v3.2.0

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==================

(Complete changelog for the 3.2.0 release, including pre-releases.)

Features added

• Builtin exception types are now inferred.
  (Github issue :issue:6908)

• The list of known, inferred and optimised Python builtins was updated.
  range is now considered a type. ascii, bin, format, hex, oct were added as functions.
  (Github issue :issue:6931)

• The f-string syntax was extended according to PEP-701.
  (Github issue :issue:5452)

• t-strings are implemented according to PEP-750. The implementation backports the template classes
  but prefers existing backports if installed separately.
  (Github issue :issue:6811)

• Unknown return type annotations with -> are no longer rejected but produce warnings.
  This allows better integration with Python type hints that are not always usable for Cython.
  -> None is also allowed now.
  Patch by jpe. (Github issue :issue:6946)

• The runtime Python dispatch for fused functions is substantially faster.
  (Github issues :issue:1385, :issue:6996)

• Freelists (via cdef class decorator and for internally used types such as async)
  are now also used in the Limited API and with extension type specs enabled.
  (Github issue :issue:7151)

• Module imports now quickly check for an already imported module to speed up reimports.
  Patch by Lysandros Nikolaou. (Github issue :issue:7035)

• Type checks on PEP-604 union types (int | None) are optimised into separate checks.
  (Github issue :issue:6935)

• Assignments to the PEP-604 union type float | None allow any suitable Python number as input
  and convert it to a Python float automatically.
  (Github issue :issue:5750)

• Item type inference was improved for looping over literals.
  (Github issue :issue:6912)

• Looping over literal sequences and strings now uses efficient C array looping if possible.
  (Github issue :issue:6926)

• Releasing the GIL from an unknown lock state is more efficient.
  (Github issue :issue:6847)

• cython.critical_section(PyMutex) now works, as with Python objects.
  (Github issue :issue:6847)

• bool(c_int/float/ptr) avoid passing through Python objects.
  (Github issue :issue:7015)

• Variables assigned inside of prange loops can now be initialised outside of the loop.
  (Github issue :issue:7178)

• Unused exceptions in except clauses are detected in some more cases to avoid their normalisation.
  (Github issue :issue:7021)

• Mixed operations on C integers with Python ints use less code and are more streamlined for Py3.12+.
  (Github issue :issue:7244)

• Some object constants are now marked as immortal to speed up their reference counting
  in recent CPython versions. This can be configured with the CYTHON_IMMORTAL_CONSTANTS C macro.
  (Github issue :issue:7118)

• Further improvements were made to reduce the size of the resulting extension modules.
  (Github issue :issue:6983, :issue:7199, :issue:7220, :issue:7238,
  :issue:7255, :issue:7265)

• Several improvements were made in freethreaded Python code.
  (Github issues :issue:6936, :issue:6939, :issue:6949, :issue:6984,
  :issue:7011, :issue:7066, :issue:7114, :issue:7200)

• Several improvements were made for the Limited API.
  (Github issues :issue:6959, :issue:6991)

• Several improvements were made for the GraalPython support.
  Patch by Michael Šimáček. (Github issue :issue:7074)

• Some GIL-safe C-API wrappers were added to the libc/libcpp declarations.
  (Github issue :issue:6829, :issue:6993)

• String and number constants use less storage space in the module.
  (Github issues :issue:6971, :issue:6978, :issue:6986)

• The managed dict/weakref support in CPython 3.12+ is used for internal types
  to benefit from future CPython optimisations here.
  (Github issue :issue:6891)

• Using NaN as exception return value is supported.
  (Github issues :issue:6900, :issue:6903)

• Declarations for C++ condition variables were added.
  (Github issue :issue:6836)

• The annotated source HTML page shows alternating +/− markers to open/close lines.
  Patch by Kamil Monicz. (Github issue :issue:7099)

• cython --embed gained a new option --embed-modules=… to list further extension modules
  that will be statically linked into the generated extension module, to get them initialised
  on application start.
  (Github issue :issue:2849)

• The setup.py script of Cython now allows passing the desired Limited API version
  like --cython-limited-api=3.11.
  (Github issue :issue:7228)

• Unicode 16.0.0 is used to parse identifiers.
  (Github issue :issue:6836)

Bugs fixed

• Special float exception values could generate invalid C code.
  (Github issues :issue:6900, :issue:6903)

• References to the Python bool type could generate invalid C code.
  (Github issue :issue:6902)

• Using cython.pymutex in an extension type declared as public or api
  generated invalid C code missing the required PyMutex declarations.
  (Github issues :issue:6992, :issue:6995)

• Cython's type sharing across modules suffered from race conditions if multiple modules
  tried to initialise and share their types concurrently. This is due to an underlying
  CPython issue and cannot easily be worked around completely. In the common case that
  module dicts are plain Python dict objects, however, Cython now uses a .setdefault()
  equivalent for thread-safe type sharing.
  See python/cpython#137422
  (Github issue :issue:7076)

