lib/PublicInbox/GitHTTPBackend.pm | 9 +++------
 lib/PublicInbox/Qspawn.pm         | 7 ++++++-

diff --git a/lib/PublicInbox/GitHTTPBackend.pm b/lib/PublicInbox/GitHTTPBackend.pm
index 974a1831340c3581a3fc55a5e0b335b7055c22f3..e84d4ff802bf763697ee9937257ec84fc6b83c0f 100644
--- a/lib/PublicInbox/GitHTTPBackend.pm
+++ b/lib/PublicInbox/GitHTTPBackend.pm
@@ -154,12 +154,9 @@ 		$ctx{env} = +{ %{$ctx->{env}} };
 		delete $ctx->{env}->{'qspawn.wcb'};
 		$ctx->{env}->{'plack.skip-deflater'} = 1; # prevent 2x gzip
 		my $res = $ctx->{www}->coderepo->srv(\%ctx);
-		if (ref($res) eq 'CODE') {
-			$res->(delete $ctx{env}->{'qspawn.wcb'});
-		} else { # ref($res) eq 'ARRAY'
-			$ctx->{env}->{'qspawn.wcb'} = $ctx{env}->{'qspawn.wcb'};
-		}
-		$res; # non ARRAY ref for ->psgi_return_init_cb
+		# for ->psgi_return_init_cb:
+		$ctx->{env}->{'qspawn.wcb'} = $ctx{env}->{'qspawn.wcb'};
+		$res; # CODE or ARRAY ref
 	} else {
 		[ $code, \@h ]
 	}
diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
index 6e24538959517b00ec1179f87318a9d875ab3db8..9ca6b3dbbcc98c6a761e34fe4cc7e94f4a94ccd4 100644
--- a/lib/PublicInbox/Qspawn.pm
+++ b/lib/PublicInbox/Qspawn.pm
@@ -237,7 +237,12 @@ 		} else {
 			$self->{rpipe}->close;
 			event_step($self);
 		}
-		$wcb->($r) if ref($r) eq 'ARRAY';
+		if (ref($r) eq 'ARRAY') { # error
+			$wcb->($r)
+		} elsif (ref($r) eq 'CODE') { # chain another command
+			$r->($wcb)
+		}
+		# else do nothing
 	} elsif ($async) {
 		# done reading headers, handoff to read body
 		my $fh = $wcb->($r); # scalar @$r == 2