set $return->{exit} right after waiting on the child

In fact, PID reuse isn't going to happen until child is reaped by
parent.

1 files changed, 12 insertions, 16 deletions

diff --git a/perl5/Local/Interactive.pm b/perl5/Local/Interactive.pm
index df6cdc32..bac754a4 100644
--- a/perl5/Local/Interactive.pm
+++ b/perl5/Local/Interactive.pm
@@ -225,22 +225,19 @@ sub _sysptycap_pty {
     while (1) {
         my $rin = "";
         vec($rin, fileno $slave, 1) = 1;
-        if (select $rin, undef, undef, 1) {
-            my $nbytes = sysread $slave, my $bytes, 8192;
-            last if defined $nbytes and $nbytes == 0;
+        my $nbytes = sysread $slave, my $bytes, 8192
+          if select $rin, undef, undef, 1;
+        if ($nbytes) {
             print $bytes;
             $return->{output} .= $bytes;
-        } else {
-            # Since there was no new output, see if child needs
-            # reaping, and end the loop if all children have died.
-            # This is needed as the child might die without the pty
-            # getting EOF, e.g. if an SSH control socket is still
-            # alive (seems to happen when using Debian's SSH jump host
-            # to SSH to salsa).
-            #
-            # An alternative is to make the whole loop 'while (kill 0,
-            # $pid)' but this is more elegant as PIDs get reused
-            last if waitpid(-1, WNOHANG) == -1;
+        } elsif (my $deceased = waitpid $pid, WNOHANG) {
+            # As there was no new output, or we got EOF, check if the
+            # child has died.  We can't just check for EOF alone
+            # because we can't rely on the pty getting EOF, e.g. if an
+            # SSH control socket is still alive (seems to happen when
+            # using Debian's SSH jump host to SSH to salsa)
+            $return->{exit} = $? >> 8 if $deceased > 0;
+            last;
         }
     }
     $slave->close;
@@ -250,8 +247,7 @@ sub _sysptycap_pty {
     my $codeset = eval { langinfo CODESET };
     $return->{output} = decode $codeset, $return->{output} if $codeset;
 
-    $return->{exit} = $? >> 8;
-    return $return;
+    $return;
 }
 
 =head prompt($prompt)