Sourced frompyo3's releases.

PyO3 0.27.1

This release fixes a clippy lint regression in PyO3 0.27.0, and exposes thePySendResult type (the return value fromBound<PyIterator>::send).

Thank you to the following contributors for the improvements:

@​alex@​davidhewitt@​reaperhulk@​tpoliaw

PyO3 0.27.0

This release is the first PyO3 release to be tested against Python 3.14.0 final. There are no significant changes to 3.14 support since PyO3 0.26 which was tested against the 3.14 release candidates.

Support for PyPy 3.9 and PyPy 3.10 (both no longer supported upstream) has been dropped.

TheFromPyObject trait has been reworked in a similar fashion to theIntoPyObject trait introduced in PyO3 0.23. This has established a performant and flexible implementation of both these traits and no further changes to the traits are anticipated in the future. Thank you for the patience upgrading through these incremental improvements at the core of PyO3.

The.downcast() family of functions are now deprecated in favour of the.cast() family of functions, which are an incremental improvement to API usability and to error messages on failed conversions.

Operations on thePyCapsule type have been changed without deprecation to fix some issues with lifetimes of return values (in.name() and.reference() specifically). The capsule API now also encourages checking of capsule names, which is one of the few defences available to protect the validity of casting data read by the capsule API.

There are also many other incremental improvements, bug fixes and smaller features.

Please consult themigration guide for help upgrading.

Thank you to everyone who contributed code, documentation, design ideas, bug reports, and feedback. The following contributors' commits are included in this release:

@​alex@​altendky@​bazaah@​bschoenmaeckers@​crepererum@​davidhewitt@​dependabot[bot]@​elbaro@​Icxolu@​jqnatividad@​mbrobbel@​NilsIrl@​rvben@​sanders41@​tdyas@​Tpt@​vvsagar

Sourced frompyo3's changelog.

[0.27.1] - 2025-10-21

Fixed

• Fixclippy:declare_interior_mutable_const warning from#[pyfunction].#5538
• Exposepyo3::types::PySendResult in public API.#5539

[0.27.0] - 2025-10-19

Packaging

• Extend range of supported versions ofhashbrown optional dependency to include version 0.16.#5428
• Bump optionalnum-bigint dependency minimum version to 0.4.4.#5471
• Test against Python 3.14 final release.#5499
• Drop support for PyPy 3.9 and 3.10.#5516
• Provide a better error message when building an outdated PyO3 for a too-new Python version.#5519

Added

• AddFromPyObjectOwned as convenient trait bound forFromPyObject when the data is not borrowed from Python.#4390
• AddBorrowed::extract, same asPyAnyMethods::extract, but does not restrict the lifetime by deref.#4390
• experimental-inspect: basic support for#[derive(IntoPyObject)] (no struct fields support yet).#5365
• experimental-inspect: support#[pyo3(get, set)] and#[pyclass(get_all, set_all)].#5370
• AddPyTypeCheck::classinfo_object that returns an object that can be used as parameter inisinstance orissubclass.#5387
• ImplementPyTypeInfo ondatetime.* types even when the limited API is enabled.#5388
• ImplementPyTypeInfo onPyIterator,PyMapping andPySequence.#5402
• ImplementPyTypeInfo onPyCode when using the stable ABI.#5403
• ImplementPyTypeInfo onPyWeakrefReference when using the stable ABI.#5404
• Addpyo3::sync::RwLockExt trait, analogous topyo3::sync::MutexExt for readwrite locks.#5435
• AddPyString::from_bytes.#5437
• ImplementAsRef<[u8]> forPyBytes.#5445
• AddCastError andCastIntoError.#5468
• AddPyCapsuleMethods::pointer_checked andPyCapsuleMethods::is_valid_checked.#5474
• AddBorrowed::cast,Borrowed::cast_exact andBorrowed::cast_unchecked.#5475
• Add conversions forjiff::civil::ISOWeekDate.#5478
• Add conversions for&Cstr,Cstring andCow<Cstr>.#5482
• add#[pyclass(skip_from_py_object)] option, to opt-out of theFromPyObject: PyClass + Clone blanket impl.#5488
• AddPyErr::add_note.#5489
• AddFromPyObject impl forCow<Path> &Cow<OsStr>.#5497
• Add#[pyclass(from_py_object)] pyclass option, to opt-in to the extraction of pyclasses by value (requiresClone).#5506

Changed

• ReworkFromPyObject trait for flexibility and performance:#4390
  • Add a second lifetime toFromPyObject, to allow borrowing data from Python objects (e.g.&str from Pythonstr).
  • Replaceextract_bound withextract, which takesBorrowed<'a, 'py, PyAny>.
• OptimizeFromPyObject implementations forVec<u8> and[u8; N] frombytes andbytearray.#5244
• Deprecate#[pyfn] attribute.#5384
• Fetch type name dynamically on cast errors instead of usingPyTypeCheck::NAME.#5387
• DeprecatePyTypeCheck::NAME in favour ofPyTypeCheck::classinfo_object which provides the type information at runtime.#5387

... (truncated)

• 9fbcf7c release: 0.27.1
• fdfddc8 Expose types::iterator::PySendResult in types module (#5539)
• a09540b update MSRV shields.io badge (#5540)
• 1e6db53 fixes#5537 -- silence a clippy warning on rust 1.83 (#5538)
• 7525512 release: 0.27.0 (#5520)
• b392013 ci: install lychee stable usinginstall-action (#5528)
• f32ed83 fix PyPyModule_ExecDef, PyPyModule_FromDefAndSpec2 definitions (#5529)
• 02b54eb make warning name distinct in warnings tests (#5532)
• 999ee8a ci: enable more tests on 3.14t (#5524)
• 8f669e7 attempt to improve unsupported Python version error (#5519)
• Additional commits viewable incompare view

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