Popular third party extension modules

To test C API changes in Python, it’s useful to test a bunch of popular extension modules to check if they still build.

Cython

The first important candidate is Cython, many projects use it:

• Cython
• lxml
• numpy (Cython + C API)
• pandas
• pyzmq (for Jupyter)
• scipy

Python C API

Use directly the C API:

• Mercurial
• Pillow
• cffi
• psycopg2