[mbUSC]

cibuildwheel v2.16.5 predates Python 3.15 and can't build or test on it. Upgrade to v4.3.3 and add cp315 to CIBW_BUILD. The wheel is abi3, so it is still built only once, on cp39; cibuildwheel reuses it for cp315 and only runs the tests there.

Side effects of going from v2 to v4, from cibuildwheel's changelog:

• Linux wheels are built on manylinux_2_28 instead of manylinux2014, so they need glibc 2.28 or newer. CentOS 7 and Amazon Linux 2 users would fall back to the sdist or the pure-Python wheel. Setting CIBW_MANYLINUX_{X86_64,AARCH64}_IMAGE to manylinux2014 keeps the old baseline.
• Each abi3 wheel is checked with abi3audit after repair, and a failure fails the build.
• Windows wheels are repaired with delvewheel, which bundles any DLLs the extension links against.
• Wheels are built with build instead of pip wheel, in environments without setuptools and wheel preinstalled. Both come from pyproject.toml's build-system.requires instead.

---

Note

Medium Risk
Changes the release wheel pipeline (cibuildwheel major upgrade, Python 3.15 test matrix, and manylinux image pinning), which affects binary compatibility and publish reliability for all platforms.

Overview
Upgrades the publish workflow from pypa/cibuildwheel@v2.16.5 to v4.3.3 so wheels can be exercised on Python 3.15. CIBW_BUILD now includes cp315-* alongside cp39-*; because the extension wheel is abi3, cibuildwheel still builds once on 3.9 and reuses that wheel for 3.15 while running tests on both ends of the supported range.

To offset cibuildwheel v3+ defaulting Linux builds to manylinux_2_28, the workflow pins CIBW_MANYLINUX_X86_64_IMAGE and CIBW_MANYLINUX_AARCH64_IMAGE to manylinux2014, preserving the older glibc baseline so older distros still install the compiled wheel instead of silently falling back to pure Python.

In accel.c, the local UTF-8 helper _PyUnicode_AsUTF8 is marked static to keep it file-local (avoids clashing with Python’s internal symbol naming during limited-API / abi3 wheel checks).

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Summary by CodeRabbit

• New Features
  • Added package wheel builds for Python 3.15, with the ABI-stable wheel tested on that version.
• Compatibility
  • Linux wheels for x86_64 and aarch64 now target manylinux2014 for broader compatibility.

[kesmit13]

I ran this branch locally with cibuildwheel v4.3.3 (Linux x86_64, cp39-* cp315-*). It needs two changes before it can merge.

1. accel.c: make _PyUnicode_AsUTF8 static

As it stands the build fails at the new abi3audit step:

_singlestoredb_accel.abi3.so: "is_abi3": false, "non_abi3_symbols": ["_PyUnicode_AsUTF8"]
cibuildwheel: error: Audit command failed: abi3audit --strict --report ...

_PyUnicode_AsUTF8 isn't a CPython function. It's our own helper at accel.c:374, and it's declared without static, so it's exported from the .so. abi3audit sees an exported _Py* symbol and treats it as a call outside the stable ABI. v2.16.5 never ran abi3audit, which is why this hasn't shown up before. abi3audit runs on every platform's abi3 wheel, so the Windows and macOS builds would fail the same way.

The helper is only used inside accel.c, so the fix is one word:

-char *_PyUnicode_AsUTF8(PyObject *unicode) {
+static char *_PyUnicode_AsUTF8(PyObject *unicode) {

The name can stay. It's there so the helper can be swapped for CPython's own function once the limited-API baseline reaches 3.10. Note that the 3.10 limited-API function is PyUnicode_AsUTF8AndSize(obj, NULL), not PyUnicode_AsUTF8, and that it returns a borrowed buffer cached on the string object rather than a copy we own. The swap would have to drop the matching free() calls and make sure each source object outlives the stored pointers.

2. publish.yml: keep the glibc 2.17 baseline

cibuildwheel v3+ builds Linux wheels on manylinux_2_28 by default, which raises the minimum glibc from 2.17 to 2.28. Customers on CentOS/RHEL 7, Amazon Linux 2 or Ubuntu 18.04 wouldn't get an error: pip would skip the binary wheel and install our pure-Python py3-none-any wheel, so they'd lose the C accelerator without any warning. The extension is plain C with no need for a newer glibc or toolchain, so manylinux_2_28 gains us nothing. Pin the old image in the "Build and test wheels" env: block:

          # cibuildwheel v3+ builds on manylinux_2_28 (glibc 2.28) by default.
          # Pin manylinux2014 (glibc 2.17) so CentOS/RHEL 7, Amazon Linux 2 and
          # Ubuntu 18.04 still get the C extension instead of falling back to
          # the pure-Python wheel without any warning.
          CIBW_MANYLINUX_X86_64_IMAGE: manylinux2014
          CIBW_MANYLINUX_AARCH64_IMAGE: manylinux2014

i686 is already skipped by CIBW_SKIP, and musllinux isn't built. Using the manylinux2014 name means cibuildwheel supplies the image version it has pinned, so it keeps getting updated as cibuildwheel is upgraded. v4.3.3 pins the 2026.10.21 build, which includes CPython 3.15.

manylinux2014 is based on CentOS 7, which is end-of-life. We should plan to move to manylinux_2_28 once pypa stops rebuilding the image, and call it out in the release notes when we do.

