This simple script will spawn N Python interpreters that aren't properly collected due to the improper error handling:

import pty
for i in range(N):
    try: pty.spawn(["/non-existent"])
    except: pass

Can a linux guru comment on this please.

The spawn() function has this code outside of any error handler:

pid, master_fd = fork()
if pid == CHILD:
    os.execlp(argv[0], *argv)

If fork() succeeds, there will actually be a parent Python process and a child Python process. If exec() then fails, an exception will escape the spawn() function in the child process, while the parent process will carry on as if all is well. Maybe it would be worthwhile studying how the “subprocess” module handles exec() failure in the child process.

The patch for Issue 26228 proposes an improvement to the situation, although it is not perfect and does not include a test. I wonder if it is possible to replace fork() and execlp() with a subprocess.Popen invokation, at least in a new Python release?