Skip to content

chore(dependencies): update dependency cython to >=3.3.0 - #183

Open
renovate[bot] wants to merge 1 commit into
masterfrom
renovate/cython-3.x
Open

chore(dependencies): update dependency cython to >=3.3.0#183
renovate[bot] wants to merge 1 commit into
masterfrom
renovate/cython-3.x

Conversation

@renovate

@renovate renovate Bot commented Aug 22, 2026

Copy link
Copy Markdown
Contributor

This PR contains the following updates:

Package Change Age Adoption Passing Confidence
Cython (source) >=3.2.8>=3.3.0 age adoption passing confidence

Release Notes

cython/cython (Cython)

v3.3.0

Compare Source

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

(Complete changelog for the 3.3.0 release, including pre-releases.)

Features added

  • PEP-634 Pattern Matching is implemented.
    (Github issue :issue:4029)

  • except * (PEP-654 exception groups) is implemented for Python 3.11 and later.
    (Github issue :issue:4993)

  • Unpacking in comprehensions (PEP-798) is implemented for list/set/dict comprehensions.
    It is not yet available for generator expressions.
    Original patch by Morax. (Github issue :issue:7898)

  • Changes were made to adapt to Python 3.15 and its Limited API.
    This does not yet cover abi3t.
    (Github issues :issue:6405, :issue:7190, :issue:7347, :issue:7348, :issue:7358)

  • Cython now uses a new export/import naming scheme for fused C functions that
    increases the resilience against seemingly compatible user code changes.
    The original names are kept for backwards compatibility.
    (Github issue :issue:7656)

  • Declared container item types (e.g. list[float] or tuple[atype, ...])
    are now used by the type system.
    (Github issues :issue:7288, :issue:7798)

  • Type inference was improved for builtin Python types and their methods.
    (Github issues :issue:7536, :issue:7644, :issue:7887, :issue:7888)

  • Exception base types are inferred for the target variable of multi-exception except
    clauses and for collections of exceptions. Properties like .args and .context
    use direct C access in CPython.
    (Github issue :issue:7783)

  • Annotations on global variables are now used by type inference.
    (Github issue :issue:7877)

  • The feature set of the shared module can be selected at build time
    by listing named features to include or exclude.
    This is an experimental configuration, subject to further improvements.
    Failures to include used features will currently result in import failures.
    (Github issue :issue:7759)

  • To control the generation of the shared module, the cython command gained
    a sub-command cython generate-shared pkg/modulename.c with additional options
    --only and --exclude.
    Patch by Raza Khan. (Github issue :issue:7842)

  • Conditions in strongly predictable if-clauses or if-else expressions can be wrapped in
    cython.likely(condition) or cython.unlikely(condition) to help the C compiler
    optimise the branch. Note that Cython automatically detects raise and assert
    statements as terminators already and marks if-clauses that directly lead to them as
    unlikely(), without user interaction.
    (Github issue :issue:7667)

  • Extension types can declare themselves explicitly as sequence or mapping with
    @cython.collection_type("sequence") or @cython.collection_type("mapping").
    This has an effect on their behaviour in pattern matching and subscripting.
    (Github issue :issue:5027)

  • Sequence types marked as @cython.collection_type("sequence") that use C integers
    in the subscript special methods now implement only the sequence and not the mapping protocol.
    This allows subscripting code to avoid creating Python index objects when the index
    is already available as C integer.
    (Github issue :issue:7435)

  • Sequence types that have their Py_TPFLAGS_SEQUENCE type flag set can benefit from
    faster subscripting via the sequence protocol as Cython now bypasses the mapping protocol
    for them if both protocols are implemented.
    (Github issue :issue:7432)

  • The Py3.15 frozendict builtin type is supported and has been backported as an alias
    for dict in older Python versions.
    Patches to adapt existing dict optimisations were contributed by Omkar Kabde.
    (Github issues :issue:7545, :issue:7647)

  • The Py3.15 sentinel builtin is supported and its C-API declarations are available in
    cpython.sentinel.

