commit 60396f2: [Fix] Selectors: Filter nil elements in lists

[Vsevolod Stakhov]

Author: Vsevolod Stakhov
Date: 2021-02-25 10:45:59 +0000
URL: https://github.com/rspamd/rspamd/commit/60396f2478b0f7284b42139d6d8e05bf81b12b20 (HEAD -> master)

[Fix] Selectors: Filter nil elements in lists

---
 lualib/lua_selectors/init.lua | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/lualib/lua_selectors/init.lua b/lualib/lua_selectors/init.lua
index cc44d0b01..9a4af2e04 100644
--- a/lualib/lua_selectors/init.lua
+++ b/lualib/lua_selectors/init.lua
@@ -349,13 +349,18 @@ exports.parse_selector = function(cfg, str)
               ret = (inp[method_name](inp, unpack_function(args or E)))
             end
 
+            -- Do not go further
+            if not ret then return nil end
+
             local ret_type = type(ret)
             -- Now apply types heuristic
             if ret_type == 'string' then
               return ret,'string'
-            elseif ret_type == 'table' then
-              -- TODO: we need to ensure that 1) table is numeric 2) table has merely strings
-              return ret,'string_list'
+            elseif ret_type == 'table' and ret[1] ~= nil then
+              local filt_predicate =  fun.filter(function(elt)
+                return elt ~= nil
+              end, ret)
+              return filt_predicate, 'string_list'
             else
               return implicit_tostring(ret_type, ret)
             end