3.0.0 (2020-??-??)

Features added

  • Cython functions now use the PEP-590 vectorcall protocol in Py3.7+.Patch by Jeroen Demeyer. (Github issue #2263)
  • Unicode identifiers are supported in Cython code (PEP 3131).Patch by David Woods. (Github issue #2601)
  • Unicode module names and imports are supported.Patch by David Woods. (Github issue #3119)
  • Annotations are no longer parsed, keeping them as strings following PEP-563.Patch by David Woods. (Github issue #3285)
  • The LIMITED_API is supported by setting the CYTHON_LIMITED_API C macro.Patches by Eddie Elizondo. (Github issue #3223, #3311)
  • 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 forlarger fused types with many specialisations.Patch by will-ca. (Github issue #1385)
  • with gil/nogil statements can be conditional based on compile-timeconstants, e.g. fused type checks.Patch by Noam Hershtig. (Github issue #2579)
  • const can be used together with fused types.Patch by Thomas Vincent. (Github issue #1772)
  • Reimports of already imported modules are substantially faster.(Github issue #2854)
  • Positional-only arguments are supported in Python functions.Patch by Josh Tobin. (Github issue #2915)
  • The volatile C modifier is supported in Cython code.Patch by Jeroen Demeyer. (Github issue #1667)
  • @cython.trashcan(True) can be used on an extension type to enable theCPython trashcan. This allows deallocating deeply recursive objects withoutoverflowing the stack. Patch by Jeroen Demeyer. (Github issue #2842)
  • Inlined properties can be defined for external extension types.Patch by Matti Picus. (Github issue #2640)
  • The str() builtin now calls PyObject_Str() instead of goingthrough a Python call.Patch by William Ayd. (Github issue #3279)
  • String concatenation can now happen in place if possible, by extending theexisting string rather than always creating a new one.Patch by David Woods. (Github issue #3453)
  • Multiplication of Python numbers with small constant integers is faster.(Github issue #2808)
  • Extension types that do not need their own tp_new implementation (becausethey have no object attributes etc.) directly inherit the implementation oftheir parent type if possible.(Github issue #1555)
  • The attributes gen.gi_frame and coro.cr_frame of Cython compiledgenerators and coroutines now return an actual frame object for introspection.(Github issue #2306)
  • Several declarations in cpython., libc. and libcpp.* were added.Patches by Jeroen Demeyer, Matthew Edwards, Chris Gyurgyik, Jerome Kieffer,Omer Ozarslan and Zackery Spytz.(Github issues #3468, #3358, #3332, #3179, #2891, #2826, #2713)
  • Deprecated NumPy API usages were removed from numpy.pxd.Patch by Matti Picus. (Github issue #3365)
  • The builtin abs() function can now be used on C numbers in nogil code.Patch by Elliott Sales de Andrade. (Github issue #2748)
  • PEP-479 (generator_stop) is now enabled by default with language level 3.(Github issue #2580)
  • The cython.view.array type supports inheritance.Patch by David Woods. (Github issue #3413)
  • Code annotation accepts a new debugging argument —annotate-fullc thatwill include the complete syntax highlighted C file in the HTML output.(Github issue #2855)
  • —no-capture added to runtests.py to prevent stdout/stderr capturingduring srctree tests.Patch by Matti Picus. (Github issue #2701)
  • —no-docstrings option added to cythonize script.Original patch by mo-han. (Github issue #2889)
  • The Pythran shape attribute is supported.Patch by Serge Guelton. (Github issue #3307)
  • The @cython.binding decorator is available in Python code.

Bugs fixed

  • The unicode methods .upper(), .lower() and .title() wereincorrectly optimised for single character input values and only returnedthe 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 andcython.locals().Patch by David Woods. (Github issues #3391, #3142)
  • Diverging from the usual behaviour, len(memoryview), len(char)and len(Py_UNICODE) returned an unsigned size_t value. They nowreturn a signed Py_ssize_t, like other usages of len().
  • Nested dict literals in function call kwargs could incorrectly raise anerror about duplicate keyword arguments, which are allowed when passingthem from dict literals.(Github issue #2963)
  • Item access (subscripting) with integer indices/keys always tried theSequence protocol before the Mapping protocol, which diverged from Pythonsemantics. It now passes through the Mapping protocol first when supported.(Github issue #1807)
  • Name lookups in class bodies no longer go through an attribute lookup.Patch by Jeroen Demeyer. (Github issue #3100)
  • Broadcast assignments to a multi-dimensional memory view slice could endup in the wrong places when the underlying memory view is known to becontiguous but the slice is not.(Github issue #2941)
  • Pickling unbound methods of Python classes failed.Patch by Pierre Glaser. (Github issue #2972)
  • The Py_hash_t type failed to accept arbitrary “index” values.(Github issue #2752)
  • The first function line number of functions with decorators pointed to thesignature line and not the first decorator line, as in Python.Patch by Felix Kohlgrüber. (Github issue #2536)
  • Constant integer expressions that used a negative exponent were evaluatedas integer 0 instead of the expected float value.Patch by Kryštof Pilnáček. (Github issue #2133)
  • The cython.declare() and cython.cast() functions could fail in pure mode.Patch by Dmitry Shesterkin. (Github issue #3244)
  • doc was not available inside of the class body during class creation.(Github issue #1635)
  • Setting language_level=2 in a file did not work if language_level=3was enabled globally before.Patch by Jeroen Demeyer. (Github issue #2791)
  • init.pyx files were not always considered as package indicators.(Github issue #2665)
  • Compiling package init files could fail under Windows due to anundefined export symbol. (Github issue #2968)
  • A C compiler cast warning was resolved.Patch by Michael Buesch. (Github issue #2775)
  • Binding staticmethods of Cython functions were not behaving like Python methods.Patch by Jeroen Demeyer. (Github issue #3106, #3102)
  • Memoryviews failed to compile when the cache_builtins feature was disabled.Patch by David Woods. (Github 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 incompatiblechange from the previous default of Python 2 semantics. The previous behaviouris available through the directive language_level=2.
  • Cython no longer generates qualname attributes for classes in Python2.x since they are problematic there and not correctly maintained for subclasses.Patch by Jeroen Demeyer. (Github issue #2772)
  • Source file fingerprinting now uses SHA-1 instead of MD5 since the lattertends to be slower and less widely supported these days.(Github issue #2790)
  • The long deprecated include files python_, stdio, stdlib andstl in Cython/Includes/Deprecated/ were removed. Use the libc.and cpython.* pxd modules instead.Patch by Jeroen Demeyer. (Github issue #2904)
  • The search order for include files was changed. Previously it wasinclude_directories, Cython/Includes, sys.path. Now it isinclude_directories, sys.path, Cython/Includes. This was done toallow third-party *.pxd files to override the ones in Cython.Patch by Matti Picus. (Github issue #2905)
  • The command line parser was rewritten and modernised using argparse.Patch by Egor Dranischnikow. (Github issue #2952, #3001)
  • Dotted filenames for qualified module names (pkg.mod.pyx) are deprecated.Use the normal Python package directory layout instead.(Github issue #2686)
  • Support for Python 2.6 was removed.