  • cython.py_int (and the same for py_float, py_complex and py_bool)
    can be used to refer to Python's builtin types in a C type context, e.g. after cdef,
    where they are normally shadowed by the C types of the same name.
    (Github issue :issue:7844)

  • The builtin Python types int, float, str, bytes and bytearray
    are special cased in comparisons to speed them up.
    (Github issues :issue:7452, :issue:7474)

  • The builtin Python types int and float are special cased in +, - and *
    operations with (compile-time) unknown Python types in order to speed them up.
    The bit operations ^, | and & are additionally special cased for int.
    (Github issues :issue:7485, :issue:7541)

  • <bool> casts can be used to convert C values to Python True / False.
    (Github issue :issue:7513)

  • cdef property methods support setters.
    (Github issues :issue:7505, :issue:7791)

  • The C restrict modifier can be used in declarations.
    (Github issue :issue:7617)

  • C arrays may now be declared with (extern or internal) enum values as their size.
    (Github issues :issue:7401, :issue:7406)

  • prange(num_threads=0) automatically selects the maximum number of OpenMP threads.
    (Github issue :issue:7586)

  • prange() and parallel() sections can be used without releasing the GIL, which
    helps in freethreading builds. When releasing the GIL as part of the section declaration,
    re-acquiring it immediately inside is now faster, e.g. to do per-thread Python initialisations.
    (Github issue :issue:6562)

  • cython.pymutex and cython.pythread_type_lock now support a .locked() method
    to check if the lock is currently held without blocking. The method works on all Python
    versions using atomic reads on Python 3.13+ and a try-acquire approach on older versions.
    (Github issue :issue:7275)

  • A simpler mechanism was added for implementing C++ exception handlers in Cython code.
    (Github issues :issue:7388, :issue:7390)

  • Repeated memoryview slicing inside of loops now avoids redundant reference counting,
    making it substantially faster.
    (Github issue :issue:5507)

  • Indexing into Cython memoryview objects from Python is faster.
    (Github issue :issue:7529)

  • Some internal call overhead in the memoryview code was removed.
    (Github issue :issue:7609)

  • Extension types use the vectorcall interface for their instantiation in many cases.
    This can be configured with a new C feature macro CYTHON_VECTORCALL_TPNEW.
    (Github issue :issue:7698)

  • Coroutine methods use the faster vectorcall interface.
    (Github issue :issue:7678)

  • Vectorcalls with literal keyword arguments use cached constant keyword name tuples.
    (Github issue :issue:7713)

  • List comprehensions that generate new objects avoid refcounting overhead for appending.
    (Github issue :issue:7748)

  • Method calls in older Limited API versions are slightly faster.
    (Github issue :issue:7707)

  • Constant frozenset objects are deduplicated and cached at module init time
    (similar to constant tuple and slice objects).
    Original Patch by Zhenbo Li. (Github issue :issue:2741)

  • C arrays are substituted for sequence iteration in more cases, also inside of generators.
    Ad-hoc C array storage on the stack and in closures was reworked along the way.
    (Github issues :issue:7323, :issue:7339)

  • Single character in-tests on str, bytes and bytearray are optimised.
    (Github issue :issue:3888)

  • Unicode string comparisons to single character literals are faster.
    (Github issue :issue:7418)

  • F-strings are a little faster in some cases.
    (Github issues :issue:7495, :issue:7526)

  • Formatting C floating point values in f-strings avoids creating Python floats in some cases.
    Patch by Vladimir Saraikin. (Github issue :issue:7797)

  • bytearray.extend(bytes) is faster.
    (Github issue :issue:7797)

  • assert conditions are constant-folded.
    (Github issue :issue:7809)

  • PyPy and GraalPython use the vectorcall protocol to enable faster Python calls in future releases.
    (Github issue :issue:7614)

  • The runtime conversion from a Python mapping to a C struct/union uses less code.
    (Github issue :issue:7343)

