imap+nntp: die loudly if ->mm or ->over disappear

While the WWW front-end can gracefully handle ->mm and ->over
disappearing (in most cases), IMAP+NNTP front-ends are completely
dependent on these and failed mysteriously when they go missing
after startup.

These will hopefully make issues like what Konstantin
encountered more obvious:

Link: https://public-inbox.org/meta/20210824204855.ejspej4z7r2rpu63@nitro.local/

3 files changed, 51 insertions, 49 deletions

diff --git a/lib/PublicInbox/IMAP.pm b/lib/PublicInbox/IMAP.pm
index 9402aa41..37e07dae 100644
--- a/lib/PublicInbox/IMAP.pm
+++ b/lib/PublicInbox/IMAP.pm
@@ -195,14 +195,14 @@ sub cmd_capability ($$) {
 # but uo2m_hibernate can compact and deduplicate it
 sub uo2m_ary_new ($;$) {
         my ($self, $exists) = @_;
-        my $base = $self->{uid_base};
-        my $uids = $self->{ibx}->over->uid_range($base + 1, $base + UID_SLICE);
+        my $ub = $self->{uid_base};
+        my $uids = $self->{ibx}->over(1)->uid_range($ub + 1, $ub + UID_SLICE);
 
         # convert UIDs to offsets from {base}
         my @tmp; # [$UID_OFFSET] => $MSN
         my $msn = 0;
-        ++$base;
-        $tmp[$_ - $base] = ++$msn for @$uids;
+        ++$ub;
+        $tmp[$_ - $ub] = ++$msn for @$uids;
         $$exists = $msn if $exists;
         \@tmp;
 }
@@ -243,7 +243,7 @@ sub uo2m_extend ($$;$) {
         # need to extend the current range:
         my $base = $self->{uid_base};
         ++$beg;
-        my $uids = $self->{ibx}->over->uid_range($beg, $base + UID_SLICE);
+        my $uids = $self->{ibx}->over(1)->uid_range($beg, $base + UID_SLICE);
         return $uo2m if !scalar(@$uids);
         my @tmp; # [$UID_OFFSET] => $MSN
         my $write_method = $_[2] // 'msg_more';
@@ -342,7 +342,7 @@ sub cmd_idle ($$) {
         my $fd = fileno($sock);
         $self->{-idle_tag} = $tag;
         # only do inotify on most recent slice
-        if ($ibx->over->max < $uid_end) {
+        if ($ibx->over(1)->max < $uid_end) {
                 $ibx->subscribe_unlock($fd, $self);
                 $self->{imapd}->idler_start;
         }
@@ -393,7 +393,7 @@ sub inbox_lookup ($$;$) {
         my ($ibx, $exists, $uidmax, $uid_base) = (undef, 0, 0, 0);
         $mailbox = lc $mailbox;
         $ibx = $self->{imapd}->{mailboxes}->{$mailbox} or return;
-        my $over = $ibx->over;
+        my $over = $ibx->over(1);
         if ($over != $ibx) { # not a dummy
                 $mailbox =~ /\.([0-9]+)\z/ or
                                 die "BUG: unexpected dummy mailbox: $mailbox\n";
@@ -418,7 +418,8 @@ sub inbox_lookup ($$;$) {
                 # if "INBOX.foo.bar" is selected and "INBOX.foo.bar.0",
                 # check for new UID ranges (e.g. "INBOX.foo.bar.1")
                 if (my $z = $self->{imapd}->{mailboxes}->{"$mailbox.0"}) {
-                        ensure_slices_exist($self->{imapd}, $z, $z->over->max);
+                        ensure_slices_exist($self->{imapd}, $z,
+                                                $z->over(1)->max);
                 }
         }
         ($ibx, $exists, $uidmax + 1, $uid_base);
@@ -722,7 +723,7 @@ sub range_step ($$) {
                 uid_clamp($self, \$beg, \$end);
         } elsif ($range =~ /\A([0-9]+):\*\z/) {
                 $beg = $1 + 0;
-                $end = $self->{ibx}->over->max;
+                $end = $self->{ibx}->over(1)->max;
                 $end = $uid_end if $end > $uid_end;
                 $beg = $end if $beg > $end;
                 uid_clamp($self, \$beg, \$end);
@@ -740,7 +741,7 @@ sub range_step ($$) {
 sub refill_range ($$$) {
         my ($self, $msgs, $range_info) = @_;
         my ($beg, $end, $range_csv) = @$range_info;
-        if (scalar(@$msgs = @{$self->{ibx}->over->query_xover($beg, $end)})) {
+        if (scalar(@$msgs = @{$self->{ibx}->over(1)->query_xover($beg, $end)})){
                 $range_info->[0] = $msgs->[-1]->{num} + 1;
                 return;
         }
@@ -781,7 +782,7 @@ sub fetch_smsg { # long_response
 sub refill_uids ($$$;$) {
         my ($self, $uids, $range_info, $sql) = @_;
         my ($beg, $end, $range_csv) = @$range_info;
-        my $over = $self->{ibx}->over;
+        my $over = $self->{ibx}->over(1);
         while (1) {
                 if (scalar(@$uids = @{$over->uid_range($beg, $end, $sql)})) {
                         $range_info->[0] = $uids->[-1] + 1; # update $beg
@@ -1114,7 +1115,7 @@ sub parse_imap_query ($$) {
         my ($self, $query) = @_;
         my $q = PublicInbox::IMAPsearchqp::parse($self, $query);
         if (ref($q)) {
-                my $max = $self->{ibx}->over->max;
+                my $max = $self->{ibx}->over(1)->max;
                 my $beg = 1;
                 uid_clamp($self, \$beg, \$max);
                 $q->{range_info} = [ $beg, $max ];
diff --git a/lib/PublicInbox/Inbox.pm b/lib/PublicInbox/Inbox.pm
index b94ffdb0..df140cac 100644
--- a/lib/PublicInbox/Inbox.pm
+++ b/lib/PublicInbox/Inbox.pm
@@ -8,6 +8,7 @@ use PublicInbox::Git;
 use PublicInbox::MID qw(mid2path);
 use PublicInbox::Eml;
 use List::Util qw(max);
+use Carp qw(croak);
 
