content_hash: skip Sender for cross posted messages

This regression was introduced long ago and matches behavior
originally specified in the comments.  It makes a noticeable
improvement with search results using -extindex ("all") and
lei results with multiple inboxes.

Update some style bits at the top of the test case while
we're at it.

Fixes: f0ef0a56a8957d6f ("v2: improve deduplication checks")

1 files changed, 3 insertions, 4 deletions

diff --git a/lib/PublicInbox/ContentHash.pm b/lib/PublicInbox/ContentHash.pm
index 838fdd6f..4dbe7b50 100644
--- a/lib/PublicInbox/ContentHash.pm
+++ b/lib/PublicInbox/ContentHash.pm
@@ -68,10 +68,9 @@ sub content_digest ($) {
 
         # Only use Sender: if From is not present
         foreach my $h (qw(From Sender)) {
-                my @v = $eml->header($h);
-                if (@v) {
-                        digest_addr($dig, $h, $_) foreach @v;
-                }
+                my @v = $eml->header($h) or next;
+                digest_addr($dig, $h, $_) foreach @v;
+                last;
         }
         foreach my $h (qw(Subject Date)) {
                 my @v = $eml->header($h);