==========================
Features added
--------------
* Cython functions now use the `PEP-590`_ vectorcall protocol in Py3.7+.
Patch by Jeroen Demeyer. (Github issue :issue:`2263`)
* Unicode identifiers are supported in Cython code (`PEP-3131`_).
Patch by David Woods. (Github issue :issue:`2601`)
* Unicode module names and imports are supported.
Patch by David Woods. (Github issue :issue:`3119`)
* Annotations are no longer parsed, keeping them as strings following `PEP-563`_.
Patch by David Woods. (Github issue :issue:`3285`)
* Preliminary support for the CPython's ``Py_LIMITED_API`` (stable ABI) is
available by setting the ``CYTHON_LIMITED_API`` C macro. Note that the
support is currently in an early stage and many features do not yet work.
You currently still have to define ``Py_LIMITED_API`` externally in order
to restrict the API usage. This will change when the feature stabilises.
Patches by Eddie Elizondo and David Woods. (Github issues :issue:`3223`,
:issue:`3311`, :issue:`3501`)
* The dispatch to fused functions is now linear in the number of arguments,
which makes it much faster, often 2x or more, and several times faster for
larger fused types with many specialisations.
Patch by will-ca. (Github issue :issue:`1385`)
* ``with gil/nogil`` statements can be conditional based on compile-time
constants, e.g. fused type checks.
Patch by Noam Hershtig. (Github issue :issue:`2579`)
* ``const`` can be used together with fused types.
Patch by Thomas Vincent. (Github issue :issue:`1772`)
* Reimports of already imported modules are substantially faster.
(Github issue :issue:`2854`)
* Positional-only arguments are supported in Python functions (`PEP-570`_).
Patch by Josh Tobin. (Github issue :issue:`2915`)
* The ``volatile`` C modifier is supported in Cython code.
Patch by Jeroen Demeyer. (Github issue :issue:`1667`)
* ``cython.trashcan(True)`` can be used on an extension type to enable the
CPython :ref:`trashcan`. This allows deallocating deeply recursive objects
without overflowing the stack. Patch by Jeroen Demeyer. (Github issue :issue:`2842`)
* Inlined properties can be defined for external extension types.
Patch by Matti Picus. (Github issue :issue:`2640`, redone later in :issue:`3571`)
* The ``str()`` builtin now calls ``PyObject_Str()`` instead of going
through a Python call.
Patch by William Ayd. (Github issue :issue:`3279`)
* String concatenation can now happen in place if possible, by extending the
existing string rather than always creating a new one.
Patch by David Woods. (Github issue :issue:`3453`)
* Multiplication of Python numbers with small constant integers is faster.
(Github issue :issue:`2808`)
* Some list copying is avoided internally when a new list needs to be created
but we already have a fresh one.
(Github issue :issue:`3494`)
* Extension types that do not need their own ``tp_new`` implementation (because
they have no object attributes etc.) directly inherit the implementation of
their parent type if possible.
(Github issue :issue:`1555`)
* The attributes ``gen.gi_frame`` and ``coro.cr_frame`` of Cython compiled
generators and coroutines now return an actual frame object for introspection.
(Github issue :issue:`2306`)
* Several declarations in ``cpython.*``, ``libc.*`` and ``libcpp.*`` were added.
Patches by Jeroen Demeyer, Matthew Edwards, Chris Gyurgyik, Jerome Kieffer
and Zackery Spytz.
(Github issues :issue:`3468`, :issue:`3332`, :issue:`3202`, :issue:`3188`,
:issue:`3179`, :issue:`2891`, :issue:`2826`, :issue:`2713`)
* Deprecated NumPy API usages were removed from ``numpy.pxd``.
Patch by Matti Picus. (Github issue :issue:`3365`)
* ``cython.inline()`` now sets the ``NPY_NO_DEPRECATED_API=NPY_1_7_API_VERSION``
C macro automatically when ``numpy`` is imported in the code, to avoid C compiler
warnings about deprecated NumPy C-API usage.
* The builtin ``abs()`` function can now be used on C numbers in nogil code.
Patch by Elliott Sales de Andrade. (Github issue :issue:`2748`)
* `PEP-479`_ (``generator_stop``) is now enabled by default with language level 3.
(Github issue :issue:`2580`)
* The ``cython.view.array`` type supports inheritance.
Patch by David Woods. (Github issue :issue:`3413`)
* Code annotation accepts a new debugging argument ``--annotate-fullc`` that
will include the complete syntax highlighted C file in the HTML output.
(Github issue :issue:`2855`)
* ``--no-capture`` added to ``runtests.py`` to prevent stdout/stderr capturing
during srctree tests.
Patch by Matti Picus. (Github issue :issue:`2701`)
* ``--no-docstrings`` option added to ``cythonize`` script.
Original patch by mo-han. (Github issue :issue:`2889`)
* ``cygdb`` gives better error messages when it fails to initialise the
Python runtime support in gdb.
Patch by Volker Weissmann. (Github issue :issue:`3489`)
* The Pythran ``shape`` attribute is supported.
Patch by Serge Guelton. (Github issue :issue:`3307`)
Bugs fixed
----------
* The unicode methods ``.upper()``, ``.lower()`` and ``.title()`` were
incorrectly optimised for single character input values and only returned
the first character if multiple characters should have been returned.