 # Long-running "git-cat-file --batch" processes won't notice
 # unlinked packs, so we need to restart those processes occasionally.
@@ -168,8 +169,8 @@ sub max_git_epoch {
 }
 
 sub mm {
-        my ($self) = @_;
-        $self->{mm} ||= eval {
+        my ($self, $req) = @_;
+        $self->{mm} //= eval {
                 require PublicInbox::Msgmap;
                 my $dir = $self->{inboxdir};
                 if ($self->version >= 2) {
@@ -177,7 +178,7 @@ sub mm {
                 } else {
                         PublicInbox::Msgmap->new($dir);
                 }
-        };
+        } // ($req ? croak("E: $@") : undef);
 }
 
 sub search {
@@ -195,19 +196,19 @@ sub search {
 sub isrch { $_[0]->{isrch} // search($_[0]) }
 
 sub over {
-        $_[0]->{over} //= eval {
-                my $srch = $_[0]->{search} //= do {
-                        _cleanup_later($_[0]);
+        my ($self, $req) = @_;
+        $self->{over} //= eval {
+                my $srch = $self->{search} //= do {
+                        _cleanup_later($self);
                         require PublicInbox::Search;
-                        PublicInbox::Search->new($_[0]);
+                        PublicInbox::Search->new($self);
                 };
                 my $over = PublicInbox::Over->new("$srch->{xpfx}/over.sqlite3");
                 $over->dbh; # may fail
                 $over;
-        };
+        } // ($req ? croak("E: $@") : undef);
 }
 
-
 sub try_cat {
         my ($path) = @_;
         open(my $fh, '<', $path) or return '';
diff --git a/lib/PublicInbox/NNTP.pm b/lib/PublicInbox/NNTP.pm
index 9df47133..13a68bb8 100644
--- a/lib/PublicInbox/NNTP.pm
+++ b/lib/PublicInbox/NNTP.pm
@@ -202,7 +202,7 @@ sub cmd_list ($;$$) {
 
 sub listgroup_range_i {
         my ($self, $beg, $end) = @_;
-        my $r = $self->{ibx}->mm->msg_range($beg, $end, 'num');
+        my $r = $self->{ibx}->mm(1)->msg_range($beg, $end, 'num');
         scalar(@$r) or return;
         $self->msg_more(join('', map { "$_->[0]\r\n" } @$r));
         1;
@@ -210,7 +210,7 @@ sub listgroup_range_i {
 
 sub listgroup_all_i {
         my ($self, $num) = @_;
-        my $ary = $self->{ibx}->mm->ids_after($num);
+        my $ary = $self->{ibx}->mm(1)->ids_after($num);
         scalar(@$ary) or return;
         more($self, join("\r\n", @$ary));
         1;
@@ -261,7 +261,7 @@ sub parse_time ($$;$) {
 
 sub group_line ($$) {
         my ($self, $ibx) = @_;
-        my ($min, $max) = $ibx->mm->minmax;
+        my ($min, $max) = $ibx->mm(1)->minmax;
         more($self, "$ibx->{newsgroup} $max $min n");
 }
 
