=False``.
  (Github issue :issue:`6556`)

* Calling ``sorted()`` could crash in 3.1.0a1.
  (Github issue :issue:`6496`)

* Calling 0-arg methods was unnecessarily slow in 3.1.0a1.
  (Github issue :issue:`6730`)

* A crash when reading the interpreter ID was fixed.

* Crashes while tracing C function returns were resolved.
  (Github issue :issue:`6503`)

* A compiler crash on ``complex/complex`` was resolved.
  (Github issue :issue:`6552`)

* A compiler crash when using the ``cpp_locals`` directive was resolved.
  (Github issue :issue:`6370`)

* Name mangling did not work correctly for attributes of extension types that have reserved C names.
  (Github issue :issue:`6678`)

* Declaring a ``@staticmethod`` in a pxd file and overriding it in a subclass could
  trigger incorrect "declared but not defined" errors.
  Patch by Aditya Pillai.  (Github issue :issue:`6714`)

* Cython's fake code objects are now compatible with GraalPython.
  (Github issue :issue:`6409`)

* Stepping through foreign code with ``cygdb`` could fail with an ``IndexError``.
  Patch by clayote.  (Github issue :issue:`6552`)

* Some PyPy incompatibilities were resolved.
  Patches by Matti Picus.  (Github issue :issue:`6592`,  :issue:`6640`)

* Interoperability with recent Pythran releases was fixed.
  (Github issue :issue:`6494`)

* The ``gdb`` compatibility of ``cygdb`` was improved.
  Patch by Kent Slaney.  (Github issue :issue:`6681`)

* Some redundant exception normalisation work was removed in Python 3.12+.
  (Github issue :issue:`6599`)

* A compiler hang introduced in 3.1a1 when overriding methods was resolved.
  Patch by Aditya Pillai.  (Github issue :issue:`6704`)

* A compiler crash was resolved when trying to issue a warning.
  Patch by Gabriele N. Tornetta.  (Github issue :issue:`6711`)

* Some incomplete import time "safety checks" from 3.1.0a1 were removed again.
  (Github issue :issue:`6671`)

* Using the ``common_utility_include_dir`` option in parallel builds on Windows could fail.

* Some "unused" warnings from the C compiler were resolved.
  Patches by Lisandro Dalcin.  (Github issue :issue:`6726`)

Other changes
-------------

* All Cython-internal types (functions, coroutines, …) are now heap types and use type specs.
  (Github issue :issue:`6633`)

* Tracing/monitoring is now disabled in parallel/prange sections.
  (Github issue :issue:`6709`)

* The ``numpy.math`` cimport module has been deprecated.
  Usages should be replaced by ``libc.math``.
  (Github issue :issue:`6743`)

* Includes all fixes as of Cython 3.0.12.
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