You shouldn't invoke setup.py directly
&gt; you can remove your setup.py file and replace it with setuptools&#x27; own declarative configuration format<p>Not if you have a Python&#x2F;C extension.<p>Not if your build step includes code generation (other than Cython).<p>Not if you have special per-file compilation args.<p>Also, in the declarative configuration format, how do I enable&#x2F;disable compile-time flags like &quot;compile with OpenMP&quot; ?<p>Yes, I have these, and it really irks me reading all of these &quot;you don&#x27;t need setup.py&quot; when as far as I can tell, I can&#x27;t.