@@ -367,7 +367,7 @@ sub cmd_group ($$) {
         $nntpd->idler_start;
 
         $self->{ibx} = $ibx;
-        my ($min, $max) = $ibx->mm->minmax;
+        my ($min, $max) = $ibx->mm(1)->minmax;
         $self->{article} = $min;
         my $est_size = $max - $min;
         "211 $est_size $min $max $group";
@@ -381,7 +381,7 @@ sub article_adj ($$) {
         defined $n or return '420 no current article has been selected';
 
         $n += $off;
-        my $mid = $ibx->mm->mid_for($n);
+        my $mid = $ibx->mm(1)->mid_for($n);
         unless ($mid) {
                 $n = $off > 0 ? 'next' : 'previous';
                 return "421 no $n article in this group";
@@ -418,9 +418,8 @@ sub xref_by_tc ($$$) {
                         $by_addr->{lc($_)} // ()
                 } (PublicInbox::Address::emails($smsg->{$f} // ''));
                 for my $ibx (@ibxs) {
-                        my $ngname = $ibx->{newsgroup} // next;
-                        next if defined $xref->{$ngname};
-                        $xref->{$ngname} = eval { $ibx->mm->num_for($mid) };
+                        $xref->{$ibx->{newsgroup}} //=
+                                                $ibx->mm(1)->num_for($mid);
                 }
         }
 }
@@ -437,13 +436,15 @@ sub xref ($$$) {
                 $xref = { $cur_ng => $smsg->{num} };
                 my $mid = $smsg->{mid};
                 for my $ibx (values %{$nntpd->{pi_cfg}->{-by_newsgroup}}) {
-                        next if defined($xref->{$ibx->{newsgroup}});
-                        my $num = eval { $ibx->mm->num_for($mid) } // next;
-                        $xref->{$ibx->{newsgroup}} = $num;
+                        $xref->{$ibx->{newsgroup}} //=
+                                                 $ibx->mm(1)->num_for($mid);
                 }
         }
         my $ret = "$nntpd->{servername} $cur_ng:".delete($xref->{$cur_ng});
-        $ret .= " $_:$xref->{$_}" for (sort keys %$xref);
+        for my $ng (sort keys %$xref) {
+                my $num = $xref->{$ng} // next;
+                $ret .= " $ng:$num";
+        }
         $ret;
 }
 
@@ -504,7 +505,7 @@ find_ibx:
                                 return '412 no newsgroup has been selected';
         }
 found:
-        my $smsg = $ibx->over->get_art($n) or return $err;
+        my $smsg = $ibx->over(1)->get_art($n) or return $err;
         $smsg->{-ibx} = $ibx;
         if ($code == 223) { # STAT
                 set_art($self, $n);
@@ -618,7 +619,7 @@ sub get_range ($$) {
         my $ibx = $self->{ibx} or return '412 no news group has been selected';
         defined $range or return '420 No article(s) selected';
         my ($beg, $end);
-        my ($min, $max) = $ibx->mm->minmax;
+        my ($min, $max) = $ibx->mm(1)->minmax;
         if ($range =~ /\A([0-9]+)\z/) {
                 $beg = $end = $1;
         } elsif ($range =~ /\A([0-9]+)-\z/) {
@@ -688,7 +689,7 @@ sub long_response ($$;@) {
 
