[Minor] Fix corner cases

diff --git a/lualib/lua_mime.lua b/lualib/lua_mime.lua
index 9dff5cfed88b8dcbe3e4b82447a7c44ad7dc0c91..038dccceb4d215a6c7d29cb41f0e3456f8f2e578 100644 (file)
--- a/lualib/lua_mime.lua
+++ b/lualib/lua_mime.lua
@@ -590,8 +590,8 @@ exports.modify_headers = function(task, hdr_alterations, mode)
 
   if mode == 'compat' then
     -- Clear empty alterations in the compat mode
-    if not next(add_headers) then add_headers = nil end
-    if not next(hdr_alterations.remove) then hdr_alterations.remove = nil end
+    if add_headers and not next(add_headers) then add_headers = nil end
+    if hdr_alterations.remove and not next(hdr_alterations.remove) then hdr_alterations.remove = nil end
   end
   task:set_milter_reply({
     add_headers = add_headers,