1 files changed, 5 insertions, 2 deletions
diff --git a/lib/PublicInbox/Eml.pm b/lib/PublicInbox/Eml.pm
index ec682b91..1fecd41b 100644
--- a/lib/PublicInbox/Eml.pm
+++ b/lib/PublicInbox/Eml.pm
@@ -368,9 +368,12 @@ sub header_str_set {
          my ($self, $name, @vals) = @_;
          for (@vals) {
                  next unless /[^\x20-\x7e]/;
-                utf8::encode($_); # to octets
                  # 39: int((75 - length("Subject: =?UTF-8?B?".'?=') ) / 4) * 3;
-                s/(.{1,39})/'=?UTF-8?B?'.encode_base64($1, '').'?='/ges;
+                s/(.{1,39})/
+                        my $x = $1;
+                        utf8::encode($x); # to octets
+                        '=?UTF-8?B?'.encode_base64($x, '').'?='
+                /xges;
          }
          header_set($self, $name, @vals);
  }