  • The error handling of memoryviews uses less code.
    (Github issue :issue:7525)

  • The runtime dispatch code of fused types uses less code.
    (Github issue :issue:7501)

  • More code is extracted to the shared utility code module.
    (Github issues :issue:7556, :issue:7570)

  • Async generator objects are slightly smaller.
    (Github issue :issue:7776)

  • Cython compiled functions have a more efficient memory layout in the Limited API.
    (Github issue :issue:7519)

  • Module string content is now compressed with LZSS by default, which reduces the footprint of the
    decompressor code compared to the 3.2.x default zlib. This also avoids a runtime dependency
    on the zlib module since the tiny LZSS decompressor can be embedded in the module.
    (Github issue :issue:7577)

  • The Py2 print statement is now implemented in Cython instead of C to make it
    thread-safe and uses a vectorcall into Python.
    (Github issue :issue:7642)

  • Several C++ exception declarations were added to libcpp.exceptions.
    (Github issue :issue:7389)

  • Missing Python type flag declarations were added to cpython.object.
    (Github issue :issue:7441)

  • Declarations for PyType_GetSlot() and the corresponding type slot IDs were added
    to cpython.type.

  • Declarations for specialised byte-conversion functions were added to cpython.long and cpython.float.
    Patch by Valentin Valls. (Github issue :issue:7738)

  • Error detection when assigning to const variables was improved.
    (Github issue :issue:7359)

  • Some cases of likely misuse of critical_section now generate warnings.
    (Github issue :issue:6766)

  • Programmatic use of Cython has become easier by avoiding the need to manually set up
    the error reporting.
    (Github issue :issue:7235)

  • Autoscaling in cymeit is a little faster.

  • TreeFragment.parse_from_strings() now supports full modules and .pxd files.
    Patch by Itamar Turner-Trauring. (Github issue :issue:7827)

  • Unicode 17.0.0 is used to parse identifiers.

Bugs fixed

  • Several issues with .close() or .throw() of Async generator asend/athrow
    objects were resolved, following fixes in CPython.
    (Github issue :issue:7777)

  • The __class__ method cell misbehaved when used together with class decorators
    and passed the decorated class (and thus an arbitrary object) into super()
    instead of the class object.
    (Github issue :issue:7721)

  • A return value from within a prange() loop could silently return the
    default value of the return type instead of the user provided value.
    (Github issue :issue:7587)

  • Assigning a Python 3.14+ .__annotate__ function to a Cython compiled function no
    longer evaluates annotations eagerly.
    (Github issue :issue:7767)

  • Generated Cython language features like properties, auto-pickle or dataclasses
    now use a critical section (on the object itself) as guard for concurrent access.
    (Github issue :issue:6621)

  • The star-import implementation needlessly rejected several names in internal use.
    They are now allowed and become regular Python module attributes.
    (Github issue :issue:4931)

  • Mixing function signature declarations in Python modules and their .pxd modules could fail.
    (Github issues :issue:5970, :issue:4388)

  • C array declarations with type and size could fail with an exception in pure Python code.
    (Github issue :issue:7372)

  • A const modifier in C++ template type arguments could be mapped incorrectly.
    (Github issue :issue:6294)

  • C++ typeid() failed to compile on more complex expressions.
    (Github issue :issue:7069)

  • Optimised Python int and float operations did not remember their result type,
    leading to less optimised code in longer expressions.
    (Github issues :issue:7363, :issue:7502)

  • Slices as dictionary keys confused the type inference of item access.
    (Github issue :issue:7702)

  • A race condition when returning from a cython.parallel.parallel section was fixed.
    (Github issue :issue:6521)

  • Cython still used (type, exc, traceback) for saving and restoring exception state,
    even though modern CPython versions only store the exception object itself internally.
    This is now modernised in many places to reduce overhead.
    (Github issue :issue:7481)

  • Exceptions originating from the Py_UNICODE_IS*() character classification macros and
    the corresponding str.is*() methods, which they alias, were not handled but ignored in
    the Limited API.
    (Github issue :issue:7602)

