[PATCH v2 3/5] pop3: TOP requests do not expire messages

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

RFC 2449 only documents "EXPIRE 0" behavior for RETR requests
which fetch the whole message.  TOP requests only fetch
the headers and top $N lines of the body, so it's probably
harmful for deletions to be triggered in those cases.
---
 lib/PublicInbox/POP3.pm |  3 ++-
 t/pop3d.t               | 11 ++++++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/lib/PublicInbox/POP3.pm b/lib/PublicInbox/POP3.pm
index 51c2b71a..2c20c84b 100644
--- a/lib/PublicInbox/POP3.pm
+++ b/lib/PublicInbox/POP3.pm
@@ -300,12 +300,13 @@ sub retr_cb { # called by git->cat_async via ibx_async_cat
 		$hdr .= "\r\n\r\n";
 		my @tmp = split(/^/m, $bdy);
 		$hdr .= join('', splice(@tmp, 0, $top_nr));
+	} elsif (exists $self->{expire}) {
+		$self->{expire} .= pack('S', $off + 1);
 	}
 	$$bref =~ s/^\./../gms;
 	$$bref .= substr($$bref, -2, 2) eq "\r\n" ? ".\r\n" : "\r\n.\r\n";
 	$self->msg_more("+OK message follows\r\n");
 	$self->write($bref);
-	$self->{expire} .= pack('S', $off + 1) if exists $self->{expire};
 	$self->requeue;
 }
 
diff --git a/t/pop3d.t b/t/pop3d.t
index d5ccb0d8..3d70935f 100644
--- a/t/pop3d.t
+++ b/t/pop3d.t
@@ -240,8 +240,17 @@ EOF
 	ok(defined($capa->{PIPELINING}), 'pipelining supported by CAPA');
 	is($capa->{EXPIRE}, 0, 'EXPIRE 0 set');
 
-	# clients which see "EXPIRE 0" can elide DELE requests
+	# ensure TOP doesn't trigger "EXPIRE 0" like RETR does (cf. RFC2449)
 	my $list = $oldc->list;
+	ok(scalar keys %$list, 'got a listing of messages');
+	ok($oldc->top($_, 1), "TOP $_ 1") for keys %$list;
+	ok($oldc->quit, 'QUIT after TOP');
+
+	# clients which see "EXPIRE 0" can elide DELE requests
+	$oldc = Net::POP3->new(@old_args);
+	ok($oldc->apop("$locked_mb.0", 'anonymous'), 'APOP for RETR');
+	is_deeply($oldc->capa, $capa, 'CAPA unchanged');
+	is_deeply($oldc->list, $list, 'LIST unchanged by previous TOP');
 	ok($oldc->get($_), "RETR $_") for keys %$list;
 	ok($oldc->quit, 'QUIT after RETR');