Be more careful about the order in which we kill processes.

In particular, don't have the watchdog kill itself. Even though
perl's `kill` takes a list of pids, they actually get signalled
one at a time, and so if the watchdog is in the middle of the
list not everything will get killed like it should be. So have
the watchdog filter itself out of the list, and then just
naturally die.

CHANGELOG

@@ -1,3 +1,9 @@
+1.0.2   2023-04-14
+
+- Be more careful about the order in which we kill processes
+  for greater reliability. If the watchdog killed itself too
+  early it might miss other child processes.
+
 1.0.1   2021-12-18
 
 - Make tests more reliable under heavy load

Makefile.PL

@@ -15,9 +15,9 @@ WriteMakefile(
         bin/ptimeout
     )],
     PREREQ_PM    => {
-        Capture::Tiny     => 0,
-        Proc::Killfam     => '1.0',
-        Test::Differences => 0,
-        Test::More        => '0.88', # done_testing
+        Capture::Tiny      => 0,
+        Proc::ProcessTable => '0.634',
+        Test::Differences  => 0,
+        Test::More         => '0.88', # done_testing
     },
 );

lib/App/ptimeout.pm

@@ -4,9 +4,9 @@ use strict;
 use warnings;
 no warnings 'numeric';
 
-use Proc::Killfam;
+use Proc::ProcessTable;
 
-our $VERSION = '1.0.1';
+our $VERSION = '1.0.2';
 
 sub _run {
     my($timeout, @argv) = @_;
@@ -27,10 +27,34 @@ sub _run {
     } else { # watchdog child process
         sleep $timeout;
         warn "timed out\n";
-        killfam SIGTERM => getppid;
+        # We can't just `Proc::Killfam::killfam TERM => getppid` because that
+        # will put the watchdog process somewhere in the list of victims, and
+        # thus anything after it in the list won't get killed. Filter this
+        # process out of the list of victims and kill everything else. The
+        # watchdog will then exit normally.
+        my $process_table = Proc::ProcessTable->new->table;
+        my @victims = grep { $_ != $$ } _get_pids($process_table, getppid);
+        kill SIGTERM => @victims, getppid;
     }
 }
 
+# Copied from Proc::Killfam::get_pids in Proc-ProcessTable-0.634 which is
+# GPL/Artistic licenced. It's undocumented there so should be considered
+# unstable, hence why copied.
+sub _get_pids {
+    my($procs, @kids) = @_;
+    my @pids;
+    foreach my $kid (@kids) {
+        foreach my $proc (@$procs) {
+            if ($proc->ppid == $kid) {
+                my $pid = $proc->pid;
+                push @pids, $pid, _get_pids($procs, $pid);
+            }
+        }
+    }
+    @pids;
+}
+
 =head1 NAME
 
 App::ptimeout - module implementing L<ptimeout>

t/ptimeout.t

@@ -33,7 +33,7 @@ eq_or_diff(
 );
 
 ($stdout, $stderr, $status) = capture(sub {
-    system(
+    my $status = system(
         @perl,
         1,
         q{
@@ -43,6 +43,10 @@ eq_or_diff(
             "
         }
     ) >> 8;
+    # keep capturing output until the sub-process would have finished
+    # were it not killed
+    sleep 15;
+    $status;
 });
 eq_or_diff(
     [$status, $stderr,       $stdout],