 sub hdr_msgid_range_i {
         my ($self, $beg, $end) = @_;
-        my $r = $self->{ibx}->mm->msg_range($beg, $end);
+        my $r = $self->{ibx}->mm(1)->msg_range($beg, $end);
         @$r or return;
         $self->msg_more(join('', map { "$_->[0] <$_->[1]>\r\n" } @$r));
         1;
@@ -714,7 +715,7 @@ sub mid_lookup ($$) {
         my ($self, $mid) = @_;
         my $cur_ibx = $self->{ibx};
         if ($cur_ibx) {
-                my $n = $cur_ibx->mm->num_for($mid);
+                my $n = $cur_ibx->mm(1)->num_for($mid);
                 return ($cur_ibx, $n) if defined $n;
         }
         my $pi_cfg = $self->{nntpd}->{pi_cfg};
@@ -744,7 +745,7 @@ EOF
         } else { # slow path for non-ALL users
                 for my $ibx (values %{$pi_cfg->{-by_newsgroup}}) {
                         next if defined $cur_ibx && $ibx eq $cur_ibx;
-                        my $n = $ibx->mm->num_for($mid);
+                        my $n = $ibx->mm(1)->num_for($mid);
                         return ($ibx, $n) if defined $n;
                 }
         }
@@ -754,7 +755,7 @@ EOF
 sub xref_range_i {
         my ($self, $beg, $end) = @_;
         my $ibx = $self->{ibx};
-        my $msgs = $ibx->over->query_xover($$beg, $end);
+        my $msgs = $ibx->over(1)->query_xover($$beg, $end);
         scalar(@$msgs) or return;
         $$beg = $msgs->[-1]->{num} + 1;
         $self->msg_more(join('', map {
@@ -770,7 +771,7 @@ sub hdr_xref ($$$) { # optimize XHDR Xref [range] for rtin
                 my $mid = $1;
                 my ($ibx, $n) = mid_lookup($self, $mid);
                 return r430 unless $n;
-                my $smsg = $ibx->over->get_art($n) or return;
+                my $smsg = $ibx->over(1)->get_art($n) or return;
                 hdr_mid_response($self, $xhdr, $ibx, $n, $range,
                                 xref($self, $ibx, $smsg));
         } else { # numeric range
@@ -783,16 +784,15 @@ sub hdr_xref ($$$) { # optimize XHDR Xref [range] for rtin
 }
 
 sub over_header_for {
-        my ($over, $num, $field) = @_;
-        my $smsg = $over->get_art($num) or return;
+        my ($ibx, $num, $field) = @_;
+        my $smsg = $ibx->over(1)->get_art($num) or return;
         return PublicInbox::Smsg::date($smsg) if $field eq 'date';
         $smsg->{$field};
 }
 
 sub smsg_range_i {
         my ($self, $beg, $end, $field) = @_;
-        my $over = $self->{ibx}->over;
-        my $msgs = $over->query_xover($$beg, $end);
+        my $msgs = $self->{ibx}->over(1)->query_xover($$beg, $end);
         scalar(@$msgs) or return;
         my $tmp = '';
 
@@ -816,7 +816,7 @@ sub hdr_smsg ($$$$) {
         if (defined $range && $range =~ $ONE_MSGID) {
                 my ($ibx, $n) = mid_lookup($self, $1);
                 return r430 unless defined $n;
-                my $v = over_header_for($ibx->over, $n, $field);
+                my $v = over_header_for($ibx, $n, $field);
                 hdr_mid_response($self, $xhdr, $ibx, $n, $range, $v);
         } else { # numeric range
                 $range = $self->{article} unless defined $range;
@@ -885,7 +885,7 @@ sub hdr_mid_response ($$$$$$) {
 
 sub xrover_i {
         my ($self, $beg, $end) = @_;
-        my $h = over_header_for($self->{ibx}->over, $$beg, 'references');
+        my $h = over_header_for($self->{ibx}, $$beg, 'references');
         more($self, "$$beg $h") if defined($h);
         $$beg++ < $end;
 }
@@ -925,7 +925,7 @@ sub cmd_over ($;$) {
         if ($range && $range =~ $ONE_MSGID) {
                 my ($ibx, $n) = mid_lookup($self, $1);
                 defined $n or return r430;
-                my $smsg = $ibx->over->get_art($n) or return r430;
+                my $smsg = $ibx->over(1)->get_art($n) or return r430;
                 more($self, '224 Overview information follows (multi-line)');
 
                 # Only set article number column if it's the current group
@@ -946,7 +946,7 @@ sub cmd_over ($;$) {
 sub xover_i {
         my ($self, $beg, $end) = @_;
         my $ibx = $self->{ibx};
-        my $msgs = $ibx->over->query_xover($$beg, $end);
+        my $msgs = $ibx->over(1)->query_xover($$beg, $end);
         my $nr = scalar @$msgs or return;
 
         # OVERVIEW.FMT
@@ -1014,7 +1014,7 @@ sub cmd_xpath ($$) {
                 }
         } else { # slow path, no point in using long_response
                 for my $ibx (values %$groups) {
-                        my $n = $ibx->mm->num_for($mid) // next;
+                        my $n = $ibx->mm(1)->num_for($mid) // next;
                         push @paths, "$ibx->{newsgroup}/$n";
                 }
         }