git: improve coupling with {sock} and {inflight} fields

While the {inflight} array should be tied to the IO object even
more tightly, that's not an easy task with our current code.  So
take some small steps by introducing a gcf_inflight helper to
validate the ownership of the process and to drain the inflight
array via the awaitpid callback.

This hopefully fix problems with t/lei-q-save.t (still) hanging
occasionally on v2 outputs since git->cleanup/->DESTROY was getting
called in v2 shard workers.

1 files changed, 14 insertions, 3 deletions

diff --git a/lib/PublicInbox/IO.pm b/lib/PublicInbox/IO.pm
index fcebac59..6593dcdf 100644
--- a/lib/PublicInbox/IO.pm
+++ b/lib/PublicInbox/IO.pm
@@ -15,8 +15,10 @@ use Errno qw(EINTR EAGAIN);
 
 sub waitcb { # awaitpid callback
         my ($pid, $errref, $cb, @args) = @_;
+        $errref //= \my $workaround_await_pids_clobbered;
         $$errref = $?; # sets .cerr for _close
-        $cb->($pid, @args) if $cb;
+        $cb->($pid, @args) if $cb; # may clobber $?
+        $? = $$errref;
 }
 
 sub attach_pid {
@@ -33,6 +35,11 @@ sub attached_pid {
         ${${*$io}{pi_io_reap} // []}[1];
 }
 
+sub owner_pid {
+        my ($io) = @_;
+        ${${*$io}{pi_io_reap} // [-1]}[0];
+}
+
 # caller cares about error result if they call close explicitly
 # reap->[2] may be set before this is called via waitcb
 sub close {
@@ -40,8 +47,12 @@ sub close {
         my $ret = $io->SUPER::close;
         my $reap = delete ${*$io}{pi_io_reap};
         return $ret unless $reap && $reap->[0] == $$;
-        ${$reap->[2]} // (my $w = awaitpid($reap->[1])); # sets [2]
-        ($? = ${$reap->[2]}) ? '' : $ret;
+        if (defined ${$reap->[2]}) { # reap_pids already reaped asynchronously
+                $? = ${$reap->[2]};
+        } else { # wait synchronously
+                my $w = awaitpid($reap->[1]);
+        }
+        $? ? '' : $ret; # use $?, AWAIT_PIDS may be cleared on ->Reset (FIXME?)
 }
 
 sub DESTROY {