  • In the Limited API, import time failures to create code objects for compiled functions,
    e.g. due to future Python API changes, are no longer fatal but generate a warning.
    (Github issue :issue:5718)

  • Several internal cases where exceptions are caught and discarded now propagate the
    BaseException errors and only discard the expected exceptions.
    (Github issue :issue:7600)

  • Error handling was improved when setting up the table of cdef methods for extension types
    and unexpected errors are propagated.
    (Github issue :issue:7613)

  • Exceptions while setting up the automatic pickle support are now propagated.
    (Github issue :issue:7613)

  • Exceptions thrown into async generators could leave the generator in an unclosed state.
    (Github issue :issue:7618)

  • In the Limited API, failures while formatting type names in exceptions are now uniformly handled.
    (Github issue :issue:7680)

  • A cpdef enum with negative values changed to non-negative in Python 3.15.
    It now uses a dedicated enum implementation class to allow this.
    (Github issue :issue:7185)

  • cpdef fused functions generated redundant code.
    (Github issue :issue:7778)

  • Automatic C++ STL conversions in different compiler directive contexts could generate
    invalid code duplications in C++ code.
    Original Patch by bjodah. (Github issue :issue:6981)

  • The global module state struct now lives in an anonymous namespace in C++ mode to
    allow linking multiple modules together in one shared library file.
    (Github issue :issue:7159)

  • Cached methods of builtin types were not GC-traversed and cleaned up as part of the module state.
    Patch by Maxwell Bernstein. (Github issue :issue:7468)

  • Dict iteration generates safer code in PyPy/GraalPy/free-threading.
    (Github issue :issue:7637)

  • The floating point parsing code relied on C implementation specific "pointer compare after free" behaviour.
    Patch by stratakis. (Github issue :issue:7463)

  • When non-heap types were used as base classes of extension heap types, the heap types
    were not correctly reference counted by their instances.
    (Github issue :issue:7483)

  • The .__signatures__ dict of fused functions is no longer writable.
    (Github issue :issue:7386)

  • A minimal implementation of .__annotate__ was added to Cython compiled functions to make
    @functools.wraps work in Python 3.14+.
    (Github issue :issue:7675)

  • The --embed-positions option no longer includes absolute file paths in the C code.
    (Github issue :issue:6755)

  • Casting to an unresolved typeof() type (e.g. cython.cast(cython.typeof(x), ...)
    where the type could not be inferred) crashed the compiler instead of reporting an error.
    Patch by Vladimir Saraikin. (Github issue :issue:7683)

  • Error reporting on missing braces in f-strings was misleading.
    (Github issue :issue:7436)

  • Declaring a __dict__ attribute in a class as public or readonly
    generated incorrect code. It is now detected as an error.
    Patch by Anthony Donlon. (Github issue :issue:7823)

  • None default values for function arguments declared as not None are now rejected
    at compile time rather than leading to errors at runtime.
    Patch by Vyas Ramasubramani. (Github issue :issue:7762)

  • Cython did not reject code with multiple contradicting type annotations on the same variable.
    (Github issue :issue:7246)

  • Cython no longer warns if @profile or @linetrace is applied to a function
    without changing the global/outer setting. This avoids annoyance when users leave
    such redundant decorators in the code for occasional use.

  • The virtualenv activation inside of cygdb when it is run from a virtualenv works in more cases.
    Original patch by Pierrick Koch and Ashutosh Varma. (Github issues :issue:1961, :issue:3629)

  • Modules with non-ASCII names could end up with UTF-8 characters in their C code.
    (Github issue :issue:7588)

  • MSVC could silently truncate long C string literals (including internal ones)
    at a 64k bytes border. This is now worked around using C char arrays.
    (Github issue :issue:7824)

  • Several C compiler warnings related to mixed signed/unsigned C integer usage were resolved.

