[PATCH] net_reader: NNTP: remove article numbers from mail_sync folders

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

NNTP article numbers are stored separately from folder names
in mail_sync.sqlite3.

Recovering from this is optional, worse case is wasting
bandwidth refetching some messages.  To (optionally) recover
from this, use:

	lei forget-mail-sync $URL_WITH_ARTNUMS

Some articles will be refetched on the next import, but
duplicate data won't be indexed in Xapian.
---
 lib/PublicInbox/NetReader.pm | 5 ++++-
 t/lei-import-nntp.t          | 4 ++++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/NetReader.pm b/lib/PublicInbox/NetReader.pm
index fbe1ac4f..eab7320e 100644
--- a/lib/PublicInbox/NetReader.pm
+++ b/lib/PublicInbox/NetReader.pm
@@ -729,7 +729,10 @@ sub _nntp_fetch_all ($$$) {
 	}
 	(defined($num_a) && defined($num_b) && $num_a > $num_b) and
 		return "E: $uri: backwards range: $num_a > $num_b";
-
+	if (defined($num_a)) { # no article numbers in mail_sync.sqlite3
+		$uri = $uri->clone;
+		$uri->group($group);
+	}
 	# 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:
diff --git a/t/lei-import-nntp.t b/t/lei-import-nntp.t
index 1eb41e0e..df0594d4 100644
--- a/t/lei-import-nntp.t
+++ b/t/lei-import-nntp.t
@@ -49,12 +49,16 @@ test_lei({ tmpdir => $tmpdir }, sub {
 
 	my $end = $high - 1;
 	lei_ok qw(import), "$url/$high";
+	lei_ok 'ls-mail-sync';
+	is($lei_out, "$url\n", 'article number not stored as folder');
 	lei_ok qw(q z:0..); my $one = json_utf8->decode($lei_out);
 	pop @$one; # trailing null
 	is(scalar(@$one), 1, 'only 1 result');
 
 	local $ENV{HOME} = "$tmpdir/h3";
 	lei_ok qw(import), "$url/$low-$end";
+	lei_ok 'ls-mail-sync';
+	is($lei_out, "$url\n", 'article range not stored as folder');
 	lei_ok qw(q z:0..); my $start = json_utf8->decode($lei_out);
 	pop @$start; # trailing null
 	is(scalar(@$start), scalar(map { $_ } ($low..$end)),