lib/PublicInbox/Qspawn.pm | 2 ++

diff --git a/lib/PublicInbox/Qspawn.pm b/lib/PublicInbox/Qspawn.pm
index 02357dbf83988fb4db2c2223a9f0a58dca17187f..78afe718d26dd21ce0d49ec60d86679d92a5f146 100644
--- a/lib/PublicInbox/Qspawn.pm
+++ b/lib/PublicInbox/Qspawn.pm
@@ -104,6 +104,8 @@ 		$wcb->(PublicInbox::WwwStatic::r($code));
 	}
 }
 
+sub DESTROY { finalize($_[0]) } # ->finalize is idempotent
+
 sub waitpid_err { # callback for awaitpid
 	my (undef, $self) = @_; # $_[0]: pid
 	$self->{_err} = ''; # for defined check in ->finish