Opaque PyObject ABI support#5807

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ngoldbaum wants to merge 239 commits into

ngoldbaum:opaque-pyobject

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ngoldbaum commented Feb 13, 2026 •

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Fixes #5786.

Adds support for the new PEP 803 abi3t ABI.
- Adds new abi3t and abi3t-py315 features to enable abi3t builds. These features work analogously to the abi3 features.
Adds a new target_abi field to the InterpreterConfig struct. This allows keeping track of a separate host and target Python version and fixing some longstanding issues with separation of concerns there.
Adds a PythonAbi and PythonAbiBuilder struct which wraps an implementation, version, and a new PythonAbiKind enum. The PythonAbiKind enum can itself be one of two enums: StableAbi or VersionSpecific. The former can be Abi3 or Abi3t and the latter can be FreeThreaded or GilEnabled. It's a lot of new types but it also allows us to track details about the target ABI in a much more fine-grained manner.

ngoldbaum added proc-macro CI-build-full free-threading CI-no-fail-fast labels

ngoldbaum force-pushed the opaque-pyobject branch from 4f82f37 to bcf9a32 Compare

February 13, 2026 20:56

ngoldbaum mentioned this pull request

docs: Document Py_GIL_DISABLED in pyo3-build-config docs #5810

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Add support for the opaque PyObject ABI #5786

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ci: expand pyclass benchmarks #5816

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ci: add a abi3 feature to pyo3-benches #5818

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Fix typo in PyType_GetTypeDataSize bindings #5819

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davidhewitt mentioned this pull request

fix memory corruption when subclassing variable-size types (e.g. abi3 + 3.12 subclassing of native types) #5823

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ngoldbaum added 10 commits

February 17, 2026 13:08


          Use PyModExport and PyABIInfo APIs in pymodule implementation

eb53c2d


          Add PyModExport function

e41b509


          DNM: temporarily disable append_to_inittab doctest

91becaf


          fix issues seen on older pythons in CI


          fix incorrect ModuleDef setup on 3.15

3afa9ae


          Expose both the PyInit and PyModExport initialization hooks

f8d6cae


          fix clippy

a590874


          add changelog entry

a96219f


          try use only slots for both init hooks on 3.15

e7ac9c0


          Always pass m_name and m_doc, following cpython-gh-144340

d981be7

davidhewitt mentioned this pull request

ci: switch to ui-test instead of trybuild #5863

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Sorry for the slow review cycle, was busy this week at the Rust All Hands.

I think this is looking great and almost ready to merge. Comments are primarily cleanups, with the most involved suggestion being to gate append_to_inittab.

guide/src/building-and-distribution.md Outdated

guide/src/building-and-distribution.md Outdated

pyo3-ffi/src/moduleobject.rs Outdated

pyo3-ffi/src/object.rs Outdated

pyo3-ffi/src/object.rs Outdated

pyo3-ffi/src/object.rs Outdated

pyo3-ffi/build.rs Outdated

pyo3-ffi/build.rs Outdated

pyo3-ffi/build.rs Outdated

src/impl_/pymodule.rs

Contributor Author

ngoldbaum commented May 25, 2026

I was looking at trying to get the maturin integration tests passing on 3.15t today and noticed that cargo build --features=abi3-py39,abi3t-py315 dies inside the pyo3-ffi build script because the detected target ABI is abi3t-py39, which is definitely wrong.

ngoldbaum added 10 commits

May 25, 2026 13:33


          make get_host_interpreter accept explicit abi3_version and abi3t_vers…

f9b50b7

…ion arguments


          never use an abi3 version on the free-threaded build


          make build-config tests pass on 3.14t

f85c163


          version-gate build-config test

fd01447


          fix logic error in get_host_interpreter

0e945b3


          skip build-config tests for stable ABI lowering on 3.14t, which doesn…

c9c3b01

…'t support any stable ABI


          further gate test

abaf0e0


          attempt to fix cross-compilation issue in maturin

a49e696


          only use abi3 version for non-free-threaded cross-compile

1cf8751


          fix incorrect version gate

e6d31b9

Contributor Author

ngoldbaum commented May 26, 2026

I'm trying to stabilize the Maturin tests but that requires pushing here, sorry for the noise. The latest discovery was that zig cross-compilation was broken which indicates I probably need to add more unit tests for generating an InterpreterConfig for a free-threaded target.

ngoldbaum added 10 commits

May 26, 2026 13:31


          further gate test onolder python versions


          expand test-version-limits tests to cover pyo3-ffi build script logic

3c25970


          Apply David's review comments

f49ee61


          expand cross-compilation tests

854062d


          fix ruff

7b3da72


          don't lower to abi3 on pypy or graalpy

91c7db3


          fix cross-compiling from PyPy

afd124c


          skip stable abi lowering test on graalpy and pypy

5d9afb9


          fix logic error

dac521d


          simplify skipping logic

4be2121

Contributor Author

ngoldbaum commented May 27, 2026 •

edited

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It looks like Maturin's CI is now stable with all test crates updated to use this PR and CI running on both 3.15 interpreters.

ngoldbaum added 4 commits

May 28, 2026 08:51


          Fix Py_UNICODE_TODECIMAL definition for PyPy

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          Merge branch 'fix-todecimal-pypy' into opaque-pyobject

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          rename USE_ABI3T_FORWARD_COMPATIBILITY to USE_STABLE_ABI_FORWARD_COMP…

e573a16

…ATIBILITY


          format

fbefb3b

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gh-146636: Add Free-threaded Stable ABI migration guide python/cpython#150580

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