@christian.heimes thanks for bringing PEP 648 to my attention. The solution proposed there would work for me, although it actually does a bit more with some extra complexity. Not a big issue though.

@eric.smith I think that, as argued in PEP 648, pth files are not meant to be used to inject arbitrary code. Besides, the way to exploit pth files wouldn't be much more different than what I described in the issue body.