MANIFEST                     |   1 +
 lib/PublicInbox/SearchIdx.pm |   7 ++++++-
 t/v1reindex.t                | 109 +++++++++++++++++++++++++++++++++++++++++++++++++++++

diff --git a/MANIFEST b/MANIFEST
index a2fcae9f4a21a646c554e2749cd503952eabc5ce..fd74a435b69d7d91157493ac227d72042857e5af 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -199,6 +199,7 @@ t/thread-cycle.t
 t/time.t
 t/utf8.mbox
 t/v1-add-remove-add.t
+t/v1reindex.t
 t/v2-add-remove-add.t
 t/v2mda.t
 t/v2mirror.t
diff --git a/lib/PublicInbox/SearchIdx.pm b/lib/PublicInbox/SearchIdx.pm
index 107cd3457133cbe9d9442045dd0e5b7a2cc06d04..0e0796c12c12373ebc211ef81446560870b4ba25 100644
--- a/lib/PublicInbox/SearchIdx.pm
+++ b/lib/PublicInbox/SearchIdx.pm
@@ -561,7 +561,12 @@ 	my $newest;
 	while (defined($line = <$log>)) {
 		if ($line =~ /$addmsg/o) {
 			my $blob = $1;
-			delete $D{$blob} and next;
+			if (delete $D{$blob}) {
+				if (defined $self->{regen_down}) {
+					$self->{regen_down}--;
+				}
+				next;
+			}
 			my $mime = do_cat_mail($git, $blob, \$bytes) or next;
 			batch_adjust(\$max, $bytes, $batch_cb, $latest);
 			$add_cb->($self, $mime, $bytes, $blob);
diff --git a/t/v1reindex.t b/t/v1reindex.t
new file mode 100644
index 0000000000000000000000000000000000000000..0df36d3fee893f6d2d38eee6c56e013c004b3ad8
--- /dev/null
+++ b/t/v1reindex.t
@@ -0,0 +1,109 @@
+# Copyright (C) 2018 all contributors <meta@public-inbox.org>
+# License: AGPL-3.0+ <https://www.gnu.org/licenses/agpl-3.0.txt>
+use strict;
+use warnings;
+use Test::More;
+use PublicInbox::MIME;
+use PublicInbox::ContentId qw(content_digest);
+use File::Temp qw/tempdir/;
+use File::Path qw(remove_tree);
+
+foreach my $mod (qw(DBD::SQLite Search::Xapian)) {
+	eval "require $mod";
+	plan skip_all => "$mod missing for v1reindex.t" if $@;
+}
+use_ok 'PublicInbox::SearchIdx';
+use_ok 'PublicInbox::Import';
+my $mainrepo = tempdir('pi-v1reindex-XXXXXX', TMPDIR => 1, CLEANUP => 1);
+is(system(qw(git init -q --bare), $mainrepo), 0);
+my $ibx_config = {
+	mainrepo => $mainrepo,
+	name => 'test-v1reindex',
+	-primary_address => 'test@example.com',
+};
+my $ibx = PublicInbox::Inbox->new($ibx_config);
+my $mime = PublicInbox::MIME->create(
+	header => [
+		From => 'a@example.com',
+		To => 'test@example.com',
+		Subject => 'this is a subject',
+		Date => 'Fri, 02 Oct 1993 00:00:00 +0000',
+	],
+	body => "hello world\n",
+);
+my $im = PublicInbox::Import->new($ibx->git, undef, undef, $ibx);
+foreach my $i (1..10) {
+	$mime->header_set('Message-Id', "<$i\@example.com>");
+	ok($im->add($mime), "message $i added");
+	if ($i == 4) {
+		$im->remove($mime);
+	}
+}
+
+if ('test remove later') {
+	$mime->header_set('Message-Id', "<5\@example.com>");
+	$im->remove($mime);
+}
+
+$im->done;
+my $rw = PublicInbox::SearchIdx->new($ibx, 1);
+eval { $rw->index_sync() };
+is($@, '', 'no error from indexing');
+
+my $minmax = [ $ibx->mm->minmax ];
+ok(defined $minmax->[0] && defined $minmax->[1], 'minmax defined');
+is_deeply($minmax, [ 1, 10 ], 'minmax as expected');
+
+$rw = PublicInbox::SearchIdx->new($ibx, 1);
+eval { $rw->index_sync({reindex => 1}) };
+is($@, '', 'no error from reindexing');
+$im->done;
+
+my $xap = "$mainrepo/public-inbox/xapian".PublicInbox::Search::SCHEMA_VERSION();
+remove_tree($xap);
+ok(!-d $xap, 'Xapian directories removed');
+$rw = PublicInbox::SearchIdx->new($ibx, 1);
+
+eval { $rw->index_sync({reindex => 1}) };
+is($@, '', 'no error from reindexing');
+$im->done;
+ok(-d $xap, 'Xapian directories recreated');
+
+delete $ibx->{mm};
+is_deeply([ $ibx->mm->minmax ], $minmax, 'minmax unchanged');
+
+ok(unlink "$mainrepo/public-inbox/msgmap.sqlite3", 'remove msgmap');
+remove_tree($xap);
+$rw = PublicInbox::SearchIdx->new($ibx, 1);
+
+ok(!-d $xap, 'Xapian directories removed again');
+{
+	my @warn;
+	local $SIG{__WARN__} = sub { push @warn, @_ };
+	eval { $rw->index_sync({reindex => 1}) };
+	is($@, '', 'no error from reindexing without msgmap');
+	is(scalar(@warn), 0, 'no warnings from reindexing');
+	$im->done;
+	ok(-d $xap, 'Xapian directories recreated');
+	delete $ibx->{mm};
+	is_deeply([ $ibx->mm->minmax ], $minmax, 'minmax unchanged');
+}
+
+ok(unlink "$mainrepo/public-inbox/msgmap.sqlite3", 'remove msgmap');
+remove_tree($xap);
+$rw = PublicInbox::SearchIdx->new($ibx, 1);
+
+ok(!-d $xap, 'Xapian directories removed again');
+{
+	my @warn;
+	local $SIG{__WARN__} = sub { push @warn, @_ };
+	eval { $rw->index_sync({reindex => 1}) };
+	is($@, '', 'no error from reindexing without msgmap');
+	is_deeply(\@warn, [], 'no warnings');
+	$im->done;
+	ok(-d $xap, 'Xapian directories recreated');
+	delete $ibx->{mm};
+	is_deeply([ $ibx->mm->minmax ], $minmax, 'minmax unchanged');
+}
+
+done_testing();