Found when testing PYTHONINSPECT for #143134, when you set PYTHONINSPECT to a "non-empty" string that is 0, it is checked in initconfig.c with _Py_get_env_flag:

But then directly with _Py_GetEnv in pymain_repl:

So, you end up in this situation:

$ PYTHONINSPECT=0 ./python -c "import sys; print(sys.flags.inspect)"
0
>>> # We still inspect, even though sys.flags.inspect is not set...

Linked PRs

• gh-143135: Fix sys.flags.inspect when PYTHONINSPECT=0 #143136
• [3.14] gh-143135: Fix sys.flags.inspect when PYTHONINSPECT=0 (GH-143136) #143153
• [3.13] gh-143135: Fix sys.flags.inspect when PYTHONINSPECT=0 (GH-143136) #143168