[PATCH 12/14] qspawn: decode $? for user-friendliness

[Eric Wong <e@80x24.org>]

The raw value of $? isn't very useful, generally.
---
 lib/PublicInbox/Qspawn.pm | 11 ++++++++++-
 t/qspawn.t                |  2 +-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
index 6859a8a..913fac8 100644
--- a/lib/PublicInbox/Qspawn.pm
+++ b/lib/PublicInbox/Qspawn.pm
@@ -30,13 +30,22 @@ sub _do_spawn {
 	$cb->($self->{rpipe});
 }
 
+sub child_err ($) {
+	my ($child_error) = @_; # typically $?
+	my $exitstatus = ($child_error >> 8) or return;
+	my $sig = $child_error & 127;
+	my $msg = "exit status=$exitstatus";
+	$msg .= " signal=$sig" if $sig;
+	$msg;
+}
+
 sub finish ($) {
 	my ($self) = @_;
 	my $limiter = $self->{limiter};
 	my $running;
 	if (delete $self->{rpipe}) {
 		my $pid = delete $self->{pid};
-		$self->{err} = $pid == waitpid($pid, 0) ? $? :
+		$self->{err} = $pid == waitpid($pid, 0) ? child_err($?) :
 				"PID:$pid still running?";
 		$running = --$limiter->{running};
 	}
diff --git a/t/qspawn.t b/t/qspawn.t
index 745ec4d..ab6e375 100644
--- a/t/qspawn.t
+++ b/t/qspawn.t
@@ -31,7 +31,7 @@ my $limiter = PublicInbox::Qspawn::Limiter->new(1);
 		my ($rpipe) = @_;
 		is(0, sysread($rpipe, my $buf, 1), 'read zero bytes from false');
 		my $err = $x->finish;
-		is($err, 256, 'error on finish');
+		ok($err, 'error on finish');
 		$run = 1;
 	});
 	is($run, 1, 'callback ran alright');
-- 
EW