lib/PublicInbox/ViewDiff.pm | 3 ++-

diff --git a/lib/PublicInbox/ViewDiff.pm b/lib/PublicInbox/ViewDiff.pm
index 95bbf2d2a7da79c78948439c687525b82fc4eba4..124a723a5fb465247963a5d01fd5c40fda593c11 100644
--- a/lib/PublicInbox/ViewDiff.pm
+++ b/lib/PublicInbox/ViewDiff.pm
@@ -212,8 +212,9 @@
 			for my $s (split(/((?:(?:^\+[^\n]*\n)+)|
 					(?:(?:^-[^\n]*\n)+)|
 					(?:^@@ [^\n]+\n))/xsm, $x)) {
+				undef $x;
 				if (!defined($dctx)) {
-					print $afh $x;
+					print $afh $s;
 				} elsif ($s =~ s/\A@@ (\S+) (\S+) @@//) {
 					print $zfh qq(<span\nclass="hunk">),
 						diff_hunk($dctx, $1, $2),