• Cython incorrectly called PyList_GetItemRef() in PyPy and GraalPython before Py3.13.
  (Github issue :issue:7269)

• Iterating over temporary memoryviews could crash Cython.
  (Github issue :issue:7005)

• Type casts on constants as part of numeric expressions could crash Cython.
  (Github issue :issue:6779)

• Long code bodies in with statements could crash Cython.
  (Github issue :issue:7122)

• Vectorcalls could use needless temp assignments for self.
  (Github issue :issue:6909)

• Indexing bytes failed to optimise in some cases.
  (Github issue :issue:6997)

• Optimised C integer formatting in f-strings failed to apply to typedef types.
  (Github issue :issue:7170)

• In auto-pickling, trying to unpickle an object that has no __dict__ from object pickle data
  that includes instance dict state is now an error.
  (Github issue :issue:7222)

• The type objects of heap types were not always correctly decrefed on deallocation.
  (Github issue :issue:7145)

• Pure mode type aliases like p_int or ulong leaked into some C type contexts,
  risking to conflict with user declarations.
  (Github issues :issue:6922, :issue:6339)

• Boolean (emptyness) tests on builtin containers could fail to handle (unlikely) errors.
  (Github issue :issue:7090)

• The return type of bytes.join() was sometimes inferred as plain object.
  (Github issue :issue:6987)

• Type inference could fail to understand prange() arguments.
  (Github issue :issue:6974)

• embedsignatures failed if lambda was used in function default arguments.
  (Github issue :issue:6880)

• An internal C function was not marked as static and leaked a linker symbol.
  (Github issue :issue:6957)

• PyType_FromModuleAndSpec was incorrectly used in Limited API code before Py3.10.
  (Github issue :issue:7181)

• Conversion code for memoryview dtypes from and to Python objects generated C warnings about
  incorrect const / non-const casting code.
  (Github issue :issue:7219)

• Cython's tools and frontend scripts now use python3 instead of just python
  in their shebang line.
  Patch by Matti Picus. (Github issue :issue:7053)

• Extension arguments defined for the shared code module were ignored in cythonize().
  (Github issue :issue:7251)

• Failures while following package attributes in import pkg.module as … were not handled.

• Trying to instantiate internal types used by Cython is now prohibited.
  (Github issue :issue:7263)

• The setup.py script in the Demos/ subdirectory failed to build.
  (Github issue :issue:7228)

• The cygdb program failed to work with virtualenvs on Windows.
  Patch by Merlin. (Github issue :issue:7268)

• Includes all fixes as of Cython 3.1.6.

Other changes

• Some lesser used platforms (Windows ARM/i686, macOS x86_64, Linux i686, musllinux)
  now use Py3.9 abi3 binary wheels instead of Python version specific wheels.
  We also added an abi3 wheel for armv7l.
  (Github issues :issue:7227, :issue:7248, :issue:7250)

• Usages of Py_TPFLAGS_HAVE_FINALIZE were removed. The constant remains available as cimport from
  cpython.object for legacy reasons.
  (Github issue :issue:6423)

v3.1.6

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==================

Bugs fixed

• Unicode characters formatted from C integers with f"{value:c}" could result in
  invalid Python string objects since Cython 3.1.0.
  (Github issue :issue:7240)

• cythonize (program and function) now uses concurrent.futures.ProcessPoolExecutor
  instead of multiprocessing.Pool to fix a hang on build failures in parallel builds.
  A possible work-around is to disable parallel builds.
  Patch by Sviatoslav Sydorenko. (Github issue :issue:7183)

v3.1.5

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==================

Bugs fixed

• Conversion from C++ strings longer than PY_SSIZE_T_MAX did not validate the length.

• Some non-Limited API code was incorrectly used in generated header files.
  (Github issue :issue:7157)

• Optimised unpacking of Python integers in expressions uses a slightly safer scheme.
  (Github issue :issue:7134)

• Empty return statements were not always reported when tracing.
  (Github issue :issue:7022)

• Value conversion errors when tracing C return statements no longer fail the trace
  but fall back to reporting None returns instead.
  (Github issue :issue:6503)

v3.1.4

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Features added

• Declarations for the new PyUnstable_*() refcounting C-API functions in Py3.14 were added.
  (Github issue :issue:6836)

Bugs fixed

• The monitoring code could crash on tracing.
  (Github issue :issue:7050)

• Initialising the monitoring code could fail with a CPython exception.
  See nedbat/coveragepy#1790 (comment)

• Optimised integer shifting triggered undefined behaviour in C.
  (Github issue :issue:7089)

• Deallocating objects that inherit from external types defined in pxd files
  could run into an infinite loop.
  (Github issue :issue:7143)

• A reference to metaclasses could be leaked on instantiation.
  (Github issue :issue:7130)

• (Unlikely) error handling during empty builtin container tests was ineffective.
  (Github issue :issue:7190)

• Generated *_api.h files used potentially unknown Cython configuration macros.
  (Github issue :issue:7108)

• cythonize() avoids parallel compiler runs on systems using spawn() in multiprocessing.
  Patch by Marcel Bargull. (Github issue :issue:3262)

• The @cython.ufunc decorator was missing in type checker stubs.
  Patch by jayClean. (Github issue :issue:7109)

v3.1.3

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Bugs fixed

• Some method calls with 0 or 1 argument failed to use PyObject_VectorCallMethod().

