fix(ci): set PYO3_CROSS_PYTHON_VERSION for aarch64 Linux cross-compilation

[polaz]

Problem

Build embedded / aarch64 (ubuntu-latest) fails with:

💥 maturin failed
  Caused by: Couldn't find any python interpreters. Please specify at least one with -i

maturin-action v1.47.0 with manylinux_2_28 + target: aarch64 on an x86_64 runner uses ghcr.io/rust-cross/manylinux_2_28-cross:aarch64 — a Debian-based cross-compilation container with no Python interpreters.

Fix

Set PYO3_CROSS_PYTHON_VERSION=3.11 for the aarch64 Linux matrix entry. This tells PyO3 to generate bindings for Python 3.11 without needing a Python binary in the container — the standard approach for cross-compilation without QEMU emulation.

The env var is only set for the aarch64 Linux matrix entry; other entries have it empty/unset. PyO3 ignores it on native builds where Python is available.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Pro

Run ID: a8c4d5dd-de0a-4b53-b61c-d6ada893570f

📥 Commits

Reviewing files that changed from the base of the PR and between 73bf4db and 269805e.

📒 Files selected for processing (1)

• .github/workflows/release.yml

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📝 Walkthrough

Summary by CodeRabbit

• Chores
  • Improved cross-compilation support for ARM64 architecture builds, enabling proper Python version targeting during the wheel build process on non-native platforms.

Walkthrough

The PR updates the .github/workflows/release.yml file to add explicit Python version configuration for PyO3 cross-compilation. A pyo3_cross_python_version: "3.11" matrix variable is added for Linux aarch64 builds and passed to the maturin build step via PYO3_CROSS_PYTHON_VERSION environment variable.

Changes

CI Cross-Compilation Configuration

Layer / File(s)	Summary
Matrix Setup .github/workflows/release.yml (lines 76–82)	build-embedded job's aarch64 Linux matrix entry adds pyo3_cross_python_version: "3.11" to specify the target Python version for cross-compilation.
Build Environment .github/workflows/release.yml (lines 138–139)	PyO3/maturin-action step now sets PYO3_CROSS_PYTHON_VERSION environment variable from the matrix value, enabling PyO3 to target the specified Python version during aarch64 cross-builds.

Estimated code review effort

🎯 2 (Simple) | ⏱️ ~5 minutes

Possibly related PRs

• #40: Modifies the same build-embedded job for aarch64 Python version and cross-compilation setup control.

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: setting PYO3_CROSS_PYTHON_VERSION for aarch64 cross-compilation in CI.
Description check	✅ Passed	The description is directly related to the changeset, explaining both the problem and the solution implemented in the CI workflow file.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch fix/#57-aarch64-pyo3-cross-python

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

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