[PATCH 1/4] learn: fix redundant ham import on dual matches

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

When learning and injecting new messages ham, we want to avoid
wasting cycles importing the same message into an inbox twice
(once for the To/Cc match and once for the List-Id match).  Our
existing %seen hash turned out to be ineffective since
PublicInbox::Inbox refs get re-blessed to PublicInbox::InboxWritable.
So we stop letting class name influence the hash key for tracking by
using the reference address instead.  We can get the reference address
by performing an arithmetic operation (+ 0) instead of having to
pay the cost of importing Scalar::Util::refaddr.
---
 script/public-inbox-learn | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/script/public-inbox-learn b/script/public-inbox-learn
index 54d31cb6..8069d919 100755
--- a/script/public-inbox-learn
+++ b/script/public-inbox-learn
@@ -110,12 +110,12 @@ if ($train eq 'spam' || ($train eq 'rm' && $opt{all})) {
 	my %seen;
 	while (my ($addr, $ibx) = each %dests) {
 		next unless ref($ibx); # $ibx may be 0
-		next if $seen{"$ibx"}++;
+		next if $seen{0 + $ibx}++;
 		remove_or_add($ibx, $train, $mime, $addr);
 	}
 	my $dests = PublicInbox::MDA->inboxes_for_list_id($pi_cfg, $mime);
 	for my $ibx (@$dests) {
-		next if $seen{"$ibx"}++;
+		next if $seen{0 + $ibx}++;
 		remove_or_add($ibx, $train, $mime, $ibx->{-primary_address});
 	}
 }