Build limited-API (abi3) wheels: mark CFFI extension py_limited_api and remove wrong bdist_wheel hack

[Copilot]

Problem

The setup.py had a custom bdist_wheel_abi_none class that incorrectly forced the ABI tag to 'none', preventing the creation of proper limited-API (abi3) wheels. This resulted in wheels like moocore-0.1.9.dev0-py3-none-linux_x86_64.whl that couldn't take advantage of Python's stable ABI, requiring separate wheels for each Python version.

Additionally, _ffi_build.py had a bug where extra_link_args was set to extra_compile_args instead of the correct extra_link_args variable.

Solution

1. Replaced the incorrect bdist_wheel override in setup.py with bdist_wheel_abi3 that automatically detects py_limited_api=True from CFFI extension modules and sets the appropriate abi3 wheel tag (cp310-abi3).

2. Marked the CFFI extension with py_limited_api=True in src/moocore/_ffi_build.py to enable limited API compilation.

3. Fixed extra_link_args to use the correct variable instead of duplicating extra_compile_args.

Result

Wheels now correctly use the Python Limited API (abi3):

• Before: moocore-0.1.9.dev0-py3-none-linux_x86_64.whl with Tag: py3-none-linux_x86_64
• After: moocore-0.1.9.dev0-cp310-abi3-linux_x86_64.whl with Tag: cp310-abi3-linux_x86_64

The generated shared library is now named _libmoocore.abi3.so, confirming it was compiled with the limited API. This allows the same wheel to work across all Python 3.10+ versions without recompilation.

Testing

• Built wheel successfully with correct abi3 tags in both filename and WHEEL metadata
• All 35 existing tests pass
• Editable installs also correctly generate abi3 wheels

Requirements

Requires recent versions of setuptools (>=77.0.3), wheel, and cffi (>=1.17.1) to properly propagate py_limited_api into wheel tags, as specified in pyproject.toml.

Original prompt

Open a pull request from branch fix/abi3-wheels into main with title 'Build limited-API (abi3) wheels: mark CFFI extension py_limited_api and remove wrong bdist_wheel hack' and body 'Problem: setup.py had a custom bdist_wheel override that set the ABI tag to 'none', preventing proper limited-API (abi3) wheels. Fix: removed the incorrect bdist_wheel override, marked the CFFI extension with py_limited_api=True in src/moocore/_ffi_build.py, and fixed extra_link_args so link flags are applied correctly. Verification: build a wheel (python -m pip wheel . in python/) and confirm the wheel filename and WHEEL file contain py3-abi3-. Notes: Requires recent setuptools/wheel/cffi to propagate py_limited_api into wheel tags.'

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[codecov]

Codecov Report

❌ Patch coverage is 81.81818% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 72.21%. Comparing base (25d4939) to head (c69566e).
⚠️ Report is 15 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #31      +/-   ##
==========================================
+ Coverage   72.17%   72.21%   +0.03%     
==========================================
  Files          57       57              
  Lines        4856     4859       +3     
  Branches      929      929              
==========================================
+ Hits         3505     3509       +4     
- Misses        999     1000       +1     
+ Partials      352      350       -2     

Flag	Coverage Δ
python	71.19% <81.81%> (+0.04%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Components	Coverage Δ
tests	100.00% <ø> (ø)
src	85.67% <81.81%> (-0.22%)	⬇️

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