Hum, this change has a big (security?) issue:

import subprocess
subprocess.Popen(["/usr/bin/id"], user=1000, group=1000).wait()

gives:

uid=1000(vstinner) gid=1000(vstinner) groupes=1000(vstinner),0(root) contexte=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

But:

import subprocess
subprocess.Popen(["/usr/bin/id"], user=1000, group=1000, close_fds=False).wait()

gives:

uid=0(root) gid=0(root) groupes=0(root) contexte=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023

=> user and group arguments are ignored when using close_fds=False: when subprocess uses posix_spawn().


Note: test_subprocess test_group() is skipped on my Fedora 30.


I wrote PR 16384 to fix the bug and enable test_group() on my Fedora (check also for "nobody" and "nfsnobody" groups).