[PATCH 03/12] mm: min/max: return 0 instead of undef

[Eric Wong <e@80x24.org>]

This simplifies callers and allows empty newsgroups to be
represented (the WWW UI may be insufficient there, too).
---
 lib/PublicInbox/IMAPD.pm      | 2 +-
 lib/PublicInbox/Msgmap.pm     | 7 +++----
 lib/PublicInbox/NNTP.pm       | 4 +---
 lib/PublicInbox/V2Writable.pm | 4 ++--
 t/msgmap.t                    | 2 +-
 5 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/lib/PublicInbox/IMAPD.pm b/lib/PublicInbox/IMAPD.pm
index bb705136..366b6922 100644
--- a/lib/PublicInbox/IMAPD.pm
+++ b/lib/PublicInbox/IMAPD.pm
@@ -45,7 +45,7 @@ sub imapd_refresh_ibx { # pi_config->each_inbox cb
 	eval { $ibx->uidvalidity };
 	my $mm = delete($ibx->{mm}) or return;
 	defined($ibx->{uidvalidity}) or return;
-	PublicInbox::IMAP::ensure_slices_exist($imapd, $ibx, $mm->max // 0);
+	PublicInbox::IMAP::ensure_slices_exist($imapd, $ibx, $mm->max);
 
 	# preload to avoid fragmentation:
 	$ibx->description;
diff --git a/lib/PublicInbox/Msgmap.pm b/lib/PublicInbox/Msgmap.pm
index f15875e3..a8c874af 100644
--- a/lib/PublicInbox/Msgmap.pm
+++ b/lib/PublicInbox/Msgmap.pm
@@ -36,8 +36,7 @@ sub new_file {
 		create_tables($dbh);
 		$self->created_at(time) unless $self->created_at;
 
-		my $max = $self->max // 0;
-		$self->num_highwater($max);
+		$self->num_highwater(max($self));
 		$dbh->commit;
 	}
 	$self;
@@ -144,7 +143,7 @@ sub max {
 	my $sth = $_[0]->{dbh}->prepare_cached('SELECT MAX(num) FROM msgmap',
 						undef, 1);
 	$sth->execute;
-	$sth->fetchrow_array;
+	$sth->fetchrow_array // 0;
 }
 
 sub minmax {
@@ -153,7 +152,7 @@ sub minmax {
 	my $sth = $_[0]->{dbh}->prepare_cached('SELECT MIN(num) FROM msgmap',
 						undef, 1);
 	$sth->execute;
-	($sth->fetchrow_array, max($_[0]));
+	($sth->fetchrow_array // 0, max($_[0]));
 }
 
 sub mid_delete {
diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index 2197d758..b641bd23 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -244,7 +244,7 @@ sub parse_time ($$;$) {
 sub group_line ($$) {
 	my ($self, $ng) = @_;
 	my ($min, $max) = $ng->mm->minmax;
-	more($self, "$ng->{newsgroup} $max $min n") if defined $min && defined $max;
+	more($self, "$ng->{newsgroup} $max $min n");
 }
 
 sub cmd_newgroups ($$$;$$) {
@@ -343,8 +343,6 @@ sub cmd_group ($$) {
 
 	$self->{ng} = $ng;
 	my ($min, $max) = $ng->mm->minmax;
-	$min ||= 0;
-	$max ||= 0;
 	$self->{article} = $min;
 	my $est_size = $max - $min;
 	"211 $est_size $min $max $group";
diff --git a/lib/PublicInbox/V2Writable.pm b/lib/PublicInbox/V2Writable.pm
index afba0220..7bef1c89 100644
--- a/lib/PublicInbox/V2Writable.pm
+++ b/lib/PublicInbox/V2Writable.pm
@@ -1367,8 +1367,8 @@ sub index_sync {
 
 		# xapian_only works incrementally w/o --reindex
 		if ($seq && !$opt->{reindex}) {
-			$art_beg = $sync->{mm_tmp}->max;
-			$art_beg++ if defined($art_beg);
+			$art_beg = $sync->{mm_tmp}->max || -1;
+			$art_beg++;
 		}
 	}
 	# work forwards through history
diff --git a/t/msgmap.t b/t/msgmap.t
index 437e106e..2d31f1de 100644
--- a/t/msgmap.t
+++ b/t/msgmap.t
@@ -12,7 +12,7 @@ my $d = PublicInbox::Msgmap->new($tmpdir, 1);
 my %mid2num;
 my %num2mid;
 my @mids = qw(a@b c@d e@f g@h aa@bb aa@cc);
-is_deeply([$d->minmax], [undef,undef], "empty min max on new DB");
+is_deeply([$d->minmax], [0,0], "zero min max on new DB");
 
 foreach my $mid (@mids) {
 	my $n = $d->mid_insert($mid);