• Walrus assignments of literal Python integers could generate invalid C code.
  (Github issue :issue:6989)

• cython.pythread_type_lock (also used as fallback for cython.pymutex)
  could stall on heavily contended locks.
  (Github issue :issue:6999)

• C string arrays (not pointers) always coerced to the Python default string type,
  even on explicit casts to other string types.
  (Github issue :issue:7020)

• Unterminated \N{} character escapes in strings could unrail the parser.
  (Github issue :issue:7056)

• An internal C function was not marked as static and leaked a linker symbol.
  (Github issue :issue:6957)

• Some Unicode letters were not recognised as lexically valid name parts.
  (Github issue :issue:7059)

• Compatibility with PyPy3.8 was lost by accident.

• The Linux binary wheels of 3.1.2 used SSSE3 CPU instructions which are not available on some CPUs.
  (Github issue :issue:7038)

v3.1.2

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Bugs fixed

• Attribute lookups failed on the bool builtin type.
  (Github issue :issue:6905)

• Type checks on or-ed union types could incorrectly return false.
  (Github issue :issue:6420)

• Negative list indexing could accidentally wrap around twice in PyPy and the Limited API.

• Iterating over literal sequences with starred (unpacked) items could infer a wrong
  type for the loop variable and fail to assign the values.
  (Github issue :issue:6924)

• Calls to C functions taking exception types failed to check for a None argument.
  (Github issue :issue:6420)

• Fused functions had an incorrect __module__ attribute.
  (Github issue :issue:6897)

• The type of Cython implemented functions had an incorrect __module__ attribute.
  (Github issue :issue:6841)

• Errors while indexing into bytearray or str in nogil sections could crash.
  (Github issue :issue:6947)

• bytearray.append() could silently accept some invalid character numbers.

• The C++11 <type_traits> header was included regardless of the C++ version.
  (Github issue :issue:6896)

• PyDict_GetItemStringRef() was accidentally used in older Limited API versions.
  (Github issue :issue:6914)

• abort() was used but not always available in the Limited API.
  (Github issue :issue:6918)

• Some dependencies were missing from the depfile.
  (Github issue :issue:6938)

• Embedded function signatures were not always separated from the existing docstring.
  (Github issue :issue:6904)

• numpy.math was missing from Cython/Includes/ and could not be cimported.
  (Github issue :issue:6859)

• Some tests were adapted for NumPy 2.x.
  (Github issue :issue:6898)

• Some C compiler warnings were fixed.
  (Github issue :issue:6870)

• Cython.Build was not officially exposing the cythonize function.
  (Github issue :issue:6934)

v3.1.1

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Bugs fixed

• A reference leak in the async delegation code was fixed.
  (Github issues :issue:6850, :issue:6878)

• Conditional if-else expressions mixing Python and C (numeric) types could end up
  inferring an overly tight result type, thus leading to unexpected type conversions,
  runtime exceptions on assignment, or incorrect "temporary assignment" compile errors.
  (Github issue :issue:6854)

• Some Limited API issues were resolved.
  (Github issue :issue:6862)

• Large C long long values could be truncated when passed into PyPy.
  (Github issue :issue:6890)

• callable() incorrectly reported False in PyPy for classes with metaclasses.
  Patch by Anatolii Aniskovych. (Github issue :issue:6892)

• The signature of fused functions was no longer introspectable in Cython 3.1.0.
  (Github issue :issue:6855)

• Coroutines could generate invalid C with line tracing enabled.
  (Github issue :issue:6865)

• Code using complex() could generate invalid C code missing type declarations.
  (Github issue :issue:6860)

• Code using e.g. list[int | None] outside of variable/argument annotations failed to compile.
  (Github issue :issue:6856)

• Code using ctuples in a const context could generate invalid C.
  (Github issue :issue:6864)

• Accessing special methods on cpdef enums failed to compile.

• Some C compiler warnings were resolved.
  Patches by Daniel Larraz. (Github issues :issue:6876, :issue:3172, :issue:6873, :issue:6877)

• Re-establish support for PyPy 3.8.
  (Github issue :issue:6867)

v3.1.0

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Other changes

• No functional changes since 3.1.0 rc 2.