net_reader: fix single NNTP article fetch, test ranges

While NNTP ranges was already working, fetching a single message
was broken.  We'll also simplify the code a bit and ensure
incremental synchronization is ignored when ranges are
specified.

1 files changed, 9 insertions, 6 deletions

diff --git a/lib/PublicInbox/NetReader.pm b/lib/PublicInbox/NetReader.pm
index 30b8f810..236e824c 100644
--- a/lib/PublicInbox/NetReader.pm
+++ b/lib/PublicInbox/NetReader.pm
@@ -725,21 +725,24 @@ sub _nntp_fetch_all ($$$) {
                 my $msg = ndump($nn->message);
                 return "E: GROUP $group <$sec> $msg";
         }
+        (defined($num_a) && defined($num_b) && $num_a > $num_b) and
+                return "E: $uri: backwards range: $num_a > $num_b";
 
         # IMAPTracker is also used for tracking NNTP, UID == article number
         # LIST.ACTIVE can get the equivalent of UIDVALIDITY, but that's
         # expensive.  So we assume newsgroups don't change:
         my ($itrk, $l_art) = itrk_last($self, $uri);
 
-        # allow users to specify articles to refetch
-        # cf. https://tools.ietf.org/id/draft-gilman-news-url-01.txt
-        # nntp://example.com/inbox.foo/$num_a-$num_b
-        $beg = $num_a if defined($num_a) && $num_a < $beg;
-        $end = $num_b if defined($num_b) && $num_b < $end;
-        if (defined $l_art) {
+        if (defined($l_art) && !defined($num_a)) {
                 return if $l_art >= $end; # nothing to do
                 $beg = $l_art + 1;
         }
+        # allow users to specify articles to refetch
+        # cf. https://tools.ietf.org/id/draft-gilman-news-url-01.txt
+        # nntp://example.com/inbox.foo/$num_a-$num_b
+        $beg = $num_a if defined($num_a) && $num_a > $beg && $num_a <= $end;
+        $end = $num_b if defined($num_b) && $num_b >= $beg && $num_b < $end;
+        $end = $beg if defined($num_a) && !defined($num_b);
         my ($err, $art, $last_art, $kw); # kw stays undef, no keywords in NNTP
         unless ($self->{quiet}) {
                 warn "# $uri fetching ARTICLE $beg..$end\n";