This will keep us from adding new unsupported (i.e. non-const) C global variables, which would break interpreter isolation.
FYI, historically it is very uncommon for new global variables to get added. Furthermore, it is rare for new code to break the c-analyzer. So the check should almost always pass unnoticed.
Note that I've removed test_check_c_globals. A test wasn't a great fit conceptually and was super slow on debug builds. A CI check is a better fit.
This also resolves gh-100237.
https://github.com/python/cpython/issues/81057
The original tool wasn't working right and it was simpler to create a new one, partially re-using some of the old code. At this point the tool runs properly on the master. (Try: ./python Tools/c-analyzer/c-analyzer.py analyze.) It take ~40 seconds on my machine to analyze the full CPython code base.
Note that we'll need to iron out some OS-specific stuff (e.g. preprocessor). We're okay though since this tool isn't used yet in our workflow. We will also need to verify the analysis results in detail before activating the check in CI, though I'm pretty sure it's close.
https://bugs.python.org/issue36876
Victor Stinner
Eric Snow