They now use the original Python methods again.
* Fused argument types were not correctly handled in type annotations and
``cython.locals()``.
Patch by David Woods. (Github issues :issue:`3391`, :issue:`3142`)
* Diverging from the usual behaviour, ``len(memoryview)``, ``len(char*)``
and ``len(Py_UNICODE*)`` returned an unsigned ``size_t`` value. They now
return a signed ``Py_ssize_t``, like other usages of ``len()``.
* Nested dict literals in function call kwargs could incorrectly raise an
error about duplicate keyword arguments, which are allowed when passing
them from dict literals.
(Github issue :issue:`2963`)
* Item access (subscripting) with integer indices/keys always tried the
Sequence protocol before the Mapping protocol, which diverged from Python
semantics. It now passes through the Mapping protocol first when supported.
(Github issue :issue:`1807`)
* Name lookups in class bodies no longer go through an attribute lookup.
Patch by Jeroen Demeyer. (Github issue :issue:`3100`)
* Broadcast assignments to a multi-dimensional memory view slice could end
up in the wrong places when the underlying memory view is known to be
contiguous but the slice is not.
(Github issue :issue:`2941`)
* Pickling unbound methods of Python classes failed.
Patch by Pierre Glaser. (Github issue :issue:`2972`)
* The ``Py_hash_t`` type failed to accept arbitrary "index" values.
(Github issue :issue:`2752`)
* The first function line number of functions with decorators pointed to the
signature line and not the first decorator line, as in Python.
Patch by Felix Kohlgrüber. (Github issue :issue:`2536`)
* Constant integer expressions that used a negative exponent were evaluated
as integer 0 instead of the expected float value.
Patch by Kryštof Pilnáček. (Github issue :issue:`2133`)
* The ``cython.declare()`` and ``cython.cast()`` functions could fail in pure mode.
Patch by Dmitry Shesterkin. (Github issue :issue:`3244`)
* ``__doc__`` was not available inside of the class body during class creation.
(Github issue :issue:`1635`)
* Setting ``language_level=2`` in a file did not work if ``language_level=3``
was enabled globally before.
Patch by Jeroen Demeyer. (Github issue :issue:`2791`)
* ``__init__.pyx`` files were not always considered as package indicators.
(Github issue :issue:`2665`)
* Compiling package ``__init__`` files could fail under Windows due to an
undefined export symbol. (Github issue :issue:`2968`)
* A C compiler cast warning was resolved.
Patch by Michael Buesch. (Github issue :issue:`2775`)
* Binding staticmethods of Cython functions were not behaving like Python methods.
Patch by Jeroen Demeyer. (Github issue :issue:`3106`, :issue:`3102`)
* Memoryviews failed to compile when the ``cache_builtins`` feature was disabled.
Patch by David Woods. (Github issue :issue:`3406`)
Other changes
-------------
* The default language level was changed to ``3str``, i.e. Python 3 semantics,
but with ``str`` literals (also in Python 2.7). This is a backwards incompatible
change from the previous default of Python 2 semantics. The previous behaviour
is available through the directive ``language_level=2``.
(Github issue :issue:`2565`)
* Cython no longer generates ``__qualname__`` attributes for classes in Python
2.x since they are problematic there and not correctly maintained for subclasses.
Patch by Jeroen Demeyer. (Github issue :issue:`2772`)
* Source file fingerprinting now uses SHA-1 instead of MD5 since the latter
tends to be slower and less widely supported these days.
(Github issue :issue:`2790`)
* The long deprecated include files ``python_*``, ``stdio``, ``stdlib`` and
``stl`` in ``Cython/Includes/Deprecated/`` were removed. Use the ``libc.*``
and ``cpython.*`` pxd modules instead.
Patch by Jeroen Demeyer. (Github issue :issue:`2904`)
* The search order for include files was changed. Previously it was
``include_directories``, ``Cython/Includes``, ``sys.path``. Now it is
``include_directories``, ``sys.path``, ``Cython/Includes``. This was done to
allow third-party ``*.pxd`` files to override the ones in Cython.
Patch by Matti Picus. (Github issue :issue:`2905`)
* The command line parser was rewritten and modernised using ``argparse``.
Patch by Egor Dranischnikow. (Github issue :issue:`2952`, :issue:`3001`)
* Dotted filenames for qualified module names (``pkg.mod.pyx``) are deprecated.
Use the normal Python package directory layout instead.
(Github issue :issue:`2686`)
* Binary Linux wheels now follow the manylinux2010 standard.
Patch by Alexey Stepanov. (Github issue :issue:`3355`)
* Support for Python 2.6 was removed.
.. _`PEP-560`: https://www.python.org/dev/peps/pep-0560
.. _`PEP-570`: https://www.python.org/dev/peps/pep-0570
.. _`PEP-487`: https://www.python.org/dev/peps/pep-0487
.. _`PEP-590`: https://www.python.org/dev/peps/pep-0590
.. _`PEP-3131`: https://www.python.org/dev/peps/pep-3131
.. _`PEP-563`: https://www.python.org/dev/peps/pep-0563
.. _`PEP-479`: https://www.python.org/dev/peps/pep-0479