Ignore empty addr sets

compile.ml

@@ -83,24 +83,25 @@ module Rules = struct
   (* Bon, ce module n'est vraiment pas très joli… *)
 
   let compile_addrs_list getter expr negate zones addrs_list =
-    Expr.Set
-      (PrefixSet.fold
+    PrefixSet.fold
       (fun prefix acc -> getter negate prefix @ acc)
       (PrefixSet.of_addrs_list zones addrs_list)
       []
-      |> List.map expr)
+    |> List.map expr
 
   let compile_match_addrs getter expr field zones addrs_list =
-    [
-      Stmt.Match
-        ( Match.Eq,
-          Expr.Payload field,
-          compile_addrs_list getter expr false zones addrs_list );
-      Stmt.Match
-        ( Match.NotEq,
-          Expr.Payload field,
-          compile_addrs_list getter expr true zones addrs_list );
-    ]
+    let equal = compile_addrs_list getter expr false zones addrs_list in
+    let not_equal = compile_addrs_list getter expr true zones addrs_list in
+    let stmts =
+      match equal with
+      | [] -> []
+      | _ -> [ Stmt.Match (Match.Eq, Expr.Payload field, Expr.Set equal) ]
+    in
+    match not_equal with
+    | [] -> stmts
+    | _ ->
+        Stmt.Match (Match.NotEq, Expr.Payload field, Expr.Set not_equal)
+        :: stmts
 
   let compile_match_ipv4 field =
     compile_match_addrs Prefix.to_ipv4_list Expr.ipv4 (Payload.Ipv4 field)