Managesieve: Fix parser issue with empty lines between comments (#5657)

CHANGELOG

@@ -20,6 +20,7 @@ CHANGELOG Roundcube Webmail
 - Fix update of group name in the contacts list header on group rename (#5648)
 - Add rewrite rule to disable access to /vendor/bin folder in .htaccess (#5630)
 - Fix bug where it was too easy accidentally move a folder when using the subscription checkbox (#5655)
+- Managesieve: Fix parser issue with empty lines between comments (#5657)
 
 RELEASE 1.2.3
 -------------

plugins/managesieve/lib/Roundcube/rcube_sieve_script.php

@@ -562,7 +562,8 @@ class rcube_sieve_script
                     $prefix .= $line . "\n";
                 }
 
-                $position = $endl + 1;
+                // skip empty lines after the comment (#5657)
+                $position = self::ltrim_position($script, $endl + 1);
             }
 
             // handle script header

plugins/managesieve/tests/src/parser_nesting.out

@@ -1,5 +1,6 @@
 # Sieve Filter
 # Erzeugt von Ingo (http://www.horde.org/ingo/) (30.09.2016, 16:02)
+# Nested rules aren't supported and will be ignored (#5540)
 
 # rule:[Ausgeschlossene Adressen]
 if address :is ["From","Sender","Resent-From"] "noreply@example.org"