lib/PublicInbox/LeiDedupe.pm   |  4 ++--
 lib/PublicInbox/LeiOverview.pm | 18 ++++++++++--------
 lib/PublicInbox/LeiToMail.pm   |  3 +--

diff --git a/lib/PublicInbox/LeiDedupe.pm b/lib/PublicInbox/LeiDedupe.pm
index 3f478aa4a786ba3280344ec2c10de9f2beb015f7..e3ae8e33c36642be9bb57aa492884fc6487a06c4 100644
--- a/lib/PublicInbox/LeiDedupe.pm
+++ b/lib/PublicInbox/LeiDedupe.pm
@@ -103,8 +103,8 @@ 	# [ $skv, $eml_cb, $smsg_cb, "dedupe_$dd" ]
 	bless [ $skv, undef, undef, $m ], $cls;
 }
 
-# returns true on unseen messages according to the deduplication strategy,
-# returns false if seen
+# returns true on seen messages according to the deduplication strategy,
+# returns false if unseen
 sub is_dup {
 	my ($self, $eml, $oid) = @_;
 	!$self->[1]->($eml, $oid);
diff --git a/lib/PublicInbox/LeiOverview.pm b/lib/PublicInbox/LeiOverview.pm
index c67e2747edfac4faeb1613abcca10a8263a73775..fa04145762c573838ee8b89e0cd2466fc6758fee 100644
--- a/lib/PublicInbox/LeiOverview.pm
+++ b/lib/PublicInbox/LeiOverview.pm
@@ -92,13 +92,14 @@ 		} else {
 			ovv_out_lk_init($self);
 		}
 	}
-	if (!$json) {
+	if ($json) {
+		$lei->{dedupe} //= PublicInbox::LeiDedupe->new($lei);
+	} else {
 		# default to the cheapest sort since MUA usually resorts
 		$lei->{opt}->{'sort'} //= 'docid' if $dst ne '/dev/stdout';
 		$lei->{l2m} = eval { PublicInbox::LeiToMail->new($lei) };
 		return $lei->fail($@) if $@;
 	}
-	$lei->{dedupe} //= PublicInbox::LeiDedupe->new($lei);
 	$self;
 }
 
@@ -201,15 +202,19 @@ }
 
 sub ovv_each_smsg_cb { # runs in wq worker usually
 	my ($self, $lei, $ibxish) = @_;
-	my $json;
+	my ($json, $dedupe);
 	$lei->{1}->autoflush(1);
-	my $dedupe = $lei->{dedupe} // die 'BUG: {dedupe} missing';
 	if (my $pkg = $self->{json}) {
 		$json = $pkg->new;
 		$json->utf8->canonical;
 		$json->ascii(1) if $lei->{opt}->{ascii};
 	}
-	my $l2m = $lei->{l2m} or $dedupe->prepare_dedupe;
+	my $l2m = $lei->{l2m};
+	if (!$l2m) {
+		$dedupe = $lei->{dedupe} // die 'BUG: {dedupe} missing';
+		$dedupe->prepare_dedupe;
+	}
+	$lei->{ovv_buf} = \(my $buf = '') if !$l2m;
 	if ($l2m && !$ibxish) { # remote https?:// mboxrd
 		delete $l2m->{-wq_s1};
 		my $g2m = $l2m->can('git_to_mail');
@@ -241,7 +246,6 @@ 		my $wcb = $l2m->write_cb($lei);
 		my $git = $ibxish->git; # (LeiXSearch|Inbox|ExtSearch)->git
 		$self->{git} = $git; # for ovv_atexit_child
 		my $g2m = $l2m->can('git_to_mail');
-		$dedupe->prepare_dedupe;
 		sub {
 			my ($smsg, $mitem) = @_;
 			$smsg->{pct} = get_pct($mitem) if $mitem;
@@ -249,7 +253,6 @@ 			$git->cat_async($smsg->{blob}, $g2m, [ $wcb, $smsg ]);
 		};
 	} elsif ($self->{fmt} =~ /\A(concat)?json\z/ && $lei->{opt}->{pretty}) {
 		my $EOR = ($1//'') eq 'concat' ? "\n}" : "\n},";
-		$lei->{ovv_buf} = \(my $buf = '');
 		sub { # DIY prettiness :P
 			my ($smsg, $mitem) = @_;
 			return if $dedupe->is_smsg_dup($smsg);
@@ -273,7 +276,6 @@ 			}
 		}
 	} elsif ($json) {
 		my $ORS = $self->{fmt} eq 'json' ? ",\n" : "\n"; # JSONL
-		$lei->{ovv_buf} = \(my $buf = '');
 		sub {
 			my ($smsg, $mitem) = @_;
 			return if $dedupe->is_smsg_dup($smsg);
diff --git a/lib/PublicInbox/LeiToMail.pm b/lib/PublicInbox/LeiToMail.pm
index 61b546b5ec8ae13892ba5070666353b845eaba62..244bfb6746a914f6436ab3ec9d7a5696a712d0da 100644
--- a/lib/PublicInbox/LeiToMail.pm
+++ b/lib/PublicInbox/LeiToMail.pm
@@ -323,7 +323,7 @@
 sub _maildir_write_cb ($$) {
 	my ($self, $lei) = @_;
 	my $dedupe = $lei->{dedupe};
-	$dedupe->prepare_dedupe;
+	$dedupe->prepare_dedupe if $dedupe;
 	my $dst = $lei->{ovv}->{dst};
 	sub { # for git_to_mail
 		my ($buf, $smsg, $eml) = @_;
@@ -464,7 +464,6 @@ 	my $not_done = delete $self->{$lei->{each_smsg_not_done}};
 	my $wcb = $self->{wcb} //= do { # first message
 		my %sig = $lei->atfork_child_wq($self);
 		@SIG{keys %sig} = values %sig; # not local
-		$lei->{dedupe}->prepare_dedupe;
 		$self->write_cb($lei);
 	};
 	my $git = $self->{"$$\0$git_dir"} //= PublicInbox::Git->new($git_dir);