Fix displaying size of attachments with zero size

CHANGELOG

@@ -54,6 +54,7 @@ CHANGELOG Roundcube Webmail
 - Fix PHP warning when handling shared namespace with empty prefix (#5420)
 - Fix so folders list is scrolled to the selected folder on page load (#5424)
 - Fix so when moving to Trash we make sure the folder exists (#5192)
+- Fix displaying size of attachments with zero size
 
 RELEASE 1.2.1
 -------------

program/include/rcmail.php

@@ -2350,6 +2350,10 @@ class rcmail extends rcube
         else {
             $size = $part->size;
 
+            if ($size === 0) {
+                $part->exact_size = true;
+            }
+
             if ($part->encoding == 'base64') {
                 $size = $size / 1.33;
             }

program/steps/mail/show.inc

@@ -202,10 +202,7 @@ function rcmail_message_attachments($attrib)
                     $title = '';
                 }
 
-                if ($attach_prop->size) {
-                    $size = ' ' . html::span('attachment-size', '(' . rcube::Q($filesize) . ')');
-                }
-
+                $size     = ' ' . html::span('attachment-size', '(' . rcube::Q($filesize) . ')');
                 $mimetype = rcmail_fix_mimetype($attach_prop->mimetype);
                 $class    = rcube_utils::file2class($mimetype, $filename);
                 $id       = 'attach' . $attach_prop->mime_id;