This starts two sleep processes and expects them to be killed on
SIGHUP.
Unfortunately, if this ever fails the second run will also fail
because it'll see the old sleep still lying around (because it'll run
for 130 seconds).
So, what we do is:
1. Keep the pids for these specific sleeps
2. Check if any of them are still running (and only fail for them)
3. Kill them from python
Fixes#9152
On macOS, the tests would often fail because calls to `pkill` would "leak"
across tests: kill processes run by other tests. This is because on macOS,
the -P argument to pkill must come before the process name. On Linux it
doesn't matter.
This improves test reliability on Mac.
This disables job control inside command substitutions. Prior to this
change, a cmdsub might get its own process group. This caused it to fail
to cancel loops properly. For example:
while true ; echo (sleep 5) ; end
could not be control-C cancelled, because the signal would go to sleep,
and so the loop would continue on. The simplest way to fix this is to
match other shells and not use job control in cmdsubs.
Related is #1362
I really kinda hate how insistent clang-format is to have line
breaks *IFF THE LINE IS TOO LONG*.
Like... lemme just add a break if it looks better, will you?
But it is the style at this time, so we shall tie an onion to our
belt.
