lib/PublicInbox/V2Writable.pm | 2 +-
 t/v2writable.t                | 3 +++

diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index 222df5c2ffa6d0cf3dae884ea734ee9973dc1619..08d18fc099a25f340432f0ad01ce22ad6f40666e 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -390,7 +390,7 @@ sub purge {
 	my ($self, $mime) = @_;
 	my $purges = $self->{-inbox}->with_umask(sub {
 		remove_internal($self, $mime, undef, {});
-	});
+	}) or return;
 	$self->idx_init if @$purges; # ->done is called on purges
 	for my $i (0..$#$purges) {
 		defined(my $cmt = $purges->[$i]) or next;
diff --git a/t/v2writable.t b/t/v2writable.t
index ec9f56d91657dbc50d5f97d72874075f8f6b4d3f..f171417513440fb578382a1471ba3e13544af26c 100644
--- a/t/v2writable.t
+++ b/t/v2writable.t
@@ -247,6 +247,9 @@ 	local $SIG{__WARN__} = sub {};
 	ok(my $cmts = $im->purge($mime), 'purged message');
 	like($cmts->[0], qr/\A[a-f0-9]{40}\z/, 'purge returned current commit');
 	$im->done;
+
+	# again
+	is($im->purge($mime), undef, 'no-op returns undef');
 }
 
 {