Local result with both changes

singlestoredb-1.18.1-cp38-abi3-manylinux2014_x86_64.manylinux_2_17_x86_64.whl
abi3audit: passed
ACCEL-OK 3.9.25  ...
Found previously built wheel ... compatible with cp315-manylinux_x86_64. Skipping build step...
ACCEL-OK 3.15.0 ... [GCC 10.2.1 20210130 (Red Hat 10.2.1-11)]

The test command here only imports _singlestoredb_accel; it doesn't run test_basics against a database. Not covered locally: aarch64, Windows, macOS, and the database tests. CI will cover those, and will also confirm that the aarch64 manylinux2014 image has cp315.

To reproduce:

CIBW_BUILD="cp39-* cp315-*" CIBW_ARCHS_LINUX=x86_64 \
CIBW_SKIP="pp* *-musllinux* *-manylinux_i686" \
CIBW_MANYLINUX_X86_64_IMAGE=manylinux2014 \
CIBW_TEST_COMMAND='python -c "import sys, _singlestoredb_accel; print(sys.version)"' \
uvx cibuildwheel==4.3.3 --platform linux --output-dir wheelhouse

[mbUSC]

@kesmit13 good catch, thank you!

1. _PyUnicode_AsUTF8 is now static, so it's no longer exported and abi3audit should pass.
2. Pinned CIBW_MANYLINUX_X86_64_IMAGE / CIBW_MANYLINUX_AARCH64_IMAGE to manylinux2014 to keep the glibc 2.17 baseline.

[coderabbitai]

No actionable comments were generated in the recent review.

Walkthrough

The publish workflow upgrades cibuildwheel, adds cp315 to the build selection, and pins Linux builds to manylinux2014. In accel.c, _PyUnicode_AsUTF8 becomes file-local.

Changes: Wheel publishing compatibility

Layer / File(s)	Summary
C helper linkage accel.c	_PyUnicode_AsUTF8 is now file-local. Its allocation and conversion behavior is unchanged.
Wheel build settings .github/workflows/publish.yml	The workflow upgrades cibuildwheel to v4.3.3, selects cp39 and cp315, and pins x86_64 and aarch64 Linux builds to manylinux2014. Comments describe the abi3 build and test selection.

Estimated code review effort: 2 (Simple) | ~10 minutes

Change: Other

Possibly related PRs

• singlestore-labs/singlestoredb-python#161: This PR also makes _PyUnicode_AsUTF8 file-local and refers to wheel filename checks involving this PR’s build.
• singlestore-labs/singlestoredb-python#146: This PR adds Python 3.15 to test matrices and identifies this PR’s cibuildwheel upgrade as the wheel build and test support for Python 3.15.

Merge Risk: Minimal · up to 8ca99

The change updates wheel publishing to test on Python 3.15 and keeps the older Linux compatibility baseline. It also makes an internal C helper file-local so the new abi3 audit can pass. No actionable merge-blocking risk is evident; CI should still confirm the aarch64, Windows, and macOS builds.

Architecture risk: Low · up to 8ca99

The change affects 1 system.

Changed systems: accel.c

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — accel.c (service) was modified; 1 changed file maps to changed impact.

Before / after behavior

• observed — Modified behavior in accel.c: _PyUnicode_AsUTF8 is now file-local rather than externally linked.
• observed — Modified behavior in .github/workflows/publish.yml: The wheel build now uses cibuildwheel v4.3.3 instead of v2.16.5, selects cp39 and cp315 builds instead of cp39 alone, and pins both x86_64 and aarch64 Linux images to manylinux2014. The added comments describe the abi3 build/test selection and the manylinux compatibility rationale.

Pre-merge checks: 4

Check name	Status	Explanation
Description Check		Check skipped - CodeRabbit’s high-level summary is enabled.
Title check		The title names the two main changes: the cibuildwheel upgrade to v4.3.3 and the addition of Python 3.15 wheel testing. The raw summary and objectives confirm both. The title does not mention the stat…
Linked Issues check		Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check		Check skipped because no linked issues were found for this pull request.

Full details: Title check

Explanation

The title names the two main changes: the cibuildwheel upgrade to v4.3.3 and the addition of Python 3.15 wheel testing. The raw summary and objectives confirm both. The title does not mention the static helper change or the manylinux2014 pinning, but those are secondary to the stated PR goal.

Finishing Touches

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Commits

Reviewing files that changed from the base of the PR and between 3266f62 and 8ca9937.

Files selected for processing: 2

• .github/workflows/publish.yml
• accel.c

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