[PATCH] config: warn on multiple values for some fields

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

Our code doesn't support multi-values for these, and having
unexpected arrays leads to unexpected results (e.g. showing
stuff like "ARRAY(0xDEADBEEFADD12E55)" in user interfaces).  So
warn and only use the last value (matching git-config(1)
behavior without `--get-all').
---
 lib/PublicInbox/Config.pm | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index 8ccf337d..abc525db 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -364,13 +364,23 @@ sub _fill {
 	my ($self, $pfx) = @_;
 	my $ibx = {};
 
-	foreach my $k (qw(inboxdir filter newsgroup
-			watch httpbackendmax
-			replyto feedmax nntpserver
-			indexlevel indexsequentialshard)) {
+	for my $k (qw(watch nntpserver)) {
 		my $v = $self->{"$pfx.$k"};
 		$ibx->{$k} = $v if defined $v;
 	}
+	for my $k (qw(filter inboxdir newsgroup replyto httpbackendmax feedmax
+			indexlevel indexsequentialshard)) {
+		if (defined(my $v = $self->{"$pfx.$k"})) {
+			if (ref($v) eq 'ARRAY') {
+				warn <<EOF;
+W: $pfx.$k has multiple values, only using `$v->[-1]'
+EOF
+				$ibx->{$k} = $v->[-1];
+			} else {
+				$ibx->{$k} = $v;
+			}
+		}
+	}
 
 	# backwards compatibility:
 	$ibx->{inboxdir} //= $self->{"$pfx.mainrepo"};