nntpd: move {newsgroup} name check to config

With 50K newsgroups in the config file, this doesn't slow down
`PublicInbox::Config->new->fill_all' any measurable amount on
my busy old workstation.

This should prevent invalid newsgroup names from getting into
into extindex and catch user errors sooner, rather than later.

v2:
  - delete {newsgroup} if invalid to avoid ->nntp_url link
  - simplify -imapd and explain remaining check

3 files changed, 26 insertions, 24 deletions

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index e7aea99b..9b9d5c19 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -437,10 +437,23 @@ EOF
                         $self->{-by_list_id}->{lc($list_id)} = $ibx;
                 }
         }
-        if (my $ng = $ibx->{newsgroup}) {
-                # PublicInbox::NNTPD does stricter (and more expensive checks),
-                # keep this lean for startup speed
-                $self->{-by_newsgroup}->{$ng} = $ibx unless ref($ng);
+        if (my $ngname = $ibx->{newsgroup}) {
+                if (ref($ngname)) {
+                        delete $ibx->{newsgroup};
+                        warn 'multiple newsgroups not supported: '.
+                                join(', ', @$ngname). "\n";
+                # Newsgroup name needs to be compatible with RFC 3977
+                # wildmat-exact and RFC 3501 (IMAP) ATOM-CHAR.
+                # Leave out a few chars likely to cause problems or conflicts:
+                # '|', '<', '>', ';', '#', '$', '&',
+                } elsif ($ngname =~ m![^A-Za-z0-9/_\.\-\~\@\+\=:]!) {
+                        delete $ibx->{newsgroup};
+                        warn "newsgroup name invalid: `$ngname'\n";
+                } else {
+                        # PublicInbox::NNTPD does stricter ->nntp_usable
+                        # checks, keep this lean for startup speed
+                        $self->{-by_newsgroup}->{$ngname} = $ibx;
+                }
         }
         $self->{-by_name}->{$name} = $ibx;
         if ($ibx->{obfuscate}) {
diff --git a/lib/PublicInbox/IMAPD.pm b/lib/PublicInbox/IMAPD.pm
index 366b6922..4a37734e 100644
--- a/lib/PublicInbox/IMAPD.pm
+++ b/lib/PublicInbox/IMAPD.pm
@@ -27,12 +27,13 @@ sub new {
 sub imapd_refresh_ibx { # pi_config->each_inbox cb
         my ($ibx, $imapd) = @_;
         my $ngname = $ibx->{newsgroup} or return;
-        if (ref $ngname) {
-                warn 'multiple newsgroups not supported: '.
-                        join(', ', @$ngname). "\n";
-                return;
-        } elsif ($ngname =~ m![^a-z0-9/_\.\-\~\@\+\=:]! ||
-                 $ngname =~ /\.[0-9]+\z/) {
+
+        # We require lower-case since IMAP mailbox names are
+        # case-insensitive (but -nntpd matches INN in being
+        # case-sensitive
+        if ($ngname =~ m![^a-z0-9/_\.\-\~\@\+\=:]! ||
+                        # don't confuse with 50K slices
+                        $ngname =~ /\.[0-9]+\z/) {
                 warn "mailbox name invalid: newsgroup=`$ngname'\n";
                 return;
         }
diff --git a/lib/PublicInbox/NNTPD.pm b/lib/PublicInbox/NNTPD.pm
index 5e287857..967850e9 100644
--- a/lib/PublicInbox/NNTPD.pm
+++ b/lib/PublicInbox/NNTPD.pm
@@ -38,20 +38,8 @@ sub refresh_groups {
         my $groups = $pi_config->{-by_newsgroup}; # filled during each_inbox
         $pi_config->each_inbox(sub {
                 my ($ibx) = @_;
-                my $ngname = $ibx->{newsgroup} or return;
-                if (ref $ngname) {
-                        warn 'multiple newsgroups not supported: '.
-                                join(', ', @$ngname). "\n";
-                # Newsgroup name needs to be compatible with RFC 3977
-                # wildmat-exact and RFC 3501 (IMAP) ATOM-CHAR.
-                # Leave out a few chars likely to cause problems or conflicts:
-                # '|', '<', '>', ';', '#', '$', '&',
-                } elsif ($ngname =~ m![^A-Za-z0-9/_\.\-\~\@\+\=:]!) {
-                        warn "newsgroup name invalid: `$ngname'\n";
-                        delete $groups->{$ngname};
-                } elsif ($ibx->nntp_usable) {
-                        # Only valid if msgmap and search works
-
+                my $ngname = $ibx->{newsgroup} // return;
+                if ($ibx->nntp_usable) { # only valid if msgmap and over works
                         # preload to avoid fragmentation:
                         $ibx->description;
                         $ibx->base_url;