  • Some compiler directives failed to apply to Cython's build, which lead to
    unintentionally (slightly) increased wheel sizes.
    (Github issue :issue:7801)

  • A regression in 3.3.0b1 that generated invalid C code for exception type checks was fixed.
    (Github issue :issue:7902)

  • Includes all fixes as of Cython 3.2.9.

Other changes

  • Support for Python 3.8 has been removed.
    As a side-effekt, support for StacklessPython and Pyston (last release was 3.8) was also removed.
    Python 3.9 is planned to remain supported for several years due to its use in LTS Linux distributions.
    (Github issue :issue:7271)

  • The vectorcall feature macros were unified to make CYTHON_VECTORCALL the only way to
    disable this feature (if need arises). Previously the option macros CYTHON_METH_FASTCALL,
    CYTHON_FAST_PYCALL and CYTHON_VECTORCALL all controlled different aspects of the
    implementation.
    (Github issue :issue:7616)

  • Setting the Limited API version macro Py_LIMITED_API in PyPy or GraalPython
    now enables the Limited API usage in these runtimes. This will currently fail
    due to lack of support in the runtimes, but is intended for initial testing
    and future improvements.
    (Github issue :issue:7831)

  • Setting Py_LIMITED_API to a newer API version x.y than the current runtime
    (and its header files) is now detected and will explicitly fail to compile,
    rather than running into less obvious C compile or runtime issues.
    (Github issue :issue:7185)

  • Coroutines no longer provide the legacy _is_coroutine property.
    (Github issue :issue:7709)

  • Two more Cython modules are compiled in the binary wheels, which should improve the
    translation speed for modules with many strings.
    (Github issue :issue:7795)

  • The distributed Cython binary wheels now use a shared utility code module to reduce their size.
    (Github issue :issue:7865)

  • Cython/Shadow.pyi has been merged into Cython/Shadow.py.
    (Github issue :issue:7376)

  • The documentation now uses the "Clarity" Sphinx theme.
    Patch by Libor Jelínek. (Github issue :issue:7564)

v3.2.9

Compare Source

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

Bugs fixed

  • Indexing into freshly created lists with an out-of-bounds index could crash.
    (Github issue :issue:7793)

  • Function arguments with default values could end up uninitialised in closures, leading to crashes.
    Patch by Anthony Donlon. (Github issue :issue:7782)

  • bytearray.append(None) could crash. The optimised code was also lacking concurrency guards.
    (Github issue :issue:7796)

  • Some rare corner cases when concatenating text strings were resolved.
    (Github issue :issue:7799)

  • Assignments of builtin string types to typedefs of object could erroneously be rejected.
    (Github issue :issue:7789)

  • Subscripting type failed with a TypeError.
    (Github issue :issue:5563)

  • Manually disabling CYTHON_VECTORCALL in CPython could lead to invalid C code.
    Patch by Florent Gallaire. (Github issue :issue:7807)

  • Some internal Limited API version checks for Py3.12 were corrected.
    (Github issue :issue:7845)


Configuration

📅 Schedule: (UTC)

  • Branch creation
    • At any time (no schedule defined)
  • Automerge
    • At any time (no schedule defined)

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


  • If you want to rebase/retry this PR, check this box

This PR was generated by Mend Renovate. View the repository job log.

@sonarqubecloud

Copy link
Copy Markdown

@codecov

codecov Bot commented Aug 22, 2026

Copy link
Copy Markdown

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 91.74%. Comparing base (0a81b4e) to head (3e1fbf6).

Additional details and impacted files
@@            Coverage Diff             @@
##           master     #183      +/-   ##
==========================================
+ Coverage   90.82%   91.74%   +0.91%     
==========================================
  Files           1        1              
  Lines         109      109              
==========================================
+ Hits           99      100       +1     
+ Misses         10        9       -1     

☔ View full report in Codecov by Harness.
📢 Have feedback on the report? Share it here.

🚀 New features to boost your workflow:
  • ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

None yet

Projects

None yet

Development

Successfully merging this pull request may